© 1989 by Institute of Chartered Foresters
A Method to detect Forest Decline in Germany—Results of a Colour-infra red Aerphotointerpretation
Landesanstalt für Ökologie, Landschaftsentwicklung und Forstplanung Leibnizstraße 10, D-4350 Recklinghausen, Deutschland
Institute of Ecology, Landscape Development and Forest Planning LeibnizstraBe 10, D-4350 Recklinghausen, West Germany
In Northrhine-Westphalia research into the causes of forest decline is aided by colour infra-red photoflights. For this purpose some small areas, and several large regions were covered by flights since 1983. The analysis reported is confined to spruce (Piceaabies (L.) Karst.) because symptoms of new forest damage are reasonably well understood.
Besides normal damage and vigour assessment, additional information such as the social status of individual trees, crown density, sample plot position in the stand and thinning activities were collected. The main outcome of the data analysis is represented by graphical illustrations. The results indicate that silvicultural treatments could not have caused the present appearance of spruce because these have not changed rapidly in the last decade and, furthermore, the research shows no correlation between thinning activities and extent of tree stress. On the contrary, dominant and edge trees indicate that all areas show the well known damage symptoms which are attributable to extreme exposure to rain, fog and wind. The new forest decline is especially unmistakable in older stands. Old trees seem more at risk than young ones.
The colour infra-red technique can only indirectly elicit relationships but the results of photointerpretation show it to be a practicable assessment method.