Allometric Scaling and Resource Limitations Model of Tree Heights: Part 3. Model Optimization and Testing over Continental China

Remote Sensing

Xiliang Ni¹  Taejin Park³  Sungho Choi³  Yuli Shi³  Chunxiang Cao¹  Xuejun Wang²  Michael A. Lefsky⁵  Marc Simard⁴ 

[1] State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China; E-Mails:;Survey Planning and Design Institute, State Forest Administration of China, Beijing 100714, China; E-Mail:Department of Earth and Environment, Boston University, 675 Commonwealth Avenue, Boston, MA 02215, USA;;Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; E-Mail:;Center for Ecological Analysis of Lidar, Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, USA; E-Mail:

关键词: tree height;    allometric scaling law;    resource limitation;    model optimization;    geoscience laser altimeter system (GLAS);    national forest inventory (NFI);   

DOI  :  10.3390/rs6053533

来源: mdpi

【 摘 要 】

The ultimate goal of our multi-article series is to demonstrate the Allometric Scaling and Resource Limitation (ASRL) approach for mapping tree heights and biomass. This third article tests the feasibility of the optimized ASRL model over China at both site (14 meteorological stations) and continental scales. Tree heights from the Geoscience Laser Altimeter System (GLAS) waveform data are used for the model optimizations. Three selected ASRL parameters (area of single leaf, α; exponent for canopy radius, η; and root absorption efficiency, γ) are iteratively adjusted to minimize differences between the references and predicted tree heights. Key climatic variables (e.g., temperature, precipitation, and solar radiation) are needed for the model simulations. We also exploit the independent GLAS and in situ tree heights to examine the model performance. The predicted tree heights at the site scale are evaluated against the GLAS tree heights using a two-fold cross validation (RMSE = 1.72 m; R² = 0.97) and bootstrapping (RMSE = 4.39 m; R² = 0.81). The modeled tree heights at the continental scale (1 km spatial resolution) are compared to both GLAS (RMSE = 6.63 m; R² = 0.63) and in situ (RMSE = 6.70 m; R² = 0.52) measurements. Further, inter-comparisons against the existing satellite-based forest height maps have resulted in a moderate degree of agreements. Our results show that the optimized ASRL model is capable of satisfactorily retrieving tree heights over continental China at both scales. Subsequent studies will focus on the estimation of woody biomass after alleviating the discussed limitations.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland