Spatial patterns of canopy dieback and forest cover change across abiotic gradients in a protected mountain watershed of the Tatra mountains (Western Carphatians, Slovakia)

Abstract Mountain spruce forests in the Tatra Mountains have experienced extensive decline in recent decades, primarily following windthrow events and subsequent bark beetle ( Ips typographus ) outbreaks. Understanding the spatial patterns of canopy dieback and early recovery is important for assessing ecosystem development under changing climatic conditions. This study examined a closed, north-facing valley in the High and Belianske Tatras, characterized by limited direct anthropogenic disturbance. We used high-resolution aerial orthophotos from 2010 to 2019 together with abiotic variables derived from a digital terrain model, including elevation, slope, potential solar radiation, a soil moisture index, and distance to previously disturbed areas. Through spatial overlay and descriptive statistics, supplemented by principal component analysis (PCA), we quantified changes in forest cover and canopy condition and assessed how these variables were distributed along topographic gradients and forest age classes. The results show a marked decrease in healthy forest and an expansion of areas with canopy dieback between 2010 and 2019. Higher proportions of damaged forest occurred on drier, steeper, and more exposed slopes, as well as closer to earlier disturbance patches. These findings highlight the strong spatial heterogeneity of post-disturbance forest dynamics and provide baseline information for future monitoring and conservation planning in protected mountain spruce forests.