Small and Light Machinery To Prevent Wildfire Risk In Mediterranean Forests

The mitigation of wildfires impact on ecosystem services and human assets can be achieved by reducing the spread rate and the intensity of the fire front. As wildfires scatter through a landscape where vegetation is available for combustion, a key strategy to reduce fire intensity and fire perimeter growth is to limit the biomass available for combustion by means of the management of vegetation fuels. Typically, these forest works are non-productive operations with negative economic results, often supported by public subsidies that aim to secure the largest area possible. The study focuses on the feasibility of small and light innovative machinery to prevent wildfire risk in Mediterranean fire-prone areas, where a mix of selective and from-below thinning was used as a preventive silvicultural method to modify the load and the arrangement of both live and dead fuels. Besides reducing wildfire risk, it also aimed at promoting the growth of the most promising trees, increasing the forest value and resilience in the long term. The focus of the study is to compare the cost and productivity of the proposed system with the current preventive silviculture treatments, mainly based on manual work. To reach our goals we used an innovative combined machine performing a double function: felling-processing as a harvester and fuel extraction as a forwarder. This double function makes forest work very flexible and minimises relocation costs also thanks to its minimal size. The study took place in the region of Catalonia, Spain, during the fall months of 2023, the site chosen was a Pinus halepensis forest naturally regenerated after a wildfire and ready for first thinning to prevent risk from fuel accumulation. Three different plots have been selected to evaluate the productivity and costs of a small-scale harvester/forwarder machine in first thinning. The mean DBH and tree density of the first plot were 16.9 cm and 1697 tree/ha, the second counts 10.35 cm and 3338 tree/ha, and the third 5.92 cm and 9620 tree/ha. The productivity of the machine varied according to the development of the vegetation, impacting the cost per hectare and in two cases becoming advantageous compared to the traditional method. The costs of the interventions per hectare of the first plot, where the quality of the wood was greater, were 64% and 52% compared to the second and the third, without including the products obtained. Timber biomass, often left on the ground with manual operations, was extracted providing a yield of 50.5, 61.2 and 27 tons per hectare respectively in the first, second and third plot. The value of this product can be used to further improve the economic balance of the preventive silviculture, allowing to secure a larger area with the same funding