Above-ground biomass estimation in closed canopy Neotropical forests using lidar remote sensing: factors affecting the generality of relationships
Above-ground biomass estimation in closed canopy Neotropical forests using lidar remote sensing: factors affecting the generality of relationships
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DOI：
10.1046/j.1466-822x.2003.00010.x
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发表时间：
2003-03-01
影响因子：
6.4
通讯作者：
Hofton, M
中科院分区：
文献类型：
--
作者：
Drake, JB;Knox, RG;Hofton, M
目标 先前的研究已经在激光雷达（光探测和测距）遥感数据的冠层指标与地上生物量（AGBM）等森林结构特征之间建立了牢固的、特定地点的关系，但这些关系的普遍性尚不清楚。在本研究中，我们研究了来自中美洲两个具有不同降水模式的研究区域的激光雷达指标与森林结构特征（包括 AGBM）之间关系的一般性。位置巴拿马的一系列热带湿润森林地点和哥斯达黎加的热带湿润森林。方法树冠指标（例如树冠高度）是根据机载激光雷达数据计算的。断面积、平均茎直径和 AGBM 是根据这两个地区正在进行的森林动态研究的一部分所进行的测量计算得出的。我们研究了激光雷达指标与森林结构之间关系的普遍性，以及可能的环境影响（例如叶子物候）。结果我们发现激光雷达指标与两个地区的平均茎直径、断面积和 AGBM 强相关（R-2：0.65-0.92）。我们还表明这些区域之间的关系有所不同。热带湿润森林地区树冠树木的落叶性解释了茎直径和断面积预测方程的差异。然而，即使在调整叶落后，两个研究区域之间的激光雷达指标和 AGBM 之间的关系仍然存在显着差异。我们将此归因于热带湿润森林中茎直径和 AGBM 之间潜在的异速生长关系的显着差异。 结论 在这些封闭冠层热带森林中采样的各种条件下，可以可靠地估计重要的森林结构特征。干旱落叶等环境因素对这些关系有重要影响。未来的工作应继续研究可能影响激光雷达指标与森林结构特征之间关系的普遍性的气候因素，并更严格地评估场源异速生长关系的普遍性。
Aim Previous studies have developed strong, site-specific relationships between canopy metrics from lidar (light detecting and ranging) remote sensing data and forest structural characteristics such as above-ground biomass (AGBM), but the generality of these relationships is unknown. In this study, we examine the generality of relationships between lidar metrics and forest structural characteristics, including AGBM, from two study areas in Central America with different precipitation patterns.Location A series of tropical moist forest sites in Panama and a tropical wet forest in Costa Rica.Methods Canopy metrics (e.g. canopy height) were calculated from airborne lidar data. Basal area, mean stem diameter and AGBM were calculated from measurements taken as a part of ongoing forest dynamics studies in both areas. We examined the generality of relationship between lidar metrics and forest structure, and possible environmental effects (e.g. leaf phenology).Results We found that lidar metrics were strongly correlated (R-2:0.65-0.92) with mean stem diameter, basal area and AGBM in both regions. We also show that the relationships differed between these regions. Deciduousness of canopy trees in the tropical moist forest area accounted for the differences in predictive equations for stem diameter and basal area. The relationships between lidar metrics and AGBM, however, remained significantly different between the two study areas even after adjusting for leaf drop. We attribute this to significant differences in the underlying allometric relationships between stem diameter and AGBM in tropical wet and moist forests.Conclusions Important forest structural characteristics can be estimated reliably across a variety of conditions sampled in these closed-canopy tropical forests. Environmental factors such as drought deciduousness have an important influence on these relationships. Future efforts should continue to examine climatic factors that may influence the generality of the relationships between lidar metrics and forest structural characteristics and assess more rigorously the generality of field-derived allometric relationships.