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通过样方调查获取森林材积 ,借助于 GPS技术为调查样方准确定位。通过研究针叶林和阔叶林材积与 Landsat TM数据各波段及 NDVI和 RVI等指数的相关性 ,筛选出估算针叶林和阔叶林材积的光谱因子。根据 TM数据 7个波段信息及其线形与非线形组合 ,应用逐步回归技术分别建立估算针叶林和阔叶林材积的最优光谱模型。进而研究了粤西及附近地区的森林生物量和森林覆盖。结果表明 :若不计少量云层及地形影响 ,粤西及附近地区的森林覆盖率约为 47.8%。西江干流以北地区的森林覆盖率明显高于西江以南 ,阔叶林主要分布在西江以北 ,西江以南主要为针叶林。粤西及附近地区的森林生物量多介于 2 3~ 45 1 t· hm- 2之间 ;在约 1 90 5 0 km2范围内 ,森林生物量共计 9.2 2× 1 0 7t左右。西江以北地区的森林生物量较高 ,西江以南的森林生物量较低。生物量 >40 0 t· hm- 2的森林主要分布在黑石顶自然保护区及附近、鼎湖山及附近、德庆东北部和广宁东部。
Through the quadrat investigation to obtain the forest volume, with the help of GPS technology to accurately locate the survey quadrat. The spectral factors for estimating the volume of coniferous forest and broad-leaved forest were screened out by studying the correlation between the volume of coniferous forest and broad-leaved forest and the bands of Landsat TM and NDVI and RVI index. According to the information of 7 bands in TM data and the linear and non-linear combinations, the optimal spectral model for estimating the volume of coniferous forest and broad-leaved forest was established by using stepwise regression technique. And then studied the forest biomass and forest cover in the west of Guangdong and its vicinity. The results show that the forest cover in the west of Guangdong and the surrounding area is about 47.8%, except for a few clouds and topography. The forest coverage in the area north of the main stream of the Xijiang River was significantly higher than that of the south of the Xijiang River. The broadleaf forest was mainly distributed in the north of the Xijiang River and the conifer forest in the south of the Xijiang River. Forest biomass in western Guangdong and the surrounding areas mostly ranged from 23 to 451 t · hm-2. Within the range of 1 905 0 km2, forest biomass totaled 9.22 × 107 t. Forest biomass is higher in the area north of Xijiang River, and forest biomass in the south of Xijiang River is lower. Forests with a biomass> 40 0 t · hm -2 are mainly distributed in and around Heishiding Natural Reserve, Dinghushan and its vicinity, northeastern Deqing and eastern Quang Ninh.