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.