Windfall stock in the natural stands of mixed coniferous and deciduous forests in the South of Primorye

Abstract

Field measurements of windfall stock including the stages of decomposition are carried out for the coniferous and deciduous forests of the forest area belonging to Primorskaya State Academy of Agriculture (PSAA) located in the southern part of Primorskiy krai (the Far East). The accounting of the windfall fragments was performed using the method of linear transects with the simultaneous inventory description of temporary sample plots. Fluctuations of windfall wood stocks in 12 sample plots are within 16,9-83,3 m 3 /ha, which averaged 17% of the total wood stock. The average value of the windfall carbon pool was calculated (8,3 t С/hа) using the coefficient for the transfer of the windfall amount into the mass of carbon. Significant correlations of windfall stock with the stand age and density were obtained (r 2 =0,74 и r 2 =0,52 relatively). The windfall distribution by age ranging from 80 to 180 years is a fragment of Ushaped curve that coincide with well known published data. It is shown that the biggest part of the windfall is concentrated in the fragments of decomposition stages 3-5 and the carbon stock by 83% is provided by fragments of decomposition stages 1-3 due to the significant loss of density. Forest plot of PSAA (area covered by prevailing Korean cedar plantings -6333,5 ha) was chosen as a model area. In the windfall of the forest stand of the model territory 36,2 thousand tons of carbon are concentrated. It makes 3% from total amount of all carbon pulls of examined stands. The windfall carbon pull, calculated for the same area with using software system for regional assessment of forest carbon stock, was 34,8 thousand tons С.