| To explore forest carbon density and its distribution pattern are important for forest and global carbon cycling. By using the forest inventory and allometric approaches, we measured carbon density and its distribution characteristics of Pinus koraiensis plantations and Larix gmelinii plantations in different regions of Heilongjiang province (Northern slope of Xiaoxing’an Mountains, southern slope of Xiaoxing’an Mountains, eastern slope of Zhangguangcai Mountains, western slope of Zhangguangcai Mountains and Wanda Mountain). The results showed that:1) Different regions and organs on the carbon content of Pinus koraiensis plantations varied significantly, were49.59～53.45%,46.29～49.68%,4.40～47.30%and46.18～50.25%, respectively. The difference of the carbon content in the litter arbor, shrub and herb in different region were43.29～46.09%,39.25～47.39%and40.31～46.34%. The difference of the carbon content in the branches and litters and Semi-decomposed litters in different region were41.73～48.66%and35.52～43.11%. Different regions and organs on the carbon content of Larix gmelinii plantations varied significantly, were44.42～49.73%,44.53～50.62%,46.38-48.64%and45.10～49.07%. The difference of the carbon content in the litter arbor, shrub and herb in different region were significantly difference, that were42.90～49.87%,43.14～51.16%and40.49～49.21%. The branches and litters and Semi-decomposed litters in different region were39.96～51.52%and34.41-39.23%. Soil carbon content were both A layer> B layer> C layer.2) Among different regions, vegetation C (carbon) pool and detritus C pool of Pinus koraiensis plantations varied significantly, but no significant differences were observed in soil C pool and total C density. Vegetation, detritus, soil and total ecosystem C density were35.95～76.36tC·hm"2,3.52～11.34tC·hm"2,101.96～173.37tC·hm-2and154.54～256.78tC·hm-2, respectively. The distribution proportion of each ecosystem components were18.78～30.34%,1.79-5.24%and65.58-79.43%, respectively, and all differed significantly among regions. Among different regions, vegetation C pool, detritus C pool, soil C pool and total C density of Larix gmelinii plantations varied significantly. Vegetation, detritus, soil and total ecosystem C density were42.49～85.00tC-hm-2.3.60～14.00tC·hm-2,110.81～324.06tC·hm"2and157.37～396.73tC·hm-2, respectively. The distribution proportion of each ecosystem components were14.99～38.25%,1.28-4.38%å'Œ57.37～81.40%, respectively, and all differed significantly among regions.3) Overstory organs (except leaves) C density and its distributions of Pinus koraiensis plantations were different significantly among regions. The C density of stem, branch, leaf and root were22.47～47.11tC·hm-2,2.30～12.31tC·hm-2,2.90-5.80tC·hm-2and7.02～17.16tC·hm-2, respectively. And the corresponding distribution proportion were51.98-64.80%,6.68～17.19%,6.55～8.34%and20.23～22.55%, respectively. Overstory organs C density and its distributions of Larix gmelinii plantations were different significantly among regions. The C density of stem, branch, leaf and root were23.65～52.47tC-hm"2,4.16～7.21tC-hm"2,1.47～2.32tC·hm-2and8.04～18.45tC·hm-2, respectively. And the corresponding distribution proportion were61.98～66.00%,7.65～12.55%,2.49～4.42%and21.06～23.86%, respectively.4) Root-shoot ratio(R/S) and ratio of soil C density (include detritus C density) to vegetation C density (SC/VC) of Pinus koraiensis and Larix gmelinii plantations were0.26-0.29and0.27～0.31,2.31～4.69and1.69～5.67, respectively, with significant difference among regions.5) Basal area of Pinus koraiensis and Larix gmelinii plantations exhibited highly significant positive correlation with overstory C density and vegetation C density (P<0.01), which can well reflect the dynamic of forest ecosystem C density. |
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