中国森林凋落量时空分布特征

Spatio-temporal distribution characteristics of forest litterfall in China

通过构建全国尺度上森林叶凋落量和总凋落量与年平均温度、年平均降雨量和实际蒸散量的关系模型,应用地统计学分析方法,并结合遥感解译的森林覆盖信息,分析2001、2006和2012年中国森林叶凋落量和总凋落量的空间分布及其变异格局.结果表明:与年平均温度和降雨量相比,区域尺度上实际蒸散量对森林叶凋落量和总凋落量有更好的解释预测关系;分布于中南地区的常绿阔叶林的年凋落量最高,为636.2 g·m^(-2),分布于东北地区的温带落叶阔叶林的年凋落量范围为339~385 g·m^(-2),其中,森林叶凋落量约占总凋落量的70%.2001、2006和2012年,全国森林凋落总量分别为801、865和1032 Tg,呈明显增长趋势,而基于遥感图像解译的森林年覆盖率分别为18%、20%和24%,呈增长趋势.我国人工林面积的迅速增加和林分生长,极大影响了森林凋落物量及其动态变化,进而对森林生态系统物质循环产生重要影响.

In this study, the relationship models at national scale between forest litteffall （and leaf litterfall） and climatic factors （mean annual mean temperature, MAT; mean annual precipitation, MAP; and actual evapotranspiration, AET） were constructed. The spatial and temporal distribution patterns of forest litteffall and leaf litterfall in 2001, 2006 and 2012 were investigated by using geostatistical analysis combining with forest cover information based on remote sensing interpretation. Results indicated that the variation in litteffall and leaf litterfall were well explained at regional scales by AET than MAT and MAP. Evergreen broadleaf forest distributing mostly in South Central China possessed the highest mean yearly litteffall （ 636.2 g · m-2 ） , and that of deciduous broadleaf forest in the Northeast of China was between 339-385 g ·m-2. The forest leaf litteffall accounted for about 70% of total forest litteffall. The total forest litteffall in China increased from 801 Tg in 2001, and 865 Tg in 2006 to 1032 Tg in 2012, meanwhile, the forest coverage in China also presented an increasing trend, 18% in 2001, 20% in 2006, and 24% in 2012. The rapid increase of plantation area and stand growth in China had a great effect on the forest litteffall and its dynamic change, and the material cycle of forest ecosystem.