森林覆盖率在森林生长对气候干旱响应上的调节作用

The mediation of forest coverage in the responses of forest to climate drought

基于归一化差值植被指数(NDVI)和标准化降水蒸散指数(SPEI),探讨了森林生长对气候干旱的响应特征,并分析了森林覆盖率对这种响应的调节作用.结果表明,中国森林站点的森林生长对气候干旱的响应有正有负,正响应多分布于中国西南地区,在不同月份、不同时间尺度均有分布,负响应多分布于中国东南沿海地区,集中于冬、春季及短时间尺度干旱.进一步的研究发现,森林的覆盖率在森林生长对气候干旱的正响应上起着调节作用,不同等级的森林覆盖率会将森林生长对气候干旱的响应值限制在不同的范围内,随着森林覆盖率的增加,森林生长对气候干旱的响应最大值会逐渐减小.研究揭示了森林覆盖率在森林生长对气候干旱响应上的调节作用,有助于为森林管理提供一定的理论参考.

In the context of climate drought due to global warming,forest growth is increasingly affected by droughts.How forest growth responds to climate drought how climate drought is mediated by limiting factors are all uncertain.Normalized difference vegetation index(NDVI)and standardized precipitation evapotranspiration index(SPEI)were used to correlate response characteristics of forest growth to climate drought and to analyze mediation of forest coverage on the response.It was found that forest growth in China's forest sites had both positive and negative responses to climate drought.Positive responses were mostly distributed in the southwest of China,in different months and on different time scales.Negative responses were mostly distributed in the southeast coastal areas of China,and were concentrated in winter,spring and in shortterm scale of drought.Further studies found that forest coverage played a regulatory role in the positive responses of forest growth to climate drought.Different levels of forest coverage limited the response of forest growth to climate drought in different ranges.With increasing forest coverage,maximum response of forest growth to climate drought would gradually decrease.This study reveals the role of forest coverage in regulating responses of forest growth to climate drought and helps to provide a certain theoretical reference for forest management.