Forschung Aktuell

 Science Service
Nr. 1, September 2000

TU Berlin Science Service of the TU Berlin
Nr. 1 / September 2000

Landscape development
Indian satellites discover forest damage in Saxony

Data from an Indian satellite has provided scientists of the TU Berlin with evidence of growing damage to forests in Saxony. The high- resolution images are being used to determine the exact degree of damage, and will provide documentation for later comparisons.

Indian satellite images are now providing evidence of the harmful effects suffered by the forests of Saxony as a result of out-dated industrial practice in the north of the Czech Republic. After the German unification, the forests showed signs of improvement, but as production began in the factories along the border sulphur dioxide pollution again increased markedly, and large areas of forest have again died. But this is only one of the findings of a research project on which researchers at the Technische Universität (TU) Berlin are currently working. Other project objectives relate to reforestation measures.

In cooperation with the Forestry Agency of Saxony, researchers at the TU Institute of Landscape Development are evaluating high-resolution satellite data. The results can be presented at a scale of 1 : 10 000. This quality now makes it possible to localise forest damage more precisely and to recognize individual tree species or types of forest. Of special interest are the affected tree species in the "Erzgebirge" and the Dübener Heide in Saxony. In addition to the Forestry Agency of Saxony, this pilot project is also supported by the German Centre for Aeronautics and Astronautics (DLR).

"At first we wanted to evaluate the data from the MOMS-2P satellite, but following the series of mishaps on the Russian MIR space station we had to rethink. We are now using the Indian satellite system IRS-1C", explained project leader Prof. Hartmut Kenneweg. This has high resolution sensors with good sensitivity throughout the spectrum and it provides images on which objects can be identified with at six metres square. "By comparing and combining various data sets we can obtain detailed images on the computer" explains team-member Bodo Coenradie. This means, for example, that firebreaks, tracks or forest clearings can be visualised particularly well.

The interpretation of the individual pixels is now automated. However, the scientists have had to define the processes beforehand, and regular cross-checking is necessary. Recognising damage to the forests still requires a trained eye. Standard evaluation is possible on the basis of the code of practice of the VDI (Verein Deutscher Ingenieure) which Hartmut Kenneweg helped to formulate. It specifies how images from the bird's eye-view should be interpreted, and shows the crowns of different types of tree with various degrees of damage.

Such an aerial inventory offers important advantages over an evaluation of forests from the ground. Firstly, it is hoped that the use of high-resolution satellite data could save time and money. But it is also possible to carry out measurements of large areas on the computer to high levels of precision. And the overall evaluation of damage to the forest can often be carried out better than a forester on the ground is able to achieve. "They have particular difficulty registering gradual changes on their daily rounds through their forest", is how Hartmut Kenneweg sums it up. In addition to the inventory of damage to the forests, it is now planned to set up an archive which will be available for comparisons with future surveys.

This method has been used in this case to draw up forestry maps for Saxony, but other applications are also possible. It could be used, for example, to monitor agricultural land, and perhaps detect fraudulent claims for EU subsidies. Survey data would also be very useful as the basis for evaluations if areas of state-owned forest are to be privatised. Only recently the effects of the storm "Lothar" demonstrated how important it can be to have accurate data. Not only does it allow an assessment of the damage caused, but it is also an invaluable aid to the foresters who have to decide on reforestation measures. The great-grandchildren of the owners will be able to manage a healthy stand of forest, thanks to the assistance provided to the planners by these satellite images.


Contact: Prof. Hartmut Kenneweg, Technische Universität Berlin, Institute of Landscape Development
Special field: Landscape planning and management, Environmental protection
Research project: "Improved forest monitoring with MOMS-Priroda data"
Address: Str. des 17 Juni 135, 10623 Berlin, Germany, E-mail, Tel.: +49 30 314-73491, Fax: +49 30 314-23507, Internet:

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