The increasing demand for solid biofuels, such as primary forest fuels, has highlighted the importance to consider that they, in contrast to fossil fuels are produced in dynamic ecosystems. Environmental effects of changes in ecosystem management policies, positive and negative, are not obvious. To that end, calculations of carbon budgets in single forest stands show that the carbon balance dramatically switches from uptake to loss at clear-felling; the time taken to recover the carbon losses after such a disturbance can span over decades up to centuries. However, forest management policy refers not to the single stand level but to the landscape scale. In order to evaluate new policies, it is therefore necessary to examine the aggregated effect from a number of individual response curves. Here we have used two different ecosystem models (Q and COUP) to compare the carbon budgets of a landscape with that of a single-stand for the consequences of extracting more biomass at each harvesting occasion, removing branches plus tops alone or in combination with stumps in addition to the conventional harvest of stemwood. In the calculations the landscape consists of all different ages, each representing one year of a given rotation period. The results show that the aggregated carbon balance in a forest landscape is less dramatic than that of a single stand. The benefit of increasing the accumulated biomass harvested in a landscape occurs immediately and increases linearly over time whereas the associated loss of soil carbon has a delayed and declining response. In the long run the aggregate carbon balance is stable over time in any landscape, provided that environmental factors and management policy remain unchanged.
|Number of pages||17|
|Publication status||Published - 2011|