Spatial Variation Of Forest Litter Carbon Density And Its Impact Factors In Zhejiang Province

Litter carbon is an important carbon storage in whole forest ecosystem，even the content is little. Ourpaper based on data of Forest Resources Monitoring Center and Continuous Forest Inventory (CFI)System in Zhejiang Province from June to September2010, spatial variability of carbon densities inforest litter in Zhejiang Province was studied by Kriging interpolation method.We also explored impactfactors of litter carbon densities spatial distribution in Zhejiang Province. Main results of our study wereas follows:（1）Forest litter carbon densities in Zhejiang Province ranged from10.2to8841.4kg·hm-2with themean value of1627.1kg·hm-2, which was at relatively low-level in China.Variation coefficient ofcarbon densities in forest litter was0.54, which suggesting that there was spatial variation in forest littercarbon densities in large-scale of the whole province or small-scale of different counties.（2） It was revealed from the optimization model analysis that mean standardized androot-mean-square standardized of Exponential model were0.03528and0.9983，respectively. Thismodel was most suitable for studying the spatial variation of forest litter carbon densities. Thesemi-variance function parameters of Exponential model were sill of0.7072，range of42.6941km,nugget of0.4438. Nugget/Sill ratio value of Exponential model was62.75%，which suggesting thatthere was spatial variation induced by random factors in forest litter carbon densities in Zhejiangprovince within the range was42.6941km.（3）It was revealed from Kriging interpolation map of forest litter carbon densities in ZhejiangProvince that spatial variation in forest litter carbon densities showed a decreased tendency from inlandto coastal and its spatial distribution was basically consistent to the alignment of mountain ridge. Thatwas to say that the spatial distribution showed the three areas with southwest to northeast direction.However，spatial variations of forest litter carbon densities occurred within a local area, such asQiantangjiang river of plain of the eastern Zhejiang, Lishui, Quzhou, and Jinhua of the basin of middleZhejiang, Lishui, Wenzhou and Taizhou border on Yandang Moutain, and coastal area in southeastZhejiang.（4）The precisions of forest litter carbon densities in Plain-coastal area, Hill-basin area, andMountain area were in the following order：Plain-coastal area> Hill-basin area> Mountain area，whichindicating that Kriging interpolation precision decreased with increasing terrain complexity degree. Theprecision of Kriging interpolation improved with increasing sampling amounts within the sametopographical unit. Sampling amounts had a greater effect on Kriging interpolation precision in themountain area than in the plain-coastal area. Therefore, greater sampling amounts were required toachieve a high precision of Kriging interpolation in the complicated topographical conditions.（5）Forest litter carbon densities increased with the elevation got higher, but some areas with lower elevation had higher values, like Fenghua, Xiangshan of Ningbo, Wenlin of Wenzhou, Qingtian countyof Lishui.The higher Vegetation coverage, the higher forest litter carbon densities, but little effect ofbush and herb coverage, and humus layer depth were observed in forest litter carbon densities. Soilorganic carbon densities and forest litter nitrogen densities were correlated with forest litter carbondensities.The tree species had great effect on litterfall. The oak-based arbor had higher litter carbondensities, but the economic forest had lowest value.