Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

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Multivolume work

Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [TP-2 SPECTRAL SIGNATURES]

Document type:: Multivolume work

Structure type:: Chapter

The change of spectral signatures of beech and spruce by forest damage W. Kirchhof & H. Hoffmann DLR - German Aerospace Research Establishment, Institute for Optoelectronics, D-8031 Oberpfaffenhofen, F.R. Germany Abstract In the Federal Republic of Germany multispectral scanner techniques were developed for forest damage classification and mapping. To improve our understanding of spectral signature changes by forest damage and to optimize damage identification and separation high resolution spectroradiometer measurements of tree components were performed in the laboratory, simulating scanner data acquisition. The measurements of healthy and damaged beech and spruce branches proved the influence of primary effects of damage on spectral reflectance in the 0.49 - 2.50 pm region. In the visible discolouration influences largely the course of spectral signatures, causes red shift of the reflexion peak and a variation of shape at the beginning to the NIR plateau. In the IR reflectance decreases with increasing damage level for beech. For spruce branches the NIR plateau level reduces also with increasing damage. For wavelengths greater 1,4 pm the curves raise with higher damage level. Keywords: Forest damage, spectral signature, beech, spruce, remote sensing, classifi cation 0 Introduction During the last decade in the Federal Republik of Germany and adjacent central European countries severe forest damage has been observed. This damage comprises large regions and varies largely. It seems neither caused by natural hazards like storms or climatic anomalies or of "classic" biotic or abiotic origin. Damage is optically visible by the loss of leaves or needles, in many cases by their discolouration (yello wing) , the thinning of crowns and anomalous branching. Damage symptoms become at first visible in the crown section. Damage measuring systems, therefore should preferably gather data with the view at the top of trees. Aerial photo graphs or multispectral scanner data from airborne or satellite plattforms fulfill these requirements. At the beginning of forest damage mainly fir and spruce trees were affected, Hermann et al., 1988, but since 1983 steep damage increase for deciduous trees was recorded, Land auer et al., 1989. Following the results of the 1987 forest damage statistics for the Federal Requblic of Germany 65,7 percent of beech and 64.5 percent of oak trees, Anon., 1987, were already damaged. 39 percent of forests are deciduous, 61 percent coniferous forests, total damage amounts to 50,2 percent in 1984 52,3 in 1987 and 52,4 in 1988. Forest damage demanded inventories of its distribution and change over large areas in support of further studies, to find the reasons for the disease. Therefore, in 1987- 1989 the German Ministry for Research and Technology (BMFT), Bonn, supported a cooperative research project for the development of methods for the detection, classification and mapping of forest damage in larger areas of Germany by the use of remotely sensed multispectral data. The main research objective was the development and to some extent the verification of new multispectral scanner techniques including image processing. This approach required a new understanding of the information content of multispectral forest data in respect to damage classes of the same species. Five university institutes, two private firms and the German Aerospace Research Establish ment (DLR) took part in the project. The test areas were selected for forest damage investigations on fir, spruce, pine, beech and oak trees and stands. A description of the project and results obtained is given in Landauer et al., 1989. At the beginning of the project forest damage inventories were based on interpretation of CIR - aerial photographs. By the use of standard evalution methods and a new forest damage classification key comparable results could be reached for sample areas in different regions and at variable data acquisition times. The main information about damage or disease was derived from colour, but this source was varying rather widely i.e. with film type, development process and flight mission. It was one of the major results of a specialist group for photo interpretation of forest damage, summarized by Kenneweg, 1989, that' a general interpretation key, applicable for different regions and flight times is possible and structural elements of tree crowns and their reproduction in aerial photographs rather than colours are used as the main source of information for identifying different damage classes". in ’ addition discolouration by forest damage can

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