基于地基激光雷达估测广西桉树人工林的林分参数

Estimation of Forest Parameters of Guangxi Eucalyptus Plantation Based on Terrestrial Laser Scanning

以地面实测数据为对照,应用地基激光雷达技术对广西国有高峰林场2,5,10 a生桉树(Eucalyptus)人工林进行扫描,评估了地基激光雷达对单木识别和单木参数提取的能力,并进一步探讨其对林分参数提取的可行性。结果显示:1)地基激光雷达对桉树人工林的单木识别能力较强,总体识别率达93.45%,提取的各类单木参数在不同林龄间均存在显著差异(P<0.05),与实测趋势相一致。2)在2 a生桉树人工林中,地基激光雷达估测的单木胸径值、胸高断面积值、单木材积值与实测值均无差异。同时发现,基于地基激光雷达结合AdQSM重建林木模型的方法是可行的,其与通过立木材积模型计算的结果呈现极显著的线性相关(P<0.01,R^(2)=0.96,MAE=0.05m^(3))。3)在林分水平上,地基激光雷达对林分平均胸径、平均树高、林分断面积、单位蓄积量的估测精度分别为94.69%,93.75%,89.66%,84.22%,具有较优的估测能力。研究表明,应用地基激光雷达可以在样地尺度上快速估测桉树人工林的林分参数。

Using ground real data as a control,this study applied terrestrial laser scanning(TLS)to scan eucalyptus plantations at different stand ages(2,5,10 a)in Guangxi State-owned Gaofeng Forest Farm,assessed the ability of TLS in individual tree identification and extraction of tree parameters and further explored its feasibility for extracting forest parameters.The results showed that:1)TLS had a strong ability to identify individual tree in eucalyptus plantations,with an overall recognition rate of 93.45%.Its extracted tree parameters of various types were significantly different among different stand ages(P<0.05),which was consistent with the measured trend.2)In the 2a eucalyptus plantation,there was no difference between the measured values and the estimated values of DBH,basal area,tree volume by TLS.At the same time,it was found that the method of reconstructing tree models based on TLS combined with AdQSM was feasible,and it had a very significant linear correlation with the results calculated by the standing tree volume model(P<0.01,R^(2)=0.96,MAE=0.05 m^(3)).3)At the stand level,the estimation accuracy of TLS were 94.69%,93.75%,89.66%,and 84.22%for the average diameter at breast height,average tree height,stand basal area,and standing volume,respectively,with superior estimation ability.The study showed that the application of TLS can rapidly estimate the forest parameters of eucalyptus plantations at the sample plot scale.