Root density and root biomass in pure and mixed forest stands of Douglas-fir and beech

Abstract

The study was restricted to fine roots (< 2 mm). The highest root length was found in a 64-year-old pure beech Fagus sylvatica stand. The smallest root length was found in a 60-year-old pure Douglas-fir Pseudotsuga menziesii stand. In the mixed stands, beech was strongly suppressed by Douglas fir, although beech managed to develop an equal or even larger root length than Douglas fir. In the mixed stands the specific root lengths of the fine roots of Douglas-fir and Beech were higher than in the pure stands, which may indicate below-ground competition. Furthermore, there are indications that in the mixed stands, beech develops a rooting strategy which ensures the possibility of above-ground expansion when the growth of Douglas-fir declines. -from Authors