Across Canada, there is a need to verify the long-term sustainability of forest management plans. This has typically required planners to demonstrate that their forest management plans provide long-term and steady fibre supply while complying with various fibre and non-fibre constraints over a projected planning horizon of between 100 to 200 years. While this is often done aspatially (without consideration to spatial planning constraints or harvest block scheduling) many planners are beginning to plan using spatial models to both comply with provincial regulations and improve planning efficiency. This begs the question: what is spatial modelling and how do planners make the conceptual jump from aspatial to spatial modelling during forest management planning?