Arbour week: Don’t plant a tree – plant biodiversity!

Estimated reading time: 6 minutes

Planting a tree might be a feel-good Spring gesture, but this tradition might be aiding climate change and hampering nature when done indiscriminately.  

“Tree planting is often presented as a cure-all for climate change,” says Prof Guy Midgley, director of Stellenbosch University (SU)’s School for Climate Studies. “But planting the wrong trees in the wrong places can actually reduce biodiversity, threaten water security, and damage livelihoods. We need science-based, locally informed decisions.”

Planting trees is often hailed as a simple solution to climate change. But when done indiscriminately, tree planting in Africa can cause more harm than good – displacing biodiverse and unique grasslands, reducing water availability, and undermining livelihoods.

Now, an ambitious research initiative, the Southern African Trees for Climate Adaptation and Resilience (SAT-CARe) project, is working to change that. Anchored at Stellenbosch University and developed in collaboration with researchers from other universities and institutions, SAT-CARe is building an open-access toolkit based on bioinformatics to guide smarter use of indigenous trees in Southern Africa – with plans to expand its reach across the continent.

The digital toolkit will draw on climate, soil, and environmental data, along with detailed species traits to help policymakers, farmers, and urban planners identify which endemic African tree species are best suited for applications such as reforestation, urban greening, ecological restoration, and livelihood support. This approach is considered crucial to move away from poorly informed decisions to plant non-indigenous species.

Afforestation a growing problem

He warns of Africa’s “afforestation problem”, not only through the spread of woody plants into grasslands driven by rising CO₂ levels, but also when external actors impose ill-advised tree-planting schemes on the continent.

“We see these big greening trends across our subcontinent,” Midgley explains. “It chokes up grasslands with shrubs, destroys people’s livelihoods, and potentially increases water use. This is not a standard northern hemisphere challenge – it is our challenge, and we need to develop our own models.”

African trees for African landscapes

SAT-CARe insists on African solutions. “Why are we planting alien tree species in our valuable catchments where they use too much water, change the soil composition, and even fuel intense wildfires? We need to leverage Africa’s indigenous resources,” Midgley told stakeholders attending a meeting at the Stellenbosch Institute for Advanced Study (Stias).

The project’s practical ambition is to identify which indigenous tree species will thrive in which landscapes – today and as the climate continues to change in future. This means looking at iconic African trees such as baobab, marula, mopane, sausage tree, miombo, and yellowwood.

By linking environmental data to species traits, the software will for instance help farmers select the best tree species for drought tolerance, fruit and oil, or livestock fodder. And urban planners will be able to use the toolkit to choose species that improve shade and air quality without depleting scarce water supplies.

Besides South Africa, SAT-CARe brings together researchers and data from Botswana, Mozambique, Namibia, Zambia and Zimbabwe, with additional input from Kenya. The models are being piloted across diverse ecosystems – from savannas to montane forests – with the aim of producing guidance that can be scaled across Africa.

Data challenge

For the project to deliver useful answers, it must integrate climate, soil, CO₂, and wildfire data with tree traits and socio-economic indicators. “This is not just a data exercise for scientists,” says Prof Kanshu Rajaratnam, director of SU’s School for Data Science and Computational Thinking. “We are building models that can be used by policymakers and communities. Our goal is a digital toolkit that is as open and usable as possible.”

Dr Jan Greyling of SU’s Faculty of AgriSciences, explains how it would work: “The idea is that users would simply type in a species name, select a climate scenario, and generate a map showing where a target tree species is likely to thrive.”

African resilience

For Prof Midgley, the project is a statement about Africa’s role in shaping global climate debates.

“Africa gets less than 3% of international funding for climate change science, and of that, about half goes to non-African scientists. So, this continent is extremely vulnerable because we are not funded to do the fundamental science that we need,” says Midgley.

However, SAT-CARe is part of the Africa-Europe Cluster of Research Excellence on Nature-based Solutions for Climate Change Adaptation and Mitigation (CoRE), convened by the African Research Universities Alliance (Arua) and The Guild of European Research-Intensive Universities. The cluster positions nature-based solutions as a promising way to reduce climate risks while protecting biodiversity and sustaining livelihoods.

“SAT-CARe is not just about trees in Southern Africa. It’s about African researchers taking the lead in generating knowledge that is locally grounded but globally relevant,” says Midgley.

Plant something this Arbour Week

If you would like to celebrate nature this Arbour Week, here is a breakdown of South Africa’s biosphere reserves along with indigenous planting ideas to inspire you. (Source: Chat GPT and verified by Plaas Media)

This project is funded by Lacuna Fund and the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ). – press release curated by Plaas Media