摘要
基于不同空间尺度即永久标准地的群落学调查与卫星遥感监测相结合研究了长白山亚高山针叶林的结构与动态 .标准地两次调查的间隔为 11年 .结果表明 ,每 10年的死亡率为 7%~ 9% ,进界比率为18%~ 2 0 % .鱼鳞云杉、臭冷杉及岳桦可以在林冠下顺利完成更新 ,而长白落叶松为先锋种 ,只能在林窗或裸地更新 .落叶松为云杉及冷杉提供良好的更新条件 ,从而在维持亚高山森林的稳定性上起着重要作用 .成熟林密度 (10 0 0株·hm-2 左右 )变化不大 .利用美国陆地卫星TM图像分析 1984~ 1997年植被变化表明 ,大规模的风倒等自然干扰很容易检测出来 .从景观尺度上 ,利用TM图像监测植被变化非常有效 .不同反射强度变化的象素数量统计结果表明 ,群落的进展演替与逆向演替同时存在 ,并处于相对平衡状态 .但由于图像分辨率 (30m× 30m)的关系 ,林窗很难同噪声区分开来 .长白山亚高山针叶林带因有大量的落叶松斑块而呈现出镶嵌结构 ,这种镶嵌结构被定义为亚高山植被的顶极状态 .在小尺度上 ,例如面积仅为几公顷的标准地 ,特别是混有落叶松等先锋树种的群落 ,种类组成随时间而变化 ,但是卫星图像分析结果证明 :整体上 ,亚高山植被处于稳定状态 .
The structure and dynamics of coniferous forests in Changbai Mountain were studied at different spatial scales,including ground survey of permanent plots and analysis of multitemporal satellite images.Plot-scale examinations showed that the mortality rate was 7%~9%,and the recruitment rate was 18%~20% per 10 years.Species composition changed over time.Picea jezoensis var. microsperma,Abies nephrolepis and Betula ermanii presented a self-maintaining capability,because they could regenerate under canopy.Larix olgensis was a pioneer species and could regenerate only in open land or gaps.This species played an important role by providing conditions for the regeneration of spruce and fir.The tree density in the mature forest was 1 000 stems·hm -2 for trees bigger than 3 cm in diameter,which showed no significant variations among different stands.Landsat TM images were used for detecting the cover changes from 1984 to 1997 Large scales of wind throw were detected by this approach.Based on the analysis of radiance changes at the landscape scale,the pixel number of the disturbed area was similar to that of the succeeding stands,suggesting that the forest was in a state of equilibrium.Fine gaps,however,were difficult to identify with the TM data because of its coarse resolution.The mosaic structure of the subalpine vegetation was characterized by scattered larch patches.At the landscape level,the vegetation was in a stable stage.
出处
《应用生态学报》
CAS
CSCD
2004年第7期1113-1120,共8页
Chinese Journal of Applied Ecology
基金
ThestudywassupportedbytheNationalKeyBasicResearchSpecialFoundationofChina(No.2 0 0 2CB412 5 )
关键词
针叶林
变化检测
森林动态
陆地卫星TM
树木枯死
Coniferous forest, Change detection, Forest dynamics, Landsat TM, Mortality