ABOVEGROUND WOODY BIOMASS PRODUCTION OF DIFFERENT TREE SPECIES IN SILVOARABLE AGROFORESTRY SYTEMS WITH ORGANIC AND INTEGRATED CULTIVATION IN SOUTHERN GERMANY

摘要

The increasing demand for bioenergy and the combination of agricultural production with conservation has made agroforestry to a sustainable land-management option. Aboveground woody biomass plays a decisive role considering the economic value of the agroforestry systems as well as the carbon storage. With the objective to study aboveground woody biomass production of agroforestry systems with different cultivation methods (organic/ integrated), short rotation plantations of different tree species were established 2009 and coppiced in 2012. The studied tree species were black alder (Alnus glutinosa), black locust (Robinia pseudoacacia), poplar “Max 3”, (Populus maximowiczii x Populus nigra) and willow “Inger” (Salix triandra x Salix viminalis). At the end of each growing season biomass production was estimated by an allometric model that predicted individual tree biomass from stem diameter. At the end of the rotation biomass was estimated directly by harvesting. Biomass production ranged from 3.9 to 10.9 tDM ha-1a-1 with poplar and locust having highest growth rates. Significant variation was observed between tree species, but not between management (organic/ integrated), what indicates that organic and integrated agroforestry systems can have a comparable tree biomass production. Small-scale differences of the soil caused high intraspecific variation and suggest the inclusion of further soil investigations.