The ecological consequences of current climate changes that negatively affect the resistance of coniferous plants to pests and polypore fungi

Abstract

The resistance of woody plants to pests and stem rot is reduced in the Non-Chernozem zone of Russia. The spread of areas where coniferous forests are compromised and of windbreak areas is a signal of an increase in the negative impact of abiotic factors and phytopathogens. The primary role in the decomposition of the woody substrate belongs to aphyllophoric fungi. The zero stage of xylolisis occurs within one growing season or a part of it and does not affect the characteristics of wood. The first stage takes 1-2 years and leads to the formation of a ring of wood-staining fungi. At the second stage, the results of oxidation of wood milieu by aphyllophoric fungi become noticeable, and wood becomes reddened. This stage lasts from 2 to 3 years. The third stage, the period of an active growth of mycelium, which lasts from 4 to 6 years, is associated with the formation of brown rot spots. At the fourth stage, mycelium metabolizes up to 70% of the substrate until rot softens. This process takes from 4 to 8 years. The final stages of wood destruction last long, from 10 to 60 years, and result in an almost complete loss of wood structure. The succession of fungi and mesofauna is associated with an alternation of saproxylic organisms in the course of changes in the qualitative characteristics of their substrate. During our study of model trees, a relationship was found between wood perforation and fruiting bodies development. With account of the specific physiological characteristics of aphyllophoric fungi, one may conclude that the development of fruiting bodies begins upon a high level of substate degradation sufficient for the formation of a secondary vegetative mycelium.