Creating woodland through natural processes: current understanding and knowledge gaps in Great Britain

•1. Creating woodlands through natural processes, as opposed to traditional tree planting, is expected to result in more structurally diverse, locally adapted woodlands that enhance the resilience of existing treescapes. However, the outcomes of natural colonisation can be variable, and there is still considerable uncertainty around the ecological processes involved. •2. To address knowledge gaps and guide a future research and policy agenda, we synthesise current knowledge of the ecology of natural colonisation in Great Britain. We combine expertise from 31 practitioners and researchers spanning varied British contexts, including insights from 15 case studies and an expert survey on the relative importance of ecological factors influencing natural colonisation. •3. The most important determinants of successful natural colonisation, identified by practitioners and researchers, were the availability of seed sources and low levels of herbivory. However, key knowledge gaps remain around the timeframe and trajectory of woodland development and appropriate management practices. Natural colonisation and tree planting can be combined to meet diverse woodland objectives, but this has been little explored to date. •4. Solutions . Land managers and advisors face uncertainty and many knowledge gaps when creating woodland through natural processes. Site monitoring and adaptive management can help meet site objectives that, in turn, can be supported by policies reflecting uncertainties in the process. Collaboration between researchers and land managers to monitor woodland development, use experimental approaches and share knowledge will help further applied ecological understanding, supporting informed decision‐making by land managers.