9 June 2021 • ACTUALITÉS

Fight against deforestation: we talk about it with an expert

Serge Morand interview

The news of the past year has been greatly disrupted by the COVID-19 health crisis, which is represented as a real awareness by all of the very fragile health of our planet. Emergence of new diseases, zoonoses, link between infectious diseases and human activities… One year after the first drastic global measures against this virus, what is really its origin? Are humans, and in particular their activities with high pressure on forests, directly implicated in this situation?  

Serge Morand is a researcher at CNRS-CIRAD, a teacher at the Faculty of Tropical Medicine in Bangkok (Thailand) and an ecologist living in Southeast Asia. His latest book published in September 2020 Man, wildlife and the plague (Fayard) presents the main causes of the appearance of new infectious diseases (including COVID-19), including in particular deforestation and the overexploitation of our forests. World. 



Planète Urgence : Let’s start at the beginning: what are the roles of forests and biodiversity for humans?


Serge Morand :

“ The forest is an essential element in the regulation of the local and global climate.[1] “

Many scientific studies demonstrate the importance of forests for climate regulation, but also for soil health or the quality of surface and ground water. In this sense, forests contribute to planetary health. Multi-specific forests are rich in biodiversity, providing important resources for local populations and more broadly for all of humanity. By providing a variety of ecosystem services, forests support many human activities and contribute to human health and well-being.

However, deforestation continues in many countries, mainly in the intertropical zone. The impacts of deforestation are very noticeable for planetary health. “Deforestation and forest fires contribute to increasing the negative contribution of forests to climate change.[2] » 

The scientific work is alarming. The degradation of habitats, and in particular of natural forests, leads to an acceleration of biodiversity loss. We are talking about a real defaunation of certain forest ecosystems, when it is not their disappearance by the combined effects of intensive, extractive and industrial agriculture. The IPBES 2019, WWF Living Planet 2020, and FAO Forests 2020 reports show that we have reached a critical point in the regeneration of both natural forests and biodiversity. The ways of life, cultures and knowledge of traditional and indigenous societies are also seriously threatened by this great acceleration of globalized extractive activities. 

We find that the increases in outbreaks of zoonotic and vector-borne diseases from 1990 to 2016 are linked with deforestation, mostly in tropical countries[3].

The health of local and global populations is also endangered by new epidemic risks. The decline in forest cover is often accompanied by an increase in livestock farming. A greater density of livestock has the direct consequence of increasing the spillover of infectious agents from wildlife and amplifying their transmission. These local transmission starts, called clusters, do not remain localized. The rapidly accelerating globalization of trade ensures the dissemination of epidemics which, from being local, are becoming global. Not only are we seeing many more epidemics caused by an increasing number of infectious and parasitic agents, but these epidemics tend more and more to become pandemics. 

indonésie reforestation planète urgence

Other changes in forest cover also have adverse effects on biodiversity and health. These are monospecific commercial plantations, such as oil palm or teak, and afforestation, i.e., the transformation of natural or traditionally cultivated grassland ecosystems into plantations of species for the international market. “[…] association between the increasing number of outbreaks of vector-borne diseases and the increase of oil palm plantations [4]”. 

Here again, the data show a correlation between the increase in epidemics of vector-borne diseases and the extension of this type of plantation. 

We can therefore clearly see how the global, with the extractive demands for living resources, increases the overflow of pathogens and local transmissions which, in a sort of boomerang, are then transmitted to the entire planet. 


What is the link between deforestation and the emergence of new epidemics?


Serge M.: There are many examples of the impacts of deforestation on human health. A comparative analysis has shown that deforestation favours mosquitoes which serve as vectors of human diseases. The association between deforestation and malaria epidemics has been documented in Brazil as well as in Southeast Asia. The re-emergence of parasitic diseases, such as leishmaniases transmitted by arthropod vectors, has also been linked to deforestation in Latin America. Several studies have also highlighted the role of forest deforestation in the emergence of zoonotic diseases like Lassa fever and Ebola in Africa. 

Deforestation and defaunation are not limited to the irretrievable loss of species. And that is already sad in itself. Many ecological regulations are affected such as predation and competition. Impoverished environments favour generalist and synanthropic reservoir species, such as rats, and vectors, such as mosquitoes or ticks, and with them many microbes and parasites potentially pathogenic for humans or their domestic animals. These reservoirs and vectors, freed from regulation by their predators, such as carnivores and insectivores, see their populations and densities increase, thereby promoting the transmission of infectious agents. The risks of local epidemics are increasing. Thus, we were able to highlight a global temporal correlation between the decline in forest cover and the number of vector-borne and zoonotic disease outbreaks.


We are still far from being able to explain the conditions of the emergence of SARS-CoV2 at the origin of the COVID-19 pandemic. One thing is sure is that we have a relationship problem with nature and particularly with animals. On the one hand, we have more and more animals raised for food, fur, the pet market, and that includes wildlife animals. On the other hand, we are increasingly destroying natural or traditionally maintained ecosystems such as grasslands and multifunctional agro-cultural landscapes. We create the ideal conditions by weakening the ecological regulations, including the regulations for the transmission of infectious agents. By weakening the resilience of ecosystems, we affect the resilience of our societies and public or veterinary health systems. 



Are epidemics therefore predictable according to our actions? are we heading towards a path of “more and more epidemics”?


Serge M.: We know enough to know that the simplification and artificialization of habitats such as the expansion of industrial agriculture and livestock farming are harmful for biodiversity, the climate and for the health of humans and non-humans. 

If we do not seriously tackle the problems caused by a short-term economic development that is reckless of the planet and its inhabitants, then we are heading for new health crises, but which will accompany ecological crises and social crises. Unfortunately, we focus our attention on the consequences, we act only in crisis situations, and often badly, and our actions are limited to emergency therapies by advocating for more biosafety and biomonitoring. Even though we must devote ourselves to the causes of these disruptions and not only to their consequences. 

“Massive deforestation, the excessive containment of waterways, the pollution of the atmosphere, water and soil lead to an unprecedented planetary disorder marked by the disappearance of a large number of animal and plant species and putting jeopardize the resilience of biological and natural systems. » [5] 

It is time to reconnect with the living, to understand that our economy, our social ties, our health and our well-being depend on functional ecosystems rich in biodiversity. The human species cannot live in a society of global risk tempted by the eradication of an “undesirable” living being and by the genetic manipulation of the rest of the “useful” living being in order to adapt it to the “unlivable” conditions created by a short-term economic system. 

A social-ecology of health recognizes the dynamic complexity of the interactions between humans, their social organizations and modes of economic production, the environment, the climate, biodiversity and including that of microbes. Social-ecology is a scientific ambition capable of contributing to the necessary dialogue between citizens and their associations, administrations, farmers and breeders, economic and political agents, in order to collectively create shared living territories, ecologically productive and resilient for health and the well-being of all, human and non-human. 

plantation tapia Madagascar

“If nothing changes, then the future is predictable, with more plagues to come. »[6] 



Can we act and reconcile the environment and the human?


Serge M.: The window for action is narrow. The international organizations of the United Nations all contribute to raising awareness and setting up an action agenda. These are first of all the Sustainable Development Goals (SDGs) or the new objectives for biodiversity. Civil society is also mobilized. Even large companies are beginning to take the measure of urgency. Local authorities are driving many projects, whether for ecological transition, climate or biodiversity. 

It is becoming urgent to preserve the world’s tropical and temperate forests, to think about forest restoration objectives and not just forest plantations which cannot contribute to ecological functioning, to the immediate needs of local societies, to planetary health as well as to the health of humans and non-humans. The theme of the year 2021 for the International Day of Forests: “Forest restoration: a path to recovery and well-beingcarried by the UN (FAO) and the United Nations Decade for the Restoration of Ecosystems should provide the agenda of the collective actions to be undertaken. 

International or national initiatives must be complemented by collective and individual actions. Reconnecting with Nature has implications for our ways of life, travel, consumption and food. It will be a question of promoting a society of citizens more economical in living resources consumed, but more demanding in psychological benefits, health and well-being provided by Nature, biodiversity, and forests. 



What do you think is the role of NGOs like Planète Urgence – which strengthens local communities – in preserving forests and biodiversity?


Serge M.: NGOs, like Planète Urgence, are essential intermediary actors between different worlds, political, administrative, economic and research, which do not work together enough for the benefit of local communities and their natural environments. 

I would have a special mention for the small French NGOs which carry a different message and values from the large American or Anglo-Saxon NGOs in general. They deserve to be more recognized and supported by French and European development agencies. 

We must ask ourselves the question of greater visibility and greater support for French NGOs that act internationally. The major French associations for the defense of the environment or biodiversity have barely integrated the necessary internationalization of their activities in order to better respond to global issues.


Controle sanitaire des plants au sud du Parc Cameroun



“Bonus” question: Last April, Planète Urgence had contributed to the citizen consultation of the “World after” the COVID-19 pandemic initiated by Make.org, the SOS Group (of which Planète Urgence is a part) or the WWF … what would your world look like after?


If we do not react collectively, the “world afterwill be that of the “world before” but worse. The world of tomorrow will be built by trusting in collective intelligence translated into local initiatives that promote living well together. The world of tomorrow will no longer be a world dominated by a short-term economy that destroys ecosystems and creates economic inequalities and injustices, but a world where the economy will be central because it is put back into the service of human well-being and non-humans. 


About Serge Morand:

à propos de Serge Morand

Serge Morand is a researcher at CNRS-CIRAD, a teacher at the Faculty of Tropical Medicine in Bangkok (Thailand) and an ecologist living in Southeast Asia. His latest book published in September 2020 Man, wildlife and the plague (Fayard) presents the main causes of the appearance of new infectious diseases (including COVID-19), including in particular deforestation and the overexploitation of our worlds’ forests.


Sources et bibliographie :

[1] MORAND S., L’homme, la faune sauvage et la peste, Fayard, p.217

[2] Idem, p.219

[3] MORAND S., LAJAUNIE C., Outbreaks of vector-borne and zoonotic diseases are associated with changes in forest cover and oil palm expansion at global scale

[4] Idem, p.6

[5] GWENAËL VOURC’H, FRANÇOIS MOUTOU, SERGE MORAND, ELSA JOURDAIN, Les zoonoses, ces maladies qui nous lient aux animaux, éditions QUAE, février 2021

[6] MORAND S., L’homme, la faune sauvage et la peste, Fayard, p.102


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