Current issue: 55(3)
Under compilation: 55(4)
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.
Soil of open and forest covered lands have different properties. Forest devastation has negative effect on forest soil, for instance, through leaching of nutrients. There are different views on how forest fire influences chemical properties of the soil. Burning of forests can have both positive and negative consequences.
The article publishes partial results from a study that aimed to find out how shifting cultivation affects the soil, and how it may change natural regeneration and forest growth of the stands. Soil samples were collected from four burnt-over sites. Of the samples, size classes of the soil particles, volatile solids and nutrient contents were determined. According to the results, the burning increased soluble nutrients, but the effect was not long-lasting. However, more sample sites would be needed to give definitive results of the differences.