ИСТИНА

The impacts of global climate change, caused by the growth of anthropogenic emissions of greenhouse gases, are becoming more pronounced. The average global temperature of the surface layer of air over the last 100 years has increased by approximately 1°C, while at the same time the average temperature in Russia has increased twice as fast. While there are no general regional patterns for precipitation change, precipitation showed a positive feedback: increasing where it was abundant already and decreasing in arid regions. One of the negative aspects of climate change is the increase in the number of natural hazards (hurricanes, floods, draughts, etc.). Since the beginning of the 1990s, the number of severe weather events has increased threefold in Russia and now amounts to 400-450 cases per year, having a considerable impact on forestry in Russia. A striking example of such impacts are the catastrophic consequences of floods and windthrows in 2016-2017 in the southern part of the Russian Far East. In August 2016, after prolonged and abundant precipitation, a river in central Sikhote-Alin flooded and destroyed two settlements. In another case, about half of the total precipitation for the whole year of 2017 occurred on two days (August 7-9, 2017). In the resulting flood event hundreds of Ussuriysk residents lost their homes. While it is important to improve early warning systems and flood management, the strong floods are associated with a larger-scale problem: the loss of the runoff-regulating function by forests on the slopes and terraces of the Sikhote-Alin mountain range as a result of forest fires and logging. The direct impact of extreme weather events on forests is also intensifying, as exemplified by large scale wind throws in Primorsky Krai during the typhoon Lionrock (2016). It was found that the area of continuous windthrows in Sikhote-Alin Biosphere Reserve amounted to 34,000 ha or 9% of the entire area of the biosphere reserve, which is comparable to the area of all forest fires recorded in the reserve since the 1950s. The mass loss of trees during the typhoon occurred due to an abnormally high amount of precipitation on the eve of the typhoon, because the anchoring of the root systems in the soil substrate was greatly weakened. Thus, the increase in the number of extreme events associated with forest ecosystems requires adaptive forest management measures aimed at reducing the risks of occurrence of these phenomena and mitigating their consequences.