Silva Cells are a suspended pavement system designed to support sidewalks and other hard surfaces while creating protected soil space below ground for tree roots. The system uses a framework of modular, plastic cells that carry the weight of pavement above, preventing the soil beneath from being crushed and compacted.
Why Silva Cells
In urban environments, soils around sidewalks and pavement are often compacted by construction, traffic, and everyday use, limiting the air and water exchange that tree roots need to survive. As a result, many street trees live only 7–10 years. Silva Cells address this challenge by supporting pavement above while creating protected soil space below for root growth. When used beneath permeable pavement, this design allows air and water to move through the soil and gives roots room to expand without causing sidewalks or pavement to heave or crack.
By providing adequate soil volume and protecting soil structure, Silva Cells allow trees to grow larger and live for decades, delivering greater benefits such as shade, stormwater capture, improved air quality, and more resilient and beautiful urban streets.
Silva Cells At Brightside
The Brightside Demonstration Garden features the Midwest’s first Silva Cell system designed with a porous surface. Installed beneath the permeable pavers in front of the office, the system supports four bald cypress trees and two redbud trees.
During installation, nearly 200 engineers, planners, foresters, arborists, and elected officials participated in workshops to learn about the system’s benefits. In addition to supporting healthy tree growth, Silva Cells allow utility lines — such as gas and electric — to run through the structure, making maintenance and access easier.
Silva Cells are now recognized as a best management practice by the Metropolitan St. Louis Sewer District and are most commonly used in municipal and commercial projects.
Create Your Own Sustainable Landscape
Want to learn more about ways to improve the health of urban trees? Visit our pages below.
Resources
To learn more about Silva Cells and how they can benefit your community, check out the DeepRoot website.
East-West Gateway Council of Governments explores St. Louis rainscaping projects.