Foreign Green, Forgotten Forests: Why We Must Uproot Eucalyptus From Africa’s Conservation Lands
Dr Dr. Mwenda Mbaka & Dr. Katherine Baxter – May, 2025
From Karura Forest in Nairobi to the miombo woodlands of Malawi, from Morocco’s cork oak groves to the dry highlands of Ethiopia—Africa’s green spaces are under pressure. Some threats arrive with bulldozers and chainsaws. Others come quietly, slowly, disguised in green. The eucalyptus tree—fragrant, fast-growing, and foreign—is one such silent threat. Planted widely across the continent in the name of reforestation, it now risks turning biologically rich landscapes into green deserts.
Karura Forest, one of Africa’s best-known urban conservation success stories, exemplifies this paradox. Beloved for its peace and biodiversity, Karura is also home to large tracts of eucalyptus—trees that consume vast amounts of water, suppress native plants, displace pollinators and birds, and heighten the risk of fire.
But Karura is not alone. The story repeats, across the continent, and around the world.
Amidst the rolling forest canopy of Karura, Nairobi breathes. Here, the city exhales its weariness into a sanctuary of birdsong and dappled light, where sunbeams trickle through ancient fig trees and the wind hums through indigenous leaves, as if whispering ancestral memories. But even within this cherished haven—a forest reborn through struggle, protected by the fierce grace of Prof. Wangari Maathai—lurks a subtle, silent undoing.
The eucalyptus tree, tall and fragrant, stands as a paradox. It is green, but not of this place. It thrives, but in its thriving, others vanish. It shades the earth, but its roots leave the soil thirsty, the microbes silent, the animals displaced. This is the story of an ecological intruder that mimics restoration while hollowing out the very foundation of coexistence between humans, animals, and the land they share.
Forests Are More Than Trees
Karura is not just a woodland. It is a living system: a home, a highway, a hospital, a pantry, a nursery—for countless species of birds, pollinators, soil microbes, and mammals, both wild and domestic. Every leaf that falls from an indigenous tree is more than litter; it is a molecular signature, recognized by microbial networks in the soil, decoded by dung beetles and fungi, and used by birds to line their nests.
Here, bee colonies have co-evolved with the timing and nectar of native blossoms. Tree-dwelling birds like the Turaco, Hornbill, and Woodhoopoe rely on indigenous cavities, and the Hamerkop on branch forks to build their giant nests. The bee, the butterfly, the beetle, the hummingbird, and many more all depend on the foraging rhythms dictated by indigenous trees, taking nectar from generous flowers in a melodic dance for life.
Beneath them, the forest floor teems with microbial life, finely attuned to the chemical language of native roots and decaying leaves, and to the delicate balance of moisture, upon which the symphony of life has played for millennia, from time zero into an infinite future, wherein we all eventually become compost for worlds we can’t yet imagine.
When eucalyptus enters this system, that symphony is silenced. The scent it exudes—pleasant to us—is a chemical warning to other species. Its allelopathic oils leach into the soil, suppressing undergrowth and suffocating the microbial diversity that supports both flora and fauna. Water disappears. The understory thins. Insects vanish. Birds fall quiet. And the ecological memory of the land begins to fade.
The Thirst That Drains the Future
Eucalyptus trees are hydrological tyrants. A mature tree consumes 60 to 90 liters of water a day. Multiply that across hundreds, and Karura becomes a sponge that can no longer serve the city. Springs dry up. Wetlands recede. Riverbeds crack. In a city where taps routinely run dry, this isn’t just an environmental concern; it’s a crisis of equity threatening access to life’s most fundamental resource.
And the damage doesn’t end with humans. Watering holes that once nourished bushbuck, porcupines, squirrels, and the insectivores that sustain nutrient loops now disappear into dust. Amphibians, singing beneath the dragonflies and the dancing water beetles—silent sentinels of water health—disappear.
Even the microbes that line the gut of domestic goats and forest antelope have evolved with indigenous foliage. They struggle to process the fibrous, resin-heavy eucalyptus leaves. What may appear as green abundance is, in truth, a monocultural mirage: alien, unpalatable, and toxic.
A Forest Ready to Burn
The oils that make eucalyptus smell sweet also make it dangerously flammable. In Karura—surrounded by palatial neighborhoods like Muthaiga, Runda, and Ridgeways; informal settlements such as Mathare; prime city infrastructure and fuel depots; and a firefighting system that barely functions—a single spark could become a firestorm.
We’ve seen this movie before: Portugal, Spain, California, Australia, South Africa—all places where, despite technological prowess and firefighting sophistication; properties, lives, and health have been devastated and turned to ash, sometimes forever.
Each testimony stands as a warning: plant eucalyptus en masse, protect it from eradication, and you plant the seeds of catastrophe.
Animals Know What We Forget
In the rustling branches of fig and croton trees, generations of monkeys, squirrels, and owls have nested, fed, and raised their young. These trees are not just habitat; they are heritage. In the soil beneath, fungi and bacteria break down leaves, nourish roots, and regulate forest health—networks finely tuned to native flora. Even within the stomachs of grazing animals, the microbiome reflects the co-evolution of animal and plant life.
Introducing eucalyptus disrupts that invisible intimacy. Insects that pollinate, birds that feed, mammals that browse, the microbes that aid them—all suffer subtle imbalances. A forest may still look green to the eye, but it becomes biologically silent.
This silence is an act of forgetting.
Conservation Is Not Just a Science; It’s a Contract
Our national constitutions, as well as the international treaties we uphold, recognize our duty to safeguard biodiversity, natural heritage, and the intergenerational rights of both people and animals to thrive in harmony. Keeping eucalyptus in Karura violates that sacred contract. It is anti-Ubuntu. It privileges convenience for a few over the continuity of the ecosystems society deserves.
We forget that our ancestors did not plant eucalyptus. They planted sycamores and olives, acacias and podocarps. They lived among landscapes that spoke their language, and which spoke back: in fruit, shade, forage, soil, and the dignity and integrity they preserved through the respect they showed for these complex living systems.
From Karura to the World: A Global Reckoning with Alien Trees
Kenya is not alone. Across Africa, eucalyptus has marched from hillsides to floodplains, from town edges to national parks. In Ethiopia, water tables are falling. In Malawi, native miombo forests are vanishing. In Uganda, tree-planting campaigns mistake eucalyptus for reforestation. In Morocco, Tunisia, and South Africa, native flora and fauna are in retreat.
The same crisis unfolds globally—in India, where birds have vanished from eucalyptus plantations; in Chile, where native amphibians can no longer breed; in Spain, where cork oak forests lose their endemic richness.
Green, it seems, is not always good.
A Return to Ecological Wisdom
This is not a call to demonize a tree. Eucalyptus has value, just not here. Not in Karura. Not in ecosystems where it never belonged. Instead, this is a call to remember; to put back together the shattered memory of ecosystems that once thrived on balance and reciprocity.
We must act:
Remove eucalyptus and other invasive exotics from Karura and other conservation zones.
Reintroduce indigenous trees and flora co-evolved with native fauna and microbial life.
Halt the commercial planting of eucalyptus in water-stressed and biodiversity-rich areas.
Educate the public and policymakers that not all trees are equal.
Frame reforestation within the values of ecological justice, human-animal coexistence, and cultural heritage.
Conclusion: Planting Belonging
Africa has a proud tradition of ecological stewardship. Kenya, through Karura, has shown the world what civic activism can do. Ethiopia has demonstrated how reforestation can combat desertification. South Africa has led wildfire mitigation research. The question now is: can we take the next bold step, together?
Removing eucalyptus from conservation lands is not an act of rejection. It is an act of renewal. A recognition that green must be guided by belonging, not just color. It is time to plant trees that feed bees, shade the soil, and remember the language of this land. Because the forests of tomorrow begin with the choices we make today. And when we choose to plant memory, we choose to protect the future—for people, for animals, and for the Earth we share.
Let us not be fooled by foreign green. Let us plant trees that remember the bees, that feed the birds, that soften the soil, that quench the thirst of elephants and donkeys—and us, alike.
Let us plant belonging: for animals, microbes, and humans.
Karura was saved once through courage and conscience. We are called now to save it again—not from bulldozers, but from the subtle erasure of what makes this forest truly alive.
Because conservation is not just about what we protect; it’s about what we choose to belong to.
Authors:
Dr. Mwenda Mbaka – Veterinarian, Animal Welfare Expert & Conservationist
Dr. Katherine Baxter – Social Scientist, Human-Animal Coexistence Expert & Policy Researcher
*With gratitude to Prof. Wangari Maathai for planting the seeds of this story, and to all those who still believe that forests can be more than just green—they can be home.