A Large-Scale Environmental Sensor Network for Forest Fire Prevention and Reforestation Monitoring

Ground-level soil-moisture and microclimatic data are scarce in Mediterranean forests, although they are relevant for wildfire prevention and reforestation planning. This paper presents the design, deployment and field operation of a large-scale LoRaWAN-based wireless sensor network in a fire-prone Mediterranean forest in Valencia (Spain). The network comprises 133 operational low-power nodes within a circular area of approximately 7854 ha (5 km radius), deployed according to the WRB soil classification, with multi-depth soil-moisture probes, multi-height temperature and relative humidity sensors, two redundant gateways and solar-powered autonomous operation supported by an explicit energy budget. During a spring campaign (April–May 2025), the network captured a common soil-moisture recharge event followed by soil-dependent drying, with higher retention in calcic Kastanozems and faster drying in haplic Calcisols; mean volumetric water content ranged from 13% to 20% among soil units. As a proof of concept, the measurements were converted into a soil moisture deficit index referenced to field capacity and a relative atmospheric stress index, combined into a locally defined composite indicator that is positioned against the Canadian FWI System and the AEMET fire-danger index. The results demonstrate the feasibility of soil-aware, low-cost in situ monitoring that can complement operational fire-danger products and support reforestation planning.