What causes the death of forests in the Siberian region? This question is increasingly being asked by residents and guests of the region. It would seem that the answer lies on the surface. There are such anthropogenic factors as fires, deforestation and impact of industrial emissions. But is it so obvious? What do we know about the forest ecosystem and the processes that affect it?

Global warming is a topic that has become popular again thanks to the Swedish schoolgirl Greta Thunberg, touched on the Siberian forest. One of the scientists' predictions is that due to warming the forest area will decrease, as there will be not enough water for coniferous trees. With climate change, forest-steppe and steppe will take the place of taiga, and fragments of deserts will appear on the border between Tyva and Mongolia. This forecast is based on climate model calculations until the end of this century.

And another unfavorable scenario is when, due to warming, new insect pests, which previously preferred more comfortable climate zones, enter Siberia. Higher temperatures and lower humidity are favourable factors for the development of many insect species. A warm climate will contribute to their increased reproduction, which means they will need new food supplies. Forestry already suffers huge losses from harmful insect activity.

Mass reproduction of insect pests leads to the fall of leaves and conifers and subsequently to the destruction of forest areas, causing huge economic and environmental damage. According to Federal Service Roslesozaschita (Russian forest protection center) in 2019 mass outbreaks of pests in the Russian forest stock are marked on the area equal to almost three million hectares. For comparison, it is a territory equal to a dozen medium-sized European states.

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Hotspots of mass reproduction of pests in Siberian forests (photo of the Federal Service Roslesozaschita (Russian forest protection center)

Over the last hundred years, ten outbreaks of mass reproduction of the Siberian silkworm, the most dangerous pest for Siberian forests, have occurred in Krasnoyarsk region. Due to warming, silkworm infestations are gradually moving north to Siberia, where they did not exist in the past. Currently, the area affected is more than one million hectares. The caterpillars completely eat the coniferous trees, and after such an invasion the trees can no longer be saved. In addition, due to dryness, the area affected by silkworm is extremely fire-hazardous.

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Siberian silkworm caterpillar (photo of the Federal Service Roslesozaschita (Russian forest protection center)

It should be noted that plantations weakened by the Siberian silkworm are a good forage base for trunk pests, including Monochamus sutor that is another dangerous insect for dark coniferous forests, in particular fir stands.

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Polygraphus proximus Blandford (bark beetle)(photo of the Federal Service Roslesozaschita (Russian forest protection center)

In addition, we observe the "intervention" of new pests that were not present in Siberia before, for example, Polygraphus proximus Blandford (bark beetle). The dynamics of the Polygraphus proximus Blandford is a prime example of insect migration due to climate change. This beetle was first discovered in Siberia in 2008 in Tomsk region. He came to us from the Far East along Trans-Siberian Railway and struck fir forests in several regions at once, including Krasnoyarsk region. Now the total area of forests damaged by the Polygraphus proximus Blandford is more than half a million hectares. The beetle is difficult to fight because the Polygraphus is under the bark, and external treatments do not produce results. An infected tree dies in two to three years. So far, the only way to prevent the insect from spreading is to cut down trees infected by the pest. At the breeding sites of bark beetles there is a decrease in productivity of dark coniferous forests, which adversely affects the ecology of the area as a whole.

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Forest areas affected by Dendrolimus sibiricus and Polygraphus proximus Blandford (photo of the Federal Service Roslesozaschita (Russian forest protection center), Krasnoyarsk region)

Based on this situation, there is an urgent need to find a solution and suppress the pest outbreaks. One of the methods of forest protection is biological. It is based on the use of living organisms against pests - their natural enemies (parasites, predators, pathogens, and others). Biological methods of control have advantages over chemical (poisoning): they do not pollute the environment, while restraining the growth of pests.

Scientists from the Institute of Forestry Technologies at Reshetnev University* have created a scientific laboratory to find solutions to this situation within the framework of the project Fundamentals of forest protection from entomo- and fittings pests in Siberia.

The main tasks of the laboratory are to increase the efficiency of the system for monitoring the growth of Siberian forest pest populations, early detection of critical moments, and development of preventive measures to control them. New biological methods of control with the use of natural enemies, such as microorganisms, will quickly and timely localize and suppress pest outbreaks. Scientists will prepare proposals to improve the sustainability of forests for implementation into the Russian forestry system. These innovations will not only reduce environmental and economic loss from insect pests, but also improve the effectiveness of forest protection measures.

Forest protection is the protection of the human environment. The forest guarantees social development and economic stability, and ensures environmental well-being. As a result of global warming, forest problems are becoming increasingly complex: threats of forest damage from fires, pests and diseases, unsustainable logging and other factors. All this requires not only the attention of specialists who have the experience and resources to solve these tasks, but also each of us.

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 "We have three years left, and if we do not take any steps now, there will be no fir left in Siberia" - says Pavel. V. Mikhailov, the head of the scientific Forest Protection laboratory of Reshetnev University.

 

*Reshetnev Siberian State University of Science and Technology