甘肃省5种典型人工林生态系统固碳现状与潜力

基于野外调查与室内实测数据,结合第八次全国森林资源清查资料,分析了甘肃省5种典型人工林生态系统(刺槐、杨树、油松/华山松、落叶松及云杉林)森林生态系统碳密度、碳储量,并估算了乔木层固碳潜力.结果表明: 5种典型人工林生态系统平均碳密度和总碳储量分别为139.65 t·hm^-2和85.78 Tg,不同人工林类型之间差异较大.不同龄组间碳密度表现为近熟林(250.70 t·hm^-2)最大,其次是成熟林(175.97 t·hm^-2)和中龄林(156.92 t·hm^-2),幼龄林(117.56 t·hm^-2)最低.碳储量表现为幼龄林(45.47 Tg)>中龄林(19.54 Tg)>成熟林(11.84 Tg)>近熟林(8.93 Tg),幼中龄林碳储量占总碳储量的75.9%.5种典型人工林乔木层现实固碳潜力合计为7.27 Tg,刺槐林(2.49 Tg)和杨树林(2.10 Tg)最大;各龄组中,幼龄林现实固碳潜力最大(3.78 Tg),其次是中龄林(2.04 Tg),近熟林最小(0.45 Tg).5种典型人工林乔木层最大固碳潜力达27.55 Tg,表现为刺槐林(9.42 Tg)>落叶松林(6.22 Tg)≈云杉林(6.36 Tg)>杨树林(3.18 Tg)>油松/华山松林(2.37 Tg);其中,幼、中龄林最大固碳潜力分别为18.48和6.89 Tg,占总最大固碳潜力的92%.

Carbon storage and sequestration potential of five typical plantation ecosystems in Gansu Province,China

Based on the data of the field investigation and laboratory and the database of the 8^th national forestry inventory, ecosystem carbon density, storage amount, and sequestration potential of tree layer were estimated for five typical plantation ecosystems (Robinia pseudoacacia, Populus spp., Pinus tabuliformis & Pinus armandii, which were grouped as one kind of ecosystems, Larix principis-rupprechtii, and Picea asperata) in Gansu Province. The results showed that the average carbon density and total carbon storage of the five typical plantation ecosystems were 139.65 t·hm^-2 and 85.78 Tg, respectively. Ecosystem carbon density varied among ecosystems. It followed the sequence of premature (250.70 t·hm^-2) > mature (175.97 t·hm^-2) > middle-aged (156.92 t·hm^-2) > young (117.56 t·hm^-2) forest. Meanwhile, carbon storage in these plantations ranked in the order of young (45.47 Tg) > middle-aged (19.54 Tg) > mature (11.84 Tg) > pre-mature (8.93 Tg) forest. Specifically, young and middle-aged plantations contributed the most and accounted for 75.9% of the total carbon storage. The realistic carbon sequestration potential (CP_r) by tree layer of the five typical plantation ecosystems in Gansu Province was estimated as 7.27 Tg. The two largest contributors toCP_r were R. pseudoacacia (2.49 Tg) and Populus spp. (2.10 Tg). Young plantations (3.78 Tg) showed the largest CP_r, followed by middle-aged plantations (2.04 Tg), and the value of premature plantations (0.45 Tg) was the smallest. The maximum carbon sequestration potential (CP_max) might be up to 27.55 Tg, the CP_max with different plantations ranked in the order of R. pseudoacacia (9.42 Tg)> L. principis-rupprechtii (6.22 Tg) ≈ P. asperata (6.36 Tg) > Populus spp. (3.18 Tg) >P. tabuliformis & P. armandii (2.37 Tg). The CP_max of young and middle-aged plantations was estimated as 18.48 and 6.89 Tg, respectively, which accounted for 92% of the total maximum carbon sequestration potential.