This special issue investigates the complex interactions between abiotic and biotic factors that shape vegetation patterns in treeline ecotones. The special issue focuses on observational (field and remote sensing) and modelling studies conducted along the extreme climatic and ecological gradients at the latitudinal and elevational treelines of the globe. These are considered sentinels of global-change effects on terrestrial ecosystems, but responses to change are varied and only partially understood. We welcome submissions that address ecological, biogeochemical, or physical processes that influence treeline dynamics and patterns at multiple spatial and temporal scales. As this topic is highly interdisciplinary in scope, we encourage submissions from diverse disciplines including ecology (e.g. plant, forest, landscape), remote sensing, geography, geochemistry, microbiology, soil sciences, geomorphology, and climatology. Integrative studies that bridge gaps between disciplines are particularly welcome. Two types of manuscript submissions are possible: (1) original and/or new scientific full-length research articles presenting new data and interpretations or (2) review and synthesis papers that are invited by the editors (upon proposals from authors) and integrate data from different studies and disciplines to address state-of-the-science questions related to either the detection and description of treeline spatial and temporal patterns or the processes that may be relevant to these patterns.