Estimation of Aboveground Biomass in Alpine Forests: A Semi-Empirical Approach Considering Canopy Transparency Derived from Airborne LiDAR Data
1
alpS-Centre for Climate Change Adaptation Technologies, Grabenweg 3, 6020 Innsbruck, Austria
2
Institute of Geography, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
3
Vienna University of Technology, Institute of Photogrammetry and Remote Sensing, 1040 Vienna, Austria
4
Faculty of Geo-Information Science and Earth Observation of the University of Twente (ITC), 7500 Enschede, The Netherlands
5
Department of Geography, University of Heidelberg, 69120 Heidelberg, Germany
*
Author to whom correspondence should be addressed.
Sensors 2011, 11(1), 278-295; https://doi.org/10.3390/s110100278
Received: 29 October 2010 / Revised: 1 December 2010 / Accepted: 23 December 2010 / Published: 29 December 2010
(This article belongs to the Special Issue Sensors in Agriculture and Forestry)
Abstract
In this study, a semi-empirical model that was originally developed for stem volume estimation is used for aboveground biomass (AGB) estimation of a spruce dominated alpine forest. The reference AGB of the available sample plots is calculated from forest inventory data by means of biomass expansion factors. Furthermore, the semi-empirical model is extended by three different canopy transparency parameters derived from airborne LiDAR data. These parameters have not been considered for stem volume estimation until now and are introduced in order to investigate the behavior of the model concerning AGB estimation. The developed additional input parameters are based on the assumption that transparency of vegetation can be measured by determining the penetration of the laser beams through the canopy. These parameters are calculated for every single point within the 3D point cloud in order to consider the varying properties of the vegetation in an appropriate way. Exploratory Data Analysis (EDA) is performed to evaluate the influence of the additional LiDAR derived canopy transparency parameters for AGB estimation. The study is carried out in a 560 km2 alpine area in Austria, where reference forest inventory data and LiDAR data are available. The investigations show that the introduction of the canopy transparency parameters does not change the results significantly according to R2 (R2 = 0.70 to R2 = 0.71) in comparison to the results derived from, the semi-empirical model, which was originally developed for stem volume estimation. View Full-TextKeywords:
airborne LiDAR; biomass; semi-empirical model; 3D point cloud; linear regression
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Jochem, A.; Hollaus, M.; Rutzinger, M.; Höfle, B. Estimation of Aboveground Biomass in Alpine Forests: A Semi-Empirical Approach Considering Canopy Transparency Derived from Airborne LiDAR Data. Sensors 2011, 11, 278-295.