Making tree-planting count

Political gimmick or killer app for Africa’s climate? It depends on the way you do it. 

Political gimmick or killer app for Africa’s climate? It depends on the way you do it. 

The news: Kenya took the unusual step of declaring a national holiday this week to plant 100 million trees – two for every citizen. 

  • The government supplied 150 million seedlings in public nurseries.

  • Software recommended species by location and monitored progress.

Numeric ambition: Few could fault Kenya’s goals.

  • Plant 15 billion trees by 2032

  • Increase national forest cover from 7% to 10%

The logic: Tree planting can have massive benefits in terms of carbon storage, soil preservation, biodiversity conservation and livelihoods for local communities. 

  • Forests support the livelihood of 1.6 billion people worldwide in timber harvesting, other forestry products and tourism. 

  • John Clark, CEO of Tupande by One Acre Fund, said, “Trees are one of the most important livelihood assets for a farmer.” 

Quality matters: What’s often overlooked is that tree planting has its pitfalls.

  • Will the trees live long enough to store significant amounts of carbon? 

Survive & thrive: Best practices are hard to follow on colourful mass activations.

  • Local residents need to look after the trees for decades, so best to get their buy-in. 

  • Paying local communities for maintenance reduces incentives to cut down trees. 

  • Figure out beforehand what grows well where, and when it should be planted. 

  • Avoid monocultures to ensure biodiversity and sustain supportive ecosystems.

  • Trees need enough water – best to figure out supply and infrastructure. 

The backlash: When such practices are ignored, the result is often damaged ecology.

  • Reducing biodiversity

  • Threatening water supplies

  • Making ecosystems less resilient

  • Speeding extinctions by introducing competing foreign species

  • Increasing temperatures as some trees absorb more heat than grasslands

Not new: In the 19th century, South Africa planted Australian acacias to stabilise dunes and produce timber. But they lowered the water table and even depleted it in places.

  • The country now spends millions of dollars every year to remove them. 

Complex dynamics: Determining when tree-planting removes carbon can be difficult. 

  • Existing ecosystems in open areas may already function as carbon sinks. 

  • When one then plants trees, this might only add marginally more carbon storage.

  • In some cases, land clearing and frequent tree harvesting in fact lead to a net negative impact. 

Done right: The Great Green Wall project across 20 countries in the African Sahel once aimed to fight desertification by planting a continuous line of trees.

  • But maintenance turned out to be near-impossible in vast uninhabited areas.

  • The project adapted and became a mosaic of green land use practices managed by local farmers instead.

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