Current issue: 52(4)
Under compilation: 52(5)
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.
The article represents, based on meteorological data from 1900-1910 and 1911-1915 and annual reports of forest directorate with descriptions or statistics about wind damages of trees in state owned lands, the biggest storms in Finland and the damage they have caused to forests. The most powerful storms of the studied period and damages they caused are presented.It was found out that the storm damages take place primarily during the growing season. Frozen ground and a snow cover protects the trees from falling.
There are lot of storm damages in the Finnish forests. They are particularly common in forests logged as strips or with clear cuts, but not absent in selection forestry either. To protect the forests from natural disasters requires more intensive management. For the forestry purposes it is important to know the most common wind directions of different parts of the country. The paper finds out which stormy wind directions are most dangerous to Finnish forests and hence need to be mostly taken into consideration when planning logging operations. The study is based on meteorological data that has been compared with the reports of storm damages in state owned forests.
The most storm damage take place during the growing season, and to some extent in late fall. The regeneration felling should take place against the primary direction of the stormy winds. The paper represents the most common wind directions for different parts of the country. However, the wind directions may vary from the primary with local conditions such as altitude differences.