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Evaluation of remote sensing techniques for estimation of forest variables at stand level

Magnusson, Mattias (2006). Evaluation of remote sensing techniques for estimation of forest variables at stand level. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2006:85
ISBN 91-576-7134-6
[Doctoral thesis]

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Abstract

There is a continuous need for accurate forest description. Forest data at stand level is required in forestry planning, in particular when scheduling treatments within the next few years. Collection of forest data is typically acquired with subjective surveying methods in the field. However, field work is labor intensive and therefore an expensive method. An alternative to surveying methods in the field is to use remotely sensed data acquired by, e.g. optical, radar, and laser sensors. In the present thesis, different remote sensing techniques for estimation of forest variables at stand level have been evaluated. All studies were performed in hemi-boreal coniferous dominated forest at a test site in southern Sweden (lat. 58°30’N, long. 13°40’E), enabling a detailed comparison. Remotely sensed data were related to field data using regression analysis. The root mean square error (RMSE) of the average stem volume using airborne laser scanning data, CARABAS-II radar data, aerial photo-interpretation, and multi-spectral optical satellite data was found to be 13%, 19%, 21-24%, and 24-32%, respectively. The analyses clearly demonstrate that airborne laser scanning is the single remote sensing technique of those investigated that gives the most accurate stem volume and tree height estimates at stand level. The estimates from laser scanning data are better than commonly achieved with subjective surveying methods in the field. The accuracy of forest variable estimation using aerial photo-interpretation of Z/I DMC images was found to be in agreement with the results using conventional film-based panchromatic photos. Hence, the results indicate that photo-interpretation of Z/I DMC images using a digital photogrammetric workstation could replace photo-interpretation of film-based photos using analog or analytical stereoplotters without loss of accuracy. Combining two or more data sources which are complementary gives the possibility of improving estimation accuracies. Here, two particularly successful approaches were found. A combination of multi-spectral optical satellite and tree height data improved the RMSE of stem volume estimation to 11-12%. Using a combination of multi-spectral optical satellite and CARABAS-II radar data improved the RMSE to about 15%. The application of the investigated remote sensing techniques in the forestry sector is restricted to the costs and the availability of remotely sensed data. In Sweden, airborne laser scanning data might be supplied by several companies operating in a pure commercial market. The National Land Survey has the mission of aerial photo mapping on a regular basis, but aerial photo mapping is also performed by commercial companies. For multi-spectral optical satellite and CARABAS-II radar data the governmental policy effects in practice what is offered to the users.

Authors/Creators:Magnusson, Mattias
Title:Evaluation of remote sensing techniques for estimation of forest variables at stand level
Year of publishing :September 2006
Volume:2006:85
Number of Pages:38
Papers/manuscripts:
NumberReferences
ALLI. Magnusson, M. & Fransson, J.E.S. 2004. Combining airborne CARABASII VHF SAR data and optical SPOT-4 satellite data for estimation of forest stem volume. Canadian Journal of Remote Sensing 30(4), 661-670. II. Magnusson, M. & Fransson, J.E.S. 2006. Evaluation of airborne lowfrequency SAR and multi-spectral optical satellite data in combination and aerial photo-interpretation for forest stem volume estimation. Submitted. III. Magnusson, M., Fransson, J.E.S. & Olsson, H. 2006. Aerial photointerpretation using Z/I DMC images for estimation of forest variables. Submitted. IV. Magnusson, M. & Fransson, J.E.S. 2005. Estimation of forest stem volume using multispectral optical satellite and tree height data in combination. Scandinavian Journal of Forest Research 20(5), 431-440. V. Magnusson, M., Fransson, J.E.S. & Holmgren, J. 2006. Effects on estimation accuracy of forest variables using different pulse density of laser data in combination with multi-spectral optical satellite data. Submitted.
Place of Publication:Umeå
ISBN for printed version:91-576-7134-6
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:forest inventories, forest stands, aerial surveying, photointerpretation, satellites, lasers, remote sensing, methods, statistical methods, evaluation, sweden
Keywords:Forest inventory, stem volume, regression models, combined estimation, aerial photography, multi-spectral optical satellite, laser scanning, synthetic aperture radar (SAR).
URN:NBN:urn:nbn:se:slu:epsilon-1189
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-1189
ID Code:1211
Department:(S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
Deposited By: Mattias Magnusson
Deposited On:21 Sep 2006 00:00
Metadata Last Modified:02 Dec 2014 10:10

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