基于林业清查资料的桂西北植被碳空间分布及其变化特征

基于2005-2010年林业资源清查数据,采用材积源生物量法,运用地理信息系统技术,估算和分析了桂西北植被碳密度及其储量的空间分布及其变化。结果显示:(1) 研究区域从2005年到2010年呈现碳汇变化趋势,植被碳储量由4.19×10⁴t增加到4.27×10⁴t(增幅为1.84%),植被碳密度从29.04t/hm²增加到29.57 t/hm²。(2) 从治理措施、林种起源方式及林种类型来看,自然保护区的植被碳密度最大,超过40 t/hm²。2005-2010年,人工植苗、直播、飞播和萌生方式植被碳密度增加,退耕还林工程的植被碳密度均呈明显增长(增加3.00 t/hm²),所有林种碳密度都呈不同程度的增长。 (3)植被碳密度空间分布上,大致表现为西部高、中东部低,北部高、南部低。西部区植被碳密度均值超过40 t/hm²,中东部区植被碳密度均值低于25 t/hm²。植被碳密度变化在空间分布上表现为无论是非喀斯特区还是喀斯特区的植被碳密度都有增长趋势,其中有7个县市植被碳密度升级为更高等级。研究表明,随着退耕还林、生态移民等治理措施的实施,区域植被碳密度显著增加,生态环境好转。

Spatial distribution and change of vegetation carbon in Northwest Guangxi, China on the basis of vegetation inventory data

Based on the vegetation inventory data, we investigated the density, storage and spatial characteristics and dynamics of vegetation carbon in Northwest Guangxi, China from 2005 to 2010, using biomass expansion factors and spatial analysis, respectively. The results showed that the total storage of vegetation carbon increased from 4.19 × 10⁴ t to 4.27 × 10⁴ t, about 1.84% per year. Similarly, the density of vegetation carbon also increased from 29.04t/hm² to 29.57 t/hm². Vegetation carbon density was highest (>40 t/hm²) in National Nature Reserve. From 2005 to 2010, vegetation carbon density in the previously non-vegetated land increased significantly through artificial seeding, direct seeding, aerial seeding or natural germination. Vegetation carbon density of revegetated land through Conversion of Cropland into Forestland Program was also increased by 3.00 t/hm². Vegetation carbon density from all types of forest stand was increased. With regards to the spatial distribution of carbon storage and density, the density was higher in the west, north, but lower in the middle-east, south. The average carbon density was more than 40 t/hm² in the west but lower than 25 t/hm² in the east and middle. The carbon storage and density in the karst areas and non-karst areas increased. Furthermore, vegetation carbon density in seven counties had increased to higher grade. Our study indicated that the carbon storage and density of vegetation in the study area was increased significantly and ecosystem conditions was improved through the application of policies of karst rocky desertification control, such as ecological migration and Conversion of Cropland into Forestland Program.