Francis Hallé, a tree and tropical rainforest expert, has designed a canopy raft to better study the canopies of tropical forests. In 2019, he began a project to restore a primary forest in Europe. In this first episode in our “Forests in Danger” series, he revisits their definition and natural state.

In the undergrowth of the primary forest of Bialowieza, northeastern Poland, June 12, 2005. (Photo by JANEK SKARZYNSKI / AFP)
In the undergrowth of the primary forest of Bialowieza, northeastern Poland, June 12, 2005. (Photo by JANEK SKARZYNSKI / AFP)

Forests are in danger. These mainstays in the fight against global warming and to preserve biodiversity may soon reach a tipping point. The proliferation of fires around the world and increasing demand for forest products and services are depleting these ecosystems. Even the Amazon rainforest, the lungs of the Earth, appears to have reached a breaking point. According to a study published in the journal Nature Climate Change in April 2021, it is now emitting more carbon than it absorbs.

Our “Forests in Danger” series explores the definition of a forest, as well as issues including the risks of pathogen release, road construction, imported deforestation in consumer products, and consequences for indigenous peoples, while also identifying solutions for the future.

Aurélie Darbouret

You can find  our series “Forests in danger”:

Francis Hallé: “Forests are a common good to be protected”
Proliferation of roads in forests causes irreversible damages on biodiversity
Importation and deforestation: a scourge from the North
How to protect forests without threatening indigenous peoples

A forest is more than multiple rows of trees. From a biological perspective, natural forests also contain flora and fauna. The older the forest, the closer it becomes to primeval forest. The fauna becomes richer and more diverse and includes large animals. In Europe, we prefer to use a definition without any reference to animals, since we have sought to destroy large fauna. But without wildlife, forests become degraded and impoverished.


Can tree plantations replace forests, thus offering a solution for wood harvesting?

Tree planting is a form of agriculture. While it is certainly necessary, it is quite different from a forest. A forest is home to incredible diversity. In general, tree plantations contain only one species. They may occasionally have two, very rarely three. There is no diversity in the ages of the trees. They are all planted and cut down at the same time (very young) and then shipped to the sawmill. The dead wood is not left to rot on the ground and therefore, all that these trees take from the soil is permanently removed from the land. This creates quite an effective means of depleting the soil! In forests, on the other hand, trees fall to the ground and rot, nourishing the soil in the process.

We need wood and we always will. Single species tree plantations must therefore be used to meet these needs. However, in return we must stop harvesting natural forests, which are now far too rare, and let them develop freely. In countries like France, tree plantations have already become the norm and the timber sector has to make do with these resources. The companies have clearly funded tree plantations, but not forests. Forests are natural phenomena that must be seen as a common good.



What links exist between a forest’s natural aspect, its resilience, and the preservation of biodiversity?

Rich fauna cannot develop in single species tree plantations, and yet a forest’s resilience is directly linked to the level of biodiversity. The more animal and plant species, the more resilient the forest becomes. Single species tree plantations are cost-effective but remain very fragile.

For tree plantations containing only one species, such as pine trees in France’s Landes department and Douglas firs in Morvan, the arrival of specialized pests that target the species can be catastrophic. Single-crop plantations have no resilience to parasitism. When severe storms hit, natural forests made up of large and small trees are much more resistant than tree plantations with trees of the same height and age. This was evident in France during the storms of December 1999: the tree plantations in the Landes suffered the greatest damage.

In the very long term, fauna is a forest’s only means of survival. To see this in action, we must travel to Białowieża, Poland’s primeval forest. There, European bison deposit enormous droppings that enrich the soil and disperse plants. In the Amazon rainforest, fish eat fruit that falls into the water. They then travel upstream and excrete the seeds in their feces. This makes the fish very efficient seed dispersers!


What are the main threats facing forests on a global level?

We are faced with a problem that is growing each year: the risk of fire. We will need to create firebreaks–gaps in vegetation with a width of a few hundred meters–around primeval forests.

Overall, too many natural forests continue to be harvested. Tropical forests are threatened by harvesting to provide timber for wealthy countries. Whether it be in Europe or the tropics, the continual clearing of forests to increase agricultural land represents real waste. We have cleared enough land at this point and must make do with the available soil. Only a few patches of forests remain here and there, isn’t it time we let them be?


Does small-scale nomadic agriculture pose a threat for tropical forests?

This is indeed something we hear quite often. But is completely wrong! This is in fact old rhetoric dating back to the colonial era. In reality, it is the loggers who create roads to remove the tree trunks. Local, small-scale farming can only begin after that point, once the large trees have been felled and roads have been created. Small-scale tropical farmers need the forests to meet their needs: instead of destroying them, they tend to cultivate them.


Given the growing demand for forest products and services, is it even possible to establish sustainable forest management?

In the tropics, agroforests have long existed, some even dating back to the 12th century. This is true for the incredible forests on the west coast of Sumatra. The farmers get all they need from the forests. They keep all the trees they can use and replace the most dangerous ones or those they cannot use with more useful trees that take up the same amount of space. This complex and sophisticated system has resulted from years of work spanning several generations. The villages are located in the middle of vast forests containing a wealth of fauna. When the farmers don’t need money, they collect interest from this capital: fruit, game, fish from the ponds, honey. And when they do need money (in the event of illness, an accident, to make a pilgrimage to Mecca) they fell a dozen large trees and earn substantial income. In the gaping hole that remains, they grow plants that grow in the sun–such as cassava and banana trees–for a few years, and then the forests close again. Agroforestry is an ingenious system that is likely to last.


Can you think of any other examples of agroforests offhand?

There are very beautiful agroforests in other Asian countries, as well as in Ethiopia, Kenya and Costa Rica. These agronomic systems offer the same resilience and benefits for soil and climate protection as natural forests and ensure a very good level of living for the owners. They must be encouraged.

In Europe, Swiss forestry also offers an excellent example of sustainable management. Swiss foresters do not try to make as much money as possible, as fast as possible, yet they are able to produce wood from a forest area without any time limit. On our continent, we have a few examples of tree plantations managed as agroforests. In Belgium for example, agroforestry systems work very well. In France, unfortunately, the National Forest Office (ONF) is asked to generate as much profit as possible as quickly as possible. This is a very destructive approach.


Is it possible to compensate for the ecological damage caused by cutting down a forest?

Forest owners who cut down their forest are the only beneficiaries. We generally consider that this is normal and believe they have the right to do so. Yet there are many who lose out in the process. All the non-owners are deprived of the forest’s beneficial functions–oxygen, carbon storage, soil fertilization, preservation of biodiversity–and even its contributions to physical and mental well-being, and its beauty and poetry. This all disappears without any compensation, and it is deeply unfair. We must find some type of compensation system, and not necessarily a financial one. The minimum requirement should be for foresters to replant what they cut down.


You are leading a project to restore a primeval forest in Europe. Can you tell us more about this?

The idea came about in reaction to destruction of Poland’s Białowieża Forest, Europe’s last remaining primeval forest. In the long-term, this ambitious initiative is destined to become a cross-border and European project. We will start with a national forest. We are looking at five different possibilities for the territory. The trees we will plant will grow old and die. They will then be replaced by “post-pioneer” trees, which will also grow old and die. Finally comes the third wave of flora, the primeval forest itself. This is a long process that will take place over several centuries. All things considered, this is a normal time frame for nature. To accomplish this, we will need 70,000 hectares. This is the amount of land required to ensure the return of wildlife. Wood harvesting, hunting and gathering will be forbidden.

We have already received enthusiastic support from the European public: in a few months, over 3,000 people from 13 European countries joined our association. The European Commission has also expressed support for our project. We’ll get there. It’s not really that complicated, we just need to avoid planting and harvesting anything. It’s important to note that this does not mean sealing off the area. Visits will be encouraged. Visitors will not be able to walk directly on the ground, however, to prevent soil compaction. They will walk on raised pathways. The problem is a psychological one: humans are convinced that they need to care for nature. Our project simply seeks to let it be.


Interview by Aurélie Darbouret



The opinions expressed on this website are those of the authors and do not necessarily reflect the official position of their institutions or of AFD.

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