Abstract: Land in the UK is a scarce resource. To meet the negative emissions required to offset aviation and agriculture for Net Zero, we must change the way we use the land. But what options should be taken where? Should we plant trees? restore peatland? invest in bioenergy crops or other forms or renewables? Move to agroforestry? If we could answer those questions across the land, given that we don’t own the land, how should we incentivise those that do to provide the change we need? In this talk we focus on one set of decisions, where and when to plant trees. Even here, we find an astronomical number of options impacting a host of ecosystem services beyond CO2 sequestration. I will present a framework that harnesses UQ to move beyond scenario analysis (a detailed exploration of 3 or 4 planting options) whilst avoiding disempowering decision makers by using relying solely on optimisation. Our approach is to attempt to invert the decision problem and to offer users a guided tour of their decision space: finding a space of options compatible with user-adjustable targets on ecosystem service levels, and exploring the diversity of options and tradeoffs within that space.