Using Moran's I and GIS to study the spatial pattern of forest litter carbon density in a subtropical region of southeastern China

[摘要] Spatial pattern information of carbon density in forest ecosystem includingforest litter carbon (FLC) plays an important role in evaluating carbonsequestration potentials. The spatial variation of FLCdensity in the typical subtropical forests in southeastern China wasinvestigated using Moran's I, geostatistics and a geographical informationsystem (GIS). A total of 839 forest litter samples were collected based on a12 km (south–north) × 6 km (east–west) grid system in Zhejiangprovince. Forest litter carbon density values were very variable, rangingfrom 10.2 kg ha⁻¹ to 8841.3 kg ha⁻¹, with an average of1786.7 kg ha⁻¹. The aboveground biomass had the strongest positive correlationwith FLC density, followed by forest age and elevation. Global Moran's Irevealed that FLC density had significant positive spatial autocorrelation.Clear spatial patterns were observed using local Moran's I. A sphericalmodel was chosen to fit the experimental semivariogram. The moderate"nugget-to-sill" (0.536) value revealed that both natural andanthropogenic factors played a key role in spatial heterogeneity of FLCdensity. High FLC density values were mainly distributed in northwestern andwestern part of Zhejiang province, which were related to adopting long-termpolicy of forest conservation in these areas, while Hang-Jia-Hu (HJH) Plain,Jin-Qu (JQ) Basin and coastal areas had low FLC density due to low forestcoverage and intensive management of economic forests. These spatialpatterns were in line with the spatial-cluster map described by localMoran's I. Therefore, Moran's I, combined with geostatistics and GIS, couldbe used to study spatial patterns of environmental variables related toforest ecosystem.

[学科分类] 地球化学与岩石