Stress‑Testing Forest Policy Pathways for Climate and Biodiversity outcomes

European forests face increasing climate extremes and disturbance pressures while being expected to deliver climate mitigation, biodiversity conservation, and multiple ecosystem services. Simultaneously, the European Union’s (EU) Green Deal aims at climate neutrality, with a growing number of EU forest-related policy targets spanning multiple sectors and including both overlapping and competing objectives. This creates uncertainty about how policy priorities translate into forest management and land-use outcomes across the EU. We thus analyse how these EU forest-related policy target portfolios, together with the institutional processes that implement them, shape climate, biodiversity, and ecosystem-service outcomes in European forests, and identify robust policy pathways under uncertain climate and socio-economic futures.

We develop and apply InsNet-CRAFTY, which couples a multi–large language model (LLM) institutional network to the agent-based land-use model CRAFTY-EU. The framework represents key features of policy processes, including bounded rationality, incremental decision-making, and unstructured information exchange, while capturing competing mandates within polycentric governance. We operationalise four interacting institutional agents representing core ministerial portfolios: Agriculture (land-use and production), Environment (biodiversity and conservation), Bioeconomy (forest-based bioeconomy innovations), and Climate (mitigation and adaptation). These agents operate in parallel, negotiate their priorities, and adjust policy instrument mixes under budget and feasibility constraints. To reflect heterogeneity across Europe, we parameterise member-state differences in institutional influence and policy prioritisation based on country-specific forest policy orientations regarding utilisation and conservation.

Institutional agents translate targets into policy instrument choices and calibrations, explicitly accounting for synergies and conflicts among instruments. We simulate policy pathways at short- (2030), medium- (2050), and long-term (2100) horizons, and evaluate outcomes using indicators of forest area and types, management strategies, carbon sequestration, biodiversity impacts, and a broad set of ecosystem services. Pathways are then stress-tested across a range of climate and socio-economic scenarios to identify when interventions trigger unintended trade-offs, or require adaptation to avoid maladaptation. The results provide a comparative assessment of pathway robustness, highlighting leverage points in instrument design, regional sensitivities, and policy mixes that maximise co-benefits for climate, biodiversity, and forest resilience under deep uncertainty.