Gemma Bastida, (EFE).- The extension of the natural forests of Spanish fir (Abies pinsapo), an autochthonous species that can only be found in the mountains of Malaga and Cádiz, has been maintained in recent decades, demonstrating great resilience and capacity of adaptation to periods of drought greater than the experts believed.
Researchers from the universities of Málaga (UMA), Jaén and the Pablo Olavide University of Seville have studied the effects of dry spells on the largest fir in the Sierra de las Nieves National Park, located in Yunquera (Málaga), and the The results have been “amazing”.
The data collected reveals that the Spanish fir, despite needing moisture, can recover quite effectively after extreme drought events, which are often accompanied by an increase in forest pests, explains the study’s lead researcher, Álvaro Cortés-Molino, to EFE. from the Department of Botany and Plant Physiology of the UMA.
A botanical gem
The Spanish fir, which is considered an “authentic botanical jewel”, is a pyramid-shaped tree that comes from the tertiary era and that only inhabits the Sierra de las Nieves, in the Sierra Bermeja, also in Málaga, and in Grazalema. , in Cadiz.
This species does not admit extreme temperatures and needs the influence of the sea, a minimum rainfall and a limited number of daylight hours per year. In this way, the firs take refuge in rainy and shady areas, normally between 1,100 and 1,300 meters above sea level.
It is estimated that in Andalusia there are slightly less than 4,000 hectares of pinsapares. These currently face three major threats: fires, droughts and pest conditions.
The impact of the drought
At the end of the 1990s, the Spanish fir forests of the Sierra de las Nieves, where the largest Spanish fir population is found, with an extension of more than 2,000 hectares, suffered a general decline. The reason was the high degree of mortality that caused clearings in the forest, mainly due to drought.
This led the experts to think that the pinsapares were in regression. A hypothesis that has now been denied by the latest studies, which have focused on the analysis of this same area.
To carry out this work, researchers from Malaga, Seville and Jaén have used data from satellite images recorded over 35 years (between 1985 and 2020). In addition, they have been supported by field sampling carried out in 2003 and 2020.
The analysis has been complemented with historical images from the National Aerial Orthophotography Plan. This has made it possible to see the evolution of the area of the pinsapar during this period.
An “unexpected” result
The results have been “totally unexpected”, according to Álvaro Cortés-Molino. In fact, they contradict what had been predicted almost twenty years ago.
However, against all odds, the vegetation cover of the pinsapar has increased in recent years. Although the mortality process is still present in these forests, there is a resilient response to this decline due to drought that had not been previously documented.
The firs that survive endure and grow more and new trees are born in the holes left by the dead specimens, the most vulnerable.
According to the UMA researcher, mortality reduces competition between trees. In this way, a kind of “liberation effect” is produced that makes those who remain have a greater capacity for growth.
In addition, the holes left by the dead specimens are filled with vegetation. This situation, in turn, favors the growth of new Spanish firs.
Don’t let your guard down
The species, therefore, has a high capacity for adaptation to climate change and to the least available rainfall. This is positive news, underlines Cortés-Molino, which has a “but”, since the limits of this resilience in the face of increasingly intense periods of drought are still unknown.
However, according to the researcher, the message that must be conveyed is that “we must not lower our guard because it is not known how long we will see this resilient response to an increase in the aridity of the climate and rising temperatures.”
In addition, the processes of mortality and dryness generate an overabundance of vegetable fuel that considerably increases the risk of fire. It is the main threat to Spanish firs today, since these trees have very thin bark that makes them especially vulnerable to flames.
Hence the need, highlights the expert, to carry out proactive management that facilitates this phenomenon of resilience and, at the same time, reduces the greater risk of fire due to the accumulation of plant material. EFE