植物生态学报 ›› 2016, Vol. 40 ›› Issue (4): 318-326.DOI: 10.17521/cjpe.2015.1080

• 研究论文 • 上一篇    下一篇

浑善达克沙地榆树疏林和小叶杨人工林碳密度特征及其与林龄的关系

赵玮1,2, 胡中民1, 杨浩1,*(), 张雷明1, 郭群1, 乌志颜3, 刘德义3, 李胜功1   

  1. 1中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室, 北京 100101
    2中国科学院大学, 北京 100049
    3内蒙古赤峰林业科学院, 内蒙古赤峰 024000
  • 收稿日期:2015-03-10 接受日期:2015-09-08 出版日期:2016-04-29 发布日期:2016-04-30
  • 通讯作者: 杨浩
  • 基金资助:
    中国科学院战略性先导科技专项(XDA- 05050201)和国家科技支撑计划项目(2013BAC- 03B03)

Carbon density characteristics of sparse Ulmus pumila forest and Populus simonii plantation in Onqin Daga Sandy Land and their relationships with stand age

Wei ZHAO1,2, Zhong-Min HU1, Hao YANG1,*(), Lei-Ming ZHANG1, Qun GUO1, Zhi-Yan WU3, De-Yi LIU3, Sheng-Gong LI1   

  1. 1Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China

    2University of Chinese Academy of Sciences, Beijing 100049, China
    and
    3Chifeng Academy of Forestry, Chifeng, Nei Mongol 024000, China
  • Received:2015-03-10 Accepted:2015-09-08 Online:2016-04-29 Published:2016-04-30
  • Contact: Hao YANG

摘要:

榆树(Ulmus pumila)疏林是浑善达克沙地的地带性隐域植被, 小叶杨(Populus simonii)是该区域主要的防风固沙造林树种。该文通过测定两种森林生态系统乔木层(叶、枝、干、根)、草本层(地上植被和地下根系)和土壤层(0-100 cm)的碳含量, 比较了两种森林生态系统的碳密度及其分配特征, 并运用空间代替时间的方法, 阐明了乔木层、土壤层和总碳密度随林龄增加的变化特征, 估算了两种森林生态系统的固碳速率。结果表明, 榆树疏林乔木层和土壤层平均碳含量都低于小叶杨人工林, 榆树疏林生态系统总碳密度是小叶杨人工林的1/2。两种森林生态系统的总碳密度中, 乔木层碳密度和土壤层碳密度总占比98%以上; 土壤层与植被层碳密度的比值随林龄的增加而降低, 过熟林时该比值分别为1.66 (榆树疏林)和1.87 (小叶杨人工林); 榆树疏林和小叶杨人工林的乔木层、土壤层和生态系统的总碳密度随林龄的增加而增加, 其中乔木层碳密度及榆树疏林总碳密度与林龄均呈现出显著的线性正相关关系。小叶杨人工林乔木层的固碳速率约为榆树疏林的5倍, 榆树疏林生态系统和小叶杨人工林生态系统的总固碳速率分别为0.81 Mg C·hm-2·a-1和5.35 Mg C·hm-2·a-1。这一研究结果有利于估算沙地森林生态系统的碳储量, 为区域生态环境恢复和增加碳汇的政策制定提供依据。

关键词: 碳含量, 碳密度, 固碳速率, 小叶杨人工林, 榆树疏林, 林龄

Abstract:

Aims
Sparse Ulmus pumila forest is an intrazonal vegetation in Onqin Daga Sandy Land, while Populus simonii has been widely planted for windbreak and sand dune stabilization in the same region. Our objective was to compare the differences in carbon (C) density of these two forests and their relationships with stand age.
Methods
We measured the C content of tree organs (leaf, twig, stem, and root), herb layers (above ground vegetation and below ground root) and soil layers (up to 100 cm) in sparse Ulmus pumila forests and Populus simonii plantations of different stand ages, and then computed C density and their proportions in total ecosystem carbon density. In addition, we illustrated the variation in carbon density-stand age relationship for tree layer, soil layer and whole ecosystem. We finally estimated the C sequestration rates for these two forests by the space-for-time substitution approach.
Important findings
The average C contents of tree layer and soil layer for sparse Ulmus pumila forests were lower than those for Populus simonii plantations. The total C density of sparse Ulmus pumila forests was half of that of Populus simonii plantations. The carbon density of soil and tree layers accounted for more than 98% of ecosystem C density in the two forests. Irrespective of forest type, the C density ratios of soil to vegetation decreased with stand age. This ratio was 1.66 for sparse Ulmus pumila forests and 1.87 for Populus simonii plantations when they were over-matured. The C density of tree layer, soil layer, and total ecosystem in both forests increased along forest development. There were significantly positive correlations between tree layer’s C density and stand age in both forests and between the total ecosystem C density of sparse Ulmus pumila forests and stand age. The C sequestration rate of tree layer was 5-fold higher in Populus simonii plantation than in sparse Ulmus pumila forest. The ecosystem-level C sequestration rate was 0.81 Mg C·hm-2·a-1 for sparse Ulmus pumila forest and 5.35 Mg C·hm-2·a-1 for Populus simonii plantation. These findings have implications for C stock estimation of sandy land forest ecosystems and policy-making of ecological restoration and C sink enhancement in the studied area.

Key words: carbon content, carbon density, carbon sequestration rate, Populus simonii plantation, sparse Ulmus pumila forest, stand age