From bare earth to grass and trees, and then the frogs showed up

Story and photos by Cathy Watson

Nairobi’s new Waiyaki Way-Red Hill Link Road opened to traffic in September 2019, offering a fast connection for thousands of vehicles.

But its road reserve was a bleak eyesore – bare earth without a blade of grass, let alone trees. Pernicious plants were encroaching and soil running off, polluting the Getathuru, Gataara and Spring Valley Rivers. Local homeowners were dismayed.

Then something great happened. The Kenya Urban Roads Authority (KURA) gave the communities that bordered the road permission to beautify it, instructing explicitly that they plant it with indigenous trees.

This was an open-minded decision. To date, six neighbourhoods along the road have planted over 3,500 trees: Nyari 700; Spring Valley 118; Hillview 600; Lower Kabete Road 200; Kihingo 700; and Kitisuru 1,250.

With each group focused on its locality, there was no overarching plan. But almost without realizing it, we were building Nairobi’s urban forest.

The UN Food and Agricultural Organization (FAO) (2016) defines urban forest as “all woodlands, groups of trees, and individual trees located in urban areas” including street trees. Today a healthy urban forest is accepted to be critical to city well-being. Among its many benefits are “ameliorating a city’s environmental footprint”.

My community addressed the roundabout at the top of Peponi Road and four slip roads. We started work on 15 December 2019, a date emblazoned on my mind. For months we had stared at the bare land. Now it was happening!

We grassed the roundabout and planted a few trees as well as wild banana to give an exuberant green. But the rains were ending, and the grass all died.

We knew we needed help and approached a nearby nursery and asked the owner, Anne Jelimo, if she might like to be involved. We said we would pay and buy plants and manure as well. She agreed.

We also reached out to former chief forester, John Orwa, who had just retired from running Karura for 17 years and had planted street trees in the suburb of Muthaiga.  He said yes too, and suddenly we had a team.

We spent early January preparing a long stretch. We dug it and removed rubble left from the road construction, placing it to catch rain and hold the soil. We put manure, and we mulched with chopped up invasives like Tithonia that were proliferating on the surrounding land.

Orwa found us 125 trees from Kenya Forest Service and other nurseries. We had our first big planting on 21 January, Orwa spacing the trees five metres apart. After we planted the trees, we laid grass.

This became our standard operating procedure: dig, manure, mulch, plant trees, plant grass. And over the past 16 months, we did it many times, planting 700 trees, over a kilometre of grass, and transporting loads of leaves from where I live and the ICRAF campus. This made a big difference to the soil.

We drew our ideas of what to plant from a list of trees from the Nairobi City Council list and Orwa’s knowledge of which indigenous trees would thrive in this zone that was formerly a tropical dry upland montane forest.

Our first planting consisted of 14 species: Croton megalocarpus, Cordia africana, Teclea nobilis, Markhamia lutea, Warburgia ugandensis, Newtonia buchananii, Prunus africana, Spathodea campanulata (Nandi Flame), Olea welwitschia (Elgon Olive), Vitex keniensis (Meru Oak), Albizia gummifera, Trichilia emetica, Millettia dura, and Sapium ellipticum.

We were proud of this choice of species. The Meru Oak grew especially fast.

Biologist Wanja Kinuthia of the Museums of Kenya came to check what we were planting and endorsed our focus on diversity.

“Planting a very diverse range of trees is very important,” she said.  “You increase other diversity, like insects, birds and even soil microorganisms. You get more stable soil. With COVID, people have realized the value of growing their own food. We need corridors of trees along roadways so pollinators can move.”

We received other indigenous species from Ely Kogei, restoration officer of Karura Forest, and Mark Nicholson, Director of Plants for Life International at Brackenhurst Botanic Garden in Tigoni, and my organization World Agroforestry (ICRAF).

Among them were Polyscias kikuyuensis, Podocarpus falcata, Zanthoxylum gilletti, Bersama abyssinica, Margaritaria discoides, Rauvolfia caffra, Drypetes gerrardii, African olive (Olea europea ssp. cuspidata), African Juniper (Pencil Cedar or Juniperus procera), Pittosporum viridiflorum, Tabernaemontana stapfiana, Trichoclaudus ellipticus, Ochna holstii, Maesopsis eminii, Turraea holstii, and Schrebera alata.

From Celia Hardy at Nairobi nursery Plants Galore, we received Cape Chestnuts (Calodendrum capense). This purple-flowering tree is a wonderful substitute for Jacaranda, which is not a Kenyan tree. (You can see flourishing young specimens at Jomo Kenyatta International Airport). She also gave Ruttya fruticosa, a Kenyan shrub with yellow-orange flowers.

We planted mugumo (Ficus thonningii) and other big fig trees where we had room; swamp palm (Phoenix reclinata) towards the rivers; and four Gardenia volkensii on the roundabout. We dotted around a few fruit trees such as Ziziphus mauritiana and two species of Syzygium (Mzambarau in Swahili, Jambula in Uganda).

We decided not to remove any wildings we found and thereby inherited other trees such as avocado, Australian bottle brush, native Acacia, Australian wattle, Euphorbia, Sesbania sesbans and Californian privet. We now have close to 60 species.

For colour, we planted 150 hibiscus, 200 agapanthus, aloes, red hot pokers, salvias, cannas and wildflowers like Kleinia abyssinica. We planted succulents on slopes.

We were always careful to plant trees three metres or more away from the road so that they did not pose a hazard to motorists or damage the road with their roots. We avoided thorny trees near where walkers might pass.

Many people donated to what we were doing. We created green jobs. Over half of our expenditure was on the labour of our dedicated team of four.

Passersby expressed their appreciation. Tree frogs of the genus Hyperolius took up residence. Nyari reported a chameleon. We are creating a habitat. Growing, the bypass trees are storing carbon and reducing air pollution.

This is a project about equity too. Humans need nature. People sit on the grass under trees. Recently a wedding party took their photos on the roundabout. It has felt especially good to work on this during the COVID-19 pandemic.

Regreening this Nairobi road with indigenous trees has promoted Kenya’s tree diversity and can be a model for East Africa where roads are planted with exotics or not planted at all.

Imagine if Ugandan highways were planted with trees like Mvule. It would deliver benefits for nature and people and protect the roads from the ravages of time and weather.

You too could create an urban forest along a road. Visitors are welcome!

Cathy Watson is Chief of Partnerships for the Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF).