Product Feature: Deep Root Silva Cells

The primary challenge of growing trees in an urban environment is the soil. Trees thrive in lightly compacted soil that provides their root systems with ready access to water and nutrients. However, due to the requirements of an urban environment soil is typically heavily compacted. This provides structures with greater stability, but can stunt the growth of trees.

Additionally, as roots grow in compact soil under sidewalks and other urban fixtures they’ll eventually displace the soil causing buckling. You’ve probably seen your fair share of old buckled sidewalks around trees from just this problem. We recently faced this challenge with a client in Washington, DC and the solution we turned to was a soil containment system called Silva Cell developed by DeepRoot Green Infrastructure who have been producing urban landscape products since 1976.

What is Silva Cell 

Silva Cell is a flexible and modular soil containment system designed to provide trees with the lightly compacted soil they need without compromising the stability of surrounding urban structures. It acts as a suspended pavement system, transferring the load from structures such as sidewalks down to compacted soil and creating a grid structure between the two where lightly compacted soil can rest.

Each Silva Cell is composed of two parts, a frame and a deck. When assembled they sort of resemble a hollow brick. The frames are 48” long x 24” wide x 16” high, and each holds 10 cubic feet of soil. The frames can be stacked up to three high before being topped with a deck to create a larger containment area for lightly compacted loam soil. Silva Cells can be spread laterally over a wide area, ensuring that trees will have ample room to grow. Each cell is about 92% void space, making it easy to accommodate utilities along with a tree’s root system.

Having a supply of lightly compacted soil just below the surface in an urban environment also provides storm water management benefits. Unlike the heavily compacted soil you’d typically find, the soil contained in the Silva Cells can absorb storm water runoff, effectively serving as an underground rain garden. Not only does this help the environment, but it can assist in complying with local storm water ordinances and regulations.