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

Bibliographic data

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:: [FA-3 FOREST DAMAGE]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Spectral response from thinning cuttings measured by multitemporal satellitedata. Hâkan Olsson

Document type:: Multivolume work

Structure type:: Chapter

850 ion Spectral response from thinning cuttings measured by multitemporal satellitedata. HSkan Olsson Dept, of Biometry and Forest Management, Remote Sensing Lab., Swedish University of Agricultural Sciences,S-901 83 UmeS. Phone +46 90 166596, telefax +46 90 165925. ABSTRACT Spectral mean values for thinning cuttings and seed tree stands were measured before and after cutting, using a time series of six digital Landsat TM acquisitions. The studied area, 30 km by 40 km, was situated in boreal forest at 65° N,20° E. The type of forest and degree of cutting were surveyed in field using objective sampling methods. Dominant species were Scots Pine (Pinus Silvestris), Norway Spruce (Picea Abies) and Birch (Betula Spp.). Linear regression functions for prediction of the DN values at the following year were computed for each of the first five Landsat acquisitions. This was done by using a systematic sample of pixels taken under a forest mask. Differences between the actually measured stand mean values and the predicted were obtained for the thinned stands. Thinning caused a minor increase in spectral radiance in the visual channels TM 1, TM 2 and TM 3, and a more significant increase in the middle infrared channels TM 5 and TM 7. A decrease in radiance was observed for the near infrared TM 4. Between 19 % and 51 % of the basal area was cut in the thinnings. The variations in spectral response among the thinnings could hardly be explained as a function of thinning grade. The most important factor found was the remaining proportion pine forest after cutting. The change in proportion of deciduous forest had a strong influence on TM 4. By multispectral discriminant analysis 81 % of the thinnings was detected. The spectral radiance starts to increase when more than 40 % of the basal area is cut. This is shown by measurements from five seed tree stands. The study is of basic interest for the development of standwise change detection in a GIS environment. The results are also of interest for the evaluation of Remote Sensing for the Swedish National Forest Inventory. KEYWORDS: Landsat TM, change-detection, thinning-cuttings. 1. INTRODUCTION The life cycle of a forest stand in Sweden is 80- 100 years. One to three thinning cuttings are normally carried out before the final cutting. The aim of the thinnings is to give space for the most valuable stems to grow to timber, the thinnings will also give pulp wood for sale. On the National level the forest resources in Sweden are monitored by the National Forest Inventory (NFI). The NFI covers yearly the whole of Sweden in a ground based sample plot design (Ranneby et. al. 1987). At present the possi bilities to incorporate satellite data analysis in the sampling design of the NFI are investigated (Thomas and Ranneby 1990). One of the questions raised is then how reliably thinning cuttings can be detected by satellite data analysis. The present study is part of a larger project at the Remote Sensing Laboratory in Umea. The overall aim of this project is to develop general methods for standwise change detection in a GIS environment. The most important features to detect with this technique are probably forest damages (Olsson 1989, 1990). The spectral changes to be detected are equally small in the cases of both thinnings and damages. The development of procedures for calibration and discrimination might therefore be carried out on thinnings, for future applications on damages. Earlier work on detection of thinning cuttings in Scandinavian forests has been carried out in Finland (Häme 1986). Häme found a mean increase in TM 3 and a decrease in TM 4. He considered thinnings as difficult to detect. In this paper the first results from a Swedish study are presented. It is investigated how spectrally separable thinning cuttings are from unchanged forest, using a multitemporal analysis. The spectral response in different channels as a function of thinning grade, type of forest and changes in tree species combinations are studied. It is also of interest to find linear combinations of the satellite channels that are effective in discriminating newly thinned stands from the unthinned stands. The approach to change-detection used in this study is calibration with regression functions. It has the advantages that no absolute calibration of the data is necessary, the regressors used can also be extended. The approach has successfully been tested by the author (Olsson 1990), as well as by others (Sing 1989) . Presented at the ISPRS commission VII Mid-Term Symposiom, Victoria, Canada. September 17-21 1990.

Access restriction

Copyright

fullscreen: Proceedings of the Symposium on Global and Environmental Monitoring (Part 1)

Multivolume work

Volume

Chapter

Chapter

Table of contents

Cite and reuse

Volume

Chapter

Image

Image fragment

Citation links

Citation recommendation