生态学报2017，Vol.37Issue(22)：7514-7527,14.DOI:10.5846/stxb201609271955
山东蒙山森林冠层绿度与树干径向生长的关系
Relationships between forest canopy greenness and tree radial growth in the Mengshan Mountains of Shandong Province
摘要
Abstract
Forest canopy greenness and tree-ring widths are important indices describing the processes of forest growth.Questions about the relationships between the two indices and their temporal stability are still not completely answered.The canopy greenness index calculated from remote sensing maps is continuous in space,whereas tree-ring width is a comprehensive index that represents the health of the sample sites.Research concerning the relationship between canopy greenness and tree-ring width could enhance the understanding of growth conditions from multi-perspectives and help transform growth conditions of forests at different spatial scales.We collected increment cores from a Pinus densiflora forest at four sample sites with different health conditions in the Mengshan Mountains of Shandong Province and analyzed the relationships between enhanced vegetation indices and tree-ring widths.We found that 1) the variation in tree-ring width was significantly caused by the variation in forest canopy greenness in April and June for healthy forests as calculated using the Granger causality analysis,whereas the relationship was complicated for unhealthy forests.April and June represent the green-up period of the growth season,and according to the results,this green-up period was closely related to radical growth;2) canopy greenness in other months and radial growth did not have a causality relationship,rather they were both driven by other environmental factors,especially climatic factors;and 3) we used superposed epoch analysis to determine the influence of canopy greenness decrease events on radical growth,and radical growth recovery following the canopy greenness decrease events.Moderate canopy greenness decreases were not always accompanied by a decrease in radial growth;however,if radial growth had already started to decline before the severe greenness loss,then the decrease would continue for five years after canopy greenness decrease event.Radial growth experienced difficult recovery after moderate canopy greenness decrease events.We identified two or three severe canopy greenness decrease events during 2000 to 2014.After these events,radial growth significantly decreased and continued to decrease for years.Radial growth was not completely recovered five years after severe canopy greenness decrease events.The results showed that changes in forest canopy greenness could not represent the beginning of forest stress or the process of forest restoration.Correlations between canopy greenness and tree radial growth existed only in healthy forests.Declines in canopy greenness strongly influenced radical growth and was difficult to recover after losses in greenness.关键词
年轮宽度/增强型植被指数/格兰杰因果分析/叠加事件分析/森林衰退/赤松林Key words
tree-ring widths (TRI)/enhanced vegetation index (EVI)/Granger causality analysis/superposed epoch analysis/forest decline/Pinus densiflora forest引用本文复制引用
汪舟,方欧娅..山东蒙山森林冠层绿度与树干径向生长的关系[J].生态学报,2017,37(22):7514-7527,14.基金项目
国家自然科学基金重点项目(31330015) （31330015）
