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森林生物量大小与森林生产力水平的高低密切相关,是反映森林生态系统功能的基本数据。以河南省西峡县为研究对象,以研究区1993—2013年5期217块森林资源连续清查固定样地数据,1993、1998、2003、2008、2013年Landsat TM/ETM+/OLI遥感图像为主要信息源,建立多元线性回归、k最邻近算法、装袋算法、随机森林4种遥感估测模型。在运用十折交叉验证法对遥感估测模型进行精度评价基础上,对研究区域1993-2013年的森林地上部分生物量进行时空分析。结果表明:(1)在4种遥感估测模型中,随机森林综合性能最高,K最邻近算法次之,装袋算法第三,多元线性回归最低;(2)在12个自变量中,海拔、坡度、亮度指数、湿度指数、垂直植被指数、有效叶面积指数这6个因子是影响研究区域森林地上部分生物量的重要环境变量;(3)1993—2013年,研究区域单位面积森林生物量经历了先下降(1993—2003)、后上升(2003—2013)的复杂发展历程;(4)1993—2013年,研究区域森林地上部分生物量的空间聚集性呈持续下降趋势,生物量变化平缓的冷点地段,主要分布在交通不便、森林茂密、人类干扰活动较少的北部深山和中部浅山区,而剧烈的地段,主要分布在交通发达、人口密度大、坡度较为平缓的中部河谷与南部丘陵地带。
The size of forest biomass is closely related to the level of forest productivity, which is the basic data reflecting the function of forest ecosystem. Taking Xixia County of Henan Province as the research object and 217 samples of forest resources from 1993 to 2013 in the study area, the data of fixed plots were continuously checked. The Landsat TM / ETM + / OLI remote sensing images of 1993, 1998, 2003, 2008 and 2013 were the main Information sources, the establishment of multiple linear regression, k nearest neighbor algorithm, bagging algorithm, random forest 4 kinds of remote sensing estimation model. Based on the accuracy evaluation of the remote sensing estimation model by ten-fold cross-validation, the spatio-temporal analysis of aboveground biomass in the study area from 1993 to 2013 was conducted. The results show that: (1) Among the four remote sensing estimation models, the comprehensive performance of random forest is the highest, followed by K nearest neighbor algorithm, the third is bagging algorithm, and the lowest is multivariate linear regression. (2) Among 12 independent variables, , Slope, brightness index, humidity index, vertical vegetation index and effective leaf area index were the major environmental variables affecting the aboveground biomass of the study area. (3) From 1993 to 2013, the forest biomass per unit area in the study area (4) From 1993 to 2013, the spatial aggregation of aboveground biomass of forest in the study area continued to decrease, and the change of biomass was gentle Of the cold spots are mainly distributed in the northern mountains and the shallow central mountains in the areas with inconvenient transportation, dense forests and less human disturbance, while the violent lots are mainly distributed in the central valley and the southern part with developed traffic, dense population and steeper slopes Hilly area.