Coniferous forests investigation in southern Spain to reduce their vulnerability to climate change

Researchers attached to one of the ceiA3’s research group ‘Forest Ecology and Landscape Dynamics’ from University of Jaén, analyse different factors that modulate the vulnerability of forests to climate change. The objective is to generate intervention protocols and treatments, improving the adaptability of forests and reducing tree mortality as a result.

The researcher and head of the UJA group, José Antonio Carreira de la Fuente, explains that a certain tendency to climate vulnerability is being observed in forestry areas around world. «There are forest decay phenomena, with speed alterations at which the tree trunks thickening occurs, the height they reach, the decrease in their percentage of usual foliage or their resistance to drought, among other features , are linked to climate stress», says the expert. In this sense, Carreira de la Fuente stresses that the main purpose of the research is to have a deep knowledge about the processes and natural mechanisms involved in this vulnerability, known as change modulators, to correct this decay in time and prevent it to tree mortality.

Many of these modulating factors are related to forest masses structure. «Where there are diverse structures with different tree species, different sizes and distances between them, the competition relationships of trees to get light and water are more asymmetric so, the tendency to mortality is lower than in more uniform forests , where the trees are more or less the same age, height and distance between their trunks «, explains José A. Carreira.

This research project is part of the Challenges Program of the Ministry of Economy, Industry and Competitiveness, and the collaboration of Pablo de Olavide University (Seville), the Pyrenean Institute of Ecology (Zaragoza) and various research centres in Switzerland, USA and United Kingdom, among other entities. Currently, forests in Southern Spain (Serranía de Ronda, Sierra Mágina, Sierra de Cazorla, Sierra de Baza) and diverse forest areas of North Africa, Turkey, Finland and Switzerland, among other locations, have been studied. The UJA researcher highlights that, although each forest has its own features, comparing results can acquire much more detailed knowledge about forests vulnerability to climate stress.

In Spain, from the 1950s, there was an abandonment of rural world in which the traditional forest management (livestock, non-industrial or massive tree felling …) was highly reduced. «There has not been a good policy planning in forest management, therefore it has appeared a strong tendency to densification of forest masses with closed structures, making increase climate vulnerability», explains the expert. This is in contrast with the forests situation analysed in Cordillera del Rif and Atlas (North of Africa), where traditional human practices persist so, symptoms of forest decay are not observed» Paradoxically, those forest areas in which stricter environmental conservation policies are applied, such as the South of Spain, forests become more vulnerable than in some areas where these measures are not applied and human intervention has persisted with less intensity», highlights the expert of the UJA.

This situation is also seen in forest areas of Southern Africa, California, Chile or Australia that have had a short tradition of human activity so, after cessation or a decrease of this activity, their forests are becoming denser; Therefore, the competition, decay and tree mortality rate have increased as a result. » When disturbances are the same type and have a proper intensity, they help ecosystem balance» notes the researcher, who adds that fire, likewise, also plays an important role from an evolutionary point of view for forests balance in the Mediterranean region.

From this work, it has been launched experimental practices of different areas of Serranía de Ronda, aimed to reduce the level of trees competition to reach light, soil and water, and making them more resistant to drought. In this sense, this research project is based on an integrated perspective that takes into account both patterns related to the landscape and the structure of forests, as well as the molecular and genomic study of trees. The goal, in short, is to use this information to create intervention programs and protocols that forest administrations can implement in their action policies. In addition, the aim is to raise awareness among the population about the importance of understanding how forests interact with climate change, and the loss of fundamental ecosystem services (carbon sequestration, wood supply, hydrological regulation, etc.) that this may entail.

In the Andalusian forests situation, the UJA expert points out that these are characterized, comparatively on a global scale, by their great diversity, both in terms of landscape and species level, which is the result of the great variability of environmental conditions and ancestral uses of the territory that takes place in the southern part of the peninsula. On the other hand, the main weakness of these forest regions is that they are in a climatic transition area, which means that it is an area particularly vulnerable to nature climatic changes. Hence the importance of this type of research.