Regularities of Changes in the Structure of Fir Forests Damaged as a Result of the Invasion of Polygraphus Proximus

Abstract

The era of globalization is accompanied by large-scale invasions of dendrophilic insects into forest ecosystems around the world. As a rule, the impact of invaders on native species leads to negative consequences. Perspective fore-casts of the development of the situation with alien species are not encouraging. In this regard, research on the nature and degree of transformation of natural ecosystems under the influence of invasive organisms is becoming increasingly important. The mechanism of invasion of Polygraphus proximus Blandf. in forests dominated by Siberian fir Abies sibirica Ledeb. on the territory of the Tomsk region is considered in the article. The aim of the research has been to evaluate structural changes in fir forests of Western Siberia damaged by Polygraphus proximus. Studies have been conducted in the southern part of the Tomsk region on permanent trial plots. The objects of research have been ferns and small-grass-green-moss fir forests. The structure of fir forests has been studied using standard methods. When assessing the health status, a specialized scale has been used. The main taxation parameters of the stand and natural renewal have been measured. As a result of the research, it has been revealed that the main influence of the invader falls on trees having an average diameter up to an average step of thickness inclusive. A consequence of this is an increase in the mean values of height, age, and diameter of the stand. Also, the result of the direct impact of the Polygraphus proximus is a decrease in the density of the stand by 34-37%, and the reserve by 30%. There is no significant influence of the provider on the change in the completeness and bonitet of the plantation. Reducing the closeness of crowns has led to the replacement of typical southern taiga and moss with high-grass groupings in the windows of desiccation. It is established that the activity of Polygraphus proximus can lead to a short-term change of species in mixed plantations, which is observed in ferns