Modelling salvage cuts in Austrian forests – II: Mortality due to drought, bark beetle infestation and wind-induced uprooting

Austrian forests are experiencing escalating disturbances beyond wind and snow breakage, including severe bark beetle outbreaks and drought-induced events, intensified by climate change. Using Austrian National Forest Inventory data (ANFI, 1981–2021), we developed mixed-effect logistic models at plot and individual-tree levels to estimate disturbance likelihood and tree survival, focusing on coniferous, broadleaved, and mixed stands. Key predictors encompass stand basal area, tree diameter, height-to-diameter ratio, competition indices, climatic variables (drought indices, temperature), and topographic factors (e.g., TOPEX, slope-aspect). Results indicate larger trees, higher competition, and elevated drought/temperature increase susceptibility, particularly in conifers such as Norway spruce (Picea abies [L.] Karst). Broadleaved species generally exhibit greater resilience. The findings further suggest that the amount of damaged wood on neighbouring plots significantly influenced the probability of salvage logging. Moderate basal area removal reduces disturbance probability in both coniferous and broadleaved forest stands. Topographic exposure, slope and aspect modulate risks, with west- to north-west-facing slopes linked to higher probabilities in coniferous stands. Model performance was strong (AUC 0.87–0.97 for tree-level models). These findings highlight the importance of species-specific, adaptive management including targeted sanitary cuts and climate-resilient thinning to enhance forest stability and support sustainable forestry under climate warming.