Investigation of ash stands' health condition in emerald ash borer (Agrilus planipennis Fairmaire) infestation: Case study in Holosiivskyi District, Kyiv, Ukraine

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The aim of this study is to comprehensively assess the health condition of ash stands in Holosiivskyi National Nature Park, Kyiv, and identify the main biotic and abiotic factors contributing to stand decline, determining damage distribution patterns and the role of individual factors in stand degradation.Field observations were conducted during the peak growing season to ensure accurate assessment of tree health parameters.This research demonstrates the complex interactions between invasive and stem pests, fungal and bacterial pathogens, and abiotic factors in ash stand degradation.Research was conducted in 2023-2024, combining forest pathological surveys, identification sample collection (n > 110), stand assessment by health condition classes, and pest monitoring using pheromone and color-based traps with D-shaped exit hole counts.The weighted average health condition index (HCI = 3.82) indicates severe stand damage and high proportions of dying trees.Most studied trees exhibited dead branches and symptoms of decline.Healthy trees (health class I) comprised only 7%, while declining or dead trees (health classes IV-VI) accounted for over 57%.Trees with 48-88 cm diameters showed the highest vulnerability.Stem pest emergence rates were: Agrilus planipennis -1.1 ± 0.2 holes/dm², Hylesinus crenatus -2.7 ± 1.3, Hylesinus fraxini -2.2 ± 1.3.Root rot and epicormic shoots were widespread, indicating intensive stress factor impacts.The most common damage combination in roadside stands was "rot + bacterial diseases" (3.0±0.98%) and "stem pests + rot" (3.0±0.72%), while in the interior of the park, the leading association was "rot + stem pests" (1.4±0.96%).. Results demonstrate that critical health conditions result from complex interactions among A. planipennis, stem pests, and fungal and bacterial pathogens, particularly affecting larger-diameter trees.

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