C-accumulation and allocation after afforestation of a pasture with Pin oak (Quercus palustris) and ash (Fraxinus excelsior)

Abstract

The aim of the study is to investigate how afforestation of agricultural land effects the C-cycle. That is why the allocation and accumulation of carbon was quantified in 2 types of deciduous forest with 2 different ages on the one side and in unforested pasture on the other. The total C-content of the pasture amounted to 128 ton C/ha. The total C-content in the young (29 years old) and old (69 years old) ash stand was 173 ton C/ha and 232 ton C/ha respectively. The young pin oak stand (27 years old) had a C-content of 117 ton C/ha, the old oak-beech stand (69 years old) one of 227 ton C/ha. It was prooved that the young ash stand evolves to a higher C-content than the C-content of the pasture. In the young ash stand the aboveground and belowground C-pools are equally big. The older the stand, the more important the portion of the soil carbon becomes. The carbon in old stands is mainly stocked in the form of stable soil carbon. After 27 years the pin oak stand has a lower C-content than the pasture. Furthermore, most of the carbon is situated aboveground. In the old oak-beech stand on the other hand the soil has been complemented. The soil carbon - as for the ash stand- takes the most important portion. This stable reservoir however is smaller than in the ash stand. This study shows that when foresting a pasture the choice of tree species has an important impact on the accumulation, allocation, evolution and stability of carbon.