This week, Nairobians were rightfully outraged by the site of chopped up trees on Aga Khan Walk in downtown. This follows similar episodes over the last year, where decades-old trees were cut down to make way for the Mombasa Road overpass.

These examples raise the important question of how we should balance “development” with “conservation.”

Just to be clear, we should acknowledge that conservation should always be carried out in the service of improving Kenyan lives. We should never subordinate Kenyans’ well-being to the aesthetic desires or lifestyle causes of the powerful.

This means we must not delude ourselves that we can “develop” without some cost to the environment. That said, there are smart ways of ensuring sustainable development. We could plant three trees for each cut down to make way for a road. Or we could design roads and walkways in a manner that preserves existing green cover.

Unfortunately, so far our urban planners and architects have shown little regard for environmental sustainability. The cutting down of trees on Aga Khan Walk was merely a symptom of this insidious disdain for creative design with an eye on sustainability.

The authorities and their contractors have never seen an old tree they did not view as a nuisance or potential source of a quick shilling as timber or charcoal.

Planting and maintaining trees in our urban environments is not just a matter of sustainability for its own sake. Research shows that urban tree cover has direct benefits including reducing street level temperatures, increasing property values (remember “leafy suburbs”?), improving safety and walk appeal, and general improvements in the aesthetic attractiveness of surroundings. And yes, trees also reduce the amount of carbon dioxide in the air.

With this in mind, Nairobi County and the NMS should take up the challenge of greening the city from Karen to Kayole.

The same efforts should go national in all urban areas. Urbanisation is not inherently inconsistent with environmental conservation.

The writer is an Assistant Professor at Georgetown University