Effect of stand age on soil respiration in managed vs unmanaged Scots pine stands

Abstract: How the forests in Sweden and around the world have been, and are still today, managed is a hot debate. The rotation forestry that is commonly used in Sweden has been the focus of debate regarding whether it is a sustainable management method, and whether it should be changed. To gain a broader understanding of how forests change, and respond to intensive management over time, one way is to investigate carbon dioxide and its fluxes between soil and atmosphere. By conducting a measurement of the carbon dioxide fluxes from the soil into the atmosphere in a chronosequence with managed stands and stands that have not been managed since the last fire over a 375-time period. It could be seen that there are trends of higher respiration; autotrophic, heterotrophic, and total, rates in managed stands compared to the unmanaged stands. The most noticeable trend can be seen for stand ages between 15 and 45 years where thinning operations have occurred in the managed stands and lead to higher rates of respiration when comparing it to the unmanaged stands. Specifically, when comparing stands with an age lower than 90 years, I found that managed stands have higher rates of respiration compared to unmanaged stands. In addition, unmanaged stands with a stand age older than 110 years having very stable respiration rates between the ages 110 and 375 years.