基于无人机影像的森林生物量估测与制图

【目的】森林生物量的精确测定,对于全球气候变化和碳循环研究具有重要的意义。【方法】以东北林业大学城市林业示范基地为研究区域,首先利用无人机平台获取整个研究区域的高分辨率无人机影像;然后在研究区域四种人工林样地中分别选取20 m×20 m的4块建模样方和4块测试样方,通过每木检尺法实测建模样方内林木的树高和胸径数据,建立H-DBH(树高-胸径)估算模型,并结合已有的DBH-SB(胸径-树干生物量)模型得到测试样方的森林生物量数据;在处理后的数字冠层高度模型(DCHM)基础上利用局部最大值法提取树高与树冠中心点位置,建立一种结合无人机影像提取树高与H-SB(树高-树干生物量)经验模型的森林生物量制图方法。【结果】不同样方的H-DBH模型R2均大于0.70,测试样方的总地上生物量平均值为6915.85 kg,总的估测精度为87%。通过ArcGIS软件结合本研究提出的方法快速得到了整个研究区域的地上生物量分布图,估测总地上生物量为4396.18 t。【结论】研究结果可为快速准确的进行森林生物量的估测提供基础数据和技术参考。

Forest biomass estimation and mapping based on high resolution UAV images

【Objective】Accurate determination of forest biomass is important for global climate change and carbon cycle research.【Method】This study took the urban forestry demonstration base of Northeast Forestry University as the research area,and firstly used the UAV platform to obtain high-resolution UAV images of the entire study area.Then four modeling quadrats and four testing quadrats of 20 m×20 m in four plantation plots of the study area were selected,and the tree height and DBH data of the modeling quadrats were measured by tally method,and the H-DBH(tree height-diameter at breast height)estimation model was established,and the forest biomass data of the testing quadrat swere obtained by combining the existing DBH-SB(stem biomass)model;Based on the processed digital canopy height model(DCHM),the local maximum method was used to extract the height of the tree and the position of the center point of the canopy,and a forest biomass mapping method combined on UAV image extracted tree height and H-SB empirical model was established.【Result】The R2of H-DBH model of different quadrats is greater than 0.7,the average total above-ground biomass of the testing quadrats is 6915.85 kg,and the total accuracy of biomass estimation is 87%.The above-ground biomass distribution map for the entire study area is quickly obtained by ArcGIS software combined with the research method proposed in this study and the estimated total above-ground biomass is 4396.18t.【Conclusion】The results of the study provide basic data and technical references for the rapid and accurate estimation of forest biomass.