Predicting forest stand characteristics with airborne scanning laser using a practical two-stage procedure and field data
Predicting forest stand characteristics with airborne scanning laser using a practical two-stage procedure and field data
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DOI：
10.1016/s0034-4257(01)00290-5
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发表时间：
2002-04-01
影响因子：
13.5
通讯作者：
Næsset, E
中科院分区：
文献类型：
--
作者：
Næsset, E
平均树高，优势树高，平均直径。利用小足迹激光扫描仪对144个地理参考样地的林分幼林和成熟林分的不同冠层高度和冠层密度指标进行回归分析，估算了样地的茎数、基材面积和材积。样地系统分布在1000 ha的研究区内，每个样地的大小为200 m(2)。平均而言，在地面上发射的激光脉冲之间的距离为0.9英寸。地块根据年龄等级和场地质量划分为三层。层特异回归解释分别为82 ~ 95%、74 ~ 93%、39 ~ 78%、50 ~ 68%、69 ~ 89%。地面真实平均高、优势高、平均直径、茎数、基面积和体积的变异率分别为80-93%。提出了一种实用的两阶段方法来预测整个林分的相应特征。研究区域内的61个立地，平均面积为1.6公顷，被划分为200米(2)的规则网格单元。利用估计的回归方程，从相应的激光数据预测每个网格单元的六个检查特性。计算了每个展台的平均值。大多数林分水平预测是无偏的（P < 0.05）。平均高度、优势高度、平均直径、茎数、基底面积和体积预测值与地面真实值的标准差分别为0.61 ~ 1.17 m、0.70 ~ 1.33 m、1.37 ~ 1.61 cm、16.9 ~ 22.2% （128 ~ 400 ha(-1)）、8.6 ~ 11.7% (2.33 ~ 2.54 m（2) ha(-1)）和11.4 ~ 14.2% (18.3 ~ 31.9 m（3) ha(-1)）。(C) 2002爱思唯尔科学有限公司版权所有。
The mean tree height, dominant height, mean diameter. stem number, basal area, and timber volume of 144 georeferenced field sample plots were estimated from various canopy height and canopy density metrics derived by means of a small-footprint laser scanner over young and mature forest stands using regression analysis. The sample plots were distributed systematically throughout a 1000-ha study area, and the size of each plot was 200 m(2). On the average, the distance between transmitted laser pulses was 0.9 in on the ground. The plots were divided into three strata according to age class and site quality. The stratum-specific regressions explained 82-95%, 74-93%, 39-78%, 50-68%, 69-89%. and 80-93% of the variability in ground-truth mean height, dominant height, mean diameter, stem number, basal area, and volume, respectively. A proposed practical two-stage procedure for prediction of corresponding characteristics of entire forest stands was tested. Sixty-one stands within the study area, with an average size of 1.6 ha each, were divided into 200 m(2) regular grid cells. The six examined characteristics were predicted for each grid cell from the corresponding laser data utilizing the estimated regression equations. Average values for each stand was computed. Most stand level predictions were unbiased (P>.05). Standard deviations of the differences between predicted and ground-truth values of mean height, dominant height, mean diameter, stem number, basal area, and volume were 0.61-1.17 m, 0.70-1.33 m. 1.37-1.61 cm, 16.9-22.2% (128-400 ha(-1)), 8.6-11.7% (2.33-2.54 m(2) ha(-1)) and 11.4-14.2% (18.3-31.9 m(3) ha(-1)), respectively. (C) 2002 Elsevier Science Inc. All rights reserved.