City planting, an urban tree strategy

City planting, a photo by Plant Design Online on Flickr.

Urban trees experience a variety of stresses. Compaction, lack of water, and pollution are three examples. The surface grate in this photo protects the tree in several ways.

The large surface area allows rainwater to reach the roots. This is important for two reasons. Obviously, the plant requires water. Less obvious, salt and other damaging pollutants that splash up from the roadway can be washed away with copious water.

The surface grate is metal, and this will protect the young tree from surface compaction. In this way the roots will be able to obtain adequate oxygen from the naturally aerated soil.

Note that the grate was installed some distance from the actual soil surface. This will allow for expansion of the tree's roots, minimizing potential damage to the built environment.

Finally the grate is pedestrian and bicycle-friendly as well as visually pleasing. I think it's a great strategy for urban trees.
--from City Planting, Plant Design Online