The combination of climate change and land abandonment is creating the perfect conditions for mega forest fires in the Mediterranean. Higher temperatures, erratic rainfall and longer droughts are becoming increasingly commonplace, as well as claims that megafires „are here to stay“. Still, not all hope is lost. Sustainable Forest Management (SFM) can help prevent fire disasters by reducing the amount of flammable biomass that accumulates in forests, among other adaptation measures.
The INFORMA case study in the Segre-Rialb basin, Spain, is an example of an area that has suffered decades of continuous rural exodus and the decurrent lack of forest management. There, the project will equip forest practitioners with insights on how to adapt to increased climate variability while ensuring the provision of ecosystem services such as water quality and quantity, wood and non-wood forest products, recreation, and biodiversity conservation.
The Segre-Rialb basin area comprises 35,000 hectares covering the six municipalities affected by the construction of the Rialb water reservoir in the 1990s: La Baronia del Rialb, Bassella, Oliana, Peramola, Ponts, and Tiurana. Continuous rural exodus led to a significant decrease in the local population during the past century. For instance, the population of La Baronia de Rialb decreased from 1.244 to 835 inhabitants between 1900-1950 and currently amounts to no more than 229 inhabitants.
As in other Mediterranean countries, rural abandonment ensued a forest transition in the last sixty years. Depopulation, associated with decreasing agricultural activities, led to land abandonment, which induced land use change in former fields which naturally evolved into new forests.
The water reservoir of Rialb is the second largest and newest water reservoir in Catalonia. It was built in 1992 and caused the submersion of the lowest and most fertile pieces of land in the valley. Eventually inaugurated in 2000, the reservoir provides water to 80 municipalities. In 2008, the Consortium Segre-Rialb was created to coordinate economic development and tourism promotion in the six municipalities. Thanks to the touristic appeal of the water reservoir, the forested landscape aesthetics and opportunities for hiking and mushroom picking, tourism is now an important source of income in the area. For instance, La Baronia de Rialb counts the highest number of rural tourism homes in Catalonia, with over 150 rural homes.
The main tree species in the case study area are black pine (Pinus nigra), holm oak (Quercus ilex), and Portuguese oak (Quercus faginea) and forests are mainly privately owned. While the most common management objective is wood production, truffles are also a good source of income for forest owners. Forestry is limited because it is considered a non-profitable activity due to the complex topography of the area and the typical low productivity of Mediterranean forests, which was further reduced by regular heavy tree thinnings or after the occurrence of wildfires.
Thirty-six per cent of the total private forest lands are under a forest management plan, in accordance with the average for Catalonia, where forest management plans are voluntary, but this figure varies considerably between the six municipalities. The highest percentage of private forests under a management plan occurs in La Baronia de Rialb (47%), due to an increase in truffle production in the municipality over the last decade.
Observations regarding non-managed forest areas indicate that they may increase the risks of large forest fires, diseases, and mortality during drought episodes, which are only expected to be exacerbated by climate change. While tree cover in the basins is essential to water quality, increasing vegetation cover impacts the amount and efficiency of water use by forests, potentially decreasing water availability for humans.
Wood production is usually the only objective for private forest owners although fire prevention measures are more and more being taken into account. The Catalan Government has recognised the threat of more extreme fires and droughts and is promoting and pushing for more sustainable forest management practices. Hence, the government is providing tools (i.e. maps with priority areas) and incentives for private forest owners to engage in forest management in strategic locations, mainly for fire prevention. Direct investments in private properties for fire prevention are also being made. In addition, research is being conducted to identify the most promising locations for water production.
Management alternatives to the current approaches foresee an increased integration of biodiversity conservation within managed forests as well as the improvement of water management. For contributing to forests as a carbon sink, enrichment plantations are also considered. They seek to introduce or increase the proportion of one or more species into the pre-existent forest. The overall aim is to increase the complexity of forest composition and structure, thus improving the resilience of forests to disturbances and taking advantage of the productive potential of the most favourable micro-sites (e.g. valley floors, ditches, affixed areas). Besides this, holm oak is planted for truffle production on former agricultural lands.