Invasive leafminer moths (Gracillariidae stainton, 1854) in fauna of the Botanical Garden of Oles Honchar Dnipro National University

The aim of research was to evaluate the dependence of bark beetles foci distribution on forest site conditions as well as on Scots pine stands origin and other characteristics. Field studies were carried out in 2014-2016 in Scots pine stands of Teterivske Forestry of the State Enterprise "Teterivske Forest Enterprise" (Ukraine, Central Polissya). Data on bark beetles foci location were obtained by inspection of Scots pine stands of this forestry. Data on Scots pine stands characteristics were taken from Forest inventory Database of Production Association "Ukrderzhlisproekt" (database of forest inventory for short) as of 2014. The distribution of bark beetles infested "spots" in forest subcompartments depending on stand origin (plantations or natural stands), forest site conditions, stand age, relative density of stocking and bonitet class was compared with respective distribution of all Scots pine stands using chi-square analyses (χ2 test) and Kolmogorov-Smirnov test (λ). It was found that in Teterivske Forestry bark beetles foci occupy 5.4 % area of Scots pine plantations and 13.1 % of natural Scots pine stands. Confinement of bark beetles foci to Scots pine stands of natural origin is statistically confirmed. Bark beetles foci are absent in stands growing in dry and moist relatively poor forest site conditions (B1 and B4 respectively). In frame of relatively poor (B) and relatively fertile (C) forest site conditions bark beetles foci are confined to humid forest site conditions (B3 and C3), but age and tree species composition of stand override the effect of forest site conditions. Percentage of bark beetles foci area from Scots pine stands area increases with stand age: 52.7 % of Scots pine stands over 100 years old were infested by bark beetles. Weighted average age of all pine stands of Teterivske Forestry is 67.9 years old and in the bark beetles foci it increased from 96.5 years old in 2014 to 105.2 years old in 2016. Average age of forest stands infested by "spring" generation of bark beetles was less than infested by "summer" generation. Confinement of bark beetles foci to Scots pine stands with relative stocking density 0.6–0.8 is proved statistically. Weighted average relative stocking density of infested Scots pine stands decreased from 0.73 in 2014-2015 to 0.67 in 2016 in result of selective sanitary felling in the first years of bark beetles outbreak. Confinement of bark beetles foci to pure Scots pine stands is proved statistically for plantations and natural forests. Hypothesis about bark beetles foci confinement to the stands with bonitet class І was proved both for plantations and natural forests.