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A look at TreeSisters-funded reforestation projects in the time of COVID-19

As it turns out, the reforestation projects that TreeSisters fund are pivotal to restoring and maintaining the vibrant life and health in forests that help to reduce zoonotic disease risk. We are also finding that reforestation projects make involved local communities particularly resilient to the economic impacts of the current crisis and, thus, future crises.

Scientists have proven that high biodiversity levels are able to interfere with the transmission of zoonotic diseases (zoonoses). The process is known as the ‘dilution effect’. (4) With high levels of animal biodiversity, the number of 'superspreaders' —hosts or vectors that are particularly competent at spreading pathogens - are balanced out by non-spreading species, reducing the overall spread of pathogens.

When forest biodiversity is depleted — as in man-made forests or forests disturbed by certain human activities - the self-regulation capacity of those forests is lost. They become out of balance and unhealthy. The alteration of forest habitats disrupts wild animal populations. Predators die or must move elsewhere to find suitable food and refuge. The absence of predators benefits small herbivores and other small mammals whose numbers increase. When they have exhausted the local food supply, they will disperse and come in contact with humans. But some of them, such as rodents and bats, are known to carry infectious pathogens.

Maintaining a healthy ecological balance is crucial to reducing zoonoses' risks. In healthy forests, all species are in a stable dynamic balance maintained by competition and predation between the plants and animals, as well as the non-living things such as sunlight, temperature, water, air, and wind - which form the climate - as well as rocks and soil. A species in excess numbers would normally die off from fires or pathogens, or its population would be controlled by predators.

To restore and maintain healthy forests, some scientists recommend the following ecological prevention actions to reduce the risk of zoonotic diseases: reforestation, avoiding deforestation, as well as respecting forests and wildlife habitats. (6,7,8) The reforestation projects that TreeSisters funds cover these solutions.


In TreeSisters-funded tropical reforestation projects, forests are regrown in or around protected areas, rivers or streams, and in and around rural communities. Forests can reduce water runoff and prevent pathogens and parasites in livestock manure from contaminating water resources and wells. Additionally, it is possible that the return of abundant animals may reduce the risk of zoonoses, with higher biodiversity acting like "dead ends" for the parasites or viruses through the dilution effect explained earlier.

Avoiding deforestation

At least 12% of the trees across all the reforestation projects funded by TreeSisters as of March 2020 have been planted on farms and community lands for subsistence and livelihood purposes, like the Yorenka Tasorentsi reforestation programme in Brazil. When the trees start producing fruit and nuts, they provide nutritious food which may be sold. Leaves and bark are reaped for medicinal use. Trees also provide timber for household use or for sale. Branches can be cut for fuelwood or for feeding domestic animals or livestock. Some of these trees are planted in association with a variety of crops under agroforestry systems, which maintain or increase crop yields. This reduces the need to clear forestlands to cultivate new farmland. It also safeguards remaining high biodiversity forests, which is essential for the prevention of future pandemic-scale zoonotic disease outbreaks.

Respecting forests and wildlife habitats

As explained above, biodiversity is an important factor in the risk of zoonoses. Some of the reforestation projects that TreeSisters funds specifically focus on biodiversity. Often they seek to recover biodiversity corridors (11) like the Atlantic forest restoration project or to increase a forest patch. The ultimate goal is to ensure wildlife movements and connectivity between isolated populations, reducing zoonosis transmission through dilution.

Role of local communities

Since the current epidemic began, our reforestation partners have been in regular communication with communities on the ground. They relay information to communities in very remote locations about the latest rules and restrictions related to COVID-19, as well as prevention and protection recommendations and equipment. The connection between healthy landscapes and healthy people is highlighted at community awareness sessions. Information on the protection measures to be adopted in the event of an outbreak is disseminated to communities.

The communities engaged in reforestation could be trained to detect early warning signs of outbreaks of reemerging known diseases in the project area. For example, the local implementing organisation of the International Tree Foundation's Mount Kenya forest restoration project, a Community-Based Organisation (CBO), which works directly with the Kenya Forest Service to prevent and alert about fires, could monitor the spread of new zoonotic outbreaks.

Role of reforestation stakeholders

The collaborations set up for reforestation projects could help limit the spread of infections and mitigate future pandemic crises. For example, in this current pandemic, the local implementing organisation of Health in Harmony's peat swamp forest restoration project in Borneo have been conducting COVID-19 advocacy outreach and providing advice to the Government of Indonesia on initial testing and antibody testing, contact tracing, and also ideas to resolve the current pandemic. Health in Harmony’s implementing organisation also specialises in healthcare and has local doctors on board.

Furthermore, reforestation projects indirectly foster know-how, expertise and infrastructures, which could be used to manage pandemics and prevent future zoonotic diseases. For instance, camera traps funded and installed by other Atlantic forest restoration project sponsors to monitor wildlife movements and abundance as indicators of forest recovery can potentially be useful to epidemiologists and public health authorities. They may flag a sudden increase of a known competent host/vector of zoonotic diseases.

The socio-economic dimensions

Since the beginning of the pandemic, reforestation work has been carried out under proper safety rules. Project team members have continued receiving salaries. Income generated by members of local communities employed to grow, plant and care for the tree seedlings have continued. Monetary savings regularly accumulated can act as a safety net during these difficult times.

Furthermore, the trees planted for subsistence and those with livelihood values also provide communities with continuous food, enhanced nutrition, and additional income to be resilient during a pandemic.

And ultimately, reforestation projects can protect remaining forests from deforestation that may increase during a pandemic.

It has been found that deforestation rates during the first month following the initial global lockdown were nearly double that of 2019. While there are many causes for this deforestation, it is realistic to think that lockdown and social distancing measures limit local economic activities, increase food insecurity, and, therefore, deforestation.

Having fruit, nut and timber trees and more productive farms under agroforestry systems can mitigate deforestation. It is thus crucial to continue funding community-based reforestation projects during these times.

Without food self-sufficiency and sufficient income or savings, local communities may be forced to return to the same old destructive practices like timber logging and slash-and-burn agriculture to pay for their health care or buy food for their families.

While planting fruit trees in or near human settlements, sometimes in association with domestic animals, could attract bats which are a known source of a number of infectious diseases, the risk of cross-species transmission, including eventually to humans, and eventually, a pandemic is likely to be low.

Indeed, the projects that TreeSisters funds are generally located in remote and rural areas that are not densely populated, as well as being quite far and not very accessible from highly populated centres. Besides, small farms under agroforestry systems harbour higher agrobiodiversity than traditional systems, which in turn attracts high biodiversity. This may reduce the risk of zoonoses due to the 'dilution effect'.

It is also important to balance the risk of zoonoses with other factors. Food insecurity, low nutrition, and lack of or low levels of health care make people in tropical developing countries more vulnerable to infectious diseases.

Health dimensions

A variety of native fruit, medicinal, and nut species, as well as the increased crop yields and quality of vegetables grown under agroforestry systems, provide healthy traditional diets and nutritional therapies which can boost the immunity of community members to fight zoonotic diseases. The medicinal properties of plants are a cornerstone of health care. Indeed, 70% of the developing world's population depends on complementary or alternative systems of medicine.

Some of the reforestation partners we support are also specialised in providing healthcare services in places with insufficient or no access to public healthcare systems. When healthcare systems are under immense pressure, like during this crisis, they are able to assist.

Whilst the planting activities of Trees for Life (a project of Isha Foundation's ecological initiative) were forced to pause during the first lockdown event in India, the health branch of Isha focused on providing the communities in Tamil Nadu with services such as nutritional advice and yoga to boost their immune system, as well as online community meditations — to mitigate the broad health impacts of COVID-19.

The climate

Tropical forests stabilise local temperatures all year round. (18) Additionally, of all the Earth's forests, tropical forests have the highest potential to draw down carbon from the atmosphere —contributing to the mitigation of climatic changes. This can potentially contribute to reducing the expansion of water-borne diseases (e.g. cholera) and vector-borne diseases (e.g. malaria, yellow fever, dengue, leishmaniasis), which are all influenced by climatic factors and deforestation.

In conclusion, protecting and restoring forests ‒the visible and invisible web of life that supports us all - is the solution to prevent future zoonoses and mitigate the adverse consequences of economic fallout that leads to increased deforestation.

When you donate to TreeSisters, you are not only creating environmental benefits by planting or assisting trees to regenerate naturally. You are also supporting communities to survive through the pandemic while safeguarding remaining intact forests and wildlife. You are supporting community-based projects which could help prevent, monitor and alert in case of an epidemic. You are investing in projects that are resilient to the current pandemic and making us all resilient to future pandemics. You are contributing to restoring global health.

Donating is about having the courage to be of service to our ‘common home’ - planet Earth. It is about the journey that will alchemise our fears, belief systems and the assumption that there is no other way than business as usual.

Image Credits: A wildlife corridor in Brazil; courtesy of WeFores. A

Health Care Services in Borneo; courtesy of Health in Harmony


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