– Angela Sheldrick

They're often called the walking trees: With stilted roots that arch into the shallows, mangroves look like spindly giants caught mid-step, suspended above the water.

But these ethereal trees serve a very real ecological purpose. They stabilise fragile shorelines, holding soil in place and preventing erosion. They stand as defensive bulwarks during extreme weather, buffering storm surges and protecting communities from wind and water damage. Their complex root systems filter excess nitrates and phosphates from runoff, protecting coastal waters from algae bloom and pollution.

Mangroves are also an essential habitat for countless species. Their subaquatic root systems form a sheltered nursery for juvenile fish and crustaceans, while birds use their branches as resting and nesting grounds. Primates feast upon the bounty of insects that live within mangroves, while sea turtles shelter within their roots. If you look closely enough, every single tree is pulsing with life.

Finally, they play a critical role in climate resilience. Capable of storing 2-10 times more carbon per hectare than terrestrial or tropical forests, mangroves are among the most carbon-dense ecosystems on Earth. While most trees store carbon in their aboveground biomass, mangroves store the majority of theirs in the soil. This waterlogged, low-oxygen environment dramatically slows decomposition, keeping organic matter from breaking back down into carbon dioxide. Instead, carbon continues to accumulate in the mud, for centuries or even millennia.

Mangroves are anchors of Kenya's coastline — but like so many ecosystems, they are under siege. In recent decades, overexploitation (overharvesting, illegal logging, charcoal production, etc.) and development pressure have chipped away at mangrove forests around the world.

Kenya is not immune to these threats. Between 1985 and 2009, about a fifth of its mangrove forests disappeared. Without strengthened protections of existing habitats and concerted reforestation efforts in degraded habitats, that loss would continue to accelerate. The stakes were particularly high in Lamu, a precious coastal ecosystem on the northern coast, which is home to more than 60 per cent of Kenya's mangrove forests.

We already had a conservation footprint in Lamu, working with Lamu Conservation Trust to engage the community in the preservation and protection of the northern coast's wildlife and marine habitats. In 2020, we started a new initiative to regenerate Lamu's mangroves.

Our first reforestation unit was recruited organically: There had long been an informal beach management unit in Lamu, made up of local volunteers who conducted beach patrols and prevented the illegal harvesting of mangroves. These people, who had already dedicated themselves to their community's conservation, became our first reforestation employees in Lamu.

Formal job opportunities are scarce in Lamu, and that scarcity has long driven people toward poaching, charcoal burning, and illegal harvesting. Employing those who might otherwise be extracting resources from local habitats addresses both problems at once. Today, we employ a mangrove team of 30 in Lamu: 24 planters, two team leaders, two boat captains, one forest monitor, and one restoration manager. Planters are selected by the local Community Forest Association (CFA), which partners with the government to protect, manage, and sustainably benefit from public forest resources.

Mangrove restoration is incredibly efficient — quick to establish, with outsized ecological return. Rather than dormant seeds that need to be planted, mangroves propagate through propagules. In the wild, these pencil-like, sprouted seedlings grow on the parent tree and then drop into coastal waters. As tides carry them far and wide, they become increasingly waterlogged, shifting from a horizontal to a vertical floating position. Eventually, they anchor straight into coastal mud or sediment at low tide, where they take root and grow.

Our team harvests propagules daily, and the previous day’s harvest is then planted at low tide. Our boat carries the team through remote waterways, delivering them to each planting site. Mimicking how they take root in the wild, each propagule is speared by hand into the mud.

In places stripped of most vegetation, the team uses a 'caregiver' method, planting new propagules close to living mangroves, where they can benefit from shade and nutrient-rich soil. Planting then proceeds in bands: once one band reaches two years old, it is established enough to support the next band planted beside it.

Deciding where to plant starts with a map. Working with the Kenya Forest Service, the team has catalogued every part of the forest showing signs of degradation. Importantly, our crews are also on the ground and in the water every day, checking sites to identify any areas that need special focus. While the majority of mangrove degradation is caused by human actions, some is the result of natural phenomena. For instance, the 1998 El Niño left bald patches of forest that never really recovered. Nearly 30 years later, the landscape is finally filling back out. The propagules we planted there really took off, with some already standing over two metres tall.

Newly planted mangroves have high survival rates, running between 80 and 85 per cent. In sections where the forest is already healthy, the team conducts 'enrichment planting', which increases forest density rather than restoring bare ground. This repair-and-replenish model both rehabilitates degraded forests and enhances existing ecosystems.

Reforestation is patient work, but even in just six years, the impact in Lamu has been transformational: To date, over 17.6 million mangroves have been propagated. We have also engendered goodwill in the community, turning conservation into a job opportunity. The walking trees are putting down roots again, thanks to the people who live alongside them.