But with global warming, the multiplication of heat waves and droughts, this fragile ecosystem is threatened. Because of the repeated heat, the trees will have to sweat again to lower their temperature. They will also need to take more water from the soil. And some trees are not very sharing. As a result, more and more forest dieback is observed every year around the world.
“Avoid a war between the trees”
To prepare our forests for the climatic conditions of tomorrow, and avoid a war between the trees, one of the solutions often mentioned is to favor forests mixed with many tree species. Unlike a monoculture, where there is only one species, a mixed forest is in theory more resistant and resilient to droughts and heat waves, because the trees can help each other. But are we so sure?
In reality, it also depends on the neighbor with whom they live. If they’re lucky, the trees can have friendly neighbors who help them get through the summer. by sharing the water resources in the ground when they run out. Fir and beech, for example, are very good friends, because their relationship reduces their sensitivity to droughts and even increases their wood production.
However, if there are good neighbours, there are also bad ones who will monopolize all the resources and leave nothing to others. The egoist, par excellence! The oak, for example, with its deep roots, will be more likely to crush the beech by depleting the water in the soil to leave nothing.
Diversity is not a martingale
That’s not all: even if the relationship between neighbors is beneficial when everything is going well, it can deteriorate when conditions become more difficult and even become negative. This is typically the case with pine and oak mixtures which share their resource fairly in normal times, but which take up arms as soon as resources run out.
For trees as for humans, the relationships between neighbors are complex and depend on different factors. This is why it is very difficult to have an absolute truth on the role of diversity in relation to the resistance of forests to droughts and heat waves.
A lot of research shows the power of diversity. They say that the more different the neighbor, the more productive and drought-resilient the forest. For my part, I have demonstrated that a different neighbor in an unfavorable situation such as during a drought is not necessarily interesting, especially if the tree itself is not adapted to its environment and competes with a Rambo.
See also: Trees can be obese, and it’s our fault
In the case of resistance to droughts, the role of biodiversity is more nuanced, because it depends on many elements such as the species of trees, their characteristics and environmental conditions.
Much research still needs to be done, such as the one launched with Federal Institute for Forest, Snow and Landscape Research (WSL) to try to decipher these complex relationships between neighbors in the forests so that one day we can better prepare them for the challenges to come. But what is certain is that, as for us, a good neighbor can make all the difference, especially for trees that cannot move!”
2023-07-05 21:46:33
#Geopolitics #trees #harmonious #forests #VIDEO #Heidi.news
