What does climate change mean for Arizona

Trees against climate changeThe increasing risk of forest fires jeopardizes the success of afforestation

Most recently, Portugal and Greece were hit particularly hard. In recent summers, devastating forest fires broke out in these two countries. The risk of such fires in Europe will increase, says Virgilio Hermoso from the Catalonian Center for Forest Science and Technology:

"According to most climate scenarios, it is to be expected for the whole of Europe that temperatures will continue to rise and dry spells will increase. This means that we will experience more frequent weather conditions that favor forest fires and lead to fires starting more easily and being able to spread more widely. "

So far, one hears of wildfires in the forest mainly from the Mediterranean region. But that will change, write Hermoso and other Spanish researchers in an article for the journal "Global Change Biology":

"We expect that forests will catch fire more frequently also in higher latitudes of Central Europe. The fire risk is also growing in the Balkans, in France and in southern and southwestern Germany, for example."

"Tree planting is not the only option"

Planting billions of trees and reforesting forests, as the EU Commission is now planning to do - in times of increasing megafires, this is a double-edged sword, warns environmental scientist Hermoso. Because the additional storage tanks for CO2 that you want could go up in smoke at an early stage. When forests and all of their tree wood burn, the greenhouse gas escapes back into the air and the positive effect on the climate is gone:

"We will perhaps create large, contiguous tracts of land that only contain forest - and are then all the more vulnerable to fires that spread in them. If our goal is to get as much CO2 out of the atmosphere as possible, then tree planting is not that Only option. We should also renature other habitats that store a lot of carbon dioxide, such as grasslands and wetlands, especially where there is a high risk of fire! If we only focus on planting trees, we are promoting combustible landscapes. "

What is needed is a well thought-out plan, but also solid fire management in Europe's forests. Such a thing exists in the Mediterranean countries. There, forest stands are thinned out so that they do not contain so much combustible tree wood, and aisles are created in the forest where conflagrations die. Without such strategies, the benefit of massive reforestation in Europe is questionable for Virgilio Hermoso: "In the northern countries of Europe, people are not yet so used to dealing with forest fires. It is advisable to learn from the south, because they already have a lot of experience there in order to."

Positive effect of forest fires on CO2 storage

If they occur only rarely, however, fires can even have a positive effect on CO2 storage in the forest. Canadian and American researchers are now describing this in the specialist journal "Science". In Alaska, spruce forests were conquered by birch and quivering aspen, as their wind-borne seeds developed much better in the scorched earth than those of the spruce.

Michelle Mack, Professor of Ecology at Northern Arizona University in the USA, says that there is five times more carbon in the forests today than in the past, in front of the fires: "For a long time we thought that with forest fires, carbon losses also increased. But here we have let's take an example in which trees more than compensate for the losses and thus counteract global warming. "

There are similar observations in Canada and Eastern Siberia. However, the transformation into higher carbon stocks took decades during which it no longer burned. Fires are now also increasing in the forests around the Arctic Circle.