The OT4CLIMA Dataset: Multiscale vegetation surveys

Abstract The OT4CLIMA dataset was developed to address the growing need to study the impacts of climate change on terrestrial ecosystems, with particular emphasis on forest vulnerability. Forest ecosystems are increasingly threatened by climate change, as reflected by the global rice in tree dieback and mortality. Understanding forest responses to these process requires a comprehensive, multi-scale and multi-proxy framework that links large-scale environmental drivers to individual tree functioning. However, datasets that combine such spatial detail and multi-proxy resolutions remain very limited. The OT4CLIMA dataset was designed to fill this gap by providing multi-source, high-resolution data from Mediterranean mountain forests in Southern Italy-regions recognised for their pronounced sensitivity to climate change. The dataset encompasses information spanning multiple organizational and spatial scales, remote sensing observations, in situ field measurements of individual trees, and detailed assessments of leaf-level physiological and photosynthetic processes. This integrative resource enables the investigation of ecosystem dynamics across hierarchical levels, supporting research on forest function, resilience and vulnerability under ongoing climate change.