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Silva Fennica 1926-1997
Acta Forestalia Fennica

Silva Fennica 1926-1997 vol. 25 | 1991

Category: Article

article id 5467, category Article
E. K. Morgenstern, Y. S. Park. (1991). Breeding of Picea mariana (Mill.) B.S.P.: seed orchard and clonal approaches. Silva Fennica vol. 25 no. 4 article id 5467.

During the past 30 years, genetics research has accumulated much information on black spruce (Picea mariana). The adoption of less intensive and faster plustree selection, establishment of seedling seed orchards and family selection significantly increased the rate of progress in improvement of the species. In New Brunswick this approach made it possible to obtain substantial quantities of seeds 10 years after the initiation of the program, and now all the seeds used in reforestation are derived from seed orchards.

Fourteen years after beginning the black spruce breeding program, second generation breeding is underway. The possibility of implementing alternative breeding strategies using ”breeding – cloning” procedures are explored for the advanced generation. Until somatic embryogenesis techniques become fully operational, ”backward selection” schemes and crossing in breeding halls followed by vegetative multiplication using serial rooted cuttings can be adopted. Larger genetic gains than those from conventional breeding are expected not only from the utilization of both additive and non-additive variances, but also from the elimination of inefficiencies of large conventional seed orchards.

  • Morgenstern, ORCID ID:E-mail:
  • Park, ORCID ID:E-mail:
article id 5466, category Article
Hely Häggman. (1991). Application of biotechnology to forest tree breeding. Silva Fennica vol. 25 no. 4 article id 5466.

Forest tree breeding involves manipulation of genetic composition of populations and individuals, and biotechnology focuses on selected individuals. The new techniques cannot replace the conventional breeding techniques but both need effective cooperation of each other. Thus, the distinction between conventional breeding and biotechnology is artificial. The biotechnology methods are new and fast developing and the future with field and progeny testing will show which techniques will be permanently adopted into tree breeding. For instance, the earlier hope of the use of somaclonal variation as a new source of variability and a powerful tool for the breeder seem today quite the opposite. Somaclonal variation constituting a major problem in present-day micropropagation is due to the unpredictable variation. Based on knowledge of today, especially micropropagation via somatic embryos, transgenic trees and the identification of major genes seem to be good candidates to be permanently adopted into tree breeding.

  • Häggman, ORCID ID:E-mail:
article id 5465, category Article
Gösta Eriksson. (1991). Challenges for forest geneticists. Silva Fennica vol. 25 no. 4 article id 5465.

Studies of phenotypic as well as mixed population plasticities are urgently needed in a world that supposedly experiences a gradual change of its environment. It is important to understand that man creates his environment and silviculture. This is one of the reasons why for breeding it cannot be expected to find optimal phenotypes in nature. Other reasons are the phylogenetic constraints and migration of pollen and seeds.

Forest genetics up to now is characterized by the study of one trait at a time. There is an urgent need for simultaneous analysis of several traits by the aid of genetic correlations or multivariate analysis. Generally there is a need for inclusion of larger numbers of genetic entries in forest genetic investigations.

For the long-rotation-time species there is a need to determine the curves for degree of dormancy and hardiness during the annual cycle. Information of plasticity in two-dimensional environments like water availability and temperature is needed. Studies on nutrient utilization and acquisition will tell us whether or not we must have different breeding populations for different soil fertilities. An understanding of the phase changes between juvenile and adult opens up possible applications such as faster generation turn-over in the breeding population via early flowering and early testing as well as better plants for frost-prone and weedy sites.

  • Eriksson, ORCID ID:E-mail:
article id 5464, category Article
Donald I. Dickmann. (1991). Role of physiology in forest tree improvement. Silva Fennica vol. 25 no. 4 article id 5464.

The paper introduces different ways plant physiology research can avail the process of tree improvement. The breeding of tree cultivars that efficiently produce a particular wood product or amenity will be an important aspect of forest management. What physiologist can provide to breeders and genetic engineers is the opportunity to move their work from empirical level towards a more theoretical level, and help to make breeding more predictable and more precise in its objectives. The areas of research discussed in the paper are biotechnology, flowering, selection criteria, adaptability and application of ideotypes.

  • Dickmann, ORCID ID:E-mail:
article id 5463, category Article
Öje Danell. (1991). Survey of past, current and future Swedish forest tree breeding. Silva Fennica vol. 25 no. 4 article id 5463.

The paper gives an introduction of the tree breeding program of Sweden that started in 1936 by the establishment of an association for the tree breeding. In 1967 the Institute of Forest Improvement was founded and it replaced the earlier association. The main species in the programme have been Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), lately also birch (mainly Betula pendula Roth.) and lodgepole pine (Pinus contorta). In addition, limited breeding has been done also with hybrid aspen (Populus tremula x P. tremuloides), oak (Quercus), larch (Larix), black spruce (Picea mariana) and a few other native and exotic species. The dominating initial effort has been to select plustrees in natural stands and use them for production of reforestation material. In addition, a considerable body of tests was built. The paper lists the status of breeding material of the different tree species and introduces the medium and short-term breeding programmes.

  • Danell, ORCID ID:E-mail:
article id 5462, category Article
Wladyslaw Chalupka. (1991). Usefulness of hormonal stimulation in the production of genetically improved seeds. Silva Fennica vol. 25 no. 4 article id 5462.

Application of growth regulators, primarily gibberellins, has become an efficient method of flowering regulation in many coniferous forest trees. In this paper some results are discussed with respect to various genetic processes in seed orchards. It is concluded that there are still several unsolved problems in the regulation of flowering in forest seed orchards. These problems are related to different genetic processes occurring in the seed orchards and they should be taken into account in endeavouring to produce genetically improved seeds. 

  • Chalupka, ORCID ID:E-mail:
article id 5461, category Article
Run-Peng Wei, Dag Lindgren. (1991). Valinnan vaikutukset monimuotoisuuteen ja jalostushyötyyn. Silva Fennica vol. 25 no. 4 article id 5461.
English title: Selection effects on diversity and genetic gain.

Four different methods of truncation selection were studied in a population consisting of a large number of unrelated full sib families of equal size: phenotype selection, family selection, within-family selection and combined index selection (optimal weighting of individual and family performance to get the best prediction of breeding value). Methods were developed for calculating diversity (”relative effective family number”) for the different selection methods. Numerical calculations were made for genetic gain and diversity. Model assumptions are additive gene control and normal distribution. Phenotypic was good at high heritabilities and between family at low heritabilities. Loss of diversity was strongly dependent on selection method and selection strength. Compared at the same diversity, genetic gain was lower for combined index compared to phenotypic. There is a need for methods combining the goals gain and diversity.

The PDF includes an abstract in Finnish.

  • Wei, ORCID ID:E-mail:
  • Lindgren, ORCID ID:E-mail:
article id 5460, category Article
R. C. Schmidtling. (1991). Perusrungon ja varttamisoksan vaikutus Pinus taedan vartteiden kukintaan, kasvuun ja neulasten ravinnepitoisuuteen. Silva Fennica vol. 25 no. 4 article id 5460.
English title: Effect of rootstock and scion on flowering, growth and foliar nutrients of loblolly pine (Pinus taeda) grafts.

In two separate studies, seedlings from 20 loblolly pine (Pinus taeda L.) families and Virginian pine (Pinus virginiana Mill.) were used as root stocks for grafting loblolly pine seed orchard clones. The rootstocks were open-pollinated seedlings from orchard clones chosen to represent a wide range of flowering and survival capabilities, based on their performance in a first-generation seed orchard. Scions were derived from the same 20 loblolly clones. The effects of scion clone were significant and large for nearly all measured traits. Rootstock significantly affected survival, growth, flowering and foliar nutrients of the grafted ramets. Neither survival nor growth of the crafts was related to survival of growth of the orchard clones from which their rootstocks were derived, however. Survival of incompatible clones was enhanced by grafting on genetically related rootstocks.

The PDF includes an abstract in Finnish.

  • Schmidtling, ORCID ID:E-mail:
article id 5459, category Article
Pertti Pulkkinen. (1991). Riippakuusen latvusmuoto ja maanpäällisen kasvun jakautuminen runkoon. Silva Fennica vol. 25 no. 4 article id 5459.
English title: Crown form and harvest increment in pendulous Norway spruce.

Crown characteristics and the distribution of three years’ (1986–88) biomass production of 20 pendulous Norway spruce (Picea abies f. pendula (Lawson) Sylvén) trees with heritable narrow crown and 15 normal-growned spruces (Picea abies (L.) H. Karst.) were studied in a 19-year-old mixed stand.

The form of the crown is conical in normal-crowned trees, columnar and narrow in pendulous trees. The partitioning of aboveground biomass to stems during the studied 3-year period was significantly higher in pendulous (0.281) than in normal-crowned trees (0.255) and also the ratio between growth of stemwood and growth of needle biomass during three years was higher in pendulous trees (0.67 g g-1) than in normal-crowned trees (0.52 g g-1). The needle biomass was distributed higher in the crown in pendula than in normal-crowned trees and they had a higher needle biomass/branchwood biomass ratio than normal trees. The difference in harvest increment between the two crown types are mostly due to the significantly lower branchwood biomass values in pendulous than in normal-crowned trees. The higher needle ’efficiency’ in pendulous trees is probably connected with high partitioning of needle biomass to the upper part of the crown in pendulous trees.

The PDF includes an abstract in Finnish.

  • Pulkkinen, ORCID ID:E-mail:
article id 5458, category Article
Jaroslaw Burczyk, Grzegorz Kosiński, Andrzej Lewandowski. (1991). Pölytyssuhteet ja tyhjien siementen osuus euroopanlehtikuusen vartteiden ylä- ja alaosassa . Silva Fennica vol. 25 no. 4 article id 5458.
English title: Mating pattern and empty seed formation in relation to crown level of Larix decidua (Mill.) clones.

The mating system was analysed in the upper and lower crown of two groups of European larch (Larix decidua Mill.) clones divided according to the percentage of full seeds in the upper and lower crown parts. The overall multilocus estimate of outcrossing rate (t) was calculated to be 0.929. The differences of outcrossing rates between crown levels and clonal groups respectively were not statistically significant. The t estimates were greater for the upper crown level and for clones with higher percentage of full seeds in the upper crown level. However, among all observations there was no correlation between outcrossing rates and percentages of full seeds for particular crown levels and groups of clones. Observed similarity of outcrossing among grafts of the same clones may indicate genetic control of self-fertilization rate in individual European larch. 

The PDF includes an abstract in Finnish.

  • Burczyk, ORCID ID:E-mail:
  • Kosiński, ORCID ID:E-mail:
  • Lewandowski, ORCID ID:E-mail:
article id 5457, category Article
Hans Roulund, Tore Skrøppa. (1991). Summary of main topics and conclusions from the meeting. Silva Fennica vol. 25 no. 4 article id 5457.

This paper summarises the main topics and conclusions from the joint meeting of two IUFRO working parties, S2.04-02, Breeding theory and progeny testing, and S2.02-16, Seed orchards, held in Tuusula, Finland on September 10–15, 1991. It concludes the main topics that need more research in these disciplines and future trends in the research.

  • Roulund, ORCID ID:E-mail:
  • Skrøppa, ORCID ID:E-mail:
article id 5456, category Article
Veikko Koski. (1991). Biological systems in tree breeding. Silva Fennica vol. 25 no. 4 article id 5456.

This issue of Silva Fennica includes the presentations given in a joint meeting of two IUFRO working parties, S2.04-02, Breeding theory and progeny testing, and S2.02-16, Seed orchardsThe sessions were held in Tuusula, Finland on September 10–15, 1991.

  • Koski, ORCID ID:E-mail:
article id 5455, category Article
Aarne Reunala. (1991). Tiedottamisesta kannattaa keskustella. Silva Fennica vol. 25 no. 3 article id 5455.
English title: Cooperation between scientists and press officers in scientific information.

The paper is a comment on a previous paper in the issue discussing the challenges in providing information on science to the public. The author points out that in this process cooperation between a scientist and a press officer is needed, and that the scientific formulation differs from that of the media.

  • Reunala, ORCID ID:E-mail:
article id 5454, category Article
Juhani Päivänen. (1991). Tieteestä tiedottaminen - meneekö metsään? Silva Fennica vol. 25 no. 3 article id 5454.
English title: The role of a researcher in providing scientific information.

This paper discusses the ways of providing scientific information and the role of a researcher in the process. The author contemplates the relationship between the researcher and a press officer and ways to present the scientific findings, and its challenges.

  • Päivänen, ORCID ID:E-mail:
article id 5453, category Article
Annika Kangas. (1991). Päivitetyn mittaustiedon käyttö ennakkoinformaationa metsävarojen inventoinnissa. Silva Fennica vol. 25 no. 3 article id 5453.
English title: Updated measurement data as prior information in forest inventory.

Old inventory data has widely been used as prior information in forest inventory using the method of sampling with partial replacement (SPR). In this method knowledge about forest growth has not been utilized. However, the accuracy of the inventory results can be improved if this knowledge is utilized. The usability of the inventory results can be improved if the prior information is updated by treewise growth models. In this paper a statistical basis is presented for a method in which such information can be used. The applicability of the method is also discussed. An example is given to demonstrate the method.

The PDF includes an abstract in Finnish.

  • Kangas, ORCID ID:E-mail:
article id 5452, category Article
Riitta Höyhtyä, Heikki Hänninen. (1991). Fotonivuon tiheyden vaikutus kuusentaimien silmudormanssin purkautumiseen. Silva Fennica vol. 25 no. 3 article id 5452.
English title: Effect of photon flux density on bud dormancy release in Norway spruce seedlings.

The effect of photon flux density on bud dormancy release in two-year-old seedlings of Norway spruce (Picea abies (L.) H. Karst.) was examined. The seedlings were first chilled for 0–21 weeks under natural conditions and then forced in a warm greenhouse either in low (15 μEm-2s-1) or in high (300 μEm-2s-1) photon flux density. Occurrence of bud burst was observed in the forcing conditions, and the observations were used for estimating the cumulative frequency distribution of the chilling requirement for growth competence. The estimated distribution had greater variance in the low photon flux density than in the high photon flux density forcing. This finding suggests that unnaturally low photon flux densities during forcing may yield overestimates of the genetic within-population variation in the chilling requirement for growth competence.

The PDF includes an abstract in Finnish.

  • Höyhtyä, ORCID ID:E-mail:
  • Hänninen, ORCID ID:E-mail:
article id 5451, category Article
Maija Salemaa, Eeva-Liisa Jukola-Sulonen, Martti Lindgren. (1991). Suomen metsien elinvoimaisuus vuosina 1986–90. Silva Fennica vol. 25 no. 3 article id 5451.
English title: Forest condition in Finland, 1986-1990.

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, ORCID ID:E-mail:
  • Jukola-Sulonen, ORCID ID:E-mail:
  • Lindgren, ORCID ID:E-mail:
article id 5450, category Article
Bo Långström, Claes Hellqvist. (1991). Ytimennävertäjien aiheuttamat kasvaintuhot ja kasvutappiot puutavaravaraston läheisyydessä sijaitsevissa männiköissä kolmivuotisen varastoinnin jälkeen. Silva Fennica vol. 25 no. 3 article id 5450.
English title: Shoot damage and growth losses following three years of Tomicus-attacks in Scots pine stands close to a timber storage site.

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, ORCID ID:E-mail:
  • Hellqvist, ORCID ID:E-mail:
article id 5449, category Article
Timo Pukkala, Taneli Kolström. (1991). Tilajärjestykesen vaikutus kuusikon kasvuun: simulointimalli. Silva Fennica vol. 25 no. 3 article id 5449.
English title: Effect of spatial pattern of trees on the growth of Norway spruce stand.

The simulation model consists of a method to generate theoretical Norway spruce (Picea abies (L.) H. Karst.) stands, and a spatial growth model to predict the growth of these stands. The stand generation procedure first predicts the tree diameters from a few stand characteristics and from tree locations. Tree age and height are predicted using spatial models. Spatial growth models were made for both diameter growth and basal area growth. Past growth was used as a predictor in one pair of models and omitted in another pair. The stand generation method and the growth models were utilized in studying the effect of tree arrangement and thinning method on the growth of a Norway spruce stand.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
  • Kolström, ORCID ID:E-mail:
article id 5448, category Article
Markku Penttinen. (1991). Metsäkirjanpidon ja kustannuslaskennan toteuttaminen - 20 vuotta metsätalouden kannattavuuden kenttätutkimusta Itävallassa. Silva Fennica vol. 25 no. 2 article id 5448.
English title: Implementing forestry bookkeeping and cost accounting – 20 years of field research on the profitability of forestry in Austria.

The profitability of forestry in the context of recent economic developments in Finland suggest a more systematic analysis of the profit and the cost structure of small-scale forestry than is normally made today. The domestic and international pressure on farming emphasizes the development of rural areas by means of other business than agriculture, in practice this may mean forestry. Financing in terms of the new law concerning agriculture requires projects to be profitable. Thus, the profitability of different lines of production, including forestry, needs to be reported more carefully than is the practice today.

A network of forestry bookkeeping farms covering the whole Austria has existed for 20 years. The organization and the operation of the forestry bookkeeping and the cost accounting system is based on the scientific cooperation and exchange of information between the organizations in charge. The practical experience and recommendations based thereon might be useful for Finland, when implementing a country-wide network of forestry bookkeeping and cost accounting.

The PDF includes an abstract in English.

  • Penttinen, ORCID ID:E-mail:
article id 5447, category Article
Jyrki Tomminen. (1991). Mäntyankeroista, Bursaphelenchus xylophilus, pakkauslaudassa. Silva Fennica vol. 25 no. 2 article id 5447.
English title: Pinewood nematode, Bursaphelenchus xylophilus, found in packing case wood.

Living third dispersal stage juveniles of pinewood nematode, Bursaphelenchus xylophilus, were found infesting pine boards in Finland. The boards had been used as building material in a packing case to hold imported machinery. Total numbers of nematodes extracted from the boards did not exceed 4 grams of dry wood. When cultured on Botrytis cinerea the nematode reproduction resumed rapidly.

The PDF includes an abstract in Finnish.

  • Tomminen, ORCID ID:E-mail:
article id 5446, category Article
Hannu Ilvesniemi. (1991). Maan kemiallisten ominaisuuksien ajallinen ja paikallinen vaihtelu eteläsuomalaisissa männiköissä. Silva Fennica vol. 25 no. 2 article id 5446.
English title: Spatial and temporal variation of soil chemical characteristics in pine sites in Southern Finland.

In producing time series of soil properties, there are many technical and statistical problems which need to be taken into account when sampling and analysing the measurement data. In field the reliable localization of sample plots and the precise distinction of different soil layers are important to reduce the variance caused by the sampling procedure. In laboratory the use of same extraction salt, sample pretreatment procedure and filter paper throughout a measurement series is important. The remarkable small-scale variation within a sampling plot leads to a need of a large number of samples to be collected.

In this study, no trends attributable to soil acidification in the contents of exchangeable base cations could be found among the years 1982, 1985 and 1988. However, in eluvial and illuvial layers the pH decreased and the content of extractable H+ increased during this period. In illuvial layer also the content of extractable aluminium increased.

The PDF includes an abstract in Finnish.

  • Ilvesniemi, ORCID ID:E-mail:
article id 5445, category Article
Taneli Kolström. (1991). Kuusen kylvö- ja istutuskoe viljavilla kivennäismailla Pohjois-Karjalassa. Silva Fennica vol. 25 no. 2 article id 5445.
English title: Results from the sowing and planting experiment of Norway spruce (Picea abies) on fertile sites in North Karelia, Finland.

Different methods of sowing and planting of Norway spruce (Picea abies (L.) H. Karst.) were compared on fertile sites in North Karelia (62°20’N, 29°35’E, 85–120 m a.s.l.). The planting material were 4-year-old bare-rooted transplants, 2-year-old bare-rooted seedlings, and 2-year-old containerized seedlings raised in plastic greenhouse. The sowing methods were band sowing and shelter sowing. Ground vegetation was controlled during the first growing season mechanically or chemically, or the control was omitted totally.

Planting of spruce gave better results than sowing. After eight growing seasons there were sowed seedlings left in 30% of the sowing pots. The average height of them was 35 cm. Seedling survival was best with large bare-rooted transplants (91%). Survival of containerized seedlings was 79% and of small bare-rooted transplants 71%. The average height of large bare-rooted transplants was 131 cm, of containerized seedlings 86 cm and small bare-rooted seedlings 68 cm.

Sowing is not an advisable method for regeneration of spruce due to the small survival rate and slow initial development when ground vegetation is controlled only once. Also 2-year-old seedlings gave a satisfactory result in regeneration. Seedlings raised in greenhouse were more sensitive to frost damage than seedlings grown on open ground.

The PDF includes an abstract in English.

  • Kolström, ORCID ID:E-mail:
article id 5444, category Article
Kari T. Korhonen, Matti Maltamo. (1991). Korrelaatiofunktiot metsäninventoinnin otannan tehokkuuden vertailemisessa. Silva Fennica vol. 25 no. 2 article id 5444.
English title: The evaluation of forest inventory designs using correlation functions.

Correlation functions of the mean volume, land use class and soil class were estimated using the data of the Finnish National Forest Inventory. Estimated functions were used for approximating the standard error of e.g. the mean volume of a cluster of plots. Standard error estimates can be used for comparing different inventory designs.

The PDF includes an abstract in Finnish.

  • Korhonen, ORCID ID:E-mail:
  • Maltamo, ORCID ID:E-mail:
article id 5443, category Article
Raimo Silvennoinen, Rauno Hämäläinen, Kaarlo Nygrén, Kim von Weissenberg. (1991). Spectroradiometric characteristics of Scots pine and intensity of moose browsing. Silva Fennica vol. 25 no. 2 article id 5443.

The light reflected from the crowns of Scots pine (Pinus sylvestris L.) clones was measured spectroradiometrically during and after growing season. Standard deviations of the spectra of pine clones showing differences in moose browsing intensity were compared. A new algorithm was developed for predicting the browsing intensity of moose (Alces alces).

The PDF includes an abstract in Finnish.

  • Silvennoinen, ORCID ID:E-mail:
  • Hämäläinen, ORCID ID:E-mail:
  • Nygrén, ORCID ID:E-mail:
  • Weissenberg, ORCID ID:E-mail:
article id 5442, category Article
Erkki Annila, Kari Heliövaara. (1991). Kuusen käpytuhojen kemiallinen torjunta siemenviljelyksillä. Silva Fennica vol. 25 no. 2 article id 5442.
English title: Chemical control of cone pests in a Norway spruce seed orchard.

The effect of three pesticides containing either dimethoate (0.5% a.i.), permitrin (0.5%) or triadimephon (0.5%) on the cone pests and flowering biology of Norway spruce (Picea abies (L.) H. Karst.) was tested in a seed orchard in mid-May or in the beginning of June. The pesticide treatments significantly reduced infestation by Laspeyresia strobiella and Kaltenbachiella strobi only. Variation in the number of cones infested by both insects and cone rusts was high between the spruce clones. Generally, the pesticides did not affect flower viability, seed quality or seed germination, but reduced drastically the germination capacity of pollen in vitro. In practice, sufficient control cannot be achieved with concentrations or methods used in the present study.

The PDF includes an abstract in Finnish.

  • Annila, ORCID ID:E-mail:
  • Heliövaara, ORCID ID:E-mail:
article id 5441, category Article
Finnish Society of Forest Science. (1991). Ohjeita kirjoittajille. Silva Fennica vol. 25 no. 1 article id 5441.
English title: Instructions to authors.
Keywords: Silva Fennica

This paper presents the publishing guidelines of the Finnish Society of Forest Science for the forest scientific series of Silva Fennica. This paper presents the instructions to authors in Finnish, the English instructions are included in a separate PDF.

  • Finnish Society of Forest Science, ORCID ID:E-mail:
article id 5440, category Article
Finnish Society of Forest Science. (1991). Instructions to authors. Silva Fennica vol. 25 no. 1 article id 5440.
Keywords: Silva Fennica

This paper presents the publishing guidelines of the Finnish Society of Forest Science for the forest scientific series of Silva Fennica. This paper includes the instructions to authors in English, the Finnish instructions are in a separate PDF.

  • Finnish Society of Forest Science, ORCID ID:E-mail:
article id 5439, category Article
Finnish Society of Forest Science. (1991). Teemapäivä metsätieteellisen julkaisutoiminnan kehittämisestä 6.2.1991. Silva Fennica vol. 25 no. 1 article id 5439.
English title: A seminar on development of forest scientific publication, held in 6.2.1991.

The article is a report on development of forest scientific publication, which was discussed in a seminar arranged by the Finnish Society of Forest Science on 6th February, 1991. The article includes the presentations held in the seminar. 

  • Finnish Society of Forest Science, ORCID ID:E-mail:
article id 5438, category Article
Juha Heiskanen, Hannu Raitio. (1991). Soil water potential during the production of bare-rooted Scots pine seedlings. Silva Fennica vol. 25 no. 1 article id 5438.
English title: Maan vesipotentiaali paljasjuuristen männyntaimien taimitarhakasvatuksessa.

The matrix potential, measured with tensiometers, and its effect on the soil air-water ratio were examined during the production of bare-rooted Scots pine (Pinus sylvestris L.) seedlings in nursery fields. Soil water potential was monitored during the growing season of 1983 at three nurseries in Finland, and from fields growing various seedling types at depths of 10 and 20 cm. In 1986, soil core samples were collected in order to assess the water desorption characteristics of the soil. In addition, the effect of polypropylene gauze covering (Agryl P 17) on the soil water potential was examined during the growing season of 1985 at two nurseries in Finland at depths of 5, 10 and 15 cm.

The soil water potential was relatively high in all the fields studied. In fields growing one- and two-year-old seedlings, the median potential was higher than -10 kPa. The potential did not fall below the limit of the measured scale (ca. -85 kPa) of the tensiometers. Soil aeriation may have been periodically insufficient in the rooting zone, as a result of high water content. The favourable water potential is below -5 to – 6 kPa. The gauze covering slightly (1–4 kPa) increased the soil water potential, an effect which could be harmful if the soil air space is low. During the second growing season, the soil water potential was lower in the fields covered by the gauze during the first year than in the fields without the covering.

The PDF includes an abstract in English.

  • Heiskanen, ORCID ID:E-mail:
  • Raitio, ORCID ID:E-mail:
article id 5437, category Article
Tapani Repo. (1991). Männyn taimien kyky karaistua uudelleen suveentumisen aikana. Silva Fennica vol. 25 no. 1 article id 5437.
English title: Rehardening potential of Scots pine seedlings during dehardening.

The ability of one-year old Scots pine (Pinus sylvestris L.) seedlings to reharden during the dehardening period was studied. Naturally hardened quiescent seedlings were preconditioned at 0°C for ten days and then placed in chambers at different forcing temperatures with different light regimes. The forcing periods were followed by cool periods. Changes in frost hardiness were monitored at intervals using freeze tests of whole plants. Frost hardiness was assessed by three methods: impedance, survival and growth retardation. Dehardening seemed to be a partially reversible process, i.e. in some growing conditions slight rehardening was found.

The PDF includes an abstract in Finnish.

  • Repo, ORCID ID:E-mail:
article id 5436, category Article
Leena Finér. (1991). Ohutjuurten biomassa lannoitetulla ja lannoittamattomalla ombrotrofisella rämeellä. Silva Fennica vol. 25 no. 1 article id 5436.
English title: Root biomass on an ombrotrophic pine bog and the effects of PK and NPK fertilization.

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

The PDF includes an abstract in Finnish.

  • Finér, ORCID ID:E-mail:

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