Epsilon Archive for Student Projects

Abstract

Human presence has always influenced the surrounding areas, the forest as well. Structure and species composition have changed during human land use. Knowledge regarding these changes should be of great interest for conservation and forestry. We have analyzed human impact on the tree species composition on five study sites during 2000 years in Ångermanland, Sweden. More specifically the change in tree species composition in percentage amongst alder, birch, spruce and pine over time. This was accomplished with pollen data from five sites. The pollen data has been converted with the value R, this was done to transform pollen percentage to tree species composition. Shannons diversity index
was used to illustrate the changes we’ve studied. Three study sites cover the 20th century and
shows higher levels in the diversity index the last century than at any time during the period before human cultivation became continuous. Four out of five study sites have shown higher values in the diversity index among the four tree species during the continuous human cultivation than previous period.