Relating Abundance of Ground Vegetation Species and Tree Patterns at Local Scale using Ecological Field Theory

The relationships between the spatial locations and attributes of trees and the abundance of individual ground vegetation species, were studied on a large database from the 1985-86 National Forest Inventory of Finland. The influence potential, derived from ecological field theory, was used as an index to quantify the effect of a tree species, and the percentage cover was applied as a measure of abundance. The nationwide scale of the inventory provided the setting for varying ecological conditions. To remove large-scale factors, the differences to the local mean were analyzed, and as the sample plots were small, an edge correction was applied to avoid bias. Observations from Scots pine, Norway spruce and birch trees, and 19 ground vegetation species were studied. Positive and negative significant correlations among the influence potential and coverage were found. The results indicate that relationships at local scale exist and are particular to each tree species and understorey species.