Bridging shared PWD-resistant consensus and implementation across Mainland Portugal: An assessment framework for large-scale mixed-forest conversion projects and their cost–feasibility

Abstract

Pine wilt disease (PWD) is one of Europe’s most acute transboundary forest health threats, with Portugal and the Portugal–Spain buffer zone forming its primary defense line. Although mixed-forest conversion is widely viewed as a promising strategy for reducing host continuity and enhancing resistance, its real-world implementation has remained unclear due to the complexity of coordinating climate-driven habitat shifts, large-area planning, and long-term costs. Here we move from scientific conception to engineering practice by developing a spatial–temporal–economic assessment framework for nationwide PWD-resistant mixed-forest establishment in mainland Portugal. Using optimized MaxEnt models under SSP1–2.6, SSP2–4.5, and SSP5–8.5 scenarios for the 2030 s and 2050 s, we show that maritime pine (Pinus pinaster Ait.) suitability contracts sharply, with a northwestward centroid shift of up to ∼101 km by 2050, while a four-species mixed forest retains markedly higher stability, maintaining ∼43.3 % suitability even under SSP5–8.5. Integrating suitability with slope, accessibility, and afforestation mechanisms, we design a three-phase conversion blueprint (2025–2050) targeting 3.61–3.62 × 10⁴ km². Implementation relies on mechanical afforestation and UAV seeding, with mechanical operations accounting for > 83 % of total area. Cost modeling indicates a required investment of 3.186–4.404 B€ (128–176 M€/yr), with Phase II comprising ∼74 % of the total effort. This framework demonstrates that large-scale mixed-forest establishment is not only ecologically advantageous but also operationally and economically feasible. It provides a transferable model for converting ecological concepts into engineered forest-resilience programs under accelerating climate and biosecurity pressures.