Fellings as an indicator of the condition of high-mountain Norway spruce forests of the Ukrainian Carpathian Mountains

Abstract

Introduction

The dieback of Norway spruce forests in the Ukrainian Carpathians is one of the most pressing challenges in contemporary forestry, as it affects extensive mountain areas and has a systemic character. Norway spruce (Picea abies (L.) H. Karst.) has historically occupied a prominent position in the structure of Carpathian forests, performing important ecological functions, including habitat formation, water and climate regulation, and soil protection.

Materials and Methods

To assess changes in the health and resilience of high-mountain Norway spruce stands within dieback foci, a retrospective analysis of thinning and sanitary fellings carried out in the Brustury Forestry Management Unit was conducted. In this forest district, Norway spruce is the principal and dominant tree species and forms predominantly pure stands. Forest management interventions during the period 2020–2024 were analysed using official forest management reports of the forest district.

Results

The study examined temporal patterns in the volume and intensity of thinning and sanitary fellings in declining high-mountain Norway spruce (Picea abies) stands within the Brustury Forestry Management Unit during 2020–2024. Particular attention was paid to the relative prevalence of tending operations and sanitary interventions, as well as to associated harvesting volumes and felling intensity. Thinnings were characterized by generally stable intensity with only minor interannual variation, whereas selective sanitary fellings demonstrated a noticeable increase in harvested volumes accompanied by a gradual rise in intensity. Monitoring of thinning operations by type revealed considerable differentiation both in their prevalence and temporal dynamics. Throughout the analysed period, thinning from above (commercial thinning) accounted for the largest proportion of interventions, and the treated area increased steadily over time. The proportion of merchantable timber within the assortments obtained from clear sanitary fellings was also analysed as an indirect indicator of stand condition, silvicultural interventions, and management effectiveness. The analysis revealed a consistent decline in the share of merchantable timber within the total harvested volume from clear sanitary fellings over the study period.

Conclusions

In the high-mountain Norway spruce stands of the Brustury Forestry Management Unit in the Ukrainian Carpathians, the study revealed a transition from a crisis state, characterized by the predominance of sanitary interventions, toward gradual stabilization. This shift became evident in 2024, when the area subjected to thinning operations equalled and subsequently exceeded the area affected by sanitary fellings. The increase in the area, volume, and intensity of thinnings, particularly during 2023–2024, indicates the restoration of systematic forest management and a transition from measures aimed primarily at mitigating the consequences of large-scale forest degradation to silvicultural practices focused on the formation and improvement of spruce stands. Overall, the obtained results confirm that felling-related indicators can serve as reliable proxies for assessing forest condition and vitality. They also highlight the importance of their systematic application for detecting degradation processes in spruce forests and for supporting evidence-based forest management strategies.

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