Fire Susceptibility
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Reduce number of hectares of forest susceptible to fire
Data collection in progress
Iron Curtain to Green Belt
Bulgaria
Problem: This region is highly vulnerable to fires and prone to aridification. In the last decade, 72% of recorded fires occurred in forests. Such fires are likely to increase in intensity and frequency with climate change. These fires are significantly exacerbated by large plantations of non-native conifers that are highly susceptible to fire. Strips of bare ground are sometimes used as fire breaks, but planting strips of native deciduous trees as green firebreaks would have greater benefits, in terms of erosion control, aesthetics, and biodiversity. However, availability of seeds and seedlings of these species is currently limited. In addition, forest management can be slow to adapt to change.
Action: The project aims to catalyse change in forestry culture and practice towards planting native deciduous tree species to reduce the severity and extent of fires. They do so by working with the State Forestry Company to develop a new forest restoration and fire prevention strategy. This will be informed by trialling green firebreaks, which the BSPB is working with the State Forestry Company to create. In addition, two nurseries are being equipped to increase the availability of acorns and oak seedlings for future green firebreak plantings.
Indicator: The BSPB will measure the impact of the project on fire resilience by modelling the fire risk for the forest before and after the project restoration actions, hopefully demonstrating the increased fire resilience as a result of the planting of green firebreaks.
Drone imagery of an effective firebreak. Photo: Dimitar Gradinarov
Drone photograph, example of the damage a fire can cause in the project landscape. Photo: Dimitar Gradinarov.
Methods
This indicator will be addressed in two parts. Firstly, an analysis of the pattern and location of past forest fires across the whole Green Belt to Iron Curtain landscape will be carried out based on satellite data available from 2013-2022. Fires larger than 500 ha will be identified and corresponding descriptions of each fire’s development will be made based on satellite images. This includes the location of each fire, time of starting, tree species burnt, cause of the fire, fire area and type of fire (ground or crown). This will be augmented with data from aerial photographs to create a spatial database of fires that can be modelled to understand which barriers contributed to breaking the spread of fires.
Once the characteristics of an effective firebreak in this landscape have been identified, this information will be used to model the fire risk for the area based on forest characteristics. The fire risk for the present and future desired states (i.e. with 3000 ha current conifer stands selected for restoration to native broadleaved oak species) will be modelled based on fuel characteristics such as volume of above-ground biomass, tree species composition and fire behaviour variables. Because of the long time period required for native tree strips to reach maturity and to see the effects of these mature strips on fire events, the impact of the project on fire risk will be assessed based on the modelled estimations of change in fire risk. The BSPB will also use these models to prioritise and recommend specific forest stands for restoration in the future, with the aim of creating effecting firebreaks and mitigating forest fires.
Results
The analysis of fire data from 2013-2022 show that 160 fires took place in the landscape over that period, covering an area of 5,833 ha. About 84% of the fires in coniferous plantations were damaging crown fires, while only 6% of the fires that occurred in deciduous forests were crown fires. Fires in deciduous forests were usually ground fires, which are less destructive and spread less quickly than crown fires. It should be noted that the area across which green firebreaks are planned to be implemented in this project is only a very small part of this larger landscape.
We will update this page once the project has modelled susceptibility to fire and can assess the modelled impacts of planting more native tree species.
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