摘要
森林可以固碳以减缓气候变化,在全球碳循环中占有极为重要的地位。将低效杉木人工林改造为生态效益较高的碳汇林是我国林业建设的主题之一。对南亚热带杉木人工林进行皆伐改造,保留单株杉木萌芽条,并采用速生、乡土阔叶树种营造针阔混交林,分析幼龄林前期(3—7 a)与后期(9—11 a)的针阔混交林植被层、凋落物层和0—100 cm土壤层碳储量的变化。结果表明:针阔混交林生态系统前期和后期的碳储量分别为138.56和158.56 t C·hm^(-2),其中土壤层碳储量分别为127.93和118.88 t C·hm^(-2),植被层碳储量分别为9.55和37.46 t C·hm^(-2),凋落物层碳储量分别为1.07和2.23 t C·hm^(-2)。乔木层碳储量从前期的8.43 t C·hm^(-2)显著增大至后期的36.93 t C·hm^(-2),平均固碳速率为5.7 t·hm^(-2)·a^(–1)。随林龄增大,小径级(胸径<10 cm)植株个体数减少,碳储量增大,但变化不显著,而大径级(胸径≥10 cm)植株的个体数和碳储量均显著增大。从幼龄前期到后期,小径级植株的个体数比例从98%下降为71%,碳储量比例从85%下降为30%;在大径级个体中,阔叶树种的个体数比例为41%,但碳储量比例达62%,表明碳储量增大的主要原因是大径级个体的增多,其中造林树种黧蒴(Castanopsis fissa)、米老排(Mytilaria laosensis)、楝叶吴茱萸(Evodia glabrifolia)、木荷(Schima superba)和山杜英(Elaeocarpus sylvestris)的平均碳储量显著大于杉木,对提高幼龄针阔混交林的固碳能力贡献较大。
Forests play an important role in global carbon cycle for the great capability of carbon sequestration. Reforestation from Cunninghamia lanceolata pure plantations to mixed forests of high carbon sequestration ability is one subject of forestry in China. To understand the role of young mixed plantations in carbon cycle, we chose young（3-11 years old） mixed plantations with fast-growing and native broadleaf species after clear-cutting as research objects, and studied the carbon storage of vegetation, litterfall and top 100 cm soil layer. The results showed that the ecosystem carbon storages were 138.56 and 158.56 t C·hm^（–2） in the early stage（3-7 years old） and later stage（9-11 years old）, respectively, with 127.93 and 118.88 t C·hm^（–2） in top 100 cm soil layer, 9.55 and 37.46 t C·hm^（–2） in vegetation layer, 1.07 and 2.23 t C·hm^（–2） in litter layer, respectively. The carbon storage in tree layer significantly increased from 8.43 t C·hm^（–2） in the early stage to 36.93 t C·hm^（–2） in the later stage, with average carbon sequestration rate of 5.7 t C·hm^（–2）·a^（–1）. Along with age increasing, the individuals decreased but carbon storage increased for DBH 10 cm arbors, insignificantly. However, there was a significant increase of both individuals and carbon storage for DBH ≥ 10 cm trees. From the early to later stage, DBH 10 cm arbors decreased from 98% to 71% for the individual ration and 85% to 30% for the carbon storage ratio. Broadleaf species accounted for 41% of total individuals and 62% of total carbon storage of DBH ≥ 10 cm trees, suggesting that the increment of carbon was due to increasing individuals of DBH ≥ 10 cm, and the contribution of broadleaf species to carbon sequestration was higher than that of Cunninghamia lanceolata. Among the DBH ≥ 10 cm trees, average carbon storages of five afforestation species, including Castanopsis fissa, Mytilaria laosensis, Evodia glabrifolia, Schima superba and Elaeocarpus sylvestris, were significant higher than that of Cunninghamia lanceolata.
出处
《生态科学》
CSCD
2017年第4期137-145,共9页
Ecological Science
基金
广东省林业科技创新专项项目"广东省典型区域碳汇林结构优化关键技术研究与示范"(2015KJCX027)
关键词
碳储量
针阔混交林
幼龄林
径级
林分改造
carbon storage
conifer and broadleaf mixed forest
young plantations
DBH class
forest transformation
