东北林区主要森林类型土壤有机碳密度及其影响因素

Soil organic carbon density and its influencing factors of major forest types in the forest region of Northeast China

2011年在东北林区研究了5种主要森林类型（针叶混交林、针阔混交林、阔叶混交林、落叶松林和白桦林）4个林龄（幼龄林、中龄林、近熟林和过熟林）的土壤碳密度．结果表明：东北林区不同森林类型的土壤有机碳含量和有机碳密度均以表层土壤最高，随土壤深度的增加逐渐减少，而随森林类型和林龄的变化并不显著；森林土壤有机碳主要集中在表层土壤，其中大兴安岭、小兴安岭和长白山森林0～20cm土壤贮存了其剖面总有机碳密度的84．7％～86．1％、51．7％～59．8％和51．2％～53．4％．随纬度的增加，森林土壤总有机碳密度明显下降，可能与东北林区土壤发生层的厚度密切相关．

The five main forest types, i.e. larch forest, birch forest, coniferous mixed forest, broad- leaved mixed forest, and coniferous and broadleaved mixed forest, with varied age classes （young, mid-aged, pre-mature, and over mature） were selected to investigate the variation of soil organic carbon density in the forest region of Northeast China. Results showed that both soil organic carbon content and density were relatively larger in the top soil layer across the five forest types, decreased gradually with soil depth, and varied insignificantly with either forest type or forest age class. The forest soil carbon density was concentrated in the top 20 cm of soil which accounted for 84.7% - 86. 1%, 51.7%-59.8% and 51.2% -53.4% of total soil carbon density in the Daxing＇ an, Xiaoxing＇ an and Changbai mountains, respectively. The total soil organic carbon density decreased significantly with increasing latitude, which might be attributed mainly to the thickness of soil layers in forest region of Northeast China.