Andalusia is greener than 30 years agoThis is the most important conclusion of one study from the University of Córdobabased on 28 years images made by NASA Satellite. It is something that can clash, Taking into account that desert formation processes seem to be progressing at a very fast pace in the same region of the country. But on the other hand, It is something we have seen all over the world.
And why does this happen? According to Rafael VillarMain investigation into work that has just been published in Ecological indicators” “The reasons are diverse and complex.” Things like «Leaving the fields after the national exodus, the adaptation of plants themselves to unfavorable climatic conditions (such as Pinus Halpensis y Quercus Ilex), The effects of atmospheric fertilization with CO₂, forest management and changes in conservation policy»They can be some.
However, as researchers indicate it, it is a statistical artifact. That is, Andalusia is on average green; But when we look at Concrete areas (such as Almería) this phenomenon does not occur or does not occur subtly.
Kidney and desert formation are also seen in NASA images
The forest landscape of Andalusia is now greener than three decades ago. Satellite recorded imagesthat the Increased trees in this autonomous community in the period between 1994 and 2021.
However, The results are not in contradiction with the fact that this autonomous community remains one of the Spanish regions that are most threatened by dryness, a phenomenon that continues to claim and that it is expected to increase in the coming years, among other things, for the effects of climate change.
To prepare your work, the research group of Terrestrial ecology of the Cordoba Academic Institution used Images of the successive NASA Landsat -Satellitesable to record information in electromagnetic spectrum stripes that are not visible by the human eye.
The data obtained show that Andalusia now has more forest mass volume than in the early ninetiesA growth that was more pronounced in the first years, between 1994 and 2005.
«The Andalusian forests have shown a general pattern of responded, that is, an increase in the volume of forest mass, indicating that many species have succeeded in preserving or even improving their photosynthetic activity during this time“, He explains Rafael VillarThe most important researcher of the group that did the scientific work, who nevertheless warns that “This change has not been homogeneous, neither in time or in the Andalusian area«.
Leaving rural space and adapting plants to climate change
For this ecologist are the reasons that explain the increase are diverse and complex. Among them he quotes the Indulgence of the fields after the national exodus or the adaptation of plants to unfavorable climatic conditionsRelated to Effects of climate changeas the Atmospheric CO2 fertilization. It also refers to Other variables such as forest management or changes in the conservation policy.
Nevertheless, another of the participating researchers has emphasized, Cristina Acosta, It is important to emphasize that «This tendency to respect is the result of an average of all Andalusia over time“hence The increase in the green Where one of the most common species, the wild pines, has shown a more moderate response due to the shortage of rainfall.
It is for this reason that the results of the study can be misleading if they do not deepen them, since then Andalusia remains one of the most endangered Spanish regions of dryness.
«In general, green values have decreased in more dry areas, which suggests a reduction in photosynthetic activity and therefore in the productivity of forests under the conditions of precipitation deficit and high temperatures«, He points out Rafael VillarTo add that «From around 2005species such as The olive tree, eucalyptus, cork oak, hate pines The growth rate has fallen considerably due to climate change«.
From Grazalema to the ruling Almeria
As described by this professor at the University of Córdoba, «In Andalusia there is generally a strong climate gradient from west to east, with wet areas such as the Sierra de Grazalema, which registers the highest levels of annual rainfall in Spain with more than 2,000 millimeters of rain per year; In a total contrast with the driest parts of the country, such as Almería and east of Granada, where we find the only desert in Europe«.
Climate variability that «Immediately influences the forest response«, Since« while in the areas with the greatest precipitation A Reproduction more consistent, In the most dry, there is a greater reduction in photosynthetic activity and a possible decrease in forest biomass ».
Villar emphasizes that the Andalusian forests, “Like any ecosystem on the planet, they are greatly exposed to the effects of climate change”That “could worsen the effects of dryness and could increase the risk of forest fires, vermin and diseases.”
However, it also emphasizes that «Some Mediterranean species have a great ability to adapt, which suggests that forests can continue to play a key role in reducing climate change if the correct management and maintenance strategies are implemented«.
And the trees?
The work, on the other hand, also emphasizes the impact of the dryness in the growing season of the trees, which, although it has been shortened in some of the species studied such as Acebuche or eucalyptus, the effect of it is even more pronounced In the wild pines, a tree that is particularly sensitive to the absence of rainfall, They reduce his growth period as an adjustment mechanism, depending on the arrival of the first autumn fees and the overtaking of the summer.
«It is clear that Every time the summers is longerBecause they start before and later. In that sense we have seen changes at the beginning and end of the growing season in many species, ”says Rafael Villar in this respect.
«In our studies we see that in general all evaluated species slow down their beginning and end of the growing season as the dryness increases. Very pronounced in the wild pines, which is very sensitive to dryness«, Continues to underline that, While species such as Carrasco Pine and Cesine have adjusted Pine to extend their growth period in greater dryness conditionsothers love Silvestre Pino itselfMore abundant in the East of Andalusia«They have clearly reduced their development capacity«.
«This means that photosynthetic activity starts later and ends earlier in the year, which reduces the period in which trees can grow and collect biomass; And it can have negative effects on forest regeneration and when offering long -term ecosystem services, “concludes this ecologist.