Sanitation felling against the <scp>European</scp> spruce bark beetle: A matter of intensity and forest type

Abstract European coniferous forests are increasingly vulnerable to forest disturbances due to climate change and more frequent extreme events, which can trigger forest pest outbreaks. In the Italian South‐Eastern Alps, the 2018 Vaia storm led to massive outbreaks of the European spruce bark beetle ( Ips typographus L.) (Coleoptera: Curculionidae, Scolytinae), severely affecting Norway spruce forests. Sanitation felling (i.e., removal of infested trees) is a common management practice, but its efficacy in reducing bark beetle populations is variable and context‐dependent. This study assesses the effect of sanitation felling performed in 2022 in Friuli Venezia Giulia (NE Italy) on bark beetle damage that occurred in 2023 across eight spruce forest types, as evaluated using multispectral satellite imagery. Information about forest composition was retrieved from local databases to assess how forest characteristics influence sanitation felling effectiveness. Results show that bark beetle damage was effectively reduced only at very high or very low sanitation felling rates. Sanitation felling increasing up to ~50% produced an increasing damage, while damage decreased progressively only over 50% sanitation felling. Pure spruce forests, especially mountain spruce forest and spruce plantations, were the most affected forest categories, while damage was reduced in alpine (i.e., &gt;1500 m elevation) and mixed formations. Sanitation felling above 50% proved effective in significantly reducing damage within the pure spruce neo‐reforestations and the pure subalpine spruce forests. Findings call for an integrated approach to compensate for the limitations of sanitation felling, to plan targeted interventions and help promote more resilient forest ecosystems to mitigate future outbreaks.