| Currently, estimations of NPP and carbon storage of forest using Eco-physiological process model and forest inventory data are reliable methods at regional or global scale. In this study, we estimated the NPP and carbon storage of forest in Jiangxi Province, China. Based on GLOBCOVER land cover、4-scale geometrical optical model and MODIS-MOD09A1 data, we analyzed the spatiotemporal characteristics of the LAI and the effects of the early 2008’great ice-storm on forest LAI and its recovery. Based on BEPS model (an Eco-physiological process model) and meteorological data, the spatiotemporal characteristics and its affecting factors of plant NPP were simulated. Using the forest inventory statistic data, calculated the carbon storage of forest in Jiangxi Province from 1988-2011, and estimated the potential carbon storage. Using forest inventory plot data, the relationship between forest NPP and forest stand age was fitted. By using GWR model and the carbon storage in forest inventory plot data, we predicted the carbon storage map of forest in Jiangxi Province in 2006.The main results are as following:1. The LAI of forest plant varied obviously with seasons, summer> spring> autumn> winter; The mean LAI of different forest types varied obviously and the order is:evergreen needle-leaf forest (5.73), evergreen broadleaf forest (4.58), mixed broadleaf and needle-leaf forest (4.01), deciduous broadleaf forest (3.19), shrub forest (1.94); the inter-annual LAI changed obviously from 2000-2012, after the 2008’great ice-storm the LAI decreased significantly showing that the forest plant was damaged severely. By 2012, the LAI was nearly recovered to the level before 2008’ice-storm.2. Simulated using BEPS model, during 2001-2010, the annual mean NPP of forest was 522.71gC·m-2·a-1, and the NPP of evergreen needle-leaf forest, evergreen broadleaf forest, mixed broadleaf and needle-leaf forest, deciduous broadleaf forest, shrub forest was 732.52 gC·m-2·a-1, 903.32 gC·m-2·a-1,566.94 gC·m-2·a-1,561.89 gC·m-2·a-1 and 347gC·m-2·a-1. The total annually NPP was 68.22TgC·m-2·a-1, and the trend of inter-annual total NPP was not significant. NPP was highest in spring, about 34.81% of total annual NPP, then summer, about 26.1%, then autumn, about 25.25%, then winter,13.85%. The effects of annual precipitation, annual mean temperature and annual solar radiation on NPP was different, annual precipitation and annual mean temperature was not limiting factors on forest plant growth, NPP was mainly limited by solar radiation.3. Based on two continuous forest inventory plot data, calculated the four parts of the plot scale NPP:NPP of live biomass, NPP of mortality, NPP of foliage turnover and NPP of fine root turnover. The relationship between NPP and forest stand age was fitted. The age structure was mainly consisted of young forests and middle age forests; NPP increased rapidly at young age stage, and peaked at middle age and mature age stage, then decresed gradually.4. Based on forest inventory statistic data and biomass-volume relationship, calculated forest carbon storage from 1988-2011 and predicted the carbon sequestration potential. The result showed that the carbon storage increased from 81.38Tg to 188.52Tg from 1988 to 2011; In 2011, the carbon density of forest was 25.95MgC·hm-2, which was considerably below the average carbon density of China and other nearby Provinces; the forest in Jiangxi province was mainly consisted by young forests and middle aged forests; with forest growing and reforestation, the carbon sequestration potential can reach 191.483TgC.5. Based on GWR model, plot scale carbon storage and environmental factors (DEM, slope, aspect, LAI, stand age and NDVI), the carbon density map of forest in Jiangxi Province was predicted. The correlation coefficient between observed carbon density and predicted carbon density was 74.6%. The result indicated that GWR can be applied to resolve spatial issue in ecology. |
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