Impact of ice rain on forests of Russky Island

Abstract

Hazardous weather events, which are increasing in frequency with global climate change, pose a threat to forest ecosystems over large areas. Heavy and destructive icy rain occurred in the south of Primorye on November 19, 2020. As a result of the breaking of branches and trunks on the territory of Russky Island, which is part of the Vladivostok urban district, 9.4 ± 1.7 m3/ha of dead fallen wood, which amounted to 4.8% of the total stock of stem wood, was produced. More than a third of all trees lost 50% of their crown. Specific losses of crown phytomass, calculated using regional allometric equations, are estimated at 12.2 ± 2.1 t/ha. The species that were most vulnerable to ice rain (Tilia amurensis and Betula dahurica) were represented by the largest trees, with a wide crown and a large proportion of branches in the total biomass. Lower canopy species (Carpinus cordata and Acer mono) were less affected. The share of the fallen stock of the forest stand (in relation to the total stock) was positively related to the height above sea level (R2 = 0.54, p = 0.039), and the average diameter of the stand was significantly correlated with the phytomass of the fallen part of the crowns (R2 = 0.51, p = 0.047). NDVI vegetation index values obtained from MODIS images for the 2020 and 2021 seasons (before and after the disturbance, respectively) differed significantly.