An ecological approach to forest protection

Abstract

In this article the following problems are discussed: (1) the nature of stability of a forest ecosystem, i.e. resistance of a forest ecosystem to pest organisms, (2) the causes that decrease such stability, (3) the interrelations between ideas about forest ecosystem stability and some ecological concepts, (4) methods by which forest ecosystem stability may be maintained by man. The stability results from the self-defense mechanism of forest trees and natural enemies of pests. Both components are disturbed by factors unfavourable for vegetation which predispose forest to pest attack. With the exception of the aged crash of forest, the most important unfavourable factors are those brought about by man, including improper silvicultural practice and negative alterations of environmental conditions. Unfavourable abiotic factors (weather), especially drought, further disturb forest ecosystem stability. The aged crash of forest occurs when soil moisture and nutrient resources have been exhausted. The maintenance of a high level of ecosystem stability by achieved by silvicultural means. Densely stocked monocultured stands are resistant to dangerous pests if they are supplied with water and nutrients. Situations are considered in which temporary suppressive measures are appropriate. Ideas of forest ecosystem stability are in concordance with a number of ecological concepts and can be helpful for their specification.