Reconstruction of the dynamics of the dark coniferous forests of the Teberdinsky Nature Reserve and prospects for their natural recovery after mass drying out

Abstract

A study was made of the mass drying of the eastern spruce (Picea orientalis (L.) Link) in the Teberdinsky Nature Reserve (North Caucasus). The main cause of the drying was an outbreak of the number of bark beetle (Ips typographus L.) whose mass reproduction occurred in the hot seasons of 2012 and 2015. The existing undergrowth was not affected. By 2019, 7 years after the beginning of the mass drying of spruce, most of the groups of drying had died out, single active bark beetle foci were noted. There are almost no live spruces of the upper tiers left. In small numbers, they have been preserved in the Dombai forestry in mixed stands of Picea orientalis (L.) Link, Abies nordmanniana (Stev.) Spach and Fagus orientalis Lipsky. As our study showed, the stands of two of the four forest areas of the reserve originated in a treeless space (250 and 350 years ago). Subsequently, three of the four underwent one strong, but local disturbance during their existence. Reconstruction of the history of dark coniferous stands of the surveyed forest areas shows a high ability for natural self-healing of the Teberdinsky fir-spruce forests after massive disturbances. In the near future (after the fall of dead wood, which is already happening), the stands of sample plots will be a sparse forest from Abies or Abies with Fagus, and most of the sample plots will become open stands with single Abies trees. The modern mass drying of the eastern spruce as a result of bark-borne epiphytotics has a much larger scale of disturbances both in the area and in the degree of destruction of the stand. This is fundamentally different from the disturbances of the past. In such a situation, the shortage of seeds will have a particularly negative impact. Therefore, the preservation of preliminary coniferous undergrowth is especially important.