Effect Of Site Types On Carbon Storage Of Natural White Birch Forest Ecosystem In Changbai Mountain, Northeast China

The effect of site types on the ecosystem carbon storage (vegetation and soil), net primary productivity (NPP) and annual net carbon sequestration (ANCS) of natural white birch forests on seven site types (the top, middle, and bottom of the sunny slope and shady slope, and the valley floor) were measured using relative growth equations and carbon/nitrogen analytical approach in Changbai Mountain, Northeast China. The results showed that:(1) The vegetation carbon storage of natural white birch forests were between 45.61±13.39 t·C·hm-2 and 87.22±6.41 t·C·hm-2, which of the upper,middle of shady slope and the valley were significantly higher 50.8%-91.2% (P<0.05) than the lower of sunny slope, and the upper, middle of sunny slope, and the lower of shady slope were higher 20.4%-44.4% (P>0.05) than the lower of sunny slope, but no significantly. The vegetation carbon storage took on the upper, middle of shady slope and the valley> the upper and middle of sunny slope, and the lower of shady slope> the lower of sunny slope change regularity.(2) The soil organic Carbon storage of natural white birch forests were between 66.71±14.92 t·C·hm-2 and 158.51±38.21 t·C·hm-2, which of the upper of sunny slope, the middle of shady slope and the valley were significantly higher 99.3%-137.6%(P＜0.05) than the upper of shady slope, and the lower, middle of sunny slope, and the lower of shady slope were higher 40.7%-67.0%(P>0.05) than the upper of shady slope, but no significantly. The soil organic Carbon storage took on the upper of sunny slope, the middle of shady slope and the valley> the lower and middle of sunny slope, and the lower of shady slope> the upper of shady slope change regularity.(3) The ecosystem carbon storage of natural white birch forests were between 139.44±42.71 t·C·hm-2 and 231.12±40.20 t·C·hm-2, which of the middle of shady slope and the valley were significantly higher 35.6%-65.7%(P＜0.05) than the lower, middle of sunny slope, and the upper of shady slope, and the upper of sunny slope and the lower of shady slope were higher 5.8%-34.7% (P>0.05) than the lower, middle of sunny slope, and the upper of shady slope, but no significantly. The ecosystem carbon storage took on the middle of shady slope and the valley> the upper of sunny slope and the lower of shady slope> the lower and the middle of sunny slope, and the upper of shady slope change regularity. Site type has also changed the structure of the birches ecosystem carbon storage, namely, the upper, lower of sunny slope and the valley of soil carbon storage and vegetation carbon storage ratio of about 7:3; the middle of sunny slope, the middle and lower of shady slope the proportion of about 6:4; the upper of slope accounting for about 5:5.(4) The NPP and ANCS of the white birch forests were between 4.92±0.51 t·hm-2·a-1 and 11.25±1.00 t·hm-2·a-1, between 2.32±0.26 t·hm-2·a-1 and 5.32±0.50 t-C-hm-2·a-1, respectively, which of the upper and middle of shady slope were significantly higher 42.5%-128.7% or 45.2%-129.3% (P<0.05) than the other five sites, and the upper, lower of sunny slope, the lower of shady slope and the valley were higher 10.6%-56.3% or 14.2%-53.4% than the middle of sunny slope, but only the lower of shady slope had significant difference with it (56.3% or 53.4%, P＜0.05). The NPP and ANCS took on the upper and middle of shady slope > the upper, lower of sunny slope, the lower of shady slope, and the valley> the middle of sunny slope change regularity.Therefore, the ecosystem carbon storage and carbon sequestration capacity of natural birch forests were strongly influenced by the site types in Changbai Mountains of China, and the site differentiation regularity should be considered in the evaluation of the carbon sink function.