吉林省东部地区植被覆盖度变化及影响因子

应用像元二分模型、多元线性回归分析方法,以2000—2010年吉林省东部植被覆盖数据为基础,综合考虑高程、气象因子、林火干扰和社会经济等因素,对吉林省东部植被覆盖度变化及影响因子进行了分析.为减少随机样本的误差,保证数据的稳定性,将原始数据集随机分为建模样本(60%)和校验样本(40%),在划分建模样本和校验样本时分别做5次重复,对5个样本分别进行模型拟合并选择显著出现3次及以上的变量进入最终模型进行拟合.结果表明:2000—2010年,吉林省东部植被覆盖呈上升趋势,但整体变化较小;研究区域植被变化类型以稳定和增加为主,占研究区总面积的91.6%,植被退化类型面积仅占研究区的8%,呈零星分布.吉林省东部的植被覆盖度变化是地形因子、气象因子和社会经济因子综合作用的结果,其影响因子重要性顺序为:"高程""月平均降水""人口密度""坡度""农村居民收入""月平均相对湿度".

Vegetation cover changes and its influence factors in eastern Jilin Province

To investigate influence factors of vegetation coverage, dimidiate pixel model and multiple linear regression analysis were applied to data on vegetation coverage of eastern Jilin Province during 2000-2010. Factors including topography, meteorological con-ditions, disturbance by forest fire, and social economics were interpreted. To minimize random sampling error and ensure data stabil-ity, 60% of the original data was used for modeling only and the rest for validation, replicated for 5 times. Fitting equation of single variable was only established when its significance occurred over 3 times. Results showed that vegetation coverage in eastern Jilin Province was on a rising trend over the study period, though the overall raise was subtle. Regions which stayed the same coverage rate and increased accounted for 91. 6% of the total coverage. Degraded vegetation scatteredly distributed across the province, ac-counting for only 8% of the study area. Regression analysis revealed that vegetation coverage in eastern Jilin was influenced by topog-raphy, meteorology and social economics. Importance of the factors in descending order is elevation, monthly mean precipitation, population density, rural resident income, and monthly mean relative humidity.