Dynamics of pathological processes in Ukrainian forests in 2018–2024

Abstract

Introduction

The main objective of forest pathological monitoring is to develop a comprehensive assessment of the forest pathological situation both at the level of individual forestry units and at the national scale. Analysis of the temporal dynamics of forest pathological processes, their relationships with mensurational and geographical characteristics of stands, and the influence of negative environmental factors enables the prediction of their occurrence and spread and provides a basis for planning appropriate forest management measures. This study aimed to assess the extent and identify trends in the spread of pathological processes in Ukrainian forests during the period 2018–2024, based on summarized observations conducted by forestry specialists and specialized forest protection services.

Materials and Methods

The study focused on forest stands in Ukraine in which pathological processes were recorded. The system for assessing forest pathological conditions was based on routine observations carried out by forestry specialists and forest protection services. The database included stands exhibiting pathological tree dieback that required the implementation of sanitary measures. Factors initiating pathological processes were identified based on characteristic symptoms and types of damage. Data collection and summarization were performed using the online Forest Pathology Monitoring system and Microsoft Excel software. Correlation analysis was applied to identify trends in the spread of pathological processes. The extent of pathological processes was quantified by the area of forest stands in which they were observed.

Results and Conclusions

An analysis of data from the “Forest Pathology Monitoring” portal for the period 2018 and 2021–2024 showed that 34–53% of total area of affected by stand dieback of the main species was occupied by Scots pine (Pinus sylvestris L.), followed by oak (Quercus robur L.; 25–38%), ash (Fraxinus excelsior L.; 5–9%), spruce (Picea abies (L.) Karst.; 5–10%), and black locust (Robinia pseudoacacia L.; 4–6%). A decreasing trend in the extent of pathological processes was observed in pine stands, whereas an increasing trend was recorded in oak stands. The largest areas of dieback in oak, ash, and black locust were concentrated in forests managed by the Tsentralnyi Regional Office, where a clear upward trend was observed from 2018 to 2024. Dieback of spruce forests was mainly concentrated in the Carpathian region, where its extent also tended to increase during the study period. The proportion of oak stands experiencing dieback increased in the Tsentralnyi, Pivnichnyi, Karpatskyi, and Slobozhanskyi Regional Offices, while a decrease was recorded in the Poliskyi, Podilskyi, and Stolychnyi Regional Offices. The proportion of ash stands affected by dieback increased in the Tsentralnyi Regional Office but decreased in the Podilskyi, Poliskyi, and, since 2021, Pivnichnyi Regional Offices. A reduction in the proportion of drying spruce stands was observed in the Poliskyi and Stolychnyi Regional Offices, whereas an increase occurred in the Karpatskyi, Podilskyi, and Tsentralnyi Regional Offices. The highest proportion of black locust stands with deteriorating health was recorded in the forests of the Tsentralnyi Regional Office, with a steady increase observed from 2021 to 2024. A similar upward trend was also noted in the Slobozhanskyi Regional Office. Compared to the 2018 survey, the total area affected by pathological processes increased to 111% in 2021, but subsequently declined to 81%, 57%, and 58% in 2022, 2023, and 2024, respectively. The decline is primarily attributed to incomplete data resulting from limited access to monitoring in areas affected by military operations.

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