Developing forest Digital Twins to foster the transition towards climate resilient forests

It is widely recognized that the management of German forests must be adapted to the challenges of climate change, especially in spruce-dominated forests, which have suffered significantly from drought and bark beetle infestation in recent years. Such a change in management is necessary to preserve the diverse ecosystem services provided by forests, such as wood production, carbon sequestration, and recreational value. In order to find a suitable management approach that is both socially acceptable and feasible, we are pursuing the Living Labs approach. To this end, we are working with stakeholders to develop a series of management scenarios for the forest in the Harz Mountains that meet the needs and expectations of the various stakeholders. We will present how we implement these management scenarios in a digital forest twin that uses the iLand landscape forest model as the virtual component. Although the iLand model is individual-based, it can simulate entire landscapes over centuries. iLand also allows forest management measures and biotic and abiotic disturbances to be taken into account in detail. The model is fed with environmental and forest growth data such as tree height, diameter increment, and weather variables. The model is initialized based on forest plots selected and established by our project partners, with three management modes: 1) natural forest regeneration (no management), 2) extensive management (natural regeneration, native tree species only), and 3) intensive management (removal of deadwood, including non-native tree species). In addition, we are working on initialization workflows based on existing forest classification and forest height products derived from remote sensing data to enable the application of the Digital Twin for every forest in Germany. The results of the Digital Twin are discussed and co-evaluated with stakeholders, and the underlying management strategies are adjusted as necessary. This process is repeated several times if necessary to arrive at management recommendations for a strategy to transform German forests into more climate-resilient ecosystems that can be supported by as many stakeholders as possible.