Carbon dioxide soil emissions in forest stands of the Primorskaya State Academy of Agriculture
Alexander V. Ivanov1 & M. Braun2
1Primorskaya State Academy of Agriculture, Prospekt Blyukhera 44, Ussuriysk, Russia 2University of Natural Resources and Life Sciences, Feistmantelstr. 4, 1180 Vienna, Austria
Global land surface emissions amount to 80x1015 g C annually which is about 10 times higher than the sum of anthropogenic emissions from fossil fuel combustion. Because of climate change organic soil losses are expected to increase, which would lead to a positive feedback between emissions and an increase in atmospheric CO2 concentration. Forest ecosystems often act as carbon sinks and can build-up considerable carbon stocks. Thus, they play an important role as a buffer abating the increase of greenhouse gases in the atmosphere. With 20% of global forested areas being in Russia, the country plays a key role in preventing or slowing down the increase in average global temperature. Currently used greenhouse gas inventories are derived from global model estimates, which in turn are based upon empirical data. When considering regional data, the information about the carbon budget for Russian forests is not evenly represented by current databases. Especially the carbon cycle of forest ecosystems in the Russian Far East remains amongst the least studied regions.
Since 2012, field investigations of carbon emissions were conducted by employees of the Institute of Forestry and Forest Park Management of Primorskaya State Academy of Agriculture (Ussuriysk). A forest stand belonging to the Academy (28,000 ha) adjoining the Ussuri reserve was used for conducting measurements to determine the temporal (seasonal and diurnal) as well as the spatial variability of carbon fluxes. After five years of measurements the data acquired encompasses three types of forest formations – oak dominant forests, pine dominant forests and ash-elm dominated floodplain forests.
Results show that soils in pine forests have temperatures above 0 degrees for about 250 days per year. Soil temperatures were determined to be the main factor for seasonal variability in soil respiration. The following mean values for total soil respiration were obtained (in g C per m² and day): 4.39-6.74 for pine forests, 7.30 for oak forests in summer, 5.22 for ash-elm floodplain forests in summer.