Articles containing the keyword 'peat'

Dry mass and nutrient (N, P, K, Ca, Mg, B) contents of field layer vegetation and a combination of bottom layer vegetation and litter (referred to as bottom/litter layer in the text) were studied one year before and three years after fertilization (NPK and PK) on a drained low-shrub pine bog in eastern Finland. The results of an earlier study on the tree layer were combined with those of this study in order to estimate the changes caused by fertilization in the total plant biomass and litter. Before fertilization the average dry mass of the field and bottom/litter layers was 8,400 kg ha^-1 and 7,650 kg ha^-1, respectively. The above-ground parts accounted for 25% of the total field layer biomass. The dry mass of the field and bottom/litter layers together was < 20% of the dry mass accumulated in the total plant biomass and litter. The corresponding figures for N, P, K, Ca, Mg and B were 44%, 38%, 30%, 38%, 31% and 17%, respectively. Fertilization did not significantly affect the dry mass of either the field layer vegetation or the bottom/litter layer. 33% of the applied P was accumulated in the total plant biomass and litter on the PK-fertilized plots, and 25% on the NPK-fertilized plots. For the other elements, the proportions on the PK-fertilized plots were K 31%, Ca 6%, Mg 11% and B 13%. On the NPK-fertilized plots, the corresponding figures were N 62%, K 32%, Ca 6%, Mg 9% and B 13%. Except for B and K, the accumulation of fertilizer nutrients in the understorey vegetation and litter was of the same magnitude or greater than the uptake by the tree layer.

• Finér, E-mail: lf@mm.unknown
• Nieminen, E-mail: mn@mm.unknown

Models for individual-tree basal area growth were constructed for Scots pine (Pinus sylvestris L.), pubescent birch (Betula pubescens Ehrh.) and Norway spruce (Picea abies (L.) Karst.) growing in drained peatland stands. The data consisted of two separate sets of permanent sample plots forming a large sample of drained peatland stands in Finland. The dependent variable in all models was the 5-year basal area growth of a tree. The independent tree-level variables were tree dbh, tree basal area, and the sum of the basal area of trees larger than the target tree. Independent stand-level variables were stand basal area, the diameter of the tree of median basal area, and temperature sum. Categorical variables describing the site quality, as well as the condition and age of drainage, were used. Differences in tree growth were used as criteria in reclassifying the a priori site types into new yield classes by tree species. All models were constructed as mixed linear models with a random stand effect. The models were tested against the modelling data and against independent data sets.

• Hökkä, E-mail: hh@mm.unknown
• Alenius, E-mail: va@mm.unknown
• Penttilä, E-mail: tp@mm.unknown

The carbon reservoir of ecosystems was estimated based on field measurements for forests and peatlands on an area in Finland covering 263,000 km² and extending about 900 km across the boreal zone from south to north. More than two thirds of the reservoir was in peat, and less than ten per cent in trees. Forest ecosystems growing on mineral soils covering 144,000 km² contained 10–11 kg C m^-2 on an average, including both vegetation (3.4 kg C m^-2) and soil (uppermost 75 cm; 7.2 kg C m^-2). Mire ecosystems covering 65,000 km² contained an average of 72 kg C m^-2 as peat. For the landscape consisting of peatlands, closed and open forests, and inland water, excluding arable and built-up land, a reservoir of 24.6 kg C m^-2 was observed. This includes the peat, forest soil and tree biomass. This is an underestimate of the true total reservoir, because there are additional unknown reservoirs in deep soil, lake sediments, woody debris, and ground vegetation. Geographic distributions of the reservoirs were described, analysed and discussed. The highest reservoir, 35–40 kg C m^-2, was observed in sub-regions in central western and north western Finland. Many estimates given for the boreal carbon reservoirs have been higher than those of ours. Either the Finnish environment contains less carbon per unit area than the rest of the boreal zone, or the global boreal reservoir has earlier been overestimated. In order to reduce uncertainties of the global estimates, statistically representative measurements are needed especially on Russian and Canadian peatlands.

• Kauppi, E-mail: pk@mm.unknown
• Hänninen, E-mail: ph@mm.unknown
• Henttonen, E-mail: hh@mm.unknown
• Ihalainen, E-mail: ai@mm.unknown
• Lappalainen, E-mail: el@mm.unknown
• Posch, E-mail: mp@mm.unknown
• Starr, E-mail: ms@mm.unknown
• Tamminen, E-mail: pt@mm.unknown

In a silviculture experiment in east-central Maine, USA, natural regeneration was sampled to measure the effects of: (1) a range of partial harvest intensities, and (2) repeated partial harvest at one intensity. Under the first objective, five treatments were compared with residual basal areas ranging from 15 to 24 m² ha^-1 for trees ≥1.3 cm diameter at breast height. For the second objective, regeneration was evaluated after four harvests at 5-year intervals. Prior to harvests, the overstory of all the treated stands was dominated by Tsuga canadensis (L.) Carr., Picea spp. A Dietr., and Abies balsamea (L.) Mill. Eleven species or species groups were identified among the regeneration: A. balsamea, T. canadensis, Picea spp., Thuja occidentalis L., Pinus spp. L., Betula papyrifera Marsh., Acer rubrum L., Betula populifolia Marsh., Populus spp. L., Fagus grandifolia Ehrh. and Prunus serotina Ehrh. Regeneration abundance was measured as counts of seedlings or sprouts taller than 15 cm but with diameters less than 1.3 cm at breast height (1.37 m). Regardless of harvest treatment, total regeneration was profuse, ranging from over 25,000 to nearly 80,000 trees ha^-1. Regeneration was dominated by conifers with a total angiosperm component of 10 to 52 percent approximately 5 years after harvest and 11 to 33 percent after 10 years. Consequently, in forests of similar species composition, tree regeneration following partial harvests should be sufficiently abundant with an array of species to meet a variety of future management objectives.

• Brissette, E-mail: jb@mm.unknown

The use of random parameter models in forestry has been proposed as one method of incorporating different levels of information into prediction equations. By explicitly considering the variance-covariance structure of observations and considering some model parameters as random rather than fixed, one can incorporate more complex error structures in analysing data.

Competition indices and variance component techniques were applied to 92 Scots pine (Pinus sylvestris L.) -dominated permanent sample plots on drained peatlands in Northern Finland. By quantifying stand, plot, and tree level variation, it was possible to identify the level (stand, plot or tree) at which the explanatory variables contributed to the model. The replication of plots within stands revealed little variation among plots within a single stand but significant variation occurred at stand and tree levels. Positive and negative effects of inter-tree competition are identified by examining simple correlation statistics and the random parameter model.

• Penner, E-mail: mp@mm.unknown
• Hökkä, E-mail: hh@mm.unknown
• Penttilä, E-mail: tp@mm.unknown

The effects of wood ash and PK fertilization on natural regeneration and sowing of Scots pine (Pinus sylvestris L.) were studied in field experiments on nitrogen-poor (N_tot 0.87–1.26%) peat substrates. The study material was derived from three drained, nutrient-poor pine mires (64°52’ N, 25°08’ E) at Muhos, near Oulu, Finland. The experimental fields were laid out in 1985 as a split-split-plot design including the following treatments; mounding, natural regeneration and sowing and fertilization; PK (400 kg ha^-1) and wood ash (5,000 kg ha^-1). The seedlings were inventoried in circles in July–August 1991.

Changes in the vegetation were small and there were no statistical differences due to the fertilization treatments in the ground vegetation. PK or ash fertilization did not cause vegetation changes harmful to Scots pine regeneration on nitrogen-poor peatlands. Both sowing and fertilization significantly increased the number of pine seedlings, but not their height. Wood ash increased seedling number more than PK fertilizer. The number of seedlings varied from 7,963 (control) to 42,781 ha^-1 (mounding + sowing + ash). The seedling number was adequate for successful regeneration even on non-mounded, non-fertilized naturally regenerated plots.

The number of birch seedlings varied more than that of pine (370–25,927 ha-¹). Mounding especially increased the number of birches. The difference between PK fertiliser and ash was less pronounced than that for pine. In addition, to the field studies the effects of ash and PK fertilizer on the germination of Scots pine seeds was studied in a greenhouse experiment. Soaking in ash solutions strongly reduced seed germination, while the PK solution was less harmful.

• Silfverberg, E-mail: ks@mm.unknown

The effects of repeated fertilizer treatment on biomass production and nutrient status of willow (Salix ’Aquatica’) plantations established on two cut-away peatland areas in western Finland were studied over a rotation period of three years. Comparisons were made between single fertilizer applications and repeated annual fertilization.

The annually repeated fertilizer application increased the amounts of acid ammonium acetate extractable phosphorus and potassium in the soil as well as the concentrations of foliar nitrogen, phosphorus and potassium compared to single application. Depending on the fertilizer treatment and application rate, annual fertilizer application resulted in over two times higher biomass production when compared to single fertilizer application over a three-year rotation period. The effect of phosphorus fertilizer application lasted longer than that of nitrogen. The optimum fertilization regime for biomass production requires that nitrogen fertilizer should be applied annually, but the effect of phosphorus can last at least over a rotation of three years. Potassium fertilizer treatment did not increase the yield in any of the experiments during the first three years. The leafless, above-ground yield of three-year-old, annually NP-fertilized willow plantations was 9.5 t ha^-1 and the total biomass, including stems, leaves, roots and the stump, averaged 17 t ha^-1.

• Hytönen, E-mail: jh@mm.unknown

The effects of fertilized treatment on the soil nutrient concentrations, biomass production and nutrient consumption of Salix x dasyclados and Salix ’Aquatica’ were studied in five experiments on three cut-away peatland sites in western and eastern Finland during three years. Factorial experiments with all combinations of N (100 kg ha^-1 a-¹⁾, P (30 kg ha^-1 a^-1) and K (80 kg ha^-1 a^-1) were conducted.

The application of P and K fertilizers increased the concentrations of corresponding extractable nutrients in the soil as well as in willow foliage. N-fertilization increased foliar nitrogen concentration. An increase in age usually led to decreases in bark and wood N, P and K concentrations and increases in bark Ca concentrations. N-fertilization increased the three-year biomass yield 1.5–2.7 times when compared to control plots. P-fertilization increased the yield only in those experimental fields whose substrates had the lowest phosphorus concentration. K-fertilization did not increase the yield in any of the experimental fields. The highest total biomass yield of NPK-fertilized willow after three growing seasons, 23 t ha^-1, was distributed in the following way: wood 42%, bark 19%, foliage 17%, stumps 6% and roots 16%. As the yield and stand age increased, more biomass was allocated in above-ground wood. Three-year-old stands (above-ground biomass 18 t ha^-1) contained as much as 196 kg N ha^-1, 26 kg P ha^-1, 101 kg K ha^-1, 74 kg Ca ha^-1 and 37 kg Mg ha ^-1. By far the highest proportion of nutrients accumulated in the foliage. The bark and wood contained relatively high proportions of calcium and phosphorus. With an increase in age and size, the amount of nitrogen and potassium bound in one dry-mass ton of willow biomass decreased while that of phosphorus remained unchanged.

• Hytönen, E-mail: jh@mm.unknown

A spatial growth model is presented for Scots pine (Pinus sylvestris L.) on a dwarf-shrub pine mire drained 14 years earlier. The growth model accounts for the variation in tree diameter growth owing to the competition between trees, the distance between tree and ditch, and the time passed since drainage. The model was used to study the effect of tree arrangement on the post-drainage growth of a pine stand. Clustering of trees decreased the volume growth by 9–20% as compared to a regular spatial distribution. Stand volume growth, for a given number of stems, was at its maximum and variation in diameter growth at its minimum when the stand density on the ditch border was 1.5–5 higher than midway between two adjacent ditches.

• Miina, E-mail: jm@mm.unknown

The water retention characteristics and their variation in tree nurseries and related physical properties were determined for commercially produced growth media made of light slightly humified Sphagnum peat. A total of 100 samples of peat media were collected from filled seedling trays in the greenhouses of four Finnish nurseries in 1990. In addition, the physical properties were determined for two growth media made of compressed peat sheets and chips. The variation in water retention characteristics in nurseries was described using linear models with fixed and random effects. The sources of variation in the mixed linear models were producer, grade, batch (greenhouse) and sample (tray).

The water retention of the peat media at different matric potentials was comparable to that given in the literature. The media shrank an average of 0–16% during desorption. The peat grades were finer than the Nordic quality standards for peat growth media. Particles < 1 mm increased and particles 1–5 mm decreased the water retention characteristics measured. The greatest total variation in water retention was at -1 kPa. The water retention of the peat media differed least at -5 and -10 kPa. The water retention characteristics of media from different producers usually differed significantly. The grades, on the other hand, did not differ from each other in their water retention characteristics nor were there significant interactions between producer and grade. The batch effect was marked but was lower than the effect within batches, where the sample (tray) effect was greater than the effect due to random measurement error. At -10 kPa, the measurement error was, however, clearly greater than the sample effect. The random measurement error was comparable to the batch effect. Aeration of the growth media is dependent on the water content retained between saturation and -1 kPa. The water availability to seedlings at the nursery phase is affected mainly by water retention between -1 and -10 kPa.
The PDF includes an abstract in Finnish.

• Heiskanen, E-mail: jh@mm.unknown

A measurement system developed for the parallel and real-time measurement of temperature, matric potential and oxygen diffusion rate (ODR) of a growth medium was assessed. The system consisted of a portable computer, a datalogger, temperature sensors, tensiometers and an ODR-meter with Pt-sensors.

For the measurements, proper sensor contact with the growth medium was needed. For matric potential measurement, appropriate shape and material of the tensiometer tips should be selected for different measurement purposes. The determination of oxygen diffusion rate is based on single, non-continuous measurements. The ODR-measurement required special care with the insertion and handling of the electrodes and selection of applied voltage. The ODR-measurement of a coarse peat medium was applicable only at matric potentials > -5 kPa. This measurement system was shown to be useful and suitable for accurate determination of thermal-, water- and aeration conditions of a growth medium under greenhouse conditions.

The PDF includes an abstract in Finnish.

• Heiskanen, E-mail: jh@mm.unknown
• Laitinen, E-mail: jl@mm.unknown

Scots pine (Pinus sylvestris L.) living root biomass (ø≤ 10 mm) was 640 g/m² on the studied low-shrub pine bog before fertilization, and that of the ground vegetation almost the same. The total root necromass was 23% of the biomass of living roots. The length of the pine roots was 2,440 m/m². The biomass of living roots and root necromass were mostly located in the top 20 cm layer of the soil. The ø < 1 mm pine root fraction accounted for almost 90% of the pine root length; in contrast, over 50% of the biomass was in the 1–10 mm thick root biomass, pine root length and PK (MgB) fertilization did not affect total living root biomass, pine root length, nor the root necromass during the three-year observation period.

The PDF includes an abstract in Finnish.

• Finér, E-mail: lf@mm.unknown

Effect of dolomite lime and wood ash (0, 0.5, 1, 2, 4, 8 and 16 kg m^-3) on the chemical composition of low humified Sphagnum peat was studied. Germination of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) and the subsequent growth of these seedlings were investigated in a greenhouse experiment. Nutrient concentrations in shoots and roots of pine seedlings were also analysed. The pH of peat increased asymptotically from 3.8 to about 7.0 with increasing lime regimen and to about 8.0 with increasing ash regimen. Wood ash linearly increased electrical conductivity and P, K, and Ca concentrations of peat. Rate of germination, within 7 days, of pine and spruce was best at low pH (<5) while birch seeds had a slightly higher pH optimum (4–6). Germination capacity, within 21 days, was not affected by pH or application regimen of either lime or ash. Pine and spruce seedlings grew best with lime and ash doses of 0.5–2.0 kg m^-3, the pH of peat being 4–5. Lime and ash treatments did not affect the growth of birch seedlings, but wood ash increased nutrient concentration of pine seedlings.

The PDF includes an abstract in Finnish.

• Rikala, E-mail: rr@mm.unknown
• Jozefek, E-mail: hj@mm.unknown

Five ploughed research areas from Finnish Norther Karelia were selected for comparison studies of plough ridges and untouched soil. Measurements were made at a depth of 10 cm in sample plots on both mineral and paludified mineral soil and peatland parts of these areas. In summer 1987 daily soil water matric potential was measured using tensiometers, and volumetric soil moisture content and density were determined from soil samples at two dates during the summer. Water characteristics of the core samples were also determined. On paludified mineral and peat soils the water table depth from the soil surface was measured.

The results indicated that in plough ridges matric potential was lowest. Plough ridges were also seen to dry and wet faster and to a greater degree than untouched soils. In untouched soils, soil water relations and aeration were not affected by the distance to the furrow. The effect of the plough ridge was smallest on peatland, where there was a good capillary connection from plough ridge to the ground water, if the ditches were not very effective. The soil in the ridges did not dry too much to restrict seedling growth. The untouched surface soil in poorly drained peat and paludified minear soil was, at least in a rainy growing season, often and also for long times so wet that 10% minimum air space required for good seedling root growth was not available.

The PDF includes an abstract in English.

• Mannerkoski, E-mail: hm@mm.unknown
• Möttönen, E-mail: vm@mm.unknown

The paper is a review on utilization of peatlands in forestry in the countries of boreal zone: Finland, Norway, Sweden, Canada, the United States and the Soviet Union. First, the concept of peatlands, the types of peatlands throughout the zone are defined, and the use of natural peatlands is described. Finally, the drainage of peatlands for forestry purposes in the countries is reviewed. According to the statistics, a total of 13 million ha of peatlands have been drained in Fennoscandia and the Soviet Union.

• Päivänen, E-mail: jp@mm.unknown

The influence of different fertilization treatments and ditch spacings on the height growth of young Scots pine (Pinus sylvestris L.) seedling stands growing under various climatic regimes were determined. Comparisons were made between naturally regenerated and planted seedling stands. The effective temperature sum had a stronger effect on the height growth of planted seedlings, and in Northern Finland the planted seedlings seemed to be influenced to a greater degree by the adverse climatic conditions. The heavier the dose of fertilizer that had been applied, the greater the difference in growth caused by macroclimate. A considerably larger proportion of natural seedlings were located on hummocks compared with that of planted seedlings, irrespective of the region. On plots with wider ditch spacings, seedlings growing on hummocks were superior in height growth to those on flat surfaces.

The PDF includes an abstract in Finnish.

• Miyazava, E-mail: tm@mm.unknown
• Laine, E-mail: jl@mm.unknown

Refertilization with PK, about 15 years after the first fertilizer application, increased tree growth and the amount of nutrients in tree litter in Scots pine (Pinus sylvestris L.) and birch (mainly Betula pubescens Erhr.) stands on a drained fertile mire in Northern Finland (65°34 N’, 25°42’ E). The increase in growth and nutrient contents after refertilization was greatest in the mature pine stand where the application of nitrogen and micronutrients gave an additional response compared to the PK-application.

The PDF includes an abstract in Finnish.

• Paavilainen, E-mail: ep@mm.unknown

The area of stands studied by line plot survey was 594 ha. On the basis of the length of the inventory line the estimated proportion of harvesting strips was 14% and that of ditch openings 6% of the area. The calculated strip road spacing was 29 m. The option of the minimum diameter made it difficult to use the number of stems as criterion for thinning intensity. Thinning intensity evaluated according to the basal area had been stronger than recommended with low values of dominant height and milder with high values. The estimated removal according to stumps was 38 m³/ha on the average between the strips. The real removal has, however, been larger than that, as the strip road openings are made in connection with the first thinning.

The PDF includes an abstract in English.

• Rantonen, E-mail: hr@mm.unknown
• Päivänen, E-mail: jp@mm.unknown

Two-year-old silver birch (Betula pendula Roth) seedlings were fertilized with three peat ash dosages (10, 50 and 150 metric t/ha) and planted at three densities (2,000, 10,000 and 25,000 seedlings/ha). The peat and mineral soil were mixed together by deep ploughing before peat ash application. The results indicate that the 10 t/ha of peat ash may be too low a dosage and 150 t/ha too high for the silver birch seedlings. The 50 t/ha ash dosage increased growth markedly, obviously due to an enhancement in soil and foliar P, Mg and Ca content, soil pH, microbial activity and mobilization of soil organic nitrogen. Both foliar and soil P were already enhanced with the 10 t/ha peat ash dosage. The K content of the peat ash was low, however, and it may be that fertilizer K should be applied later.

The PDF includes a summary in Finnish.

• Lumme, E-mail: il@mm.unknown

Possibilities of developing suitable willow (Salix spp.) clones for short-rotation forestry on mined peatlands in the north-western area of Finland were studied in a field experiment in which 300 willow clones were tested during 1985–87. Most of the tested clones started to grow from cuttings on limed and fertilized peat soil. Salix viminalis L. clones of southern origin had a higher leafless above ground biomass production than the well adapted control clone and the local Finnish willows, but their winter hardiness was not satisfactory. The growth habit of some southern willows was also better than that of the control clone. It was also possible to select clones with good sprouting capacity. There were few Salix myrsinifolia Calisb. clones of Finnish origin, which had better cold tolerance than all other willows tested and higher biomass production than that of the control clone. The most critical factor to be selected for this is the optimal combination of winter hardiness and biomass production. This is attempted by selecting clones on the basis of this experiment for a breeding program.

The PDF includes a summary in Finnish.

• Lumme, E-mail: il@mm.unknown
• Törmälä, E-mail: tt@mm.unknown

The effect of drainage on structure of tree stands is analysed by comparing the average structural characteristics (e.g. diameter distribution) of stands in the data for different drainage age classes and selected site types. The material consists of ca. 4,400 relascope sample plots, which are part of a large drainage area inventory project. The uneven-aged structure of the virgin peatland forest is preserved for several decades after drainage. This is enhanced by the post-drainage increase of small-diameter trees, especially birch. The number of trees per hectare increased during a period of ca. 30 years and levelled off thereafter. The increase in the number of saw log stems is clearly related to the fertility of the site and its geographical location.

The PDF includes a summary in English.

• Hökkä, E-mail: hh@mm.unknown
• Laine, E-mail: jl@mm.unknown

A light seismic method, a short-pulse radar and a microwave probe are tested in assessing the properties of a forest road constructed on peatland. The light seismic method gave reliable values for estimating the bearing capacity of the road. It was found that bearing capacity was mostly dependent on embankment thickness, but quality of fabric might also have an influence. Embankment thickness and peat depth can be measured on the radiogram, and some additional information on road bed and peat obtained. The microwave peat probe permits recording of the continuous moisture profile in situ, which improves accuracy of planning.

The PDF includes a summary in Finnish.

• Saarilahti, E-mail: ms@mm.unknown

The solubilityof various phosphorus and potassium compounds in a sedge peat soil was studied in an incubation experiment aimed at screening potential fertilizers for the cultivation of fast-growing willows. (KPO₃)n proved not to be a source of the slow-released K regarded as most desirable for this kind of cultivation as it was hydrolysed completely in the soil during incubation. Phosphorus from easily soluble or hydrolysable compounds (superphosphate, KH₂PO₄, (KPO₃)n) was bound in the soil largely by Al and Fe and elevated the level of readily soluble P considerably, whereas rock phosphates were found to be practically unchanged after incubation and did not contribute to the readily soluble P in the soil. Apatites proved to be quite insoluble and are therefore assumed to be unsuitable as P fertilizers for fast-growing willows, which have a high nutrient demand.

The PDF includes an abstract in Finnish.

• Lumme, E-mail: il@mm.unknown
• Yli-Halla, E-mail: my@mm.unknown

This is the latest report in a series of publications from an on-going investigation which is concerned with the influence of different fertilization treatments and ditch spacings on the growth of Scots pine (Pinus sylvestris L.) seedlings and transplants growing on nutrient drained poor bogs in different parts of Finland. This paper concentrates on duration of the growth response to NPK-fertilization on the experimental plots. The experiment was established and the treatments performed in 1965–66.

The results show that climate, expressed as effective temperature sum (dd°C, threshold +5°C) has a clear influence on the duration of the fertilization effect. In Southern Finland (>1,200 dd°C), the duration was at least 15 years. In Central Finland (1,200–1,000 dd°C), it appears to be almost 10 years, and in Northern Finland (<1,000 dd°C), slightly shorter. The amount of fertilizer applied clearly influenced the duration of the fertilization effect. The dosage of 500 kg/ha (N 14, P 7.8, K 8.3 per cent) had, on average, a shorter duration than the greater dosages of 1,000 and 1,500 kg/ha. However, there was no clear difference between the latter two dosages.

The PDF includes a summary in Finnish.

• Heikurainen, E-mail: lh@mm.unknown
• Laine, E-mail: jl@mm.unknown

This bibliography consists of monographs, papers published in periodicals and journals and collections of scientific papers from research and educational institutes, and transactions from scientific congresses, seminars, symposia and meetings.

The publications have been divided into three basic sections. In each section the publications are listed in alphabetical order by the author(s) or title. The total number of the titles in this bibliography is 465.

• Mälkönen, E-mail: –
• Paavilainen, E-mail: –

Transects from upland to peatland sites were laid out so as to encounter a wide range of nutritional and hydrological conditions and volumetric soil samples were taken at 20 m intervals. For organic material, in particular peats, the correlation of ignition loss with CEC and total N were clearly higher when the variables were expressed volumetrically. The volumetric expression of variables made comparison of soils with varying organic matter contents possible. In preliminary analyses of the relationships between soil variables and dominant height of the tree stand on mineral soil sites volumetric exchangeable bases, pH and C/N -ratio in the raw humus layer showed a significant correlation.

The PDF includes a summary in Finnish.

• Westman, E-mail: cw@mm.unknown
• Laine, E-mail: jl@mm.unknown
• Starr, E-mail: ms@mm.unknown

A survey was carried out among forest foremen and forest technicians to record their observations on the value of various swamp and forest types as producers of berries and on the effect of drainage of peatlands upon the berry yields. Comparative agreement existed on the best blueberry (Vaccinium myrtillus L.) forest types and on the best lingonberry (Vaccinium vitis-idaea L.) forest types of rather dry upland sites. Fuscum pine swamps or fuscum bogs were considered best for the most part as regards the yield of cloudberry (Rubus chamaemorus L.). The replies showed rather great dispersion.

Agreement existed as well on the relation between drainage of peatlands and the yields of our economically most important swamp berries, cloudberry and cranberry. 90% of those responding were of the opinion that drainage reduces the cloudberry yield in the long term and a full 97% indicated that cranberry crop diminishes as well.

The PDF includes a summary in English.

• Sepponen, E-mail: ps@mm.unknown

The study discusses the amplitude of the simultaneous groundwater table fluctuations in different parts of pine mires, and factors influencing it. The assumption generally used in hydrological computations that the simultaneous vertical fluctuation in the groundwater table in different parts of mires are equal does not hold good in detail. Numerous cases were detected where the fluctuation at one place did not correspond to that at another site to a statistically significant degree. The main reason for the unequal fluctuation at the different sites seems to be the difference in the microtopography and in the hydraulic conductivity between the sites.

The PDF includes a summary in Finnish.

• Kurimo, E-mail: hk@mm.unknown

The effects of variations in the intensity of drainage and NPK fertilization on the natural regeneration and planting results and the subsequent development of seedling stands under various climatic conditions on drained nutrient poor pine bogs was investigated in a 16-year-old study.

Comparison of height development of Scots pine (Pinus sylvestris L.) stands on drained peatlands to that of pine stands growing in mineral soil sites show that in Southern Finland the most efficient forest improvement measures (10 m ditch spacing and 1,000 kg/ha NPK-fertilization) resulted in growth that corresponds a to a height index of a stand in a Vaccinium type site. Less efficient treatment (30 m ditch spacing and no fertilizer) resulted in growth corresponding the development of young stand in a Calluna type site. In Northern Finland the effect of fertilization on height growth was almost negligible. This is possibly due to a decrease in the nitrogen mobilization from south to north of Finland. Thus, it seems evident that fertilization of young Scots pine stands on nutrient poor drained peatlands can be recommended only in the southern part of the country.

The effect of ditch spacing is same in the whole country. The narrower the spacing the better the height growth. In the south planted stands thrive better than naturally regenerated stands, but the situation is reversed in the north.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown
• Laine, E-mail: jl@mm.unknown
• Lepola, E-mail: jl@mm.unknown

Altitude fluctuation of mire surface proportional to that of the groundwater table is presented for three virgin pine mires in Eastern Finland during the growing season 1982. The average amplitude of the surface fluctuation was found to be dependent on the period representing a certain type of weather, being limited to a certain maximum. The average amplitude of the surface fluctuation ranged from 18 to 45 mm; each of the mires followed a fluctuation scale of its own.

The daily fluctuation rates were low, generally 0.5–1 mm. No sudden fluctuation peaks occurred. Regularities in the surface fluctuation were caused by the duration of the period representing continuous sinking or rise of the groundwater table, and magnitude of it. The daily rate of the surface fluctuation related to that of the groundwater table was smaller in the beginning of such period than at the end of the same period. The one-directional rise or sinking of the altitude of the mire surface according to the groundwater table fluctuation is responsible for the autocorrelation of the long-term regression data.

The PDF includes a summary in Finnish.

• Kurimo, E-mail: hk@mm.unknown

The present study deals with the effect of forest drainage on some quality factors of brook waters. Under study were several brooks in the basin of the Kiiminkijoki River as well as its main tributary, the Nuorittajoki River. These are located in Northern Finland and belong to the international water program Project Aqua.

The following values were determined for the water samples: pH, electric conductivity, colour, concentration of suspended solids., NO₂, NO₃, and NH₄ nitrogen concentrations, dissolved and total phosphorus, and Ca, Mg, K and Fe concentrations. Water quality in the brooks was monitored prior to and after ditching. A statistically significant change was noted in colour, in the concentration of suspended solids, in the NH₄ concentration and in some brooks also in the pH value and in the total phosphorus, K, and Fe concentrations.

The PDF includes a summary in English.

• Hynninen, E-mail: ph@mm.unknown
• Sepponen, E-mail: ps@mm.unknown

The aim of the paper was to describe the development of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) seedling stands on drained peatlands and to find out the principal factors influencing their growth. The material under survey consists of 180 sample plots distributed from southern coast of Finland to the Polar Circle.

The most important growth factors have been the accumulated temperature sum, site quality, drainage intensity and silvicultural condition, such as the density of the stand, the proportion of birch in the stand, and the amount of possible shelterwoods. The influence of these factors, and to some extent the influence of fertilizing, and the disturbing effects of some forest damages, such as frost, growth disturbances and elk damages were investigated. Comparisons of the development in the seedling stands on drained peatlands with the known development of seedling stands in mineral soils were made.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

The study discusses the amount of shrinkage of volumetric undisturbed peat samples when drying to an oven-dry (105°C) condition. The amount of shrinkage is related to various physical properties of peat. In addition, some observations were performed on the shrinkage phenomenon during the drying process. The study results may be used when predicting the shrinkage of peat samples with various peat properties. Knowledge of this kind is particularly important in connection with peat harvesting.

The PDF includes a summary in Finnish.

• Päivänen, E-mail: jp@mm.unknown

The objective of the investigation was to determine the differences between timber grown on a peatland before and after draining, in respect of compressive strength parallel to the grain, static bending strength and density. In addition, the characteristics of boundary zone between the wood formed before, and after the draining with wider growth rings was studied. 41 Scots pine (Pinus sylvestris L.) and 22 Norway spruce (Picea abies (L.) H. Karst.) trees were studied.

The compressive strength of pine usually decreased from the butt end upwards, but no trend was observed in spruce wood. In coniferous trees, wide-ringed wood formed subsequent to draining was slightly lighter than the close-ringed wood produced prior the draining. The density of pine as well as spruce increases as the width of the growth rings decrease up to a certain limit. The strength of the different kinds of wood seems to decrease from the butt end upwards.

In both species, the compressive strength parallel to the grain and the bending strength are lowest in such wood that contains exclusively wide-ringed wood formed subsequent to draining. Also, compressive and bending strength increase with decreasing width of the growth rings. The longitudinal shrinkage of compression wood in spruce was several times that of normal wood, and the bending strength was lower than that of normal wood particularly in spruce. The compressive strength parallel to the grain in dry condition was, however, higher than in normal wood both in pine and spruce.

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• Ollinmaa, E-mail: po@mm.unknown

Questionnaires were sent out to determine the volume of wood harvested from peatlands during 1978 and the harvesting problems encountered. In total there were 110 responses which accounted for 8 million m3 of wood harvested, of which 1.0 million m3 (14%) was harvested from peatlands. The largest proportion of wood harvested from peatlands was during the winter. Most of the respondents reportet that they wait for the soil frost to set before harvesting is started on peatlands. Respondents indicated a total of 263 machines bogging down in to the soil or, for 1978, a total for Finland of 750 to 1,000 machines.
The PDF includes a summary in English.

The PDF includes a summary in English.

• Saarilahti, E-mail: ms@mm.unknown

The present paper deals with the most important factors of peatland hydrology and the influence of forest drainage on the hydrology of peatland itself and its surroundings. It is compiled of six seminar papers written by students in the Department of Peatland Forestry in the University of Helsinki. Special attention is paid to the hydrological consequenses of the maintenance of drained areas. Also ways and measures to minimize the negative environmental effects of these treatments are discusses.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown
• Joensuu, E-mail: sj@mm.unknown

The forestry working group of the committee for scientific and technical cooperation between Finland and the Soviet Union initiated cooperation work between the two countries in the field of forestry almost ten years ago. The Finnish organizations the Department of Peatland Forestry, the Finnish Forestry Research Institute, and the Institute of Peatland Forestry of the University of Helsinki participated in the activity. From the Soviet Union the participants have been the Ministry of Forestry, the Russian Federation of USSR, and the Forestry Research Institutes of Leningrad and Estonia.

This paper includes the papers presented in the joint symposium arranged at the Forest Field Station of University of Helsinki on 17.9.1979. The 9 Russian lectures and the 8 Finnish ones, are presented either in their entirety or slightly condensed variably in Finnish, English or Russian. The summary of the seminar is presented in English and in Russian.

• Paavilainen, E-mail: –
• Seppälä, E-mail: –

Gleysol profiles of five southern Finnish sites dominated by Norway spruce (Picea abies (L.) H. Karst.) were described according to the Canadian system of soil classification, and the total contents of five metals (Pb, Zn, Cu, Mn, Fe) were analysed in each soil profile. Lead, zinc and manganese showed highest concentrations in the organic surface horizons with a decrease towards mineral soil horizons. Vopper distribution was somewhat irregular. Iron had maximum values in the mineral soil: in A-horizon of Rego Gleysols and in B-horizon of Fera Gleysols. A preliminary comparison of metal pools in soil (root layer) with annual atmospheric input shows that the role of atmospheric deposition is relatively greater in the case of Cu, Zn and Pb than for Fe or Mn.

The PDF includes a summary in English.

• Vasander, E-mail: hv@mm.unknown
• Mäkinen, E-mail: am@mm.unknown
• Pakarinen, E-mail: pp@mm.unknown

The paper deals with the nutrient status of surface peat layer from virgin sedge-pine swamps and its relationship to peatland types. When the nutrients are expressed in mg/100 g peat, only easily extractable Ca and Mg correspond to the productivity status of the peatland type. N, P, and K levels in the herb rich sedge-pine swamp are generally lower than in the small sedge-pine swamps, which are the least productive ones. The differences between the site types in all the five nutrients become much clearer when the results are expressed in kg/ha. P, K, and Ca are significantly different between the site types, and correspond to the productivity of the site type. For N and Mg the same tendency can be seen. The organically bound nutrients N, and to a lesser extent, P appear to comply with the hypothesis of an increase in nutrient availability in Southern Finland.

The PDF includes a summary in Finnish.

• Starr, E-mail: ms@mm.unknown
• Westman, E-mail: cw@mm.unknown

The ash content has been found to correlate with the fertility of peatlands. Relationship between height of 80-year-old stands and ash content of peat in topmost 30 cm layer was examined in Lithuanian conditions. On drained peatlands with ash content of peat from 3% to 8% pine stands increase in height. Ash content of peat being about 7% Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands on drained sites are found to be of equal height. Ash content of peat more than 8–9% has no significant effect on growth of pine or spruce stands. Birch (Betula verrucosa (B. Pendula Roth.) and Betula pubescens Erhrh.), stands are less sensitive to ash content of peat compared with other species. Black alder (Alnus glutinosa L. Gaertn.) stands occurred in sites with ash content of peat more than 8–10%. The height of the stands become equal both in drained and undrained sites in the cases where ash content of peat is about 16–18%. Ash (Fraxinus exelsior L.) stands attain high productivity on drained sites with ash content of peat about 20%.

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• Kapustinskaité, E-mail: tk@mm.unknown

During the next decade there will be a marked increase in the allowable cut in drained peatlands. At the same time, the mechanization in logging proceeds, and in short-distance haulage the use of forwarders will increase. This study, based on literature and some observations, deals with logging conditions in drained peatlands with special reference to the suitability of heavy logging machines for use in such terrain. In addition, soil frost and the bearing capacity of the frozen peat soil were studied.

Freezing of the soil in a drained peatland area depends prevailingly on the weather conditions during early winter. The factors influencing soil freezing of a drained peatland are completely different from those regulating the freezing of natural peat soils. The frost penetrates in general deeper in the drained than virgin peatland. The topmost peat layer does not, however, freeze uniformly. Generally speaking, the bearing capacity of a drained peat soil is lower than that of undrained peat due to lower water content.

It is concluded that heavy logging machines are probably not fitted for use in drained areas on peatland even if the average soil frost values recorded would suggest it. Moreover, because of their extremely superficial root systems, peatland forests are exposed to damages by heavy machines in thinning operations.

The PDF includes a summary in English.

• Hannelius, E-mail: sh@mm.unknown

Peat industry is rapidly expanding in Finland. Consequently, during next decades peat will be removed from thousands of hectares. Because timber production probably is the most rational use of this area after the peat production has ended, some experiments of afforestation of such areas have already been conducted. This article reports results of two experiments which were started in Kihniö, Western Finland, in 1953 and 1964.

In the first experiment fertilization with wood ash proved very effective whereas seeding and planting without fertilization resulted in almost complete failure. In the second experiment, interplanting with grey alder (Alnus glutinosa L. Gaertn.) greatly promoted the growth of Scots pine (Pinus sylvestris L.). The effect of slight fertilization lasted a few years only. The reasons for the remarkable effect of alder need further research. Although alder is known as a nitrogen-fixing plant, its beneficial effect was most clearly seen in the K and P contents of pine needles. Inoculation with mycorrhizal fungi was beneficial but not necessary. Experiments hitherto show that afforestation of bogs after peat removal is possible although some additional measures like fertilization or interplanting with alder may be needed.

The PDF includes a summary in English.

• Mikola, E-mail: pm@mm.unknown

The paper describes the results obtained from an investigation into the effect of ditch spacing, ditch depth and furrowing on ground water table and on development of a Scots pine (Pinus sylvestris L.) plantation on open small-sedge bog in Central Finland (60° 50’ N; 24° 20’ E), drained in 1967. The area was planted in 1968 with 2+1 Scots pine transplants, and fertilized with Y fertilizer for peat soils. The seedlings were measured in 1972.

The depth of the ground water table was greater, the narrower the ditch spacing. The water furrows shortened the duration of the high ground water and lowered the ground water table particularly in the case of ineffective drainage. The narrower the ditch spacing within the blocks, the higher were the young trees. On the other hand, the differences in the height of the trees between the ditch spacings were eliminated by the effect of the furrows.

The PDF includes a summary in English.

• Päivänen, E-mail: jp@mm.unknown

The significance of water budget in June and July for forest and peatland vegetation, and consequent effects on fauna, climate and agriculture has been studied.

In June, the difference between evaporation and precipitation is greater than it is later in the summer. North of the line zero difference of evaporation and precipitation, coinciding with a line of sharp change in forest vegetation, the uppermost part of podsol remains wet throughout the summer. During July, the line of zero difference moves from north to south over the greater part of Finland, run-off being minute and podsol at the driest in this month. This line, indicating the length of the period with evaporation greater than precipitation and causing a sharp change in forest vegetation, in frequency of peatlands, amount of growing stock productive capacity of forests etc. This line is significant also for cultivation: because of the lower evaporation north of this line, night temperature below the freezing point often appear in summer.

The PDF includes a summary in English.

• Solantie, E-mail: rs@mm.unknown

The study describes the relationships between a method developed by the author for the calculation of the profitability of forest drainage and the old biological method. The calculations were based on empirical data, and they aimed at finding out the effect of a variation in the profitability limit in the areas in hectares to be drained, and on the profitability of drainage. The study deals also with the profitability of present-day drainage activities. The results showed that the profitability coefficient (the ratio between the discounted increase in returns and the costs of drainage) averages 3.04 for the whole country. The corresponding value was 5.68 for Southern Finland, 3.19 for Central Finland and 1.67 for Northern Finland.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

The aim of the study was to assess, through field experiments, the possibilities of using peat briquettes in the seeding of Scots pine (Pinus sylvestris L.) in Southern Finland. The briquettes were dug into the soil in the middle of patches of mineral soil. The seeds were covered by a 2-5 mm layer of mineral soil. The seedings were inventoried in the three following autumns.

According to the results, the briquettes were clearly inferior to the control, which was ordinary drill seeding. This was mainly due to the fact that no rain was received after the seeding, and that the third summer from seeding was extremely dry. Abundant germination was observed during the second summer after seeding in both briquette seeding and the control. During more rainy summers the result might have been better.

The PDF includes a summary in English.

• Lehtiniemi, E-mail: tl@mm.unknown

The paper deals with the relationships between macronutrients, ground vegetation and tree crop on a drained peatland area in Central Finland. The former herb-rich spruce swamp was drained in 1930s. The Norway spruce (Picea abies (L.) H. Karst.) stand was established by planting under a nurse crop of birch, which was removed later.

There was a negative correlation between the thickness of the peat layer and the volume and mean height of the growing stock. This was found to depend on the negative correlation prevailing between the potassium content of the topmost peat layer and the thickness of the peat cover. The deficiency of potassium is clearly discernible as deficiency symptoms in the needles, the intensity of which showed a strong correlation with the stand characteristics studied. Among the nutrient characteristics of the topmost peat layer, total potassium and the N/K and P/K ratios showed the closest correlation with the stand characteristics. The communities into which the ground vegetation was divided differed from each other with regard to the calcium content of the peat substrate.

The PDF includes a summary in English.

• Mannerkoski, E-mail: hm@mm.unknown

The paper describes the results obtained from an investigation into the effect of thinning of different intensity and fertilization on the depth and water equivalent of the snow cover as well as on the depth of the soil frost in a young Scots pine (Pinus sylvestris L.) stand growing on drained peatland in Central Finland. Thinnings and fertilization was carried out in 1968, and the snow cover was followed in the winters 1970/71 and 1971/72.

Only extremely heavy thinnings (60% of the volume) seemed to increase the depth and water equivalent of the snow cover. The indirect effect of fertilization on the snow cover was insignificant. In the clear-cut sample plot of the study, soil frost was either not found at all or the depths of the frozen soil layer was smaller than in the other plots. When deciding the silvicultural measures to be taken in the case of tree stands growing on drained peatlands, there seems to be reason to avoid radical thinnings. Otherwise, the favourable influence of the trees on a site on its water relationships will be diminished.

The PDF includes a summary in English.

• Päivänen, E-mail: jp@mm.unknown

The purpose of this study was to compare the development of Scots pine (Pinus sylvestris L.) seedlings sown on substrates off milled peat and milled bark. Mille peat, ordinary milled bark, milled inner bark waste, and a mixture of milled peat and milled bark in the ratio of 1:1, were all compared in the plastic greenhouse. In addition, two fertilization applications were used with milled park: ordinary surface fertilization and double surface fertilization. The germination and development were measured twice during the summer.

It is concluded that milled bark seems to be a rather useful substrate for use in plastic greenhouses, as long as its special requirements are taken into consideration. In the first measurement, there were no differences between the treatments, in the second measurements seedlings growing on a mixture of peat and bark were slightly more developed than the others. Growth of the seedlings was slightly better in ordinary milled bark. Double surface fertilization increased disease and mortality compared to ordinary fertilization.

The PDF includes a summary in English.

• Laatikainen, E-mail: pl@mm.unknown

The aim of the present study was to assess whether two-year old Betula verrucosa Ehrh. (now Betula pendula Roth.) transplants can be used in afforestation of drained peatlands and what factors affect the development of the young trees. The seedlings were planted in 1967. The site was repair planted next spring due to mortality caused by a undefined fungal disease, and the plantations were fertilized with NPK fertilizer (soil application. The seedlings were measured twice a year until the autumn 1970.

Only 28% of the original transplants, and 73.4% of the repair plantations were alive in 1970. In some cases, fertilization improved the results, while in others it was detrimental to the trees or had no effect on survival. According to peat analysis, the poor survival and development of the plants could be due to the too high ratios of N/Ca and N/P. Stunted or dead trees displayed often necrosis caused by Godronia multispora. According to the experiences, Betula verrucosa plantations are inferior to those obtained with Scots pine (Pinus sylvestris L.). In addition, the results indicate that in old draining areas calcium and phosphorus are often too low in comparison to nitrogen.

The PDF includes a summary in English.

• Lehtiniemi, E-mail: tl@mm.unknown
• Sarasto, E-mail: js@mm.unknown

The possibilities of using a pot method to determine the need for fertilizer application were studied. Seedlings of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) were grown in peat samples that had cylindrical shape with a diameter of 25 cm and height of 35 cm. The samples represented three different peatland types, and were fertilized with two levels of phosphorus, potash and nitrogen. Two transplants were planted per pot. The development of the seedlings was followed for three years.

Phosphorus seemed to be of greatest importance for the growth of the seedlings, but nitrogen was also required in the poorest peatland type. Potash did not give statistically significant results. NPK application gave the best response. The usability of the method was studied by following the development of the roots. It seemed that the diameter of the pots was too small and restricted the growth of the root systems.

The PDF includes a summary in English.

• Erjala, E-mail: pe@mm.unknown
• Saramäki, E-mail: js@mm.unknown

The changed in size and shape of ditches made by draining plows and tractor diggers were followed over a one-year period after the draining in four different peatland types. The material consists of 51 ditches made with each method in dwarf-shrub pine bog, herb-rich spruce swamp, in herb-rich sedge bog and sedge pine bog. The measurements were made immediately after the digging, and one month and a year later.

Ditches made by plowing and surrounded by peat became shallower quickly during the first 2–3 days after plowing due to the pressure of the surrounding peat. Ditches made with tractor diggers did not become shallower as fast, and their bottom did not widen to the same extent than plown ditched. During the first year, machine-made ditches change in a same way as handmade ditches, especially when compared to ditches made by tractor digger.

Immediately after digging the ditches made by tractor digger were 10 cm deeper and 0.13 m³ larger than plown ditches. One year later the values were 7,5 cm and 0.09 m³, respectively. Plown ditches made in the peat were 14.4 cm deeper than ditches that penetrated into the subsoil, for tractor digger the value was 13.2 cm. Ditches made with a tractor digger were deeper than plown ditches both in soils with deep and shallow peat layer.

The changes were largest and fastest in the wettest peatland type herb-rich sedge bog. In herb-rich spruce swamps, which have a shallow peat layer, the shallower plown ditches kept their form better than ditches dug by tractor digger.

The PDF includes a summary in English.

• Timonen, E-mail: et@mm.unknown

The paper describes the results obtained from an experiment of fertilization of drained treeless peatlands in connection of planting in three sites in Central Finland. Scots pine (Pinus sylvestris L.) seedlings 2+0 was used. The fertilizer (Y-fertilizer for peat soils, 14% N, 18% P₂O₅, 10% K₂O) was applied in rates of 0, 20, 40 and 80 g/transplant. The fertilizer was strewn either around the plant within a circular patch of 20 cm in diameter, in a ring with a radius of 10 cm and in a ring with a radius of 20 cm. The seedlings were measured two and five years after planting.

The greater the quantity of fertilizer applied and the closer it was applied to the plant the higher was the mortality of transplants. Fertilization increased the mortality during the first two growing seasons after application. Later, however, the mortality decreased to a similar level irrespective the way the fertilizer was applied. In the beginning of the second growing season the fertilized plants showed considerably better height growth than the control plants. The smallest quantity of fertilizer applied produced almost full increase in growth. The pattern of application of the fertilizer had little effect on the growth.

It was concluded that a use of small amounts of fertilizer can be recommended in connection with planting and that it should not be applied very near the seedlings.

The PDF includes a summary in English.

• Seppälä, E-mail: ks@mm.unknown

The aim of the present study was to increase the knowledge of the anaerobic conditions prevailing in virgin peat soils of different kinds, and on the fluctuation of the aerobic limit. Silver rod method was used to indicate anaerobic conditions and to locate the aerobic limit. The material included 18 peatland sample plots on treeless bogs, in pine bogs and in spruce swamps in Southern Finland. Observations of the discoloration of the silver rods and measurements of ground water level were made from 8 June to 13 August 1968.

The results show that the location of the aerobic limit is dependent of the depth of the ground water table, and usually lies 5–15 cm above the ground water table. Down to 10–20 cm below the aerobic limit, where it reaches maximum, the rate of decomposition of sulfurous organic matter is positively correlated with the distance from the aerobic limit. Deeper it gradually decreases, and in the depth of 25–35 cm no hydrogen sulphide seems to be released.

In the forested peatland types the volume of the growing stock and the increment were dependent on the depth of the aerobic limit only when nutrient content and pH of the peat was more or less constant. Where the aerobic limit was close to the ground surface but the nutrient contents were relatively high, the volume of the growing stock may be comparatively high. Birch (Betula sp.), better than the conifers, is able to stand conditions poor in oxygen. The growing stock was poor in sites where the aerobic limit was near the ground surface, but the nitrogen and phosphorus contents were high, or vice versa. Consequently, aerobic limit is of great importance as an indicator of site quality.

The PDF includes a summary in English.

• Lähde, E-mail: el@mm.unknown

The study attempts to establish to what extent the present regional allocation of the forest improvement subsidies equalize the profitability of forest drainage in Finland. The benefit/cost ratio has been used to describe the regional variation of the profitability

The study revealed that the forest improvement subsidies granted in 1968, even the highest possible subsidies, did not equalize the profitability of forest drainage. According to the results, the northern regions are at a disadvantage compared to the southern parts of the country. To fully equalize the profitability of forest drainage the average subsidies granted in 1968 should have been raised in the second financing zone from 22 to 32%, in the third zone from 32 to 60%, and in the fourth, northernmost zone from 43 to 86%. The study also suggests that the boundary lines of the financing zones should run, at least in Central and Northern Finland, from southeast to northwest instead from east to west, as it is now.

The PDF includes a summary in English.

• Numminen, E-mail: jn@mm.unknown

This paper presents the results of a contest performed on behalf of the Finnish bank Kansallis-Osake-Pankki and the Central Forestry Board Tapio on growing trees on peatlands. Over 5,000 sample plots were established on drained peatlands in various parts of Finland. The aim was to achieve a best possible growth of seedling stands on peatland. The factors influencing the growth of 85 best Scots pine (Pinus sylvestris L.) and 60 best Norway spruce (Picea abies (L.) H.Karst.) sample plots were studied.

The height growth of the seedling stands decreased towards the north. Fertilization seemed not to decrease the regional differences; rather on the contrary. On the other hand, fertilization increased height growth, but evidently so that the increase obtained was greater in the southern than in the northern parts of the country. Light fertilization (50 kg/ha of K₂O and 60 kg/ha of O₂P₅) caused a clear increase in height growth while heavy fertilization (100 g/ha of K₂O and 120 kg/ha of O₂P₅), had same effect but to much greater extent than the former. Spruce seedling stands in particular benefitted of the heavy fertilization.

Fertilization did not eliminate the original differences in the quality of the sites in question, but these could still be seen in the height growth after fertilization. The effect of drain spacing on the height growth was not very clear. In dense seedling stands (800 seedlings/ha) the height growth of the dominant seedlings was greater than that obtained in stands of lower density. Hold-overs caused a decrease in the growth of the seedling stands.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown
• Ouni, E-mail: jo@mm.unknown

This study determined the correlation between the bulk density, humification degree and laboratory volume weight of the surface peat of virgin and drained peatlands. The material consists of 316 peat samples 250 cc in volume.

The correlation between bulk density and the laboratory volume weight was found to be close. Eliminating the ash and moisture content of air-dry samples did not improve the correlation. There were distinct level differences among peat types; difference between bulk density and laboratory volume weight was the greatest for Sphagnum and the smallest for woody peats. The Carex peats were intermediate. The water content at sampling may partly determine these differences. When the data were treated as a whole, the difference between bulk density and laboratory volume weight seemed to increase, as the water content increased.

The correlation was also close between bulk density and the degree of humification. For all data, multivariable correlation analysis revealed that bulk density was determined for the largest part by the degree of humification, least by the water content at sampling, laboratory volume weight being intermediate. Thus, already the determination of the degree of humification provides a clear picture of the bulk density for each peat type. It can be also determined by fair accuracy on the basis of the laboratory volume weight. The bulk density is required for e.g. water regime studies, to convert the water content of peat measured in weight units into volume percentages.

The PDF includes a summary in Finnish.

• Päivänen, E-mail: jp@mm.unknown

The present paper is a preliminary report of a project designed to determine the order of profitability of various forest improvement measures – seeding and planting, drainage, and fertilization – in various types of stands and in different parts of the country on drained peatlands. Sample plot data on the effect of draining on increment was derived from areas drained 28– 36 years ago. The study was carried out in the southern half of Finland.

The observations on increment changes are based on two measurements of the sample stands 12 years apart. Supplementary calculations indicate that the stands on drained peatland, depending on site quality and tree species, have either continued to grow like mineral-soil sites of similar fertility or have somewhat increased their growth rate.

The effect of draining intensity was studied using strip measurements. It was found that both the total amount of wood produced (current stand + cutting removal + natural removal) and the current annual volume increment for the 5-year period systematically decrease as the ditch interval increases. The decrease is, however, relatively slight. In Eriophorum vaginatum pine swamps, the total amount of wood produced and the increment show a decrease of ca. 20% with an increase in ditch interval from 20 to 60 metres. In other sites, the decrease is ca. 5-10%

It can be concluded that if the increase in ditch interval do not result in considerably poorer timber assortment distributions than indicates by stand production and increment, it is profitable to pan for a relatively large ditch interval and a slightly smaller than maximum wood production. Supplementary data and check calculations may cause some changes in these preliminary results.

The PDF includes a summary in English.

• Seppälä, E-mail: ks@mm.unknown

Due to mechanization of draining of peatlands, also open peatlands have been included in the draining projects due to technical reasons. Some research has been published on afforestation of open drained peatlands, but there is yet no experiments that reaches the entire development of the stands. The purpose of this paper is to discuss the possibility of extending the planting season of Scots pine (Pinus sylvestris L.) over the entire growing season in drained peatlands, where the water condition of the site is probably not the factor limiting forest development. An open low-sedge swamps in Southern Finland were planted in early summer and two weeks in midsummer in 1967.

In the light of the results, planting Scots pine would seem possible in drained peatlands throughout the growing season. However, plants may suffer considerably from lifting for the plantation in August. The success of planting at the turn of September and October is also uncertain. The nursery must be situated close to the areas to be planted, since the transportation and handling of plants during the growing season must be carried out with extreme care. The seasonality of planting work could be decreased by extending the planting season. In the future, several transplant storing methods should be tried out in connection with similar planting-time experiments.

The PDF includes a summary in English.

• Päivänen, E-mail: jp@mm.unknown

The many unsolved questions concerning fertilization makes it difficult to forecast accurately its biological and economic consequences. Some of the problems are discussed in this paper. The most common types of forests in Sweden, Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands on well-drained mineral soil, respond strongly to nitrogenous fertilizers, but the effect of phosphate, potash or lime is small or nil, at least within 5–10 years after application. The response of nitrogen lasts 4–5 years in pine and somewhat more in spruce.

Drained peatlands usually respond to mineral fertilization, but the improvement brought about by a PK application depends, inter alia, on the nitrogen content of the peat. Peatlands with a peat low in nitrogen need NPK fertilization. For deep peatlands, a moderate or high nitrogen content, a single PK application improves growth conditions for a very long time. Experience of fertilizing shallow peatlands and poorly-drained mineral soil is very limited, but it seems easy to get a growth response either with nitrogen alone or with NPK.

The results of fertilization at the time of planting have not, as a rule, been very good in Sweden. An exception is the afforestation of abandoned fields on drained deep peat, where PK fertilizer around the plant seems to be essential for both survival and growth.

• Tamm, E-mail: ct@mm.unknown

About one third of the land area of Finland is covered by peatlands, furthermore, some mineral soils are troubled by excess water. Due to the prevalence of peatlands, forest drainage has been the most important form of forest improvement work. Consequently, peatlands have been an extensively studied topic within forest sciences in Finland. This paper gives a review on the central research subjects in science of peatlands, introducing little less than a hundred of the hundreds of publications published in the field. The author describes in more detail research on the formation and area of peatlands, peatland types and their suitability for forest draining, site factors on peatlands, techniques of forest ditching and the management of peatland forests.

The PDF includes a summary in Finnish.

• Heikurainen, E-mail: lh@mm.unknown

There are about 155,000 ha of fen-like pine swamps (eutrophic pine bogs) in Finland, major part of which are situated in Northern Finland. In the classification system for drainability of peatlands, this type of peatlands had been placed in the first class. The study presents a new evaluation for the peatland type, based on vegetation and tree growth.

According to a previous study, the vegetation of fen-like pine swamps can be characterised by distinctive plant communities that seem to reflect the fertility and high pH of the underlying soil. In this study, the fen-like pine swamps were divided in two subtypes based on the vegetation: proper fen-like pine swamps and fen-like pine swamps with ericaceous shrubs. Both have distinctive vegetation, which is described in the article. The distribution of the subtypes seems to be different: fen-like pine swamps with ericaceous shrubs are more common in eastern parts of Northern Finland. The two subtypes could be divided in different drainability classes according to tree growth, proper fen-like pine swamps belonging to class 1 and fen-like pine swamps with ericaceous shrubs to class 4.

The article includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

Silva Fennica Issue 92 includes presentations held in 1956 in the 8th professional development courses, arranged for forest officers working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

In 1925-1944 the Finnish Swamp Cultivation Association (now Finnish Peatland Society, Suoseura) carried out research on the arability of peatlands, mostly on state lands that were the main object of settlement work and the arability of which had been little explored. Later the work has been transferred to the Settlement Department of the Ministry of Agriculture (ASO) and some other authorities. ASO has prepared arability maps based on the nutrient analysis of the lands.

• Kotiaho, E-mail: ak@mm.unknown

When ditches are dug in forest drainage, smaller stones are removed by hand, but the larger ones require the use of explosives or stone lifting machinery. Use of explosives have been a more common method for the larger stones. Due to development of detonation methods, it has also been used for smaller stones than earlier.

The investigation was a time study comparing five different stone lifting machines. Time needed for different stages of the work was measured. The stages lasted approximately as long for all of the machines. However, the effectivity of the machines could not be determined, because the stones removed were not similar enough. Stone lifting machine Pekka appeared slightly more effective than the other four machines. It was also easy to assemble, disassemble and move.

The article includes a summary in German.

• Yli-Vakkuri, E-mail: py@mm.unknown

Silva Fennica Issue 80 includes presentations held in 1952 in the 7th professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes the factors that limit growth of trees in peatlands, and principles of draining of peatlands.

• Mansner, E-mail: pm@mm.unknown

Growth capacity of peatlands after draining depends largely on quality of the surface peat. The future growth capacity can be determined with considerable accuracy by the vegetation of the peatland. The aim of this study was to draw guidelines to identify the fertility of a peatland and its potential for draining based on its vegetation.

Certain species and plant associations were identified to describe the fertility of different peatland types. Brown mosses indicate an abundant nutrient content of the site, certain herbs moderately abundant nutrient content, sedges (Carex sp.) moderate nutrient content, shrubs poor nutrient content and vegetation indicating an oligotrophic peatland indicates excessively poor nutrient content. The article includes detailed descriptions of the vegetation of different peatland types.

Supplementary features, such as thin peat, flooded parts or abundance of Spangnum fuscum can be used as additional indications to determine the drainability of the site. The article describes an identification tool to determine the drainability of a peatland based on vegetation and the supplementary features of the peatland.

The article includes a summary in English.

• Huikari, E-mail: oh@mm.unknown

The government of Finland appointed a committee to make a suggestion of measures to be taken to arrange fuel supply during the heating season. The committee drafted also a plan to regulate and govern the fuel economy.

The committee estimated that the total consumption of coal, coke, firewood, waste wood and fuel peat, converted into pine firewood increased from 33.8 million eu.m in piled measure in heating period of 1952-53 to 42.9 million in 1955-56. According to the report, the demand of fuel is met increasingly through imported fuels, such as coal, coke and oil. The change is mainly due by their lower price and technically easy handling compared to domestic fuels.

The committee suggests that the production of domestic fuels, peat and firewood, should be increased and rationalized. In addition, financial support should be targeted to construct hydroelectric plants. Fuel peat industry should be developed further. The use of oil should be promoted, and boilers able to use different kinds of fuel should be constructed. To be prepared in changes in international situation, stocks of fuel are needed.

• Polttoainekomitea, E-mail: –

According to the second National Forest Survey, peatlands covered before the World War II 11,156,000 hectares, 32% of the land area of Finland. The early drainage of peatlands in 1700th century had aimed at preventing frost and increasing area of agricultural land. The experiences proved that drainage of wet forests was lucrative also in the point of view of forestry. The drainage of state-owned forest lands was promoted by the Crown Forest Committee in its report in 1900. The systematic drainage work in state lands begun in 1909. In the end of 1920s 500-700 km of ditches was dug annually.

The drainage of private lands begun after 1928, when forestry promotion work in private forests begun. By the end of 1950, 4,815 forest drainage projects had been approved by the Forest Service in the private lands. In addition, 286,000 ha of peatlands was drained on work organized by the central forest associations in 1930-1950, and 239,272 ha by timber companies in 1902-1950. The drained area totalled 755,892 ha. The area of drainable and drained peatland was estimated to be 4.4 million ha.

The article includes an abstract in English.

• Tirkkonen, E-mail: ot@mm.unknown

The aim of the study was to develop an determination method to define vegetation type of fen-like pine swamps, which are combinations of two peatland types, quagmire and pine swamp. Typical for this peatland type is that the vegetation is very heterogenous. Patches of different types of plant communities are found within a small area, but in a large scale, there are only few main types of plant communities. The commonly used way to use sample plots to study tree stands suit poorly to determine the type of this kind of heterogenous ground vegetation. The article compares strip survey and circular plot survey, of which circular plot survey is determined to be less time consuming. The article describes a way to choose the locations of sample points to achieve most correct areas for different plant communities.

The article includes an abstract in German.

• Heikurainen, E-mail: lh@mm.unknown

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes the history and present stage of forest drainage in Northern Finland. The first peatlands were drained in the area in 1909. About 6% of the 600,000 hectares of peatlands suitable for drainage was drained at the time in Perä-Pohjola. The areas to be drained are characteristically very large.

• Metsänheimo, E-mail: um@mm.unknown

Silva Fennica issue 52 includes presentations held in professional development courses, arranged for foresters working in public administration in 1938. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation discusses forest management practices of drained peatlands and the allocation of responsibilities in draining of peatlands between district forest officers and forest officers responsible of drainage work. Problems has occured in those cases, when the process of draining had lasted so long that at the time of final assessment of the project the first ditches have already needed maintenance.

• Lukkala, E-mail: ol@mm.unknown

Silva Fennica issue 46 includes presentations held in professional development courses, arranged for foresters working in public administration in 1937. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service. 

This presentation describes inspection of forest regeneration of mineral soil forest types and drained peatlands, and inspection of ditches. 

• Ahola, E-mail: va@mm.unknown

Silva Fennica issue 46 includes presentations held in professional development courses, arranged for foresters working in public administration in 1937. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service. 

This presentation describes afforestation of drained peatlands. 

• Lukkala, E-mail: ol@mm.unknown

Silva Fennica issue 42 includes presentations held in professional development courses, arranged for foresters working in public administration in 1936. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service

This presentation describes the effects of draining of peatlands on water management in the peatland and the surrounding area.

• Metsänheimo, E-mail: um@mm.unknown

Silva Fennica Issue 39 includes presentations held in professional development courses in 1935 that were arranged for foresters working in public administration. The presentations focus on practical issues in forest management and administration, especially in regional level.

This presentation discusses the use of peatlands in agriculture and peatlands' suitability to farming.

• Kotilainen, E-mail: mk@mm.unknown

Silva Fennica Issue 39 includes presentations held in professional development courses in 1935 that were arranged for foresters working in public administration. The presentations focus on practical issues in forest management and administration, especially in regional level.

This presentation gives guidelines for draining of peatlands.

• Cautón, E-mail: ac@mm.unknown

Silva Fennica Issue 39 includes presentations held in professional development courses in 1935 that were arranged for foresters working in public administration. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes different kinds of peatlands and their suitability to draining and forestry.

• Lukkala, E-mail: ol@mm.unknown

Metsähallitus (Forest Service) decided to protect two areas around Hiisijärvi lake in Eastern Finland already in 1916. Later, a natural park was suggested to be established in the area. A survey of the vegetation in the area was composed in 1931-1932. The total land area of the protected area was 3.5 km³. A vegetation map was drawn based on a nature inventory. A detailed description of the forest site types, peatland types, aquatic flora and the vegetation of the area are included in the article. The calcareous soil promotes rich vegetation. Typical for the area are also rich fens. The area can be divided to a eutrophic and a oligotrophic part.

The PDF includes a summary in German.

• Brandt, E-mail: ab@mm.unknown

Systematic draining of peatlands begun in the state forests of Finland in 1908. It was considered necessary, because 41.4% of the state forests, 5.6 million hectares, consist of peatlands. Of the peatlands, 1.9 million hectares was estimated to be suitable for draining. Furthermore, paludification still continues in the forest lands. By the year 1926, a total of 52,275 hectares of peatland had been drained in the state lands.

Certain factors decide whether the peatland is suitable for draining: the growth increment capacity after draining, technical difficulties in draining, and difficulties in regeneration. Peatland type indicates the growth capacity of the drained peatland. The peatland should turn at least to Vaccinum forest site type or better type to be worth of draining. If the peat layer is thin, the quality of peat is an important deciding factor. The peatland may also be too expensive to drain due to, for instance, long ditches, main ditches difficult to dig, small inclination, uneven surface, and deep cavities at the bottom. The younger the trees of the stand, the faster the growth of the stand revives. The peatlands usually regenerate naturally provided there is sufficient seed trees, and there is seldom need for artificial regeneration.

The PDF includes a summary in English.

• Lukkala, E-mail: ol@mm.unknown

Draining of peatlands requires careful planning because of its costs. Only peatlands that have sufficient growth capacity in future should be drained. The future growth capacity can be estimated based on peatland type, the botanical composition of the peat layers and the quality of the surface peat layer of the swamp.

Also the draining methods should be cost effective. To keep the amount of drains low, the drain network and drain lines should be planned so that each drain has high drain effectivity. Most of the peatlands drained in Finland have been forested. Especially the young trees regain soon their growth when the peat begins to dry. It is recommended to leave the young trees, but most profitable to harvest the older forests in the drained area. Practical experiences have shown that even drained open peatlands can be naturally regenerated. Natural regeneration is almost guaranteed to succeed on peatlands, which have seed trees.

A summary in Finnish is included in the PDF.

• Lukkala, E-mail: ol@mm.unknown

The present investigation revealed that the influence of a forest cover on the water economy of the soil is very great in Finland. Cutting of the forest gave cause to a rise of the ground water table, which, when clear-cutting is in question, reached a magnitude of 20–40 cm. The water supplies of the soil increased 40–60 mm. In the winter, too, the ground water remaind at a lower level in the forest than in opening, however, the difference is rather small. Thinnings had same kind of effect as clear-cuttings, but the influence of even heavy thinnings was still relatively small.

The water supplies of the soil after felling decreased mainly due to the decrease in the interception in the canopy. When the water table is at the same level in the forest and in opening, evapotranspiration might be greater in the forest than in openings. However, when the water level is during the growing season considerably lower in the forest than in an opening, the evapotranspiration is strongly decreased in the forest, which means that more water is evaporated and transpirated from the opening than from the forest. Because the water table is at a higher level in the opening than in the forest, runoff from clear-cut areas has exceeded that from the forest. This means that the influence of felling on the water economy of the soil is actually even greater than indicated in this work.

The results mean that the influence of the forest cover makes up that of drainage. This affects the need for maintenance of ditches. On the other hand, the final cutting will rise the ground water strongly.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

The objective of this project was to determine the amount of gas exchange in peat samples collected from several swamps, using the Warburg method in the laboratory measurements. Special attention was directed on the influence of the lowering of the ground water level through drainage, on oxidation-reduction conditions in the samples from both forested and treeless peatlands, by measuring oxygen uptake and CO₂ release. The biological activity in situ was determined by the cellulose decomposition rate in the sample plots. The six areas examined were both in drained peatlands and peatlands in natural condition.

The results show that in the sample plots in open swamps there was no consistent differences in the CO₂ release rate in peat samples taken from different depths. However, in the sample plots on forested swamps rapid decrease is seen with increasing depth. The decreased biological activity of peat is caused by the oxidation-reduction conditions. The CO₂ release rate may also be due to the respiration of tree roots, which are very shallow in peatlands.

The rate of in situ cellulose decomposition experiment and CO₂ release indicated by the Warburg measurements appear to be correlated. The results indicate improved conditions for cellulose-decomposing microbes after draining. It is also possible that the biological activity of peat after draining increases to a considerable depth until the decrease of easily decomposable substances limit the activity in an old drainage area. The cellulose decomposition rate would still increase as the oxidation-reduction conditions improve.

• Lähde, E-mail: el@mm.unknown

The aim of this work was to study, on the basis of material published earlier (Heikurainen 1959), the effect of temperature on stand increment, to find out if there is any differences between Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.), and to study the effect of site quality on the relationship between stand increment and temperature. The calculations were based on data collected from 396 sample plots on drained peatlands in different parts of Finland.

There seemed to be no differences due to tree species or site quality in the relative amounts of growth under different climatic conditions. Thus, differences in the absolute growth between poor and fertile sites are noticeably smaller in Northern Finland than in Southern Finland. The author suggests that this implies that the lasting maximal increase of growth which can be produced, for instance, by using soil-improving agents must be less in unfavourable conditions than in favourable.

• Heikurainen, E-mail: lh@mm.unknown
• Seppälä, E-mail: ks@mm.unknown

The present study deals with correlation between level of ground water table and water content of peat in peatlands drained for forestry. The results have been obtained partly from field studies and partly from experiments in the laboratory.

Both the field and laboratory experiments proved that a close rectilinear correlation exists between the level of the ground water table and the water content of surface peat. A given change in the level of the ground water table corresponds to a smaller change in the water content the deeper the peat layer examined is situated. The change in the water content in the surface layer (0–20 cm) in the cases studied was of such a magnitude that a change of 10 cm in the level of the ground water table corresponded to a change of about 5 volume per cent. In deeper layers the change was smaller. The state of equilibrium regulating the water content of the peat is relatively stable. It is possible that the so-called optimum drainage of a peatland for each tree species can be theoretically determined on the basis of the correlation between the water content of peat and the level of ground water table.

The method used in the study, the repeated weighing of peat samples in their original place, has proved to be very useful and decisively better than the method based on one-time samples. The experiment also indicate that the correlation can be determined with laboratory experiments.

• Heikurainen, E-mail: lh@mm.unknown
• Päivänen, E-mail: jp@mm.unknown
• Sarasto, E-mail: js@mm.unknown

Lowering of the ground water table is caused by decrease in the amount of water because of evapotranspiration. Evapotranspiration of a forest is determined by converting a lowering of the ground water table into a decrease in the amount of water. This paper describes a method to determine the transpiration of tree stands and ground vegetation as well as total evaporation on a Finnish drained peatland, which ground water table was relatively high, by measuring the level of the ground water table.

It was shown that in drained peatlands with relatively high ground water level, the ground water table fell during the day between about 9 a.m. and 6 p.m., and remain at approximately same level during rest of the day. The fall of ground water table was caused by transpiration of the trees and ground vegetation, and could be over 20 mm. Thus, measuring the daily lowering of ground water table can be used to estimate transpiration of the trees. When the method is applied to measuring the total evaporation of longer periods of time, also rainfall, interception, stand rainfall and stemflow have to be measured. The method is applicable only on sites with relatively high ground water level.

The PDF includes a summary in Finnish.

• Heikurainen, E-mail: lh@mm.unknown

The determination of biologically most favourable strip width in peatlands to be drained has been hindered by lack of information of the temperature conditions in the surface peat and in the air close to the ground after drainage of different intensities. Temperature measurements were carried out on peatlands drained to different degrees in Central Finland in the summers of 1960 and 1961. The ground water level in the measuring points, and the strip width served as the criterion for differences in water condition.

When the drainage became more intensive, the temperature of the surface peat decreased. However, temperature differences were small, and discernible only when the differences of water conditions were considerable. The effect of strip condition to temperature seems to be of similar nature than the ground water level. Even in extreme cases temperature differences due to different drainage intensity were relatively small, and seldom exceeded 2°C.

Differences in temperature dependent on the growing stock may be as high as 10°C. Thus, the temperature of the surface peat may be dependent on factors more important than temperature differences caused by aspects of drainage. A well-drained peatland is coldest at the beginning of a growing season compared with poorly drained peatland. The temperature differences increase deeper in the peat. This is caused by the better heat conductivity of the moist peat. Also, daily variations in temperature in the surface peat are large in moist peat.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown
• Seppälä, E-mail: ks@mm.unknown

The aim of the study is to find out 1) whether and how the original moor type can be found out based on vegetation regardless the phase of drainage; 2) whether the different phases of draining can be distinguished based on the vegetation; and 3) is it possible to classify the well drained moors into vegetation types that would reflect the productive capacity of the land.

The data consists of samples collected from ditched areas. There are 11 moor types from two climatic ditching zones. The results show that the original moor type can be determined based on vegetation, the phase of drainage can be determined under some limitations, and the classification for productivity can be done for practical purposes.    

The PDF contains a summary in Finnish. 

• Sarasto, E-mail: js@mm.unknown

The objective of the investigation was to determine the differences between faultless timber grown on a peatland before and after draining, in respect of compressive strength to the grain, volume weight, and shrinkage. In addition, the influence of the boundary zone between the close-ringed wood formed before draining and the wide-ringed wood produced after draining on strength of the timber was studied. The material consisted of 15 sample trees of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.), white birch (Betula pubescens Ehrh.) and silver birch (B. Pendula Roth).

The volume weight of wood of the tree species in ascending order is; spruce, pine, white birch, silver birch. The volume weight of Scots pine seems to decrease from the butt end upwards, while no trend was revealed for spruce. In the coniferous trees, the wide-ringed wood formed subsequent to draining was slightly lighter than the close-ringed wood produced prior draining. No distinct trend was seen in the birch species. The volume weight of pine and spruce increased with decreasing width of the growth rings up to a certain limit, after which the conditions inverted.

The compressive strength of the different kinds of wood seems to increase from the butt end upwards, but after height of two meters it begins to decrease considerably. In birch, this point of inversion is in somewhat greater height. In spruce timber, the compressive strength parallel to the grain is lowest for wood which contains exclusively wide-ringed wood formed after draining. The boundary zone between the woods formed before and after draining is very distinguishable, but has no remarkable influence on the compressive strength parallel to the grain. Shrinkage of close-ringed wood is higher in all three principal directions than that of wide-ringed wood. This can be explained by the variations in volume weight and fibrillar orientation of the tracheid walls.

The PDF includes a summary in English.

• Ollinmaa, E-mail: po@mm.unknown

The Finnish forest industry is undergoing a vast expansion, which has raised questions of forest balance. This paper studies the possibilities to increase the amount available timber by means of forest drainage. About third of the Finnish land area is peatlands. The calculations of the investigation are based on Forestry Board districts. Based on earlier studies, there is estimated to be 3,042,000 ha of true drainable swamps, 973,000 ha of poor swamps, 1,381,000 ha of uplands in need of drainage, and 1,205,000 ha of drained peatlands. Therefore, the area of drainable and drained lands totals 6,6 million ha, and requirement of forest drainage 5,4 million ha. The drainage hardly reaches this extent, however. It can be assumed that part of the poor swamps is uneconomical to drain. In addition, a half of the paludified forest land will probably not be drained. Thus, it can be estimated that the area to be drained in the future is about 5 million ha. It seems possible that this area could be drained within about 50 years with the present draining capacity.

Draining of all objects of forests would increase the annual increment of our forests, in time, by about 10.5 million m³. This would signify an increase of 23% compared to the present growth of the forests. The increase in the growth consists mainly of softwood: 16% is birch, and the remaining 84% almost equally of Scots pine and Norway spruce. The increase of growth is relatively slow. Depending on the rate of the drainage program, the mean increase of growth will be reached in about 25–35 years. The increase in removal indicated by the increase in the mean increment will be reached in only 50–60 years.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

Decomposition of the peat using von Post Humification Scale (1–10), developed by Lennart von Post, can be determined based on characteristics of peat, such as fibre integrity, colour and viscosity of exudate, and presence of colloidal particles, of handful of peat squeezed in the hand. It is easy to use and has proved useful in the practical work. The method developed by Pjavthenko is mostly based on specific weight off a dried sample in percentage, and requires analysis in the laboratory. The aim of this study was to compare the results of these two methods by measuring 156 peat samples representing different stages of decomposition.

The methods are based on different principles, which is reflected in small differences of the results. The maximum scores of the methods are clearly in different level. The maximum grade of 9–10 in von Post scale correspond decomposition percentage 51 in the scale of Pjavtsheko. However, the decomposition values in von Post scale are placed evenly on the scale of Pjavtshenko. This suggests that the von Post Scale is consistent and accurately developed. According to the study, the Pjavtshenko method is a good method to validate results of von Post Humification Scale, and can be used when decomposition of peat samples is determined in laboratory.

The PDF includes a summary in German.

• Sarasto, E-mail: js@mm.unknown

Since Finnish professor A.K. Cajander published his theory on forest types, there have been discussion and contradictory studies on certain forest types. This paper is a litterature review on the thick-moss type in Northern Finland and its parallel types in Kainuu and Southern Finland. First, the principles of Cajander’s theory on forest types is described and discussed. It is concluded that Cajander has described forest site types as their common, genuine variants. Borderline variants have been excluded from the description. 

Second, the North Finnish thick-moss type (Hylocomnium-Myrtillus type, HMT) and its position in Cajander’s system is discussed. Concepts of this forest type have varied considerably, and it has been argued that the type does not fit Cajander’s system very well, as it arises as a result of the invasion of other forest types by Norway spruce (Picea abies (L.) Karst.) with consequent degeneration of the site.  

The writer concludes findings of the results of the previous studies about MHT and its relations to the Myrtillus type. Cajander in his system included the thick-moss type in the moist upland forests as a type whose vegetation is less exacting than that of the Myrtillus type. This position seems to be the right one. Some factors point out the moist nature of HMT: the ability of Norway spruce to compete, a relatively high persipitation, the humidity of the climate in general and the rather poor water percolation capacity of the moraine soil. The HMT sites are relatively poor. It is stated that the opinion that the thick-moss type is secondary state of development of the Myrtillus type has no plant sociological, ecological, mensurational or silvicultural foundation. The type is probably Finland's most dynamic forest type, but in the natural forest its dynamics are confined to such changes as are permitted within the same forest type. HMT must be described as three series of plant association types, which differ from another to some extent. 

The PDF includes a summary in English. 

• Keltikangas, E-mail: vk@mm.unknown

Prescribed burning has been used to treat the mineral soil sites, but the method has been little used in drained peatlands. The course and methods of prescribed burning in drained peatlands, and the effect of burning on sprouting of broadleaved trees, growth of ground vegetation and regeneration of Scots pine (Pinus sylvestris L.) by sowing was studied in drained pine bogs in Southern Finland. The top layer of the peat was mostly Sphagnum peat. The material included a prescribed burned 12 ha drained peatland area in Tuomarniemi district, in addition to which ten previously burned areas were investigated.

The burning had succeeded mostly well, but also unsuccessfully burned sites were observed. Estinguishing of the fire was easy, and no peat fires occurred. The fire burned only the logging residue, ground vegetation and the dry top layer of the peat. The roots of brushwood and grasses survived in the peat that insulated the top layer from the heat. For instance, the abundance of cloudberry (Rubus chamaemorus L.) increased after the fire. Similarly, burning did not affect sprouting of the stumps of downy birch (Betula pubescens Ehrh.). It cannot thus be used as a method to restrict the growth of coppice in regenerated areas. The seeds of Scots pine germinated well on the burned surface. 46% of the seeds developed to seedlings on sphagnum-shrub vegetation and 16% in feathermoss-shrub vegetation.

The PDF includes a summary in German.

• Yli-Vakkuri, E-mail: py@mm.unknown

Draining transforms root systems of trees growing in peatlands towards the ones growing on mineral soil. However, even after efficient draining the root systems differ from the root systems of trees growing on mineral soil. This investigation concentrates on root systems of forests of similar mire types growing in similar draining conditions but having different tree species compositions. The peatland, situated in Pieksämäki in Southern Finland, was drained in 1937. Sample plots, measured in 1956, consisted of mixed forest of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and birch (Betula sp.) in different compositions, and were in natural condition.

The sedge pine bog studied in this investigation was shown to have larger total amount of roots and mycorrhiza than in previously studied dwarf shrub pine bogs. This reflects better growth conditions of the better site. The depth of root system was, however, similar. Root systems of birch were deeper than those of the coniferous tree species. Differences between Scots pine and Norway spruce were small. Corresponding differences between the species were found in the density and total number of mycorrhizas. The abundance of mycorrhizas in the roots of birch increased in deeper layers of peat, but decreased especially in spruce roots. In earlier studies the abundance of mycorrhizas decreased in the roots growing in deeper layers in pure Scots pine stands, but no such variation was seen in this study. The result suggest that the deep root system of birch may affect also the root systems of the coniferous trees. On the other hand, birch roots can have advantage over the coniferous trees.

The PDF includes a summary in German.

• Heikurainen, E-mail: lh@mm.unknown

According to studies following the development of vegetation of drained peatlands, it seems that they have transformed to a relatively stable plant communities during the succession. In earlier studies it was assumed that after drainage a mire type would develop to a corresponding forest site. This investigation studies what kinds of plant communities are formed during succession of different mire types on peatlands drained for forestry in the southern half of Finland. Understorey vegetation was studied in 18 sample plots established by Forest Research Institute on drained peatlands. In addition, sample plots were studied on peatlands in natural state.

The results suggest that understorey vegetation on peatlands drained for forestry have developed into plant communities, the most advanced of which are the so-called dry plant communities. They represent transformed site types, which are the following: drained peatlands with upland herb-rich vegetation, drained peatlands with upland grass-herb vegetation, drained peatlands with upland Myrtillus site type vegetation, drained peatlands with upland Vaccinium site type vegetation, and drained peatlands with upland Calluna site type vegetation. Drained peatlands with upland Cladonia site type vegetation seem to be a temporary type caused by incomplete drainage. The transition between Myrtillus and Vaccinium dominated dry plant communities is not clear, but especially the pure Vaccinium vitis-ideae communities justify its place as an independent plant community. The dry drwarf shrub plant communities are also stable.

The PDF includes a summary in German.

• Sarasto, E-mail: js@mm.unknown

The article deals with forest ditches dug by manual labour in drained peatlands in Central and Southern Finland, ranging in age from 16 to 25 years. The ditches have been allowed to develop in a natural state. A total 1,160 of randomly selected sample plots were studied.

The results show that the originally dug ditch depth has not been the decisive factor from the viewpoint of maintaining the ditch repair. Ditches dug in thick peat layer have maintained their repair better than those dug in thin peat layer. Apparently, the influencing factor is the type of soil, to a certain extent parallel to the thickness of peat layer. In ditches dug mainly in mineral soil, the type of soil has essentially contributed to maintaining the ditch repair. Ditches in coarse-grained soils maintained a better repair than those in fine-grained soils. Also, the steeper the gradient of the ditch the better the ditch repair has been maintained. There was no relationship between the thickness of peat and the filling up of ditch bottom, because of the influence of mineral soil. Filling up of a ditch seems to be mainly due to the sinking of peat. The filling up of ditch bottom was more pronounced in clay-silt soil than in other soil types. The filling up of ditch bottom by varying gradient is due to the fact that with a small gradient the speed of water is so slow as to permit the soil particles to sink to the bottom. Another factor affecting filling up of the ditches is wetness of the peatland. Deepening of ditches happens mainly through erosion, if the gradient is large enough. The study suggests that a 50-m spacing with about 60-cm ditchc depth would be most profitable.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

The root system of a Scots pine (Pinus sylvestris L.) growing on a peatland is restricted, according to earlier studies, on the top layers of the peat above the groundwater level. Drainage of the peatland affects growth of the root system. This investigation aims at studying the root systems on the point of view of draining of peatlands. The structure and distribution, and the growth of mycorrhiza in Scots pine roots in pine swamps varying from natural state to well drained state is studied.

The study shows that Scots pine on pine swamps has more extensive root system than has earlier assumed, it is common to find 1,000 m of roots in one cubic meter in a healthy stand. The trees reach this density of roots early on. In a drained peatland, the total root length is markedly higher than in a similar stand in natural state. The root systems proved to be very shallow. Even in a well-drained site the roots did not grow deeper than 20 cm. 70% of all roots were found in the upper 5 cm layer of peat, and 90% in the upper 10 cm layer. Root systems were deeper in drained peatlands, but the difference was small. In a site in natural state the average depth of the roots was 4 cm, and in a drained site 5 cm. About 85% of the roots were under 1 mm of diameter. Short roots were found only in the fine roots. Draining increases strongly the number of short roots. Mycorrhizas of the types A, B, C and D as well as pseudomychorrizas were found in the pine roots.

The PDF includes a summary in German.

• Heikurainen, E-mail: lh@mm.unknown

The seasonal changes of the roots systems of a pine stand on the peatlands have been studied with samples collected during summers 1952-1954 and winter 1955. There are altogether seven sample areas that are located in the district of Korkeakoski.  

The amount of roots is at the smallest in the spring, increasing then rapidly and peaking at the end of July. After that the amount of roots decreases again against the winter to the same size than in the spring. Variations seem to be similar in every year and also similar to other studies on mineral soils.

The PDF contains a summary in Finnish. 

• Heikurainen, E-mail: lh@mm.unknown

Pine swamps are easily regenerated by natural regeneration of Scots pine (Pinus sylvestris L.). Usually seeding felling is used, but also strip system or clear cutting and regeneration along stand edge has been suggested. This article discusses the regeneration by clear cutting and sparing the existing undergrowth. The article focuses on pine swamps to be drained and the ones in natural state.

Pine swamps in natural state usually have plenty of trees of smaller diameter classes, that can be trusted to form the future tree generation after the felling. This shortens the rotation by 20-30 years. The undergrowth has been shown to recover quickly. The method suits for regeneration of drained peatlands but could fit also for regeneration of pine swamps in natural state.

The seedlings in the pine swamps are mainly 1-5 years old, and the stock is changing. It seems that larger trees produce a wider selection of age groups, but the seedlings survive longer under smaller mother trees. Part of the younger generations of seedlings seem to be destroyed when the peatland is drained. Further studies are needed to investigate how the draining and felling are to be performed to spare the young seedlings.

The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.

The PDF includes a summary in German.

• Heikurainen, E-mail: lh@mm.unknown

One of the factors that influence if a peatland is suitable for draining is the time required until fellings bring income, even if it the discounting calculations has uncertainties. This article discusses the factors that affect the economic profitability of draining peatlands.

The profitability of draining increases the more the yield or increase of the yield exceeds the costs of draining. Estimation of the yield is in Finland based on the peatland type, which reflects production capacity of the site. In addition, the growing stock of the site can vary in peatlands within same peatland type. The density and size of ditches affects the draining costs. Thus, productivity based on a peatland type alone does not describe well enough the drainability of a peatland area.

In Finnish classification of site quality of the peatlands, the treeless bogs and rich fens have been given too high a class compared to well stocked spruce swamps and pine swamps. Also, the drainability of two spruce and pine swamps can differ markedly in economic point of view if the tree’s quality, volume and ability to recover differ. The article discusses different methods to assess profitability of draining that have been descibed in the previous studies. It is suggested that the classification of peatlands by their drainability should be more selective.

The PDF includes a summary in German.

• Keltikangas, E-mail: vk@mm.unknown

According to the theory of peatland types, particular peatland types, after sufficient drainage, change into certain forest types. It has been found, that the range of forest types in peatlands in different stages of draining is as large as on mineral soil; and comprise Cladina, Calluna, Vaccinium, Myrtillus Oxalis-myrtillus and grove types. Poor peatland types change into poor forest types, better for better types. However, a Swedish scientist Mellin suggested that after effective drainage especially oligotrophic bogs, when well drained, change usually into Myrtillus type.

The different conclusions are due to the fact that the same bog type may develop into different forest types according to the effectiveness and duration of the drainage. Greater the decay of the peat bog layer, the more exacting is the type of vegetation which appears. Bog types of classes V, IV and III (Finnish classification of site quality) change into a Myrtillus type, as do the poorer peatland types of class II. The types vary, however, in their economical drainage value. The fact that bogs which in their natural stage are clearly different in their site quality change after through drainage into the same forest type, is explained by the chemical quality of the peat. However, class I and the best types of class II bogs change into better forest types because they as eutropchic bogs are richer in nitrogen and lime. This difference persists despite of effective draining.

It has been shown that the development of eutrophic peatland types at the forest type stage also differs clearly from the development of oligotrophic peatland types. The Finnish classification of drainage value shows correctly the relative drainability when using normal spacing of ditches. The notes on forest types on mineral soil should, however, be replaced by corresponding notes on the transitive types between bog and forest types.

The PDF includes a summary in Swedish and English.

• Keltikangas, E-mail: vk@mm.unknown

The aim of the investigation was to study natural regeneration of Norway spruce (Picea abies (L.) Karst.) in drained peatlands and frost injuries in seedlings, and to compare microclimates of the regeneration areas. The experiments included peatlands in Satakunta in Western Finland. Restocking of the areas with seedlings and their survival was followed in 1935-40 at sample plots that were mainly 1 are large.

Susceptibility to freezing was shown to be dependent on the stage of development of the shoots. Shoots that have just begun to grow contain little water, and withstand better freezing temperatures than shoots in later stages of growth. Damages to the seedlings were observed when the temperatures decreased to -2.8–-4.3 °C. The most severe damage to a seedling was caused by the death of the leading shoot by spring frost.

Norway spruce regenerates easily on moist peatlands, but peatlands with dry surface tend to have little or no seedlings. The species regenerated better in marshy sites than correspondingly fertile mineral soil sites. However, it needs shelter to avoid frost damage. On clear cut spruce swamp the undergrowth spruce seedlings that were left in the site got severe frost damage. If the site had birch (Betula sp.) coppice or undergrowth, spruce seedlings survived in their shelter depending on the height and density of the birch trees. To be effective, the protective forest should have relatively even crown cover. Young spruce seedlings could grow well even under relatively dense birch stand.

The PDF includes a summary in German.

• Multamäki, E-mail: sm@mm.unknown

The article introduces methods that can be used to calculate economic profitability of draining of peatlands, and discusses their advantages and weaknesses. The time span from draining of a peatland and the future income is usually decades, which makes it difficult to assess profitability for the investment. For instance, income from future fellings depends on chosen rotation time, and price of timber that can fluctuate strongly.

When calculating the profitability, the drained area can be treated as a separate unit of account or as a part of the forest holding. In the first case, several methods can be used. First, yield in terms of value is a suitable method only if the peatland has no existing forest. Second, annual yield of a drained peatland and peatland in natural state can be compared. In this case yield can be defined in several ways. Third method uses value increment of the growing stock. Fourth method estimates value of increment for both the growing stock and land. Fifth method is based on present value of the future felling income, and sixth on actual value of the growing stock and yield in terms of value.

The PDF includes a summary in German.

• Saari, E-mail: es@mm.unknown

The article presents the characteristics of different vegetation areas (meadows and peatlands) by their distinctive vegetation. The study area is by the Barents Sea and is the northernmost part of continental European Russia. Different sites are classified by plant communities and/or vegetation units.

The article continues on the second PDF-file. 

• Kalela, E-mail: ak@mm.unknown

Ground vegetation can be used to determine the fertility of the peatlands. This information is needed when deciding if a peatland is suitable for drainage. The spruce and pine swamp types of Finland have been well established. The aim of the study was to develop further the peatland type classification for treeless bogs in Finland, presented in earlier studies. The treeless bogs consist of diversity of small patches of different vegetation that blend into complexes. Consequently, classification that is based on defining bog complexes makes it easier to determine a peatland type for a larger peatland area. A system describing peatland complexes for treeless bogs is presented with detailed description of the vegetation. The study identifies nine different peatland complex types for treeless bogs.

The PDF includes a summary in German.

• Paasio, E-mail: ip@mm.unknown

The aim of the study was to investigate how the drain network and dimensions of ditches change after the drainage. The studied drained peatlands were situated in the municipalities of Parkano and Virrat in Central Finland. The ditches were in average 15 and 17 years old. The depth and width in the surface of the peatland were in average one quarter smaller than after the drainage. The width at the bottom of the ditch has, however, almost doubled. Peat had sunken more in peatlands with thick peat layer and higher humidity. Sinking of peat influenced the depth of the ditches. The volume of the ditches decreased about 30%. The decrease of the ditches by the drying and sinking of the peat was greater than the increase caused by erosion.

The PDF includes a summary in German.

• Multamäki, E-mail: sm@mm.unknown

Stones can be removed in drain digging of peatlands by using explosives or hoisting devices. The report is based on observations, and time and motion studies on drainage sites in the state forests in Northern Finland in 1931‒1933. Dynamite has been previously the most common explosive used in drainage sites. The new explosives containing potassium chloride proved to be cheaper, and safer to handle and transport than dynamite. According to the time and motion studies, the use of hoisting devices to lift stones that are removable, was significantly cheaper than explosives.

The PDF includes a summary in English.

• Metsänheimo, E-mail: um@mm.unknown