In recent decades, forest fragmentation has been shown to directly increase forest mortality by increasing stress, damaging habitats, and heightening vulnerability to disturbances. It also disrupts local climates and ecological processes across various regions. Therefore, we aim to summarize the literature on forest fragmentation and forest mortality. The Web of Science Core Collection (WoSCC) database was searched using the PRISMA 2020 framework. We searched for publications from 1990 to 2023 and included research articles that reported on fragmentation and mortality. Out of the 159 articles found, we selected 119 research articles for systematic review. Our review documents that most studies on forest fragmentation and forest mortality tend to be relatively short-term, focused on a local or regional scale, and based on ground survey data. We identified articles from 35 countries and major hotspots for research on forest fragmentation and mortality. The results identified that the most underrepresented biomes are Mediterranean forests, woodlands and shrubs, boreal forests, and tropical and subtropical dry broadleaf forests. The longer the time horizon of the studies, the more neutral and positive effects of forest fragmentation are reported. These positive effects are more likely to be reported for temperate biomes and studies using field measurements. The study highlighted the importance of adopting a global perspective and integrating diverse methodologies to advance our understanding of forest fragmentation and mortality. Based on our findings, we recommend that future research on forest fragmentation and mortality should have a consistent geographic distribution, use varied methodologies, and perform the efficient integration of existing data types to improve the comparability and reliability of the results.

Forest mortality (FM) is influenced by several independent factors, including forest fragmentation (FF) at different spatial scales and multi-scales, site conditions, and stand characteristics. The aim of this study was to investigate the relationship and effect of FF at various spatial scales on the probability of Scots pine FM. The presented study also analyzed the relationship of the multi-scale fragmentation index effect on forest dieback. The relationship between multiple stressors emphasizes the distinct role of FF in influencing pine FM probability. Data on forest cover, deadwood volume of Scots pine forest, and environmental variables were obtained from the Forest Information System for Europe, the Polish National Forest Inventory, and existing databases, respectively. A generalized additive model approach was used to develop models. The results showed that, at small (50–600 m), large (800–3000 m), and multi spatial scales, the FF effect on Scots pine FM probabilities was statistically significant. There is a partial effect of multi-scale fragmentation on the probability of Scots pine FM, given a holistic view of the fragmentation effect that captures both small and large-scale effects. The study concludes that to calculate FF for a particular area, analyzing different scales and capturing multi-scale level fragmentation indices is crucial to studying the cumulative effect of fragmentation on the probability of Scots pine FM.