小兴安岭谷地云冷杉林的碳密度与生产力

Carbon density and production in valley spruce-fir forest in Xiaoxing'an Mountains,China

采用样地清查和异速生长方程法,量化了处于衰退状态的小兴安岭谷地云冷杉林的森林碳密度和生产力.结果表明:2011年森林碳密度总量为268.14 t C·hm-2,其中植被碳密度、碎屑碳密度和土壤碳密度分别为74.25、16.86和177.03 t C·hm-2.2006—2011年,乔木层碳密度从80.86 t C·hm-2减少到71.73 t C·hm-2,主要树种冷杉、白桦、云杉和兴安落叶松的碳密度年均减少比例分别为0.5%、1.2%、2.7%和3.7%,毛赤杨、红松和花楷槭的碳密度年均增加比例分别为2.9%、3.9%和7.2%.森林净初级生产力(NPP)为4.69 t C·hm-2·a-1,地下部和地上部NPP比值为0.56,凋落物损失部分是总NPP的最大组分,所占比例为34.5%.森林生态系统中2个主要碳输出途径异养呼吸和粗木质残体分解的年通量分别为293.67和119.29 g C·m-2·a-1.森林净生态系统生产力(NEP)为55.90 g C·m-2·a-1.研究结果表明,处于衰退状态的谷地云冷杉林仍具有一定的碳汇功能.

The carbon density and production were measured using both forest inventory and allome- try approaches in the declining valley spruce-fir forest in Xiaoxing＇ an Mountains. Results showed that the total carbon density of the forest was 268.14 t C · hm-2 in 2011, and carbon densities of the vegetation, detritus and soil were 74.25, 16.86 and 177.03 t C · hm-2, respectively. From 2006 to 2011, tree layer carbon density decreased from 80.86 t C · hm-2 to 71.73 t C · hm-2. The average decrease proportions per year of carbon density were 0.5%, 1.2% , 2.7% and 3.7% for Abies nephrolepis, Betula platyphylla, Picea spp. , and Larix gmelinii, respectively. However, car- bon densities were increased by 2.9%, 3.9% and 7.2% per year for Alnus sibirica, Pinus koraien- sis and Acer ukurunduense, respectively. Net primary production （NPP） of the forest was 4.69 t C · hm-2 · a-1 The ratio of belowground NPP to aboveground NPP was 0.56. Litterfall accounted for the largest proportion of the NPP of forest with a value of 34.5%. As the two most important carbon output approaches of forest ecosystems, the fluxes of heterotrophic respiration and coarse woody debris decomposition were 293.67 and 119.29 g C · m-2 · a-1, respectively. Net ecosystem production （NEP） of the forest was 55.90 g C · m-2 · a-1. The results indicated that the valley spruce-fir forest in the declining state still had a certain carbon sink capacity.