Current issue: 56(4)
Silva Fennica issue 52 includes presentations held in professional development courses, arranged for foresters working in public administration in 1938. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.
This presentation describes growth and form of root systems of different tree species in different sites and how growth of roots affect forest management.
Silva Fennica issue 46 includes presentations held in professional development courses, arranged for foresters working in public administration in 1937. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.
This presentation describes the effect of properties of soil on forest regeneration.
The aim of the study was to investigate effect of growth conditions on germination and growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings in greenhouse conditions. Germination of seeds becomes markedly slower as the soil temperature decreases. It seems that low temperatures affect more Norway spruce than Scots pine. When temperature rises, the fresh weight of the seedlings increases more in pine seedlings than in spruce seedlings. Accordingly, lower temperatures affect less the weight growth of spruce seedling than that of pine seedlings.
An experiment testing how root competition affect germination showed that adjacent seedlings decrease germination of seeds more than shading with branches. The effect was strongest on pine and spruce seedlings when the shading tree species was fast growing birch (Betula sp.). On the other hand, shading affected most height growth of birch seedlings. Growing space can vary in relatively large range without it affecting greatly tree growth.
The PDF includes a summary in German.
Norway spruce (Picea abies (L.) H. Karst.) is a species that becomes in Finland over time the dominant species in the sites that are suitable for it. The reason that it covers only a quarter of the forest areas in Finland depends mainly on forest fires. The aim of this review was to discuss the biological factors that affect competition between Scots pine and Norway spruce.
Especially important is the ability to regenerate and grow past seedling stage. There does not seem to be significant differences in the number of good seed and seedling years of the species. Spruce regenerates better on moss covered forest floor than pine. On the other hand, pine seedlings grow faster than spruce seedlings, and tolerate better dry conditions. Consequently, one of the defining biological differences is that Norway spruce needs more humid conditions than Scots pine. Spruce is shown to have greater transpiration than pine. Spruce also has higher site requirements, however, growing as undergrowth, it seems to be better able to compete of the nutrients with the larger trees than pine. It also tolerates shading better. Spruce is less frost tolerant than pine.
The PDF includes a summary in German.
Water and amount of light are the most important growth factors and the article discusses their relationship. It is knows that the more space is needed by a tree the worse the site is. The number of stems varies between tree species. Common understanding is that amount of light is decisive to self-thinning and regeneration of a stand. On a good site the adequacy of water may substitute the lack of light. However, the fertility of soil and moisture content is more important than light.
The question of the importance of light, soil fertility and water content, as well as their relationship is important when optimizing the forest management.
The PDF contains a summary in Finnish.
After critically reviewing earlier studies on soil properties and their influence on forest growth and yield, it seems that defining the forest yield could be possible by means of soil properties. To be able to do so, the site needs to be defined and delineated in some other way. It is also necessary to decide the right soil properties to study for the purpose.
For the classification of forest sites the results of soil analyses need to be compared with growth and yield data from the site. To further the practice of classification of forest sites by means of soil studies, four aspects need to be taken into account:
1) the site needs to be delineated beforehand according its vegetation, preferable with Cajander’s forest type classification
2) the experiments about soil needs to be done for as many properties as possible
3) the studied sites need to be as representative as possible in their class
4) there are as many samples for one site as possible studied
The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.
The article discusses the growth factors, the influence of the seed tree to the seedlings and the relations of the trees within one age class in sense of growth of the trees and their effect for practical forest management.
The author concludes by noticing that there is a remarkable gap in knowledge about growth factors and more research is needed especially on the interactions of various growth factors. Earlier research on forests has not taken the characteristics of the site and its effect into account adequately. In addition to the observations in the nature, the individual growth factors and their interactions should be studied quantitatively.
Forest management practices have deployed during the centuries very differently in different regions. The geographical as well as other nature related factors influence them heavily. During the first half of 19th century was shelterwood felling much used practice especially in Prussia. Meanwhile the clearcutting with planting the seedlings became also more popular. The method is still widely used in many countries. Becoming more popular the clear cut and planting practice changed the modus operandi of forestry from close-to-nature to economically-oriented.The article discusses based on literature the most important developments of the forest management practices, especially regarding felling and regeneration methods. The article concludes with the view that usage of boarder selection felling as well as continuous forest management system are not suitable for small-scale forestry (on small private estates) on in Finland common barren sites. On more fertile soils the boarder selection felling would give good results and could be recommended also for more use. However, the bad market conditions make the more intensive forest management impossible in most parts of Finland. More research is needed in order to find best felling methods for fertile small-scale private forests.
The article deals with laboratory experiments of humus containing soil samples that were tested for leaching of iron and lime. The humus and soil samples were collected in five different areas in Silesian state forests, Germany.
The chemical content of the extracts was measured in the beginning of the test. The flocculation experiments and experiments in glass tubes took place. The stronger or weaker the podsolization, the greater or smaller was the protective action of hums at the respective place. However, more research is needed. The results of the glass tube experiments seem to indicate that with humus there were smaller amounts of Ca and Fe leaching than with merely water.
This is a working paper. It presents the laboratory experiments with soil samples from northern Finland, in which the precipitation of iron (Fe) was tested with limewater (Ca). There was no clear difference between samples with limewater and samples without limewater. However, the lime prevented the infiltration of iron almost totally.
The mineral content of soil effects the forest growth and yield and hence it is of interest for forestry. More research is needed both as field experiments and in the laboratory.
The article contains a literature review about the spatial order of plants and a description of the small-scale experiments with corn. The literature is primarily of German origin. The question of the spatial conditions of trees in forest is important for practice of silviculture. The first part of the article illustrates based on the literature the importance of roots and root concurrence for the development of plants or forest stands. The second and third part deepens the methodological knowledge on root research. Fourth part is the field experiments with corn. There are no clear relation to be found between yield and the number of plants.
The data has been collected in the dry heathy forests in Harjavalta commune in south-west Finland and in Sodankylä commune in Lapland in summer time 1918 and 1919. The aim to the study was to find out how does the water consumption of the trees affect the moisture conditions of the soil and how they are linked to the regeneration of the forest.
Trees in one age class have a certain spatial distribution: the greater the distance between trees the older the trees and the smaller the distance, the younger the trees. This seem to rather be due to the development of the root system and the nutrition intake of a tree than the competition for light. The moisture content of the upper soil layers is higher in the open areas than in the closed canopy stands. Hence there are more seedlings growing in open areas. However, it is not clear whether the results apply for other forest site types as well, and more research is needed.
The study presents and describes the abundance and distribution of tree roots in specific stands of heathy forest types in Lapland. The data was collected in the Sodankylä commune.
Due to the shortcomings in the data, conclusions can be drawn only regarding pine forests. The result of study states that the root competition plays an important role in the development of the forests, and most of the other observed phenomena are linked with root competition. The more infertile the soil the vertically and horizontally wider and more abundant the root system. It seems that the abundance of the root system is similar in forest of same fertility class and same density and age.