Shade as infrastructure, canopy as care

Alderway is one of Seattle's hottest and least shaded neighbourhoods, and its residents face some of the highest health risks during heat waves. The city asked a simple question: how much can a forest actually cool a neighbourhood, and how should it be planted?

Soil first

Trees in dense urban sites usually fail below ground. We installed 18 inches of engineered soil across the site and structural soil cells under the path edges, so roots can spread beneath paving instead of lifting it.

Three forests, side by side

We planted 1,200 trees in three layouts: a dense grove, a widely spaced savanna and a linear allée along the main walking route. A grid of thermal sensors compares surface and air temperature across all three against the open lawn next door.

Shade where people are

Three summers of data show the dense grove cools the ground most, but the savanna is where people spend their time. Shade-tolerant understory planting now links the forest to the river as a wildlife corridor, and summer cooling workshops and guided tours bring residents in on the hottest days.