Useful Life of Prescribed Fires in a Southern Mediterranean Basin: An Application to Pinus pinaster Stands in the Sierra Morena Range

Mapping opportunities for the use of land management strategies to address fire risk in Europe

Many parts of Europe face increasing challenges managing wildfires. Although wildfire is an integral part of certain ecosystems, fires in many places are becoming larger and more intense, driven largely by climate change, land abandonment, and changes in fuel management with important socioeconomic, environmental, and ecosystem services consequences for Europe. In order to envision a comprehensive fire risk mitigation strategy for Europe, a spatial assessment of opportunities to manage fuels at the landscape-scale is needed. Our study explored the suitability of three land management strategies (LMS)-herbivory, mechanical fuel removal, and prescribed burn-which can create more heterogenous fuelscapes, thereby reducing an element of fire risk. We created suitability maps for each of the LMS using adoption factors identified in a systematic literature review (n = 123). We compared these maps with areas of historical fire occurrence as a proxy for fire risk to prioritize key areas for intervention. We found that over a quarter of Europe was suitable for multiple LMS within areas of greater fire risk, creating opportunities for concurrent and synergistic use of the strategies. Options were more limited in areas of southern Europe, where prescribed burn was found to be uniquely viable amongst the LMS evaluated. Opportunities were also restricted in some areas of high fire risk in northern Europe, where herbivory was found to be the only suitable LMS. Our findings take a wide-view of fuel management to target landscape-scale decision making focused on reducing fire risk. However, many other factors must be taken into account to successfully manage fuels at local scales, including the socio-cultural appropriateness of the LMS, the viability of incentive schemes, and possible trade-offs with other management goals, such as carbon storage and biodiversity.

Designing a conceptual framework for strategic selection of Bushfire mitigation approaches

Fires are an important aspect of environmental ecology; however, they are also one of the most widespread destructive forces impacting natural ecosystems as well as property, human health, water and other resources. Urban sprawl is driving the construction of new homes and facilities into fire-vulnerable areas. This growth, combined with a warmer climate, is likely to make the consequences of wildfires more severe. To reduce wildfires and associated risks, a variety of hazard reduction practices are implemented, such as prescribed burning (PB) and mechanical fuel load reduction (MFLR). PB can reduce forest fuel load; however, it has adverse effects on air quality and human health, and should not be applied close to residential areas due to risks of fire escape. On the other hand, MFLR releases less greenhouse gasses and does not impose risks to residential areas. However, it is more expensive to implement. We suggest that environmental, economic and social costs of various mitigation tools should be taken into account when choosing the most appropriate fire mitigation approach and propose a conceptual framework, which can do it. We show that applying GIS methods and life cycle assessment we can produce a more reasonable comparison that can, for example, include the benefits that can be generated by using collected biomass for bioenergy or in timber industries. This framework can assist decision makers to find the optimal combinations of hazard reduction practices for various specific conditions and locations.

Fire ignition patterns to manage prescribed fire behavior: Application to Mediterranean pine forests

Climate change and the accumulation of surface fuel are leading to global changes in the occurrence of increasingly severe fires. In light of current budgetary constraints, prescribed fire can be a very cost-efficient tool for both reducing wildfire hazards and managing fire-prone landscapes. However, despite its widespread use in some countries, social and administrative constraints arise when applied at the European or larger scales. Science-based knowledge concerning fire behavior, fuel load reduction, and tree impacts is required to support the use of prescribed fire. Spatial ignition patterns can increase or decrease the spread rate, flame length, and flame residence time according to the objectives of a prescribed fire. This work aims to analyze fire behavior using different fire ignition patterns (strip-heading fire, flanking fire, and spot-heading fire) and meteorological and fuel conditions. Seventy-seven observations or sampling units using twenty-three prescribed fires were established for fire monitoring. Non-linear models based on environmental variables were fitted for the spread rate and flame length. Our study proposes a novel way of sharing scientific knowledge in relation to the most common distances between ignition lines and ignition points used in the southern Iberian Peninsula. The spread rate and flame length can be increased in strip-heading fire, by more than 3.5-fold and more than 1.95-fold, respectively, by modifying only the distance between ignition lines. Flanking fire could lead to a decrease in the spread rate by approximately half. Although spot-heading fire can reduce the spread rate by more than 78% and flame length by more than 41%, the highest distances between points could increase the flame residence time by 39-132%. This research seeks to achieve a trade-off between fire intensity and the impacts of fire on trees, soil, and surface roots.