The forests of Collserola and the Marina and Litoral mountains are one step away from entering the UCI, according to a new tool presented yesterday, the map of vulnerability due to drought in the network of natural parks of the Provincial Council of Barcelona. These forest enclaves suffer water stress between 40 and 60 days a year and may reach an extreme situation in the coming years, as warned by Jaime Coello, R&D specialist at the Forest Science and Technology Center of Catalonia (CTFC), at the conference. on the impact of climate change held in Barcelona.
The researcher considers that a forest suffers from water stress when the resistance capacity of the main species is exceeded due to temperature, lack of water and the characteristics of the soil and the forest mass. Coello indicates that the 2010-2020 period has been compared with the climate evolution expected in 2030-2040. During this time interval, it is estimated that practically the entire surface area of ??the Collserola, Marina and Litoral natural parks will face a high or very high risk of water stress. An increase of a few days a year enduring this situation would lead to a very worrying vulnerability. These forecasts have been made based on the projections of the Intergovernmental Panel on Climate Change (IPCC) Report.
The horizon invites us to join efforts to reduce the spread of fires as much as possible. Joan Rovira, forestry engineer of the Barcelona Provincial Council, highlights that “of the factors that determine the risk of fires, the type of soil, the climate and the structure of the forest, only the latter can be influenced and that means promoting clearing of bushes and clearing.”
The experts’ discourse urges the need to increase forest management, especially in Collserola due to its proximity to population centers. “Decades ago, until the sixties, in Collserola there were crops, livestock and the forest was exploited; There were fewer trees and less risk of fire, but as the countryside is abandoned, the natural firebreaks, crops and pastures disappear, so that the grove becomes denser and more continuous. The open spaces that existed before are taken over by the forest,” says Coello. “The approach we defend – he adds – goes beyond logging; In addition to reducing the density of the forest so that there is less competition for water and therefore the trees are healthier, less dry and tolerate drought better, we also promote the recovery of the mosaic landscape.” The CTFC researcher remembers that forest management contributes to increasing the volume of blue water, which ends up in rivers, streams, springs or reservoirs. Specifically, he states that in normal years this action helps increase aquifer flows by up to 25%, although in times of extreme deficit its impact is low.
Rovira clarifies that another of the factors that feed the vulnerability of Collserola is “the prevalence of more fragile species, such as holm oaks, and a soil with less water retention capacity.” “Mediterranean species have the capacity to adapt but have reached the limit; Forest management is necessary to adapt to new scenarios and have more vital forests,” he indicates. The conclusion is that in different areas of Collserola there are more trees than they can fit, that the fight to obtain the scarce available water is fierce and therefore there is more fuel at the mercy of the flames.