Valuing urban natural capital for health and resilience: A stakeholder-informed system dynamics model for Dublin

• Integrated greening, de-paving, and care deliver broad citywide benefits • Maintenance gaps undermine even ambitious tree-planting programmes • Community stewardship accelerates gains but cannot offset funding gaps • Model acts as a stress-test tool for greener, people-centred urban planning Urban natural capital - including trees, soils, grasslands, and waterways - supports flood mitigation, air-quality regulation, carbon storage, and human well-being. However, urban greening interventions such as planting, de-paving, and maintenance are often planned and budgeted in isolation, limiting their long-term effectiveness. We co-produced a system dynamics model for Dublin that integrates seven land-cover classes with hydrological, air-quality, carbon, biodiversity, and access-related services, informed by participatory stakeholder workshops. The model was used to explore four 15-year scenarios (2025–2040), representing policy-aligned investment, no planting, underfunded maintenance, and reduced community engagement pathways, alongside sensitivity analysis of maintenance funding. Results indicate that an integrated strategy - combining sustained planting, gradual conversion of sealed surfaces to permeable green space, adequate operations and maintenance, and community stewardship - produces durable ecosystem-service and health benefits over time. In contrast, scenarios with underfunded maintenance exhibit endogenous failure modes, including declining tree health, stalled canopy growth, and substantially reduced hydrological and health outcomes, despite similar planting efforts. Sensitivity analysis highlights maintenance funding as the dominant driver of long-term performance, with positive economic returns emerging only when funding approaches full requirements. By representing feedbacks, delays, and governance constraints, the model demonstrates how well-documented urban-forestry mechanisms interact dynamically to shape long-term outcomes. The study contributes a transferable, stakeholder-informed system dynamics framework that complements static natural-capital valuation approaches and supports realistic, policy-relevant evaluation of nature-based strategies in cities.