南京城市森林生态系统生产力与碳储量的计算

Urban forest ecosystem NPP and carbon storage based on the CASA model in Nanjing

基于遥感数据Landsat TM影像与气象数据,利用温度、水分胁迫系数改进CASA模型,对南京市森林生态系统NPP与碳储量进行估算。结果表明,南京城市森林生态系统植被NPP空间分布较均匀,平均在200～1400g/(m2.a)之间;河流、市城区裸地植被NPP最小,在0～100g/(m2.a)之间;整个南京市植被NPP空间分布由北向南呈现逐渐增加趋势,由于最南部地区为自然森林区,保留了原始的自然环境状态,NPP最大。而分布在南京市的各个森林区,森林植被NPP均在1300～1426g/(m2.a)之间。利用生物量-蓄积量方程计算出南京市针叶林、阔叶林、针阔混交林碳储量分别占全市森林碳储量的24%、59%、17%。全市森林生态系统碳储量为111.73万t,平均森林植被碳密度为17.38t/hm2,郊区和县的森林植被碳储量远远高于市区,但是两者的碳密度并无很大的差异。

Based on remote sensing data of Landsat TM and meteorological data, the forest ecosystem NPP and carbon stor- age were estimated for Nanjing city by a CASA model improved by temperature and water stress coefficient. The results showed that the NPP spatial distribution of Nanjing forest ecosystem was relatively uniform, average value was between 200 -1 400 g/（m^2 ·a）. NPP value of river and bare land in urban area was the minimum, between 0-100 g/（ m2 ·a）. The NPP spatial distribution of Nanjing city from the north to the south showed a trend of gradual increase. Because of the southern area of the city was natural forest area, which retained its original natural state, the NPP value was the largest. Forest NPP values of various forest area distributed in Nanjing were between 1 300-1 426 g/（ m2 ·a）. The carbon stocks of coniferous forest, broadleaf forest and mixed forest were accounted for 24%, 59% , and 17% of the city＇ s total forest car- bon stocks which were estimated by use of biomass-volume equation. The carbon reserves of whole city forest ecosystem were 1.117 3 million tons, average carbon density of forests was 17.38 t/hmz. The carbon storage of suburban and county forest vegetation was much higher than that of urban areas, but there were no great differences in the carbon density.