Climate effects of managed boreal forests : combining effects from carbon balance and albedo

Abstract: Boreal forests are considered as a global carbon (C) sink and are utilized for climate-change mitigation. Judging the climate impact of a forest solely on its C balance might leave an incomplete picture, since forest-climate feedbacks are also caused by various other biophysical and biogeochemical processes, e.g., albedo effects. Previous research showed a high importance of albedo effects in the boreal zone compared to other biomes, mainly due to the presence of snow. This study quantifies the net climate effect of a forest in boreal North Sweden by considering its C and albedo dynamics. For this purpose, remotely sensed high spatial resolution albedo and ground-based C balance data were combined into a radiative forcing (RF) model. The results suggest a distinct age-related albedo pattern and the possibility of using age as a proxy for successional biophysical changes in the forest landscape. Moreover, C-flux-induced climate cooling (75% of total RF) was found to overrule albedo-induced warming (25% of total RF), which challenges previous research. The findings point towards the need for biome-specific forest management practices to yield maximum climate cooling potentials. Keywords: Boreal Forests Climate Effect, Remotely Sensed Albedo, Age-Albedo pattern, C-flux Radiative Forcing.