Why Planting Trees in Drylands Isn’t a One‑Size‑Fit Climate Fix

When the United Nations warned that we’ll likely miss the 1.5 °C goal by 2030, the image that popped up everywhere was a forest‑filled Earth, each new sapling a tiny carbon‑vacuum. It’s an easy story: more trees, more carbon taken out of the air, a cooler planet. That narrative fuels massive pledges, from the Bonn Challenge’s 350 million‑hectare restoration target to Africa’s Great Green Wall, which set out to halt the Sahara’s southern march by planting trees across 22 countries.

But the reality is messier. A tree is not a universal climate hero, and a landscape that lacks dense forest cover isn’t automatically degraded. In fact, drylands—grasslands, shrublands and savannas—cover roughly 40 % of the planet, support billions of lives, and are key players in the global carbon cycle’s yearly swings.

These ecosystems have evolved under low, erratic rainfall, frequent droughts and regular disturbance. Their native grasses, scattered shrubs, occasional trees and even the thin crust of microbes on the soil are not signs of failure; they’re evidence of a functioning, resilient biome. Swapping that open mosaic for a blanket of trees can do more harm than good.

Why tree‑planting can backfire in drylands

First, trees drink. In a place where every drop counts, introducing water‑hungry species—especially if they’re non‑native—can shrink stream flows, depress groundwater tables and jeopardise downstream farms and households. The trade‑off becomes stark: you might lock away a tonne of carbon, but you also risk a community’s water security.

Second, there’s the albedo effect. Open, light‑coloured soils and grasses reflect a good chunk of sunlight back into space. A dense, dark canopy absorbs more solar energy, warming the surface. Researchers have shown that this shift can offset a sizable portion of the climate benefit that the new trees were supposed to deliver, especially in arid zones where the albedo change is dramatic.

Restoration that actually works

Instead of a one‑size‑fits‑all tree‑planting mandate, many practitioners are turning to context‑specific approaches. In Niger, farmer‑managed natural regeneration lets native white acacia and other useful species sprout from existing roots or seeds, re‑greening about five million hectares without the expense of mass‑seedling nurseries. Because the farmers pick the species and tend the regrowth, the method dovetails with crop and livestock needs.

Burkina Faso offers another clue: the revitalised “zaï” technique. Farmers dig tiny pits that capture runoff, then fill them with manure or compost. The resulting micro‑reservoirs boost soil moisture, allowing crops to thrive even when rains are fickle. Here, restoration isn’t about turning the land into a forest; it’s about restoring soil function, vegetation cover and the livelihoods that depend on them.

Other dryland strategies include protecting native grass cover, managing grazing pressure, safeguarding seasonal mobility, controlling invasive plants, conserving biological soil crusts and assisting the recovery of locally adapted shrubs and trees. The key is simple: match the intervention to the ecosystem, not the other way round.

When does planting trees make sense?

If a piece of land has been genuinely deforested, if water is plentiful, if land tenure is clear and if the chosen species are native and climate‑appropriate, then tree planting can be a win‑win. Agroforestry—growing trees alongside crops or livestock—often delivers carbon, shade, fodder and market products without compromising water resources.

The mistake lies in treating those success stories as a universal rule. More trees ≠ better climate outcomes everywhere. In drylands, the focus should shift from the number of saplings to the health of the whole ecosystem.

So, before you pledge to plant a million trees in the savanna, ask: What water will those trees need? How will they change the land’s reflectivity? Will local people benefit, or will they lose access to water and grazing? The answers will tell you whether you’re really planting a solution—or just a well‑intentioned illusion.