Silva Cells

Beneath the sidewalk, something amazing is happening. Tree roots are growing through strong plastic structures, called Silva Cells, that firmly support the sidewalk and contain rich top soil.

The Silva Cell is a modular suspended pavement system that uses soil volumes to support large tree growth and provide powerful on-site stormwater management through absorption, evapotranspiration, and interception. To learn more about silva cell technology, please visit

Silva Cells give the trees at Fifth Avenue Place access to about three times more good soil than average urban trees. With all of this extra soil, the tree roots will be able to absorb a lot of nutrients, water and oxygen to help them grow and flourish over the next few decades.

As trees grow, so do the environmental, economic, aesthetic and social benefits we receive from them. Trees lower heating and cooling costs, reduce air pollution, and capture rainwater to reduce flooding. Street trees in Pittsburgh provide about $2.4 million in benefits to city residents every year.

TreeVitalize Pittsburgh planted fifteen Silva Cells trees around Fifth Avenue Place thanks to a generous grant from the Colcom Foundation and support from Highmark.

Highmark believes that good health and a healthy environment go hand in hand. "We're committed to being a sustainable company - in our business practices, at our offices, in the communities we serve, and together with our customers and partners," said Phyllis Barber, Highmark's sustainability coordinator. Learn more about Highmark's environmental initiatives at

Image of Silva Celll and tree roots