Model based comparison of forest carbon uptake by forest growth and CO2 Release due to forest operations for case studies in Europe and South Africa

When dealing with CO2 in- and outflows of forest ecosystems, the CO2 emissions due to harvest operations have been mostly not included into the analyses, so far. Therefore, to demonstrate an integrative and more holistic view, we used the generic simulation model care4cmodel for assessing relevant silvicultural concepts for pine species in different European (Pinus sylvestris, Pinus pinaster) and South African (Pinus pinaster, Pinus radiata) climatic conditions and management regimes. The concepts covered different thinning and regeneration systems, ranging from clear cut to target diameter harvest. Our focus was on the CO2 emissions due to forest operations (CEF) and their relation to the CO2 uptake due to wood increment (CUI). Simulations covered a time span of 50 years and different scenarios of the initial shares of stand development phases on a large virtual forest area. Our simulations suggest that, across all concepts and countries, the CEF are about 2-3 orders of magnitude smaller than the CUI. More importantly, while the initial situation strongly matters for development of the increment and harvest amounts, it does considerably less so for CEF and CEF/CUI. This provides leeway for silvicultural decisions regarding the above-mentioned CO2 flows.