Variability of carbon uptake in managed and un-managed forests 1. Background
The role of both managed and un-managed forests are clear for the sequestration of human induced increment in carbon dioxide gas. About 1.476 million hectares of the forest area in central Europe as undisturbed forest (FOREST EUROPE, UNECE and FAO 2011) and 0.1 million hectares in Germany as unmanaged and mainly old-growth forests has been reported (NFI 2010 as cited in Krug et al. 2012). Meta-analysis of Luyssaert et. al (2008) has reported that such old-growth and unmanaged forests can continue to accumulate carbon in contrary to the long term stand view that they are carbon neutral. There is however an ongoing controversial dispute about the ability and magnitude of carbon dioxide sequestration exceeding decay processes in unmanaged forests (Krug et al 2012). Krug et al. (2012) further emphasize use of CO2 flux measurements based on critical considerations of uncertainties and system boundaries, use of wood products for material from managed forests and impacts of changing environment conditions leading to obvious increase in growth as facts for inadequacy to infer the importance of unmanaged forests for climate change mitigation compared to managed forests.
Anthoni et. al. (2004) has reported that proposed sites have very similar net CO2 uptake rates. However, the data for short span of time was analyzed. So, it is important to see how the carbon uptake has varied after a decade of that study. Clais et. al (2005) reported that warming events (heatwaves in year 2003) may have negative impact on forest growth. There is evidence that weather-related extreme events, at the margins of current local climate distributions, will increase in frequency and intensity in the future (Palmer and R¨ais¨anen, 2002; Beniston et al., 2007 as cited in Smith & Lawson, 2012). Thus, it is