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Estimation of canopy structure and individual trees from laser scanning data

Lindberg, Eva (2012). Estimation of canopy structure and individual trees from laser scanning data. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2012:33
ISBN 978-91-576-7669-6
[Doctoral thesis]

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Abstract

During the last fifteen years, laser scanning has emerged as a data source for forest inventory. Airborne laser scanning (ALS) provides 3D data, which may be used in an automated analysis chain to estimate vegetation properties for large areas. Terrestrial laser scanning (TLS) data are highly accurate 3D ground-based measurements, which may be used for detailed 3D modeling of vegetation elements.
The objective of this thesis is to further develop methods to estimate forest information from laser scanning data. The aims are to estimate lists of individual trees from ALS data with accuracy comparable to area-based methods, to collect detailed field reference data using TLS, and to estimate canopy structure from ALS data. The studies were carried out in boreal and hemi-boreal forests in Sweden.
Tree crowns were delineated in three dimensions with a model-based clustering approach. The model-based clustering identified more trees than delineation of a surface model, especially for small trees below the dominant tree layer. However, it also resulted in more erroneously delineated tree crowns. Individual trees were estimated with statistical methods from ALS data based on field-measured trees to obtain unbiased results at area level. The accuracy of the estimates was similar for delineation of a surface model (stem density root mean square error or RMSE 32.0%, bias 1.9%; stem volume RMSE 29.7%, bias 3.8%) as for model-based clustering (stem density RMSE 33.3%, bias 1.1%; stem volume RMSE 22.0%, bias 2.5%).
Tree positions and stem diameters were estimated from TLS data with an automated method. Stem attributes were then estimated from ALS data trained with trees found from TLS data. The accuracy (diameter at breast height or DBH RMSE 15.4%; stem volume RMSE 34.0%) was almost the same as when trees from a manual field inventory were used as training data (DBH RMSE 15.1%; stem volume RMSE 34.5%).
Canopy structure was estimated from discrete return and waveform ALS data. New models were developed based on the Beer-Lambert law to relate canopy volume to the fraction of laser light reaching the ground. Waveform ALS data (canopy volume RMSE 27.6%) described canopy structure better than discrete return ALS data (canopy volume RMSE 36.5%). The methods may be used to estimate canopy structure for large areas.

Authors/Creators:Lindberg, Eva
Title:Estimation of canopy structure and individual trees from laser scanning data
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :2012
Volume:2012:33
Number of Pages:78
Papers/manuscripts:
NumberReferences
ILindberg, E., Holmgren, J., Olofsson, K., Wallerman, J., & Olsson, H. (2010). Estimation of tree lists from airborne laser scanning by combining single-tree and area-based methods. International Journal of Remote Sensing 31(5), 1175-1192.
IILindberg, E., Holmgren, J., Olofsson, K., Wallerman, J., & Olsson, H. Estimation of tree lists from airborne laser scanning using model-based clustering and k-MSN imputation (manuscript).
IIILindberg, E., Holmgren, J., Olofsson, K., & Olsson, H. Estimation of stem attributes using a combination of terrestrial and airborne laser scanning. European Journal of Forest Research Accepted
IVLindberg, E., Olofsson, K., Holmgren, J., & Olsson, H. (2012). Estimation of 3D vegetation structure from waveform and discrete return airborne laser scanning data. Remote Sensing of Environment 118, 151-161.
Place of Publication:Umeå
Publisher:Institutionen för skoglig resurshushållning, Sveriges lantbruksuniversitet
ISBN for printed version:978-91-576-7669-6
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K10 Forestry production
P Natural resources > P01 Nature conservation and land resources
U Auxiliary disciplines > U40 Surveying methods
Subjects:(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 207 Environmental Engineering > Remote Sensing
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:forest inventories, canopy, trees, lasers, remote sensing, photogrammetry, crown
Keywords:forest inventory, individual trees, canopy structure, laser scanning, LiDAR, ALS, TLS
URN:NBN:urn:nbn:se:slu:epsilon-e-497
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-497
ID Code:8888
Department:(S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
External funders:FORMAS and Hildur och Sven Wingquists stiftelse för skogsvetenskaplig forskning and Swedish Environmental Protection Agency
Deposited By: MSc Eva Lindberg
Deposited On:18 May 2012 06:55
Metadata Last Modified:02 Dec 2014 10:50

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