1973~2013年黑龙江省森林碳储量及其动态变化

基于1973~2013年8次省森林清查数据以及实测数据改进的生物量蓄积量转换参数，利用生物量转换因子连续函数法，研究了近40a黑龙江省森林碳储量及其动态变化.结果表明：黑龙江省森林碳储量从1973~1976年的1159.35 TgC下降到2009~2013年的833.99 TgC，其中天然林减少387.51 TgC，人工林增加62.15 TgC；森林总体表现为碳源（-10.88 TgC/a），主要归因于天然林面积的减少.不同森林类型的碳储量存在较大差异，桦木、落叶松和阔叶混是碳储量的主要贡献者；大多数森林类型的碳密度呈上升趋势.森林以中、幼龄林为主，中龄林碳储量占同期全省总量的27.9%~46.6%，其他龄组的碳储量均呈减少趋势，以成熟林最为明显（201.17 TgC）；幼龄林、中龄林和近熟林的碳密度分别增加2.20、3.21和3.43MgC/hm²，成熟林和过熟林则有所下降；不同龄组森林面积和碳密度的变化是导致其碳储量变化的主要原因.

Biomass carbon stocks and dynamics of forests in Heilongjiang Province from 1973 to 2013

Based on the data from eight consecutive provincial forest inventories for the period of 1973~2013, and the updated biomass-volume relationship retrieved from field measurements, the dynamics of forest biomass carbon stocks were systematically analyzed using the newly refined continuous biomass expansion factor model in Heilongjiang Province over the past four decades. The results showed that the provincial total biomass carbon stocks decreased from 1159.35 to 833.99 TgC between 1973~1976 and 2009~2013. Natural forests completely contributed to such stock reduction of 387.51TgC, while planted forests increased by 62.15TgC. Forests functioned as a biomass carbon source of -10.88TgC/a, primarily caused by the decrease in the area for natural forests. Different types of forests exhibited substantial temporal variations of the biomass carbon stocks. Betula, Larix, and mixed coniferous and broadleaf forests were the major contributors to the total biomass carbon stocks. The biomass carbon density for most types of forests increased from 1973 to 2013. Currently, forests were dominantly young and middle-aged forest stands in Heilongjiang. Middle-aged forests had the largest proportion ranging from 27.9% to 46.6% of the total biomass carbon stocks during 1973~2013. The biomass carbon stocks decreased in all forest age groups but middle-aged forests, with the largest decrease of 201.17 TgC for mature forests. The biomass carbon density for young, middle-aged and premature forests significantly increased by 2.20, 3.21 and 3.43 MgC/hm² during the entire study period, respectively. However, the biomass carbon density for mature and overmature forests showed a downward trend. The dynamics of biomass carbon stocks for different age groups were mainly driven by the changes in forest area and biomass carbon density.