The decline of European forests

Forests around the world are in serious trouble. Compared to thirty years ago, the area covered by natural habitats and forests has increased slightly, thanks to growing awareness of their importance in the fight against climate change. Yet, in addition to growing, forests have also weakened, and their survival is gravely at risk. Today, more than 20% are already in critical condition, and many more are approaching that point.

This vulnerability is due to climate variability, namely a climate now characterized by sudden and severe fluctuations in temperature and precipitation. Most plant species living in forests are affected by these changes and become more fragile, less resistant to any critical event. If native species are no longer suited to the climate they inhabit, they cannot survive for long. And this is precisely what is happening to European forests.

1. What forests are used for
2. The decline of European forests in numbers
3. Assisted migration
4. The role of the Dry garden

What forests are used for

In the popular imagination, forests are useful because they provide oxygen and are valuable to human activity because they provide wood. In short, their function is often reduced to these two simple elements, which are certainly important to the global ecosystem, but do not fully capture their value.

It is true that most of the oxygen we breathe comes from forests, namely places where vast numbers of plants are concentrated. But their function does not stop there. They are indispensable to ecosystems for many different reasons. Trees, first of all, are our primary allies against global warming, as they can absorb carbon dioxide from the air and store it in the soil. European forests, for example, absorb the equivalent of 7% of all greenhouse gas emissions for which the EU is responsible each year. The more emissions are stored in the soil, the less greenhouse gases warm the atmosphere, and thus the more climate change is mitigated.

Furthermore, forests are also an integral part of the water cycle. Trees absorb water from the ground through their roots and use it in the process of photosynthesis. However, they do not use all the water they absorb, and thus release all the unused water into the air as water vapor. It may seem like a small amount, yet a single tree releases hundreds of liters of water into the atmosphere every day.

Finally, the plant species living in forests, in addition to being biodiversity themselves, also host vast numbers of animal species and provide habitats for many different living beings. In short, forests are essential to ecosystems, and their increasing vulnerability can only put life on Earth itself at risk.

The decline of European forests in numbers

Global Environmental Change, a scientific journal specializing in climate and environmental changes, recently published a study on the impact that the decline in biodiversity within European forests has on their survival. The study was conducted by Italian researchers from the University of Helsinki, in collaboration with the University of Florence's Department of Engineering and the Joint Research Centre of the European Union.

The weakening of forests is caused primarily by a combination of two factors. On the one hand, climate change is severely testing many species, which are accustomed to living in environments that in many cases have changed completely, both due to different temperatures and different precipitation patterns—increasingly scarce, but offset by torrential downpours. On the other hand, human activity, deforestation, and the encroachment of concrete constructions in formerly natural areas further weaken biodiversity.

According to the study, by 2100, the ecosystem services provided by European forests could collapse by 23%, and many specimens would fail to survive. However, this figure is only an average, with countries bordering the Mediterranean being at the greatest risk: the decline could even reach over 50%. This is because most aridity will affect Mediterranean areas above all others, making the survival of native species much more difficult.

The vulnerability of the forests we are discussing is directly related to biodiversity. Only a few varieties will be able to withstand the new conditions, while plants and trees that are less resistant to drought, torrential downpours, and intense heatwaves will not survive. And if forests are composed of very few different species, the soil will become impoverished, animal populations will decline, and the microbiota will also become impoverished. If it is biodiversity that determines the richness of forests, its weakening will inevitably lead to their decline, as well as the disappearance of many species no longer able to survive in the places where they originated.

Assisted migration

If some of the tree species in European forests are no longer able to survive in this environment, we must find a way to protect them from extinction. This is precisely the purpose for which some researchers have begun experimenting with assisted migration. This practice helps plants “relocate” to places with climatic conditions as similar as possible to their original environment, by collecting their seeds and transplanting the new trees elsewhere.

The term “assisted migration” was coined in 1992 by forest geneticists F. Thomas Ledig and JH Kitzmiller. Their work paved the way, and several biologists have since put the same technique into practice to move forests before they disappear.

Researchers have also studied the impact of a series of alternative strategies based on assisted migration theories on the decline of European forests. One study has established that the projected decline in ecosystem services could be reduced by 10–15%. However, it remains very high in the Mediterranean region: still over 30%.

This strategy is certainly not perfect, but it seems to be the only way to save species from extinction. However, it does not protect Mediterranean forests from impoverishment, as little can be done when the increasingly hot and dry climate and advancing desertification are turning our formerly mild and life-friendly territory into an inhospitable place. Addressing climate change is, naturally, the most important thing to do.

The role of the Dry garden

The philosophy behind the Dry garden is to focus on plants and lawns that can survive in a dry climate with little rainfall without the need for abundant irrigation and, therefore, without contributing to the environmental damage caused by climate change. The Dry garden, therefore, cannot save forest species that are no longer able to survive in this climate, but it can help prevent the situation from worsening. To save forests, climate change must be stopped, and this depends on many small daily choices that do not contribute to wasting resources.