Current issue: 56(4)
Under compilation: 57(1)
Silva Fennica Issue 92 includes presentations held in 1956 in the 8th professional development courses, arranged for forest officers working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.
In 1925-1944 the Finnish Swamp Cultivation Association (now Finnish Peatland Society, Suoseura) carried out research on the arability of peatlands, mostly on state lands that were the main object of settlement work and the arability of which had been little explored. Later the work has been transferred to the Settlement Department of the Ministry of Agriculture (ASO) and some other authorities. ASO has prepared arability maps based on the nutrient analysis of the lands.
Typical for the area of Längälmävesi, in Satakunta in Southern Finland, are densely populated fertile lowland areas near the waterways and poorer sparcely populated upland areas. The changes in fertility of the land influence the vegetation, and has directed where the population has settled. A vegetation survey was made using specific plant species as indication to fertility. A detailed description of the species composition and distribution of the plant species indicative for fertile land is presented in the article.
Analyzing the fertility only based on the plant species indicative for rich soils underestimates the proportion of fertile lands. Farmlands, on the other hand, have been cleared also on less fertile soils, which would give an overestimate of the fertile lands. A map of fertile lands was drawn based on both vegetation and location of the fields. The changes in fertility influenced also bird species observed in the area.
The PDF includes a summary in German.
The article presents a survey on distribution of fertile lands, soil types and site classes in Savo and Karelia in the central and eastern parts of Finland. The survey was based both in existing publications and statistics, a line survey, and visual observations during field trips. The site quality classification is based on the vegetation and occurrence of indicator plant species. The article lists distribution of indicator species in different forest site types on maps of the area. In addition, a review of history of land use and agriculture give indications of the location of the fertile lands in the area. A map of the forest site types in different parts of the area illustrate the data collected from the different sources.
The PDF includes a summary in German.
The aims of the present study were to determine physical and physio-chemical properties of some Finnish forest tree nursery soils, and to examine relationships between these properties and the amount of organic matter in the soil.
The following soil tillage layer properties of 33 fields belonging to 8 forest tree nurseries were determined: soil particle size distribution, organic matter content, bulk density and density of solids, total pore space, soil water volume at potentials pF 2.0 and 4.2, available water content and air space at potential pF 2.0, active acidity, electrical conductivity index and cation exchange capacities at pH 4.5 and 8.0. The soil texture class of the tillage layer parent material was sand, only in a few cases did higher percentage of silt and clay indicate a morainic nature of parent material. The amount of organic material in the soils varied within wide limits, reflecting differences in amelioration policy between the single nurseries.
Relationships between the physical properties of the soil parent material and those related to fertility were in most cases strongly influenced by the amount of soil organic matter. Soil density values decreased as the organic matter content increased from 2 to 25%, giving rise to the increase in the total pore space. However, the amount of water held at potential pF 2.0 and the available water content did not increase with increasing organic matter content. This was due to the absence of the particle fraction in the sand. Nursery soil amelioration, involving in most cases a mixture of Sphagnum peat with sand, thus gives rise to an increase in the content of drainable water.
Cation exchange capacities were positively correlated with the organic matter content. However, the absolute number of exchange sites expressed as equivalents in the tillage layer did not increase in accordance with the increase in organic matter content due to the influence of the organic matter content upon the ratio of solids in the voids.
The PDF includes a summary in English.