基于森林资源清样调查资料的森林生产力估算模式--以中国油松林为例

摘要

准确地评估森林净第一性生产力(NPP)对于评估全球收支有着十分重要的作用.本文充分利用森林资源清样调查资料,并动态地评估森林生产力,以油松林为例建立了反映生物因素(蓄积量V和林龄A)和气候因素(年实际蒸散E)综合影响的中国油松林生物气候生产力(NPPa)模型.基于所建模型和第四次我国油松林资源的清样调查资料(1989-1993年),估算了中国油松林的净第一性生产力,并借助于地理信息系统软件给出了中国油松林的分布格局.结果表明:我国油松林的平均净第一性生产力为7.82 t-hm-2-a-1,其变化幅度为3.32(11.87 t-hm-2-a-1.中国油松林净第一性生产力有明显的区域差异,表现为南高北低的分布趋势.山西和陕西为中国油松林的集中分布区,生产力水平处于中等,约为7.4 t-hm-2-a-1;油松林集中分布区的南部(四川、湖北、河南等省),生产力水平较高,均大于7.7 t-hm-2-a-1;而在油松林集中分布区的北部和西部(内蒙古、宁夏等省),生产力水平较低,NPP均低于5 t-hm-2-a-1.该研究为利用森林资源清样调查资料评估森林NPP的动态及研究其对气候变化的响应提供一个有效思路.图3表2参46.%Accurately estimating forest net primary productivity(NPP)plays an important role in study of global carbon budget.A NPP model reflecting the synthetic effects of both biotic(forest stand age,A and stem volume,V)and climatic factors(mean annual actual evapotranspiration,E)was developed for Chinese pine(Pinus tabulaeformis)forest by making full use of Forest Inventory Data(FID)and dynamically assessing forest productivity.The NPP of Chinese pine forest was estimated by using this model and the fourth FID(1989-1993),and the spatial pattern of NPP of Chinese pine forest was given by Geography Information System(GIS)software.The results indicated that mean NPP value of Chinese pine forest was 7.82 t·m-2·a-1 and varied at the range of 3.32-11.87 t·hm-2·a-1.NPP distribution of Chinese pine forests was significantly different in different regions,higher in the south and lower in the north of China.In terms of the main distribution regions of Chinese pine,the NPPs of Chinese pine forest in Shanxi and Shaanxi provinces were in middle level,with an average NPP of 7.4 t·hm-2·a-1,that in the southern and the eastern parts(e.g.Shichuang,Hunan,Henan,and Liaoning provinces)was higher(over 7.7 t·hm-2·a-1),and that in the northern part and western part(e.g.Neimenggu and Ningxia provinces)was lower(below 5 t·hm-2·a-1).This study provides an efficient way for using FID to understand the dynamics of foest NPP and evaluate its effects on global climate change.