Articles containing the keyword 'age'

The objectives of this study were to record residual stand damage during harvesting operations and evaluate the influence of factors such as distance of the tree from the strip road, machine parts, operational phase, on the occurrence of tree wounds. The machine was a farm tractor equipped with a crane mounted on the front axle and a single grip harvester head. The study was carried out in two stands located in Southeast Sweden. Stand 1 was a 30-year-old Norway spruce (Picea abies (L.) H. Karst.) plantation on an afforested pasture while stand 2 was a 90-year-old mixed stand of Norway spruce, Scots pine (Pinus sylvestris L.), birch (Betula pendula Roth) and aspen (Populus tremula L.).

The mean damage percentage was 6.3% for the first stand and 6.5% for the second stand. Sixty-five percent of the wounds were less than 50 cm², with 91% of the damage occurring on the stem and 91% of the damage on or below the root collar. Sixty-six percent of the wounds produced by the stem under processing or by the harvesting head while only 10% of the wounds were produced by the tractor wheel. Damaged trees were distributed evenly in the crane reach zone. Significant differences were found between rut depths after one, two, four and six passes of the tractor in stand 1.

• Athanassiadis, E-mail: da@mm.unknown

This study examined the relationships between forest management planning units and patches formed by forest habitat components. The test area used was a part of Koli National Park in North Karelia, eastern Finland. Forest management planning units (i.e. forest compartments) were defined by using a traditional method of Finnish forestry which applies aerial photographs and compartment-wise field inventory. Patches of forest habitat components were divided according to subjective rules by using a chosen set of variables depicting the edaphic features and vegetation of a forest habitat. The spatial distribution of the habitat components was estimated with the kriging-interpolation based on systematically located sample plots. The comparisons of the two patch mosaics were made by using the standard tools of GIS. The results of the study show that forest compartment division does not correlate very strongly with the forest habitat pattern. On average, the mean patch size of the forest habitat components is greater and the number of these patches lower compared to forest compartment division. However, if the forest habitat component distribution had been considered, the number of the forest compartments would have at least doubled after intersection.

• Uuttera, E-mail: ju@mm.unknown
• Hyppänen, E-mail: hh@mm.unknown

The existence and direction of causal relationships between the time series for the Finnish roundwood market for the period 1960–1994 is tested. Using simple bivariate analysis, we found evidence that for both logs and pulpwood, the lagged prices are helpful in forecasting quantity for the next year, but not vice versa. Saw log stumpage prices have significantly Granger-caused pulpwood prices over the business cycles, but the effect has diminished towards the present time. For quantities traded, the direction of causality was rather from pulpwood to saw logs. The consistency of bivariate test results was checked by the Granger-causality tests within trivariate VAR-models for both markets, and the results were found to be fairly similar to bivariate tests. The price fluctuations in the international markets for forest products have been found to be carried to domestic wood markets dominantly via the pulpwood part of the market.

• Toppinen, E-mail: at@mm.unknown

Within the European Community snow damage affects an estimated 4 million m³ of timber every year, causing significant economic losses to forest owners. In Northern Europe, for example, the occurrence of snow damage has increased over the last few decades mainly due to the increase in total growing stock. The most common form of damage is stem breakage, but trees can also be bent or uprooted. Trees suffering snow damage are also more prone to consequential damage through insect or fungal attacks.

Snow accumulation on trees is strongly dependent upon weather and climatological conditions. Temperature influences the moisture content of snow and therefore the degree to which it can accumulate on branches. Wind can cause snow to be shed, but can also lead to large accumulations of wet snow, rime or freezing rain. Wet snow is most likely in late autumn or early spring. Geographic location and topography influence the occurrence of damaging forms of snow, and coastal locations and moderate to high elevations experience large accumulations. Slope plays a less important role and the evidence on the role of aspect is contradictory. The occurrence of damaging events can vary from every winter to once every 10 years or so depending upon regional climatology. In the future, assuming global warming in northern latitudes, the risk of snow damage could increase, because the relative occurrence of snowfall near temperatures of zero could increase.

The severity of snow damage is related to tree characteristics. Stem taper and crown characteristics are the most important factors controlling the stability of trees. Slightly tapering stems, asymmetric crowns, and rigid horizontal branching are all associated with high risk. However, the evidence on species differences is less clear due to the interaction with location. Management of forests can alter risk through choice of regeneration, tending, thinning and rotation. However, quantification and comparison of the absolute effect of these measures is not yet possible. An integrated risk model is required to allow the various locational and silvicultural factors to be assessed. Plans are presented to construct such a model, and gaps in knowledge are highlighted.

• Nykänen, E-mail: mn@mm.unknown
• Broadgate, E-mail: mb@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Peltola, E-mail: hp@mm.unknown
• Quine, E-mail: cq@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

Cut-off importance sampling (CIS) is introduced as a means of sampling individual trees for the purpose of estimating bole volume. The novel feature of this variant of importance sampling is the establishment on the bole of a cut-off height, H_C, above which sampling is precluded. An estimator of bole volume between predetermined heights H_L and H_U > H_C is proposed, and its design-based bias and mean square error are derived. In an application of CIS as the second stage of a two-stage sample to estimate aggregate bole volume, the gain in precision realized from CIS more than offset its bias when compared to the precision of importance sampling when H_C = H_U.

• Robinson, E-mail: ar@mm.unknown
• Gregoire, E-mail: tg@mm.unknown
• Valentine, E-mail: hv@mm.unknown

Three most promising protection methods of pine pulp wood stacks against the attacks of Tomicus piniperda L. were compared. The methods were the covering of stacks by fibreglass-strengthened paper or twofold achrylene netting, removing the upper parts of stacks, and enhanced planning of the placement of the timber store using ARC/INFO GIS-software. T. piniperda was observed to strongly prefer the upper parts of the stacks: 90 % of the beetles occurred within 0.5 meters of the top of the stacks. Covering of the stacks decreased the attack density of T. piniperda, and the protection effect of covering was 80 %. Due to long transport distances and fragmentation of forest landscape the relocation of timber store was found to be an unsuitable method in the practical level. Also, taking into account the costs of the method, removing of the upper parts of stacks was considered to be the optimal solution.

• Jääskelä, E-mail: mj@mm.unknown
• Heliövaara, E-mail: kh@mm.unknown
• Peltonen, E-mail: mp@mm.unknown
• Saarenmaa, E-mail: hs@mm.unknown

Distribution and occurrence of bark beetles and other forest insects in relation to environmental variation were analysed by multivariate methods. Eight different forest edges were studied using 10 x 10 m sample plots that formed 200 m linear transects perpendicular to the forest edge. Forest edge affected the distribution of insect species only in the edges between mature, non-managed spruce stands and clear cuts or young seedling stands, but not in the pine stands. The occurrence of the selected forest insects mainly depended on variables associated with the amount and quality of suitable woody material. The most significant environmental variables were forest site type, crown canopy coverage, tree species, number of stumps, number of dead spruce trunks and amount of logging waste at site. Quantitative classification of species and sample plots showed that some specialized species (Xylechinus pilosus, Cryphalus saltuarius, Polygraphus poligraphus and P. subopacus) adapted to mature spruce forests, tended to withdraw from the forest edge to interior stand sites. By contrast many generalized species (Pityogenes chalcographus, P. quadridens, Pissodes spp., Hylurgops palliatus, Tomicus piniperda, Dryocoetes spp. and Trypodendron lineatum) benefitted from cuttings and spread over stand borders into mature forest.

• Peltonen, E-mail: mp@mm.unknown
• Heliövaara, E-mail: kh@mm.unknown
• Väisänen, E-mail: rv@mm.unknown

This paper is an assessment of what in Finland are referred to as local forest management associations (LFMAs); the local units of a non-profit, forestry-promotion institution. First, the concept of organisational effectiveness is explored and an attempt is made to define it with respect to the LFMAs. The study then seeks to identify the environmental constraints, organisational characteristics and managerial practices differentiating the most effective and least effective associations. Discriminant analysis revealed four determinants of effectiveness: agrarian prosperity in the given area, activeness in marketing services to forest owners, the board of governors' role, and goal setting practices. The results thus indicate that the comparison of managerial policies and practices among LFMAs can provide useful information for improving their effectiveness.

• Viitala, E-mail: ev@mm.unknown

Growth data were collected from 40 European aspen (Populus tremula L.) stands growing on eight localities in Sweden. The stands ranged in latitude from 56 to 66°N. The mean age of the stands was 32 years (range, 12–63), the mean stand density 1978 stems ha^-1 (range, 300–6,000), and the mean diameter at breast height (on bark) 17 cm (range, 8–34).

Site index curves were constructed for total age. Curves for H₄₀ (dominant height at 40 years total age) were made for total Sweden. Curves fitted for H₄₀ total age have another shape than curves presented by other Nordic studies. The curves from the present study have slower growth for young aspens than curves from Norwegian and Finnish conditions. For 50–70-year-old aspen stands, curves from the present study indicate taller heights than from Nordic studies.

Classified soil types from the stands were grouped into three groups: sandy till (17), light clay (15) and medium clay till (4). As there was only one stand growing in the fine sand group and one stand in the heavy clay till group and two stands in the silty till group, these stands were not presented with growth curves. There were no statistically significant differences in site index between the three soil type groups. Some recommendations for management of aspen stand are given. Damages caused by moose, fungi and other injuries are discussed as a problem for height yield production and a good timber quality.

• Johansson, E-mail: tj@mm.unknown

Four governmental efforts are underway to reach consensus on indicators of sustainable forestry. Through the Helsinki process, European countries have developed and reached a pan-European, binding consensus, The Montreal process includes non-European Temperate and boreal forest countries, the International Tropical Timber Organization (lTTO) have developed guidelines for the sustainable management of natural tropical forests, and the countries around the Amazon basis have developed a joint initiative for creating guidelines of sustainable forest management of the Amazonian tropical rain forests. It is estimated that as many as 15–20 distinct processes are under way in the private sector by non-profit organizations and for-profit companies, some domestic and other international in scope. Perhaps the most wide-ranging definition work of non-governmental organizations is the undertake by the Forest Stewardship Council, FSC. The paper discusses the Helsinki and Montreal processes and the tasks for research.

• Parviainen, E-mail: jp@mm.unknown

A presentation based on the historical development of Russia is given in the form of an overview of the development of Russian forest resources, of the wood, non-wood, and biological aspects of the forest ecosystem. The list of non-wood forest resources includes resin, saps, oils, berries, wild nuts, mushrooms, hay harvesting, game animals, etc. The dynamics of the system are presented in the light of the data of the Forest State Account (FSA) of Russia for the period 1956–1993. The most significant changes in the dynamics of Russia's forest resources are related to concentrated, large-scale wood harvesting operations. The dynamics of non-wood resources follow the process of the economic recession in all parts of the forest sector of Russia, the said recession having begun in the mid-1980s. The forests of Russia are considered to be of immense social and cultural value and a globally significant factor contributing to the sustainable development of forest resources.

• Pisarenko, E-mail: ap@mm.unknown
• Strakhov, E-mail: vs@mm.unknown

The productivity of Scots pine (Pinus sylvestris L.) under changing climatic conditions in the southern part of Finland was studied by scenario analysis with a gap-type forest ecosystem model. Standard simulations with the model predicted an increased rate of growth and hence increased productivity as a result of climatic warming. The gap-type model was refined by introducing an overwintering sub-model describing the annual growth cycle, frost hardiness, and frost damage of the trees. Simulations with the refined gap-type model produced results conflicting with those of the standard simulation, i.e., drastically decreased productivity caused by mortality and growth-reducing damage due to premature dehardening in the changing climate. The overwintering sub-model was tested with frost hardiness data from Scots pine saplings growing at their natural site 1) under natural conditions and 2) under elevated temperature condition, both in open-top chambers. The model predicted the frost hardiness dynamics quite accurately for the natural conditions while underestimating the frost hardiness of the saplings for the elevated temperature conditions. These findings show that 1) the overwintering sub-model requires further development, and 2) the possible reduction of productivity caused by frost damage in a changing climate is less drastic than predicted in the scenario analysis. The results as a whole demonstrated the need to consider the overwintering of trees in scenario analysis carried out with ecosystem model for boreal conditions. More generally, the results revealed a problem that exists in scenario analysis with ecological models: the accuracy of a model in predicting the ecosystem functioning under present climatic condition does not guarantee the realism of the model, nor for this reason the accuracy for predicting the ecosystem functioning under changing climatic conditions. This finding calls for the continuous rigorous experimental testing of ecological models used for assessing the ecological implications of climatic change.

• Hänninen, E-mail: hh@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Leinonen, E-mail: il@mm.unknown
• Repo, E-mail: tr@mm.unknown

This paper deals with the testing of dynamic stratification for estimating stand level forest characteristics (basal areas, mean diameter, mean height and mean age) for a 117 ha study areas in Finland. The results do not show possibilities to achieve more accurate estimates using only Landsat TM principal components as auxiliary data opposed to static stratification. It was found that in dynamic stratification non-measured observations should be assigned the mean characteristics of the measured observations that belong to the same cube (class) instead of stratification variable classes until a certain limit. If only one principal component is used the number of classes has, however, little influence. Low field values are overestimated and high values underestimated.

The only successful results were obtained using two variables of different origin – the qualitative development stage class and the quantitative 1st principal component. The lowest root mean square error in estimating basal area was 6.40 m²/ha, mean diameter 3.34 cm, mean height 2.65 m and mean age 14.06 years. This increase of stratification accuracy is mainly resulted by the use of development stage class as an auxiliary variable.

• Mozgeris, E-mail: gm@mm.unknown

The effect of species mixture was studied in a mixed stand of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) by simulating around 100 different treatment schedules during the rotation in a naturally regenerated even-aged stand located on a site of medium fertility in North Karelia, Finland. Both thinning from below and thinning from above were applied. Optimum rotations were determined by maximising the net present value calculated to infinity and different treatment schedules were compared with the net present value over one rotation as per rotation applied. In the optimum treatment programme, the proportion of pines was decreased by half of the basal area in the first thinning stage and by the end of the rotation to about one third. In thinning from above, the proportion of pines can be maintained at a slightly higher level. It is economically profitable to maintain the growing stock capital at approximately the level recommended by Forest Centre Tapio, a semi-governmental forestry authority. With non-optimum species composition, the loss in net present value over one rotation can be about 10 % in thinning from below and about 20 % in thinning from above.

• Vettenranta, E-mail: jv@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

In this study, logistic regression and neural networks were used to predict non-industrial private forests (NIPF) landowners’ choice of forest taxation basis. The main frame of reference of the study was the Finnish capital taxation reform of 1993. As a consequence of the reform, landowners were required to choose whether to be taxed according to site-productivity or realized-income during the coming transition period of thirteen years.

The most important factor affecting the landowners’ choice of taxation basis was the harvest rate during the transition period, i.e. the chosen timber management strategy. Furthermore, the estimated personal marginal tax rate and the intention to cut timber during next three years affected the choice. The descriptive landowner variables did not have any marked effect on the choice of forest taxation basis.

On average, logistic regression predicted 71% of the choices correctly; the corresponding figure for neural networks was 63%. In both methods, the choice of site-productivity taxation was predicted more accurately than the choice of realized-income taxation. An increase in the number of model variable did not significantly improve the results of neural networks and logistic regression.

• Pesonen, E-mail: mp@mm.unknown
• Kettunen, E-mail: ak@mm.unknown
• Räsänen, E-mail: pr@mm.unknown

Budburst timing and the relationship to storage temperature and duration were investigated in four varieties (entries) of 1–2 metres tall silver birch (Betula pendula Roth) trees. A total of 2,160 shoots were sampled, and the material stores in darkness at 0, 3 or 6 °C from November 29, 1993. When the shoots were placed in storage, they had been through a period of 29 days with temperatures below 0°C (since October 15). By that time the autumn dormancy was assumed already broken, and the trees were expected to respond to increased temperature by bud development. On January 4, 1994, and on four subsequent dates, January 19, February 1, March 4 and March 17, shoots were taken out of storage and set in growth chambers at 9, 12 or 15°C. The time to budburst was recorded.

Duration of storage, storage temperatures and varieties were all highly significant for budburst. The interaction terms were of less statistical importance. Based on the contrast between the three different growth chamber environments, three different methods were used to calculate the threshold temperatures for each entry. In spite of the pre-selection of variable budburst performers, the threshold values, varying between 0°C to -2°C, could not be shown to be statistically different. According to the results, the time of budburst changes in accordance with both winter and spring temperatures, being extremely early after a mild winter and warm spring, given sufficient autumn chilling. The similarities in the threshold temperatures indicate that the ranking in earliness between varieties will most likely be the same from year to year without regard to climate change.

• Skuterud, E-mail: rs@mm.unknown
• Dietrichson, E-mail: jd@mm.unknown

Temperature sums required for budburst in various Norway spruce (Picea abies (L.) H. Karst.) provenances were determined, and weather statistics were then used to predict the risk of potentially damaging frosts at 11 locations in Sweden. Frost risk was quantified as the probability of a frost occurring within 100 day-degrees (two weeks) after budburst. The examples provided show that a spruce seedling from central Sweden has to sustain almost twice as many frost occassions as a seedling from Belorussia, when planted in southern and central Sweden. The method presented here can be used for mapping early summer frost risk in Sweden and for supporting provenance transfer guidelines.

• Hannerz, E-mail: mh@mm.unknown

Snow damage to forests in Southern Finland in November 1991 was examined in relation to meteorological conditions. The combined effect of different factors proved to be necessary for severe damage. First, the snow load, in terms of precipitation, should exceed a certain limit. The limit can be set for weak or moderate damage at about 40 mm and for very severe damage at about 60 mm. Second, temperature at the time of precipitation should be above 0°C, which enables the slightly wet snow to attach to twigs during the subsequent period with temperature below 0°C. On the other hand, temperatures exceeding 0.6°C prohibit damage by permitting the snow load to fall from the branches. Wind speed exceeding 9 ms^-1, as observed 15 m above ground, were strong enough to dislodge the snow which is not attached, and thus reduce the damage. There are few statistics either of snow damage or of the relation between the snow damage and precipitation. However, there is causal connection between snow damage and heavy snowfalls. Therefore, the regions with a high frequency of heavy snowfalls, as indicated by orographical features and occurrence of thick snow cover, were investigated.

• Solantie, E-mail: rs@mm.unknown

For non-industrial private forest (NIPF) owners land with its timber production is an example of a capital asset. Developments in the asset’s value and yield depend not only on forest management but also on other factors that the owner cannot control, for example timber prices and the production circumstances, such as soil and climate. One important basis for decision making related to management strategy and, in the short run, to cutting and silvicultural activities is economic analysis and accounting. The owner has to decide whether to invest more in his property (planting, cleaning, building of forest roads) or disinvest (sell timber or the holding). He has to find ways to increase revenue and cut costs.

However, generally accepted accounting practices for NIPF owners are lacking. Applying business economic accounting principles and forestry accounting traditions, we outline a proposal for a profit and loss accounting and balance sheet for NIPF holdings with a view towards increasing economic awareness among private owners. Key concepts are net profit of the enterprise and calculated profit of the property. Other profit measurements that are used are gross margin, forestry margin, operating margin and operating profit. Calculated profit is based on adjusted net profit. The main concern, however, is to consider the change in the holding’s market value caused by changes in stock volume, quality and price. The contents of the accounting framework development here are applied to three management strategies. The return on investment (ROI) of forestry is compared with other investment alternatives.

• Hyder, E-mail: ah@mm.unknown
• Lönnstedt, E-mail: ll@mm.unknown
• Penttinen, E-mail: mp@mm.unknown

Damage on Scots pine (Pinus sylvestris L.) caused by Gremmeniella abietina (Lagerb.) Morelet was assessed in the summer of 1992 in 67 stands in eastern Lapland. The area and severity of damage were smaller and lighter than had earlier been estimated and occurred especially in stands in the first-thinning stage or in middle-age. Significant new infection of 1991 occurred in stands previously heavily infected by G. abietina near Kemihaara river, lake Naruska, the Naruska river, the Tuntsa river and lake Vilma. Fresh damage occurred mainly in the lower or middle parts of the Scots pine canopies.

• Kaitera, E-mail: jk@mm.unknown
• Jalkanen, E-mail: rj@mm.unknown

Variation in needle nutrient concentrations with age and vertical location in the crown was studied in three Scots pine (Pinus sylvestris L.) stands growing on peat soils in Eastern Finland. The concentrations of N, P, Fe and Zn decreased down the crown and those of Ca and Mn increased. Potassium and magnesium concentration patterns differed between sites.

Potassium and Mg concentrations were highest in the current needles at all heights in the crown, iron and manganese concentrations were highest in the oldest needles. The concentrations of N, P and Zn did not vary with needle age.

• Finér, E-mail: lf@mm.unknown

Abundant snowfalls and thick snow cover influence forest ecology mainly in two ways. Snow loading increases the number of damaged stems, which increases the amount of decay in stems, in its turn important for many animals. Second, the ground remains unfrozen under the snow cover, which is of crucial importance for many perennial species of ground vegetation. These winter phenomena also have influenced the early Finnish culture as man in his everyday life in the wilderness was in close contact with nature. In this paper, ecological interactions between snow conditions, forest flora, fauna and early culture are discussed mainly with reference to the province of Uusimaa in Southern Finland.

• Solantie, E-mail: rs@mm.unknown

Drying of pulpwood bolts of Scots pine (Pinus sylvestris L.), birch (Betula spp.) and Norway spruce (Picea abies (L.) H. Karst.) was studied by measuring the drying of sample bolts placed in experimental piles. The results revealed that the main factors affecting timber drying are debarked surface area, moisture content at the time of felling and the size of the bolt. Furthermore, pine and spruce bolts located in the upper part of the pile dry better than bolts near the ground.

The investigation of green weight changes of whole piles of pine and birch was based on data collected in 1987–91. The green weight of piles was dependent mainly on storage time and on region; effect of weather variables could not be distinguished. Specific calibrating coefficients for motor-manual and mechanical cutting were included in the green weight equations.

Comparison between green weight equations and detected weight losses of sample piles indicates that fitted models seem to produce at least approximate results for the green weights, the said results thus lending themselves to be utilized as part of a transportation cost model.

The PDF includes an abstract in Finnish.

• Kokkola, E-mail: jk@mm.unknown

In the method presented in this study, a group of experts evaluate, in a pairwise manner, a set of forest areas with respect to the game species considered. On the basis of these comparisons, relative priorities of forest areas are estimated using the eigenvalue technique. Using regression analysis, a habitat suitability function is estimated in which the priority is predicted by measures already familiar in forest planning. As a case study, a habitat suitability function was estimated for black grouse (Tetrao tetrix, Lururus tetrix L.). The function is applicable in forestry planning carried out using modern planning techniques.

The PDF includes an abstract in Finnish.

• Kangas, E-mail: jk@mm.unknown
• Karsikko, E-mail: jk@mm.unknown
• Laasonen, E-mail: ll@mm.unknown
• Pukkala, E-mail: tp@mm.unknown

According to a recently presented hypothesis, the predicted climatic warming will cause height growth onset of trees during mild spells in winter and heavy frost damage during subsequent periods of frost in northern conditions. The hypothesis was based on computer simulations involving a model employing air temperature as the only environmental factor influencing height growth onset. In the present study, the model was tested in the case of eastern Finnish Scots pine (Pinus sylvestris L.) saplings. Four experimental saplings growing on their natural site were surrounded by transparent chambers in autumn 1990. The air temperature in the chambers was raised during the winter to present an extremely warm winter under the predicted conditions of a double level of atmospheric carbon dioxide. The temperature treatment hastened height growth onset by two months as compared to the control saplings, but not as much as expected on the basis of the previous simulation study. This finding suggests that 1) the model used in the simulation study needs to be developed further, either by modifying the modelled effect of air temperature or by introducing other environmental factors, and 2) the predicted climatic warming will not increase the risk of frost damage in trees as much as suggested by the previous simulation study.

The PDF includes an abstract in Finnish.

• Hänninen, E-mail: hh@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Laitinen, E-mail: kl@mm.unknown
• Pajari, E-mail: bp@mm.unknown
• Repo, E-mail: tr@mm.unknown

The paper discusses the principles of forest management in the state forests of Finland, and the contradictions in choosing between the different land uses. These principles of the forest management are sustainable use of natural resources, economic and effective management, and taking in account nature conservation, protection of environment, recreation services and employment issues in all activities of the Forest Service. Even regional policy affects the management planning in the state forests.

• Kotimäki, E-mail: tk@mm.unknown

Forests have been economically important for Finnish private forest owners at all times, but the use of forests has changed markedly since 1920s, when forests were mainly used for collecting household timber, and the cuttings were often exploitative because of the farmer’s need for money. The present situation is totally different. Need for household timber is marginally small, and private forestry produces mainly timber for sale. The sales of timber have increased, but due to better forest management the growing stock in the private forests has increased. The article discusses how the changes in values of forest owners has and will affect the stage of private forestry.

• Järveläinen, E-mail: vj@mm.unknown

The paper discusses how the general trend towards increasing growth and productivity in the European societies is expressed also in forestry. It is reflected, for instance, in the increasing production and productivity of forest industries. Technological progress and call for economic growth require great flexibility from all resources. These pressures for effectiveness and production also concern Finnish forestry and forest management. Industrialization, urbanization and development of forestry have increased the pressure to use forests in recreation, preserving human environment and nature conservation in addition to production of timber. Through the development the definition of sustainability has become wider.

• Vehkamäki, E-mail: sv@mm.unknown

Model-based information systems have proved valuable planning tools for analysing the production possibilities of forests as well as for understanding forest resources dynamics, stand management practices and forest economics. Computerized forest models implemented in the users’ information systems facilitate the transfer and application of research results in practical forestry.

Conclusions and visions concerning modelling are drawn from experiences in developing the MELA system and its application in solving timber production problems on both the national and forest holding level in Finland. The precondition for predicting forest resource dynamics and for planning the utilization of forests is to accept conditions, uncertainties and a restricted period of time.

The interactive process of forest resource, growth and drain monitoring, and forest management planning supported by forest research and modelling, are the means to enable an operational information base for a dynamic regulation and adaptation strategy for forest resource management under changing conditions and uncertainty.

The PDF includes an abstract in Finnish.

• Siitonen, E-mail: ms@mm.unknown

A range of different indices are available for assessing the health of trees in forests. An even larger range can be used for the assessment of the health of forest ecosystems. Most studies made in connection with ”forest decline” and the impact of air pollution and other environmental stresses on forests have concentrated on the assessment of crown transparency and crown discoloration in individual trees. These are non-specific indicators which are now known to be sometimes of relatively little value when determining the health of a forest ecosystem. Numerous problems exist with both, and the standardisation of assessments between and even within countries has not been achieved. Consequently, studies claiming to compare ”defoliation” between different countries cannot be substantiated. The emphasis on crown transparency and crown discoloration has resulted in the neglect of a number of other indices that could be of considerable value. These include a variety of visual measures of crown condition and also several non-visual bioindicators. Some of these techniques are objective, reducing the present reliance on observed standardization. A large number of potential techniques are currently at the research stage and have yet to be adequately tested in field trials. This represent an area where a substantial amount of further research is required.

• Innes, E-mail: ji@mm.unknown

A model for the mechanism of windfall and stem breakage was constructed for single Scots pine (Pinus sylvestris L.) at the stand edge. The total turning moment arising from the wind drag and from the bending of stem and crown was calculated along with the breaking stress of the stem. Similarly, the support given by the root -soil plate anchorage was calculated. Windspeed variation within the crown and the vertical distribution of stem and crown weight were taken into account. Model computations showed that trees having a large height to diameter ratio were subjected to greater risk of falling down or breaking than trees with a small height to diameter ratio. The windspeed required to blow down a tree or break the stem of a tree decreased if the height to diameter ratio or the crown to stem ratio of trees increased.
The PDF includes an abstract in Finnish.

• Peltola, E-mail: hp@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown

The matric potential and unsaturated hydraulic conductivity of peat-based growth media in containers was measured continuously as a function of drying. The particle size distribution and the water retention characteristics of the media were determined from parallel samples. The growth media used were a light, coarse graded Sphagnum peat, a medium graded Sphagnum peat and a mixture of a perlite and the medium graded Sphagnum peat. Containers of two types were packed with the media and allowed to evaporate from saturation. Matric potential was measured automatically using tensiometers during drying.

In both container types, the matric potential of the media was similar down to 10 kPa at each of the three levels measured during drying. Further drying resulted in a large matric potential gradient between the upper and the middle levels. During drying, there was also clear shrinkage of the media. When the matric potential at the upper level reached ca. -80 kPa, the decrease in height of the media was 5–23 %. The estimated hydraulic conductivity of the media during drying was rather similar. The hydraulic conductivity of the peat-perlite mixture was, however, slightly lower than that of the pure peat media. The hydraulic conductivity decreased linearly on a log-log-scale from ca. 10^-5 to less than 10^-10 m/s as the matric potential decreased from -3 to -60 kPa. The hydraulic conductivity of the media was comparable to coarse sand at matric potentials below -10 kPa. The decrease in hydraulic conductivity during drying and the possible weakening of soil-root contact due to shrinkage may considerably affect the availability of water to plants.
The PDF includes an abstract in Finnish.

• Heiskanen, E-mail: jh@mm.unknown

Ten trails, one kilometre each, were evaluated by 15 persons for scenic beauty, recreational value and variety. All trails passed through commercially managed forests dominated by conifers. The trails were first evaluated by viewing computer simulations based on a series of graphical illustrations of forest landscapes, then from a slide show, and finally in the field. In the computer simulation and slide show, landscape pictures along the trail at an interval of 35–40 m were presented for 3–4 seconds. The ranks between slide show and field were slightly more similar than those between simulation and field. The mean correlation of 12 persons between the field ranking and assessment of either computer simulations or slide shows or graphics than scenic beauty or recreational value. Spearman’s rank correlations computed from median scores of a group of 12 peers were clearly better than the average of individual persons varying from 0.6 to 0.9.

The PDF includes an abstract in Finnish

• Nousiainen, E-mail: in@mm.unknown
• Pukkala, E-mail: tp@mm.unknown

The profitability of jointly owned forest holdings in the two northernmost forest board districts of Finland was studied by means of ratio analysis. A time series of profit and loss statements and balance sheets from 33 holdings covering the fiscal years ending 1981–1990 served as the database. The studied area was 348,038 ha, the allowable cut 304,300 m³ per year and the average turnover, deflated by the wholesale price index, FIM 57.6 million per year. The key result obtained was that the average annual profit was FIM 107 per hectare and FIM 110 per m³. The time series showed that the ratios had increased significantly over the calculation period.

The PDF includes an abstract in Finnish.

• Penttinen, E-mail: mp@mm.unknown
• Kinnunen, E-mail: mk@mm.unknown

The efficacy of pine tar as a moose (Alces alces L.) contact repellent was tested in young Scots pine (Pinus sylvestris L.) stands suffering from moose damage in Southern Finland during the winter 1981–82. Application of tar to shoots by spraying protected the trees satisfactorily throughout the winter.

The PDF includes an abstract in Finnish.

• Löyttyniemi, E-mail: kl@mm.unknown
• Heikkilä, E-mail: rh@mm.unknown
• Repo, E-mail: sr@mm.unknown

An alternative approach to formulating a forestry goal programming problem is presented. First, single objective optima levels are solved. The Analytical Hierarchy Process is applied in the estimation of a priori weights of deviations from the goal target levels. The ratios of the weights can be interpreted as relative importance of the goals, respectively. The sum of the weighted deviations from all single optima levels associated with the management goals is minimized. Instead of absolute deviations, relative ones are used. A case study problem of forest management planning with several objectives, measured in different units, is analysed.

The PDF includes an abstract in Finnish.

• Kangas, E-mail: jk@mm.unknown
• Pukkala, E-mail: tp@mm.unknown

Managing forests and other natural resources requires merging of data and knowledge from many fields. Research efforts in many countries have simultaneously aimed at computer applications to help managing the large amounts of data involved and the complexities of decision making. This has invariably led to large integrated systems. An integrated system is software that consists of modules for various tasks in natural resource management, spatial analysis, simulation and optimization, diagnostic reasoning, levels, and communicating with the user.

The paper presents an overview of the need, levels and historical development of integrated systems. Newly emerged technologies, especially object-oriented programming and the X Window System with its associated environment have given new flexibility and transparency to the designs. The client-server architecture is found out as an ideal model for integrated systems. The paper describes an implementation of these ideas, the INFORMS system that supports the information needs of district level forest management planning.

The PDF includes an abstract in Finnish.

• Loh, E-mail: dl@mm.unknown
• Saarenmaa, E-mail: hs@mm.unknown

Model computations on the management of Scots pine (Pinus sylvestris L.) at the seedling stage showed that a rising temperature due to the suggested climate change could increase the competition capacity of birch species (Betula pendula) more than Scots pine, whose growth could even decline during the course of a rise in temperature. A temperature rise could, thus, bring the time of removal of birches forward when aiming at Scots pine timber stands composed of these tree species. The increasing proportion of birches makes the removal of birches even more urgent and emphasizes the need for careful management of Scots pine stands under rising temperatures. The first thinning of Scots pine is generally brought forward; this is particularly the case when wide spacing is applied in planting. A furthrer rise in temperature magnifies the above patterns by reducing further the competitive capacity of Scots pine in relation to birches.
The PDF includes an abstract in Finnish.

• Kellomäki, E-mail: sk@mm.unknown
• Kolström, E-mail: mk@mm.unknown

The main stem of young Scots pine (Pinus sylvestris L.) trees was cut off halfway along the current leading shoot and the two previous years’ leading shoots to simulate moose (Alces alces) damage. Trees of the same size were chosen as controls before treatments. The experiment was inspected ten years after artificial stem breakage. Removing the current leading shoot and the second shoot did not essentially affect the height and diameter growth of the trees. Removal down to the third shoot reduced the height as well as diameter growth. The average loss in growth was equivalent to less than one year’s growth. When the stem was cut off at the second or third shoot, stem crookedness and the presence of knots resulted in stem defects that will subsequently reduce the sawtimber quality. A high proportion of the stem defects will obviously still be visible at the first thinning cutting. Removing injured trees as pulpwood and pruning the remaining parts of cut stems evidently improves the quality of pine stand with moose damage.

The PDF includes an abstract in Finnish.

• Heikkilä, E-mail: rh@mm.unknown
• Löyttyniemi, E-mail: kl@mm.unknown

The results of the Finnish forest condition survey carried out during 1986–90 in background areas are presented. The same 3,388 forest trees (1,897 Scots pines (Pinus sylvestris L.), 1,289 Norway spruces (Picea abies (L.) H. Karst. And 202 broadleaves) on 450 mineral soil sample plots were examined annually. Growth characteristics (defoliation, the number of needle age classes, branch damage and needle discolouration), fertility and abiotic and biotic damage express the general vitality of the trees and are not specific for air pollutants. A correlative approach was applied in analysing the factors which may explain the regional pattern and changes in defoliation.

Average tree-specific degree of defoliation was 9% in pine, 21% in spruce and 12% in broadleaves in 1990. Altogether 11% of the pines, 42% of the spruces and 16% of the broadleaves have lost over 20% of their needles or leaves. Defoliation in spruce was the same as in the previous year, but in pine and broadleaves it had slightly decreased. Defoliation had increased by 5 %-units in pine, 16 %-units in spruce and 7 %-units in broadleaves during the whole study period 1986–90.

High stand age and different weather and climatic factors greatly affected forest defoliation in background areas in Finland. Pine cancer (Ascocalyx abietina) has enhanced defoliation in pine in the western part of the country. Air pollutants have evidently contributed to the increase of defoliation in the most polluted parts of Southern Finland. In pine a significant positive correlation was found between modelled sulphur deposition and the average stand-specific degree of defoliation as well as with the increase in average 5-year defoliation in Southern Finland. It is suspected that green algae growing on needles of spruce in Southern Finland indicates elevated nitrogen deposition levels.

The PDF includes an abstract in Finnish.

• Salemaa, E-mail: ms@mm.unknown
• Jukola-Sulonen, E-mail: ej@mm.unknown
• Lindgren, E-mail: ml@mm.unknown

Shoot losses due to maturation feeding by pine shoot beetles (Tomicus piniperda (L.) and T. minor (Hart.), Col., Scolytidae) and subsequent growth losses were studied in Scots pine (Pinus sylvestris L.) stands growing at different distances from a timber yard, where pine timber was stored during the years 1982–84. In autumn 1985, pine trees were felled at 20, 40, 80, 500 and 1,500 m distance from the timber yard, five trees in each distance class. Trees were analysed for beetle attack, needle biomass and growth. In autumn 1988, increment cores were taken from 20 trees in each distance class.

In 1985, different damage estimates showed that beetle damage was more than 10-fold in the crowns of pine trees growing close to the timber yard as compared to less damaged trees in greater distance. Crude needle biomass estimates indicated that the trees attacked most had lost more than half of the total foliage. Following three years of attack, basal area growth decreased for 2–3 years and recovered during the subsequent 3 years, the total period of loss thus being 5–6 years. The loss in volume growth during 1983–85 was ca. 70, 40, 20 and 10% at 20, 40, 80 and 500 m distance from the beetle source, respectively, compared to the stand at 1,500. Growth losses did not occur until the number of beetle-attacks, ”pegs”, exceeded ca. 200 per tree. The highest observed growth losses occurred in trees with more than 1,000 pegs per tree.

The PDF includes an abstract in Finnish

• Långström, E-mail: bl@mm.unknown
• Hellqvist, E-mail: ch@mm.unknown

The effects of plantation characteristics on moose (Alces alces) browsing intensity was studied in 82 Scots pine (Pinus sylvestris L.) plantations in Southern Finland. Moose browsing occurred most commonly in plantations established on relatively fertile soil, and the degree of damage was at highest in plantations with openings. A high amount of brush, especially aspen, increased the risk of damage. Furthermore, damage was intensified in plantations situated on hills, slopes or at a long distance from main roads or settlements.

The PDF includes an abstract in Finnish.

• Heikkilä, E-mail: rh@mm.unknown

The writer reports in this discussion article of four stands in Finland that have died due to a bolt of lightning. A death of a group of trees because of lightning has been relatively uncommon for the forest professionals. The trees may not have no lightning marks. The four sites are presented in detail. Characteristic for this type of death of trees is, for instance, that trees have died within a circular area (of usually 30 m of diameter), only conifers have died, trees die from the top down, sometimes marks can be found in trees in the centre of the area, and under the bark may be brown patches or stripes.

• Nuorteva, E-mail: mn@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

Decision making in the forest protection involves diagnosing the pest, making predictions of the effects of the pest on forest, knowing the possible control tactics, and cost/benefit integration. To cope with all that, a generalist forest manager needs a tool like an expert system to support decisions.

This paper presents an expert system that approaches the goals of integrated pest management. With the systm, the user can make diagnosis and predictions of 12 North European bark beetles. Written in Common LISP and Flavors, the expert system has a combined frame- and rule-based knowledge representation. Frames are used to represent the hierarchy of insect taxonomy in diagnosis. Prediction is made with qualitative reasoning with rules. The interface engine applies both forward and backward chaining. The system has a graphical user interface that supports exploring the sensitivity of advice on input.

It is concluded that expert systems and artificial intelligence have high applicability everywhere in forestry where complicated decisions have to be made. Especially, an integrated pest management system in forestry is largely equivalent to a computerized decision-making aid.

The PDF includes an abstract in Finnish.

• Saarenmaa, E-mail: hs@mm.unknown

Differences in vegetation cover estimation by field biologists of the 8th National Forest Inventory in Finland were tested. Eleven observers estimated the canopy coverages of six forests taxa in 25 sample plots, located in one stand. The experiment was arranged after the field work. The coverage of Vaccinium vitis-idaea and the ground layer appeared to be the most difficult to estimate. The mean of the highest estimator was about double that of the lowest one. The least abundant species and the sample plots with the smallest coverages had the largest estimation errors. The most important compositional gradient of the data was natural, even though the test was made in a homogenous area. However, the effect of the observer could be recognized. The differences between observers could be caused by the differences both in visual estimation level and in placing the sampling frame. The results suggest that tests should always be made when several observers are used in vegetation surveys. If calibration is used, it should be made separately for each species.

The PDF includes an abstract in Finnish.

• Tonteri, E-mail: tt@mm.unknown

The paper presents a simple model of long-term forest management planning in tree plantations. The model is particularly suitable for developing countries where the research resources are limited. The management plan is prepared in two steps. First, one or several treatment schedules are simulated for each calculation unit (age class, compartment, etc.) over the selected planning period. Second, an optimal combination treatment schedules according to the selected objectives and constraints is searched by mathematical programming. The simulation of growth is based on the prediction of the diameter distribution at the desired time point. All stand characteristics are derived from this distribution. The models needed in the yield simulation can be estimated from temporary sample plots. A case study management plan for 13,000 ha of Pinus kesiya (Royle ex Gordon) plantations in Zambia is presented to demonstrate the system.

The PDF includes an abstract in Finnish.

• Pukkala, E-mail: tp@mm.unknown
• Mubita, E-mail: om@mm.unknown
• Saramäki, E-mail: js@mm.unknown

Based on literature this paper describes the natural afforestation of Finland that took place after the last ice age and the changes which have taken place during the last 10,000 years. The origin and development of the vegetation and trees are related to the changes in the edaphic and climatic factors. The first tree species to arrive in Finland were the primary colonizing species, birch and Scots pine. The appearance of Norway spruce dates back to about 5000 B.P. There have been great changes in the species composition of Finnish forests during the last several thousands of years but some 2,000–3,000 years ago the various species reached their present balance. The epoch of naural forests, which had lasted some 9,500 years, came to a conclusion, however, when man started to have a marked effect on the forest’s development 300–400 years ago.

The PDF includes an abstract in English.

• Alho, E-mail: pa@mm.unknown

This paper is a review on the development of sustainable forest management and what has been meant with the term in different times. The article summarises the birth of sustainable use of forests in the world and in Finland, and discusses sustainability in forest management, for instance from the point of view of one forest holding, large clearcuttings performed in Lapland, biological sustainability, business economics and overall planning.

• Kilkki, E-mail: pk@mm.unknown

This review discusses whether forests are affected by biotic damages due to present or future environmental disturbances, and do environmental threats, such as air pollution and climatic change, weaken the condition of forest in a way that makes them vulnerable to damages by fungi and insect. The defence mechanisms of trees and factors affecting the development of an outbreak are described. Finally, the ways that air pollution and climatic change may affect biotic damages are discussed. 

• Annila, E-mail: ea@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

The model computations indicate that the climatic change in the form of higher temperatures and more precipitation could increase the productivity of the forest ecosystem and lead to higher rates of regeneration and growth. More frequent and intensive thinnings are needed to avoid the mortality of trees induced by accelerated maturation and attacks of fungi and insects. The climatic change could support the dominance of deciduous tree species and necessitate an intensification of the tending of seedling stands of conifers. The rise of air temperature during autumn and winter could change also the annual growth rhythm of trees and result in dehardening and subsequent frost damages and attacks of insects and fungi. The pest management could be the greatest challenge to the future silviculture, which could be modified most in Northern Finland.

The PDF includes an abstract in Finnish.

• Kellomäki, E-mail: sk@mm.unknown
• Hänninen, E-mail: hh@mm.unknown
• Kolström, E-mail: tk@mm.unknown

Frost resistance during shoot elongation in seedlings of Norway spruce (Picea abies (L.) H. Karst.) was studied in two experiments. The aim of the first study was to evaluate the effect of varying mineral nutrition. Except for potassium, only minor differences in mineral elements concentrations were established, presumably due to low levels of irradiance and thus a low rate of dry matter production. No significant differences in frost injuries were found between the treatments in the experimental series, but the control seedlings were significantly less injured. It is assumed that poor hardiness development at the end of one growth period resulting from low levels of irradiance may decrease the frost resistance during the next shoot elongation phase. Observations from the second experiment with Norway spruce nursery stocks representing different seedling ages and production systems, support this assumption.

The PDF includes an abstract in Finnish.

• Rostad, E-mail: hr@mm.unknown

Visible frost damage to forest trees in Sweden seldom occurs in winter but is frequent in late spring, summer and early autumn. Frosts are frequent in all seasons in various parts of Sweden, even in the southernmost part (lat. 56°, N) and temperatures may be as low as -10°C even around mid-summer. Ice crystal formation within the tissues, which in most seedlings takes place at around -2°C, causes injury, not the sub-zero temperatures themselves.

The apical meristem, the elongated zone, and the needles of seedlings of Picea abies (L.) H. Karst. in a growing phase were damaged at about -3°C and those of Pinus sylvestris L. at about -6°C. Other species of the genus Pinus were tested and most were found to be damaged at about -6°C, with some variations. Picea species tested were damaged at about -3°C to -4°C.

A method has been designed to compare the response of different species to winter desiccation, which occurs under conditions of (1) low night temperature, (2) very high irradiation and increase in needle temperature during the photoperiod, (3) frozen soil, and (4) low wind speed. There were differences in response to winter desiccation between pine and spruce species. Seedlings of Pinus contorta tolerated these winter desiccation conditions much better than those of P. sylvestris or Picea abies. Picea mariana was the least tolerant of the species tested.

The PDF includes an abstract in Finnish.

• Christersson, E-mail: lc@mm.unknown
• Fircks, E-mail: hf@mm.unknown

Electrical impedance characteristics of plant cells are dependent on such physiological factors as physiological condition, developmental stage, cell structure, nutrient status, water balance and temperature acclimation. In the measurements also such technical and physical factors as type of electrodes, frequency, geometry of the object, inter-electrode distance and temperature have an effect. These factors are discussed especially with respect to the impedance method in frost resistance studies of plants.

The PDF includes an abstract in Finnish.

• Repo, E-mail: tr@mm.unknown

This issue of Silva Fennica consists of eight articles, which are based on a co-nordic conference ”Frost hardiness and over-wintering in forest tree seedlings”, held in Joensuu, Finland, during December 1–3, 1986. The whole annual cycle of the trees is considered. Emphasis is given on methods for the study of frost hardiness, genetic variation in frost hardiness, nitrogen metabolism, bud dormancy release, and joint effect of natural and anthropogenic stress factors in the winter damage of forest trees. Practical implications for tree breeding and nursery management are discussed.

The PDF includes an abstract in Finnish.

• Hänninen, E-mail: –
• Pelkonen, E-mail: –

The study presents methods that incorporate the amenity of a forest area into the management planning. The management plan is based on treatment schedules simulated for each compartment over the 20-year planning period. The best combination of treatment schedules is selected by multi-objective optimization. The amenity is divided into two parts: (1) within-stand amenity and (2) the amenity of landscape when viewed afar (distant scene). The within-stand amenity is expressed in terms of adjective sum which is estimated from stand characteristics. The adjective sum of the whole area in a selected year can be taken as an objective or constraining variable of optimization. The assessment of the distant scene is based on computer illustrations which show the predicted temporal change of landscape according to a particular management plan.

The PDF includes a summary in Finnish.

• Pukkala, E-mail: tp@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

Logical structure of three simulation models and one conceptual model concerning effects of temperature on dormancy release in woody plants was examined. The three basic types of simulation models differed in their underlying assumptions. Contrasting implications of the models were inferred by deduction. With the aid of these implications, the model types can be tested using experiments with continuous and interrupted chilling. Similarly, implications of the conceptual model of rest phases were inferred, by which the model can be tested using experiments with continuous chilling and forcing in multiple temperatures. The possibilities to synthetize the conceptual model with any of the three simulation model types, as well as the biological interpretation of the model variables, were discussed.

The PDF includes an abstract in Finnish.

• Hänninen, E-mail: hh@mm.unknown

Effects of varying rotation, thinning, fertilization and harvest intensity on the productivity and nitrogen cycle of Scots pine (Pinus sylvestris L.) stand were studied on the basis of computer simulation. The increasing intensity of management increased the loss of nitrogen in the cycle. Short rotation, associated with early thinning by means of the whole tree harvest, proved to be especially detrimental regarding the productivity of the forest ecosystem. Fertilization associated with thinnings is of great importance in maintaining the productivity of a forest ecosystem during an intensive timber harvest.

The PDF includes an abstract in Finnish.

• Kellomäki, E-mail: sk@mm.unknown
• Seppälä, E-mail: ms@mm.unknown

In this paper, the author explains the characteristics of the Japanese forestry planning system and points out some of the problems found therein from the viewpoint of the management of privately-owned forests relating to the economic background and governmental policy.

The forestry planning system is a centralizes type of planning, the planning begins at the top and flows downward and outward the periphery. In order to make this planning system an effective instrument, the district forestry planning founded under the system must approach the problem of how to combine the resources of the forest with the district’s inhabitants and the forest owners; and further, the extent of the effective union of the district and the local timber manufacturing must be examined.

• Shimotori, E-mail: ss@mm.unknown

Non-industrial private landowners hold about two-thirds of the forest land in the southern United States. The types of public (state) and private (consulting and industrial) assistance offered to these owners is reviewed. In total, about 1,600 foresters in the South provide management assistance to non-industrial private forest owners. They assist at least 72,000 owners annually, including provision of management plans for about 10 million acres and supervision of over 4 million acres of leased lands.

• Cubbage, E-mail: fc@mm.unknown
• Hodges, E-mail: dh@mm.unknown

Comprehensive state laws regulating the practice of forest management on private lands are in effect in seven of the United States. Established to protect a wide range of non-timber forest resources and to ensure reforestation after harvest, these laws may impose significant administrative costs on states and significant compliance costs on landowners and timber operators. Total state administration costs for 1984 are estimated at $10.1 and total private sector compliance costs are estimated at $120.5 million, for a total regulation cost of $130.6 million.

The resource protection effectiveness of state forest practice regulation is difficult to quantify. However, agreement is strong that regulation has led to significant improvements in forest resource conditions and has helped to increase reforestation.

• Henly, E-mail: rh@mm.unknown
• Ellefson, E-mail: pe@mm.unknown

In order to understand the present forest policies for the small woodlot of Quebec, it is essential to understand the history of settlement of Quebec. Following this brief description, the author introduces the various forest policies (programs) which have been initiated in Quebec by various levels of governments in order to deal with the management of these lands.

• Gendreau, E-mail: cg@mm.unknown

Development of timber sale accounting system for the U.S. Department of Agriculture, Forest Service ordered by the U.S. Congress, has entailed numerous evaluations and research projects. Critics of the current process claims administrative costs are not recovered by the prices paid for Federal timber. However, management of multiple resources for multiple uses makes traditional accounting difficult; i.e., keeping track of cash flows. A further complication involves allocating costs to the various resources (joint cost allocation), for which no nonarbitrary method currently exists. A concurrent issue involves the building of roads for timber harvest into areas released from wilderness consideration. Environmentalists see the road building program of the Federal land management agencies as an additional reason Federal management costs are not recovered from timber-generated revenues. The heart of the issue is which lands are economically suited for timber management, and what nonmarket benefits and costs accrue from the timber management.

• Risbrudt, E-mail: cr@mm.unknown

The basic density of the wood of the rowan tree (Sorbus aucuparia L.) is almost the same along the stem but that of the bark is increasing along the stem. The moisture content of the wood and of the bark is increasing along the stem. Its strength in the bending and in the compression is high. The volume shrinkage is high.

The PDF includes an abstract in Finnish

• Maasalo, E-mail: km@mm.unknown

Paratization of Petrova resinella L. in the gall stage was studied in the surrounding of Harjavalta, south-western Finland, in relation to industrial air pollution. Of the studied 283 galls, 28% produced a moth, 52% of the larvae/pupae were paratisized, and 20% were empty or contained a dead larva. The proportion of paratisized galls did not depend on the distance from emission sources of industrial air pollutants.

The PDF includes an abstract in Finnish.

• Heliövaara, E-mail: kh@mm.unknown
• Väisänen, E-mail: rv@mm.unknown

This paper is a theoretical study of what is considered to constitute the proper perception of time in forest economics and management. A stumpage appraisal model that recognizes the influence of time is developed within the framework of a national aggregate economy. To demonstrate how a socially optimal land for timber production may be determined in a given nation, a stock-supply model is derived. The stumpage appraisal rule of development determines the market stumpage price that maintains a state of balance between timber production and other land use activities.

The PDF includes an abstract in Finnish.

• Omwami, E-mail: ro@mm.unknown

The relationship between industrial air pollutants and the occurrence of galls of Petrova resinella (Lepidoptera, Torticiadae) was studied around the industrialized town of Harjavalta in Western Finland. There were 44 sampling sites set out at logarithmic distances along five transects (NW, W, SW, SE) froma a distive source of emissions. Each site consisted of three circular sample plots (30 m²) in young Scots pine (Pinus sylvestris L.) stands. The number of galls, including cankers from several years earlier, was highest in the vicinity of the factory complex on each transect. The highest number of two-year-old galls containing living larvae was usually recorded at the ends of the transects several kilometres from the factories. However, the significance of the differences both between zones and transects was rather low. Correlations between the deposition of heavy metals (Cd, Cu, Ni, Pb, Zn), used as an indication of the general level of air pollution, and the total number of galls, were positive and generally highly significant. It is concluded that P. resinella has benefitted from air pollution although perhaps to less extent than some sap-sucking species.

The PDF includes an abstract in Finnish.

• Heliövaara, E-mail: kh@mm.unknown

Six seed collections were made in September–December 1984 in a natural Scots pine (Pinus sylvestris L.) stand in Southern Finland. The seeds were germinated immediately after the cone collection and three photoperiods (0.8 and 24 hours) were used in germination tests.

The seeds collected in September and October possessed relative dormancy, i.e. they did not germinate in darkness and at 10°C. Later in November and December the seeds were capable to germinate in darkness and at low temperature also. The gradual change in germination capacity is attributed to chilling temperatures in natural environments or in cone storage.

The PDF includes a summary in English.

• Nygren, E-mail: mn@mm.unknown

The Forest 2000 Programme is a long-term programme for forestry and the forest industries in Finland. It attempts to obtain a better integration of timber production and other forms of forest use. The total annual cut is to be increased by 15 million m³ by the year 2010. This is almost one third greater than the level during the first few years of the 1980’s. In order to achieve the cutting targets, the cut area will have to be increased by almost one third by the turn of the century. The area of thinnings will experience the greatest increase. Considerable changes are proposed in silvicultural and basic improvement work. According to the programme, the growth of the raw-material base and the consumption of the wood-based products will permit an annual increase of about 3% in the production of the forest industries as a whole until the end of the century. This would be the same as the target growth rate of the GNP.

The PDF includes an abstract in Finnish.

• The Forest 2000 Programme sub-commitee, E-mail: –

The size, nutrient contents and terpene composition of needles of Scots pine (Pinus sylvestris L.) saplings untouched and repeatedly browsed by the moose (Alces alces L.) were compared. Material was collected from a 14-years old and 2.5 m high pine stand in Bromarv, Southern Finland. The average length and fresh and dry weight of the needles were measured, and nutrient content (N, P, K, Ca, Mg, B, Cu) was determined.

The needles of repeatedly browsed pines became long and robust. There was, however, no difference between the dry matter percentage between the needles. The average nitrogen content was higher in the rebrowsed trees. Nitrogen content is, however, not directly correlated with the palatability of pine needles. Even phosphorus and boron content were higher in the damaged trees. No difference was found in Ca, K, Mg and Cu contents of the browsed and control pine saplings.

The PDF includes a summary in Finnish.

• Löyttyniemi, E-mail: kl@mm.unknown

Especially in forest vegetation studies, the light climate below the canopy is of great interest. In extensive forest inventories, direct measurement of the light conditions is too time-consuming. Often only the standard tree stand parameters are available. The present study was undertaken with the aim to develop methods for estimation of the light climate on the basis of readily measurable tree stand characteristics. The study material includes 40 sample plots representing different kinds of more or less mature forest stands of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.).

In each forest stand, a set of hemipherical photographs was taken and standard tree stand measurements were performed. A regression approach was applied in order to elaborate linear models for predicting the canopy coverage. The total basal area of the stand explained 63% of variance in the canopy coverage computed from hemipherical photographs. A coefficient representing the relative proportion of Norway spruce in the stand increased the explanatory power into 75%. When either the stand density (stems/unit area) or dominant age of the stand was included into the model, increment of the explanatory power into 80% was achieved. By incorporating both of the preceding predictors, an explanatory power of 85% was reached.

The PDF includes a summary in Finnish.

• Kuusipalo, E-mail: jk@mm.unknown

The aim of this literature review was to compare Finnish Norway spruce (Picea abies (L.) H. Karst.) sawn goods to Central European spruce sawn goods which contain fir in some amount. However, it was found that no statistically valid comparisons have been made. Therefore, conclusions have been based mainly on the relationship between various properties and growth rate. According to this analysis, most properties of Finnish spruce are better, although small in practice.

The PDF includes a summary in English.

• Kärkkäinen, E-mail: mk@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: –

Young Norway spruce (Picea abies (L.) H. Karst.) are susceptible to early summer frost damage. Birch (Betula pubescens Ehrh.) naturally colonize rich or fairly rich drained peatlands after clear cutting, and can provide protection for developing seedlings. The report describes the development of spruce stands after various types of handing of the birch nurse crops.

Different proportions of birch and spruces did not have any influence on the spruce stand production. In cases where the nurse crop stand is removed when the spruce stand age was 20 years and height 4 m the spruce suffered badly but recovered with time, reaching the spruce stand growing under a nurse stand within the next 20 years. The height growth of spruce depends on the density of the nurse stand, especially on fertile sites. The development of diameter growth also depends on the density of the nurse trees. Removal of the nurse stand in spruce stands on the sites concerned should be done when the spruce stand is 20 years old and at the height of 4 m.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

Norway spruce (Picea abies (L.) H. Karst.) boards sawn from outer layers of logs were sampled from a sawmill in Northern Finland and another in Southern Finland. Test pieces 20 mm x 20 mm x 20 mm were selected according to maximum variation in growth ring width. Volumetric and longitudinal shrinkage from a soaked to a dry condition were measured. It was found that wood density correlated positively with the volumetric shrinkage but negatively with the longitudinal shrinkage. Dry density was a better predictor than basic density. With constant density and an increase in growth ring width, there was increased shrinkage, especially in samples from Northern Finland. Besides this, when density was kept constant, the shrinkage was higher in the spruce wood from Southern Finland than from Northern Finland.

The PDF includes a summary in Finnish.

• Kärkkäinen, E-mail: mk@mm.unknown
• Marcus, E-mail: mm@mm.unknown

Data management is pointed out as a phase of research process. It covers research activities from observation recording to data matrix derivation. Some concepts of logical and physical database implementation are introduced.

The TUTKA -software system is introduced and observed as an instrument of research data management. Attention is paid to TUTKA’s five design criteria. Database implementation and use with TUTKA are observed precisely. Three different phases of implementing a data base are specified. Finally, some aspects to the data management of forest research are presented.

The PDF includes a summary in English.

• Kaila, E-mail: ek@mm.unknown

The goal of this research was to study the position of forest supervisors, their education, number, pay system, professional organizations and work situations in Nordic countries. The study belonged to a joint Nordic project of the Nordic Research Council on Forest Operations. Participating in the actual work the number of forest supervisors were Denmark (year 1978) 715, Finland (1980) 8,000, Norway (1967) 1,055, and Sweden (1975) 6,400. In Denmark, 87% of the supervisors worked in forestry, in Finland 91%, in Norway 98% and in Sweden 86%.

Forest supervisor education started at the end of the last century. In the 1950s and 1960s the forest supervisors’ education has been renewed in all four countries. Supervisors have a special 1 to 4.5 years’ training, but many have a forest technician’s education, too. In Finland and Sweden forest supervisor education was reformed at the end of the 1970s. Supervisors work in functional as well as in regional organizations. In Nordic countries, supervisors are paid monthly salaries. Salaries are a little higher in private than in public sector companies. In 1981 the start salary in Finland was 3,107 FIM and in Sweden in 1980 about 4,425 FIM. Most supervisors in the Nordic countries belong to some union.

The PDF includes a summary in English.

• Juntunen, E-mail: mj@mm.unknown
• Engsås, E-mail: je@mm.unknown
• Gustafsson, E-mail: lg@mm.unknown
• Mäkinen, E-mail: pm@mm.unknown
• Theilby, E-mail: ft@mm.unknown
• Vik, E-mail: tv@mm.unknown

The Society of Forestry in Finland (now the Finnish Society of Forest Science) arranged on 26th April 1984 a Forestry Science Day centred on the theme ”The role of Forestry Research in Providing a Scientific Basis for Practical Forestry”. Specialists in forestry and forest policy reviewed the role, present situation and future tasks of forest research from different points of view, in their papers. This article includes the talks given in the event in Finnish and an English summary.

• Mälkönen, E-mail: –
• Finnish Society of Forest Science, E-mail: –

1983 was the so-called ”Year o the Forest” in Finland. To mark the occasion, the Society of Forestry in Finland (now the Finnish Society of Forest Science) arranged a series of Studia Forestalia lectures which covered, in general form, a wide range of subjects. 12 of the 14 lectures given in this series are included in this edition.

The PDF includes a summary in English.

• Leikola, E-mail: –
• Koponen, E-mail: –

Curly birch (Betula pendula var. carelica (Merklin) Hejtmanek) is widely distributed over north-western part or Russia, including the Baltic Soviet Republics and Belorussia. Experiences of growing this decorative species in Soviet Karelia and Leningrad region are presented. Commonly used classifications of the species are described, and recommendations for management of curly birch cultures and production of planting stock in greenhouses are given.

The PDF includes a summary in English.

• Jevdokimov, E-mail: aj@mm.unknown

This article reviews experiments and practical experience of forest management by the selection system in Finland. In an experiment of 25-year duration the annual growth of uneven-aged Norway spruce (Picea abies (L.) H. Karst.) stands was only about 50% of the average annual yield of even-aged stands in normal rotation on the same site.

In Finland the selection system is applicable under exceptional conditions only, viz. In intensively managed park stands and, on the other hand, on very marginal sites, e.g. on peat bogs and mountains near the tree-line. Even normal silviculture, however, may include cuttings which somewhat resemble selection system, e.g. removal of standards or restoration of mismanaged forests.

The PDF includes a summary in English.

• Mikola, E-mail: pm@mm.unknown

The paper presents a method based on two phase sampling and applicable to forest inventories. The first phase estimates are obtained from satellite imagery and, if required, from extra material such as maps. Second phase estimates are measured in the field. The method is flexible and also applicable to compartmentwise forest inventories. The experiments were based on six study areas with 439 relascope plots. The correlation coefficients between first and second stage estimates varied largely according to the study area.

The PDF includes a summary in Finnish.

• Poso, E-mail: sp@mm.unknown
• Häme, E-mail: th@mm.unknown
• Paananen, E-mail: rp@mm.unknown

The aim of the present study was to survey the occurrence of Otiorrhynchus nodosus Müller weevils and their significance for the natural regeneration of Scots pine (Pinus sylvestris L.). The study was carried out during summer 1982 at Inari in northern Lapland.

There were two sample plots, one situated in a Scots pine seed-tree area and the other, the control sample plot, in an area with a coverage of mountain birch (Betula pubescens subsp. tortuosa, now subsp. czerepanovii). A total of 177 Otiorhynchus weevils were caught. Movement of the weevils reached its climax in July. There were 86% more individuals in the seed-tree area than in the mountain birch area. No damage to the pine germlings or seedlings was not observed, although the situation could be different during the peaks of the veewil populations.

The PDF includes a summary in English.

• Suoheimo, E-mail: js@mm.unknown

In the 1980 and 1981, windthrown and felled Scots pine (Pinus sylvestris L.) were examined at 8 localities in Sweden. The number and length of egg galleries as well as the number of exit holes of Tomicus piniperda (L.) and T. minor (Hart.) were recorded on sample sections (30 m in length) distributed at 3 m intervals on the 37 fallen pine stems, which were successfully colonized by the beetles. In addition, 78 uprooted pines were surveyed in 6 localities. Most trees were attacked by T. piniperda, but only a few by T. minor. Successful colonization often resulted in the production of several thousand beetles per tree, the maximum being approximately 1,800. The attack density of T. piniperda seldom exceeded 200 egg galleries/m³ bark area, and the brood production usually remained below 1,000 beetles/m³. Much higher figures were obtained or T. minor. In T. piniperda, the rate of reproduction (i.e. the number of exit holes /egg gallery) decreased rapidly with increasing attack density, whereas T. minor seemed to be less sensitive to intraspecific competition.

The PDF includes a summary in Finnish.

• Långström, E-mail: bl@mm.unknown

A literature survey based on Nordic literature deals with the biology, use, harvesting and economy of birch (Betula sp.). According to the results, the easily quantified hard facts are against cultivation of birch: lower growth, poorer production of valuable assortments, lower price of pulp, higher planting costs, and higher harvesting and transport costs than for conifers. The soft facts, which may be true, are not easily measured or their importance evaluated: the possible improvement of soil, decreasing risk of insect and fungi attacks, shelter against frost etc. Due to the differences in the nature of the facts the discussion of cultivation of birch will probably continue.

The PDF includes a summary in English.

• Kärkkäinen, E-mail: mk@mm.unknown

Flight periods of insects breeding on birch (Betula sp.) timber were observed by means of window flight traps baited with freshly cut birch logs in five locations in Finland from 1972 to 1976. Only few species were caught during the study. In general, these species were on the wing during midsummer, although flight periods of some of them were relatively long. Scolytus ratzeburgi Jans. caused harmful staining of wood within a month from attack, but the damage by the wood-boring pests remained negligible throughout the first storage summer.

The PDF includes a summary in Finnish.

• Löyttyniemi, E-mail: kl@mm.unknown

The effect of nitrogen fertilization and two insecticides on the occurrence of the plant pine bark bug, Aradus cinnamomeus Panzer, was investigated in a young Scots pine (Pinus sylvestris L.) stand in Southern Finland. Three years after the treatment the bug density was lowest in the trees treated with lindane or dimethoate. However, in spite of the increasing height growth of the trees, they did not grow significantly faster than the control trees. Nitrogen fertilization increased both bug density and the height growth of the trees. Thus, the value of nitrogen fertilization against Aradus cinnamomeus remains obscure.

The PDF includes a summary in Finnish.

• Heliövaara, E-mail: kh@mm.unknown
• Annila, E-mail: ea@mm.unknown
• Terho, E-mail: et@mm.unknown

An inventory of Scots pine (Pinus sylvestris L.) graft collection in Kolari (67°15’ N, 23°45’ S) showed that severe damage by arctic hare (Lepus timidus L.), root and bank vole (Microtus oeconomus Pallas and M. agrestis L.) and moose (Alces alces L.) was done to grafts in size and in rather poor condition. Furthermore, the damage by arctic hare was dependent on the dry matter content of the needles. Another inventory in a fertilization experiment in a pine pole-stage forest showed that nitrogen fertilization increased the damage by arctic hare. On the basis of the present results, an assumption was made that the formation of repellent substances against herbivorous mammals is connected with wintering process of northern pines.

The PDF includes a summary in Finnish.

• Rousi, E-mail: mr@mm.unknown

Length of the regeneration period is a criterion commonly used for comparing different reforestation methods. The time factor should be evaluated using a realistic system for long-term planning. In this paper the preliminary evaluation is made by simplified calculations based on the development series. The slow regeneration method is assumed to be otherwise equal to the rapid one but it has a 5- or 10-years delay at the beginning, and the rotation is thus the final cutting age plus 5- or 10-years delay. Cost of the time delay is taken to be the difference in reforestation costs that makes the rapid and the slow methods equivalent. Calculations are made using zero costs for the slow method; but if the cost of the slow method increases, the critical cost difference decreases very slowly. The final cutting age and the regeneration method must be decided simultaneously. Therefore, the cost of the time delay is presented as a function of final cutting age. By maximizing the average annual revenue, rotation can be even increased if more rapid but more expensive regeneration method is used.

The PDF includes a summary in English.

• Lappi, E-mail: jl@mm.unknown

The resistance of Finnish softwood timbers to Macrotermitinae termites was tentatively tested under tropical conditions in Zambia using a field microtest method. Picea abies (L.) H. Karst. and Larix sibirica L. sapwood and heartwood, as well as Pinus sylvestris L. sapwood, and the sapwood of the locally grown Pinus kesiya, exhibited no natural termite resistance. On the other hand, Juniperus communis heartwood appeared to be virtually immune and the heartwood of P. Sylvestris had some resistance. There were also some differences in the resistance of the heartwood of the different P. Sylvestris individuals tested, which was correlated with the width of the annual rings in the wood samples. The termite species involved were Microtermes sp. and Odontotermes sp. The possibilities of using different types of Finnish softwood timber in the regions in the tropics where there is a risk of termite damage is discussed.

The PDF includes a summary in Finnish.

• Löyttyniemi, E-mail: kl@mm.unknown

Relationships between densities of pine bark bug, Aradus cinnamomeus Panzer and the height growth of young Scots pine (Pinus sylvestris L.) were studied in several habitats, including a highly infested area in Southern Finland. The slower the growth of the pines was, the greater was the height up to which bugs were found. On the average, maximum bug density was noted at a height corresponding to a fifth of the height of the tree. In stands restocked by natural generation, the greatest bug densities were noted in pines about three metres high and over twenty years old. Bug densities in trees whose height growth had been decelerating for five years were twice those in trees whose growth was accelerating. A significant negative correlation was found between the bug density and the last-year height increment.

The PDF includes a summary in Finnish.

• Heliövaara, E-mail: kh@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 publication comprises proceedings of a conference held in Helsinki in 1981. Forest tree populations are investigated for population genetic structure, mating systems, mechanisms of genetic adaptation and ecological adaptation. Methods and techniques used in population genetic research of forest trees are presented. Much concern is given to applications by means of forest tree breeding, particularly the seed orchard breeding technique. Generally, the application of population genetics in cultivated forests is discussed.

The PDF includes a preface and the presentations of the conference (25 short papers) in English, and a comprehensive summary of the themes of the conference in Finnish.

• Tigerstedt, E-mail: –

Scanning Electron Microscopy was used to study structural changes in epicuticular vax of Pinus sylvestris L. with time. Changes in the contact angle of water droplets and in cuticular transpiration were also measured. By using material from a polluted and an unpolluted site it was shown that the ageing process occurs faster on polluted air, leading to greater cuticular transpiration and smaller contact angles at polluted sites.

• Cape, E-mail: jc@mm.unknown
• Fowler, E-mail: df@mm.unknown

Air-borne Cu and Zn from a brass foundry at Gusum, SE Sweden, have considerably disturbed the lichen and bryophyte vegetation in the coniferous forest environment. The occurrence of lichens on Norway spruce twigs decreased rapidly with increasing Cu concentrations in Hypogymnia physodes above 90 ppm (background value 10–15). The epiphytic vegetation is reduced within 2–3 km from the foundry. Only stunted individuals occur in the close vicinity of the pollution source.

The cover of one of the quantitatively most important mosses, Hylocomnium splendens, is greatly reduced by the heavy-metal deposition. Cover values of 20–50% are not uncommon in distant sites (Cu concentration 15–35 ppm). There is a significant negative correlation between Cu concentration in the moss and its cover. The moss cannot survive much more than ca. 130 ppm Cu (and 360 ppm Zn). Live individuals are no more found within 1.5 km from the foundry.

• Folkeson, E-mail: lf@mm.unknown

A technique for instrumental scoring of damaged leaves on tobacco (Nicotiana tabacum) indicator plants caused by ozone in the lower atmosphere is being developed. The leaves are photographed in situ with an integrated unit, which illuminates the leaf from behind and keeps the camera in a well-defined position. By using microfilm and a minus green filter, it is possible to obtain negatives where the necrotic flecks appear as dark spots on a white leaf. The negatives are scanned in a TV-system and the size of the damaged fraction of the leaf is calculated by a microprosessor and is shown as a percentage of the leaf.

• Mortensen, E-mail: lm@mm.unknown
• Weisberg, E-mail: kw@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

Needle damages, transpiration, photosynthesis and needle and stem height growth of Scots pine (Pinus sylvestris L.) seedlings treated with dilute sulphuric acid were studied. The acidity of the solution was pH 3. Application of a dilute solution of sulphuric acid equivalent to the normal amount of precipitation occurring during the growing season damaged the surface of two-year-old needles but not that of the current-year needles. A reduction in the photosynthetic rate of 10–30% was observed compared with the untreated seedlings. Transpiration of the seedlings was not affected by the treatment. Needle growth and stem height growth of the seedlings growing on a substrate representing poor sandy soil were reduced. Increased needle growth and stem height growth were characteristic for the seedlings growing on substrate representing fertile moraine.

The PDF includes a summary in English.

• Katainen, E-mail: hk@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown

In Finland the first trade union in the field of forest work and timber floating was founded in 1946 and the first formal collective agreement was achieved in 1962. Information about the development of wage payments and work conditions (lodging and food) in forest work prior to the formal agreements was dispersed in a number of different sources, and is already partially in danger of being forgotten. The aim of this study was to bring together all available information concerning the matter in question.

The PDF includes a summary in English.

• Makkonen, E-mail: om@mm.unknown

The amount of volatile oil and monoterpene composition in Scots pine (Pinus sylvestris L.) needles were studied in trees growing near two factories and in the city of Kuopio, Central Finland. Trees in these locations are exposed principally to sulphur dioxide and fluoride emissions.

The amount of volatile oil increased with increasing injury class in the trees growing near the fertilizer factory. The amounts of volatile oil in trees near the pulp mill differed in the various injury classes. More oil was found in younger needles. The greatest differences in monoterpene composition were in the amounts of camphene, α-pinene, myrcene and tricyclene.

The PDF includes a summary in Finnish.

• Lehtiö, E-mail: hl@mm.unknown

In dealing with the effectiveness of forest taxation reform as a means of economic policy, the paper starts by recalling certain objectives of taxation, as well as the effect on aggregate demand of taxation in general. The effect of forest taxation depends on such factors as (1) whether the woodland owner has a regular income from a source other than forestry; (2) the system of taxation (whether taxation of actual stumpage revenue or of area-based yield); (3) the progression of taxation; and (4) the woodland owner’s income level.

The problem is illustrated by an example taken from Finland, where forestry revenue is taxed on the basis of area-based yield. A shift to taxation of actual stumpage revenue, as is proposed, is assumed. The effectiveness of this change is studied in terms of how far the assumed change is consistent with the objectives of the national economy. It is assumed that a shift to taxation of actual stumpage revenue would cause a decline in roundwood supply. A sensitivity analysis is then applied to detect the effect on tax revenue and national income of the tax reform. It is likely that a 10% decrease in fellings would bring about a reduction of tax revenue which would not be compensated for by the more perfect exposure of forestry income to taxation brought by the reform. The effect on investment, production, employment, differences in individual and regional income, and on the international balance of payments also disfavour the suggested change.

• Riihinen, E-mail: pr@mm.unknown

The paper discusses certain aspects of the capital management of forest assets. These aspects are of importance when one wants to consider what means to use to influence the capital management on both small and big forest properties. When quantifying the effects of different uses of capital, one must necessarily have a scale. The rate of return is for this purpose the usual measure of profitability. We will first discuss the differences between nominal and real rate of return, and point out the assumptions which are often implicit in analyses of the profitability of investments in forestry. We will the discuss certain liquidity and risk aspects of capital investments in forestry, and at the end deal with certain consequences of taxation.

• Eid, E-mail: je@mm.unknown

The landscape preferences and attitudes of inhabitants of Puolanka, north-eastern Finland, to the effects of silvicultural practice on the forest landscape were studied by a postal inquiry. The effect of silvicultural practice on the forest landscape was mainly negative. Birch (Betula sp.) stands and mixed coniferous and deciduous tree species were the most preferred by the Puolanka inhabitants. The landscape preferences were related to socio-economic background of the inhabitants. The quality of the living environment also influenced the preferences, since uncommon features in the living environment were favoured most.

The PDF includes a summary in English.

• Karhu, E-mail: ik@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown

Variation of wood characteristics was studied in two mature trees of Betula pendula Roth and two of B. pubescens Ehrh. by stressing the interrelationships of some of the structural features, basic density and shrinkage. Correlation analysis revealed that basic density was related to some of the variables studied, viz: number of rings (age) and distance from pith, height from the ground, ring width, fibre length and double wall thickness. Multiple regression equation showed that age from pith and height from the ground explained 80% of variation of basic density in B. pendula. Two structural variables, viz: fibre wall thickness and ring width accounted for only 28% of variation of basic density in B. pubescens. No significant relations could be found between shrinkage and any of the wood parameters measured in B. pendula while some of the relationships were significant in B. pubescens. However, only 55% of variation of volumetric shrinkage was explained by two related factors, viz: basic density and moisture content while only 35% of variation of tangential shrinkage was explained by ring width and fibre width. Increase in fibre length was highly associated with the increase in fibre width, double wall thickness and vessel length in either species.

The PDF includes a summary in Finnish.

• Bhat, E-mail: kb@mm.unknown

On the basis of a limited material, the drying of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) timber at room temperature decreased the thickness of the bark proportionally to the decrease in the moisture content. The decrease was the greatest in the middle portion of the trunk. In the spruce material, the decrease in bark thickness was exceeded by the shrinkage of the wood. During soaking, the bark thickness of both tree species decreased, too, contrary to the presupposed hypothesis. In both cases, the shrinkage was the greatest in the middle portion of the trunk. In the spruce material, the decrease in bark thickness was exceeded by the shrinkage of the wood. Possible explanation for the phenomenon is discussed.

The PDF includes a summary in English.

• Kellomäki, E-mail: sk@mm.unknown

Snow and rime, attached to branches of conifers, seriously damaged forests in a region of 11,000 km² in Southern Finland during a passage of two nearly occluded cyclones in 1959. The roles of different weather elements were studied by considering the variations occurring in them over this region and its surroundings. Damage occurred only inside an accentuated pattern of copious orographic precipitation. Precipitation only became attached to and retained on branches in such parts of the area where temperature varied on both sides of freezing point but did not exceed 0.6°C. Furthermore, damage only occurred in forests where rime formed (above a certain level and on sloping towards the prevailing wind).

The PDF includes a summary in English.

• Solantie, E-mail: rs@mm.unknown
• Ahti, E-mail: ka@mm.unknown

Samples that had extensive pith flecks, caused by the larvae of Dendromyza betulae (now Phytobia betulae E.Kang), were collected from two trees of Betula pendula Roth and two B. pubescens Erhr. The age of the trees varied from 45 to 56 years. The effect of larvae injury on the rays was studied. The width of affected rays in both species was more than twice that of normal rays. The height and frequency also increased considerably. When describing the anatomy of Betula species the pith flecks should be treated with caution in order to avoid confusion and misinterpretation. 

The PDF includes a summary in Finnish. 

• Bhat, E-mail: kb@mm.unknown

The dying-off of more trees in an over-aged Norway spruce (Picea abies (L.) H. Karst.) stand caused by Ips-bark beetles was reduced by a pheromone preparation, ipslure. 20 preparations placed in trapping bolts captured more than 13,700 specimens of Ips typographus L. and Ips duplicatus Sahlb., which alone corresponded to a saving of five old trees in this valuable exhibition and seed collection stand. Attractance of ipslure to the following predators of bark beetles was also examined; Thanasimus formicarius, T. rufipes, Epuracea bickhardti, Rhizophagus ferrugineus, Pityophagus ferrugineus.

The PDF includes a summary in English.

• Selander, E-mail: js@mm.unknown
• Nuorteva, E-mail: mn@mm.unknown

Soft X-ray radiation (Grenz rays) has been used in the X-ray radiography of seeds. It is based on the principle that the different parts of the seed absorb X-rays to a slightly varying extent. Empty seeds and empty regions in the seeds appears as dark areas on the film. X-ray radiography without staining and X-ray contrast radiography were compared to study the stored seeds of Scots pine (Pinus sylvestris L.). The results were compared with the results of germination in a Jacobsen germinator according to ISTA norms.

Normal X-ray radiography gave too good estimates of germinative capacity of the seeds, and was shown to suit only when it is used to study fully ripe seeds which have recently been collected in an undamaged condition. The results of X-ray contrast radiography when barium chloride was used as the stain, however, followed closely the germination results.

The PDF includes a summary in Finnish.

• Ryynänen, E-mail: mr@mm.unknown

Forest balance is a comparison between the growing stock volume at the beginning and end of a balance period and the gross increment and drain during that period. The forest balance of Finland during that period 1967-1973 and the increment and drain balance during the period 1953-1977 are used as examples in the paper. Forest balance is a check of the accuracy of basic estimates. If the discrepancy between the calculated growing stock at the end of the balance period and the growing stock estimated by an inventory is great, it calls for improvements in forest inventory methods and timber utilization statistics.

Balance may reveal possibilities for improving the utilization of forest resources. If natural losses are great, increased thinnings and regeneration cuttings of mature and over-mature tree stands increase the supply of timber. If logging losses are great, the efficiency of harvesting should be improved. An overcutting situation calls forth efforts to increase timber production or to decrease the uses of timber in order to avoid overexploitation. If gross increment is greater than the drain there are possibilities to increase harvesting, forest industrial expansion etc.

Forest balance is a way to check and improve the basic estimates of forestry production, to increase the effective use of timber grown in the forest, to commerce policies and measures concerning increment and to control timber utilization on the basis of sustained yield.

The PDF includes a summary in Finnish.

• Kuusela, E-mail: kk@mm.unknown

The development of Scots pine (Pinus sylvestris L.) seedlings and damage caused by Hylobius abietis L. (Coleoptera, Curculionidae) were studied during a three-year period. Olfactory responses of H. abietis was studied in laboratory with several volatile oils isolated from different kinds of P. sylvestris seedlings. Resistance of seedlings against H. Abietis was evaluated in terms of their monoterpene composition. Three aspects of resistance (preference, antibiosis and tolerance) were evaluated separately. Seedling chemotype was found to be associated with these aspects of host resistance on only minor scale. Discussion was attached to a further search for host resistance arising from other properties and constituents of oleoresin. Height growth of the seedlings recovering from weevil damage was 86–91% compared to healthy seedlings.