Tree planting has been the most common woodland expansion strategy in the UK for many decades. Despite its many benefits, this approach is increasingly being questioned following overestimates of benefits, poor targeting and challenges in scaling-up tree planting at the level required to meet ambitious woodland expansion targets. Consequently, there is growing interest in incorporating 'natural colonisation' (allowing trees to colonise new areas naturally) into woodland expansion strategies, partly because it is assumed that naturally created woodlands will be more structurally diverse, ecologically complex and resilient than planted sites. Embracing natural colonisation as a complementary approach to tree planting has the potential to radically transform UK treescapes and unlock woodland expansion at scale. Tree planting and natural colonisation may be used in complementary and blended combinations across a landscape, depending on the local conditions and the benefits expected. However, we know very little about the socio-ecological consequences of creating woodlands through approaches incorporating natural colonisation. We also have a poor understanding of land managers' attitudes towards woodland creation approaches other than tree planting, and it is not clear which kinds of land managers do, or would, engage with woodland creation through alternative approaches incorporating natural colonisation, and why. Using an inter-disciplinary approach, we will explore agricultural land managers' attitudes towards woodland creation strategies spanning the planting to natural colonisation continuum. We will also quantify the differing ecological and social consequences of these approaches, and identify factors associated with woodland resilience. Finally, we will integrate socio-ecological evidence to demonstrate how tree planting and natural colonisation can be used in combination to scale-up woodland expansion for a range of objectives on agricultural land. We will focus on broadleaf, and mixed broadleaf and conifer, woodlands created in agricultural landscapes with varying degrees of land-use intensity (from intensive arable lowland to marginal grassland on the upland fringe) and surrounding woodland cover, as these factors are likely to influence stakeholder perceptions and socio-ecological outcomes of woodland creation methods. These landscapes represent a major portion of UK land area with potential for woodland expansion. We will exploit two unique and complementary networks of woodland sites across the UK to create a novel platform from which to assess stakeholders' perceptions and socio-ecological consequences of woodland creation approaches spanning the planting to natural colonisation continuum. These sites provide a rich data resource and access to a diverse range of land-mangers. TreE_PlaNat will provide the evidence base to inform how, where, and for whom different strategies along the 'planting' to 'natural colonisation' continuum can be used to meet Government woodland expansion targets. Stakeholder organisations, including NGOs, statutory agencies and industry, are embedded in this proposal as co-applicants and project partners, demonstrating the co-development of this project and facilitating implementation of our findings.