Street Trees

Tree Diversity

Street trees provide a number of important functions besides making a neighborhood more attractive.  Some of these functions include: reducing stormwater runoff and erosion, keeping urban areas cooler, providing food and shelter for wildlife, capturing airborne pollutants, and slowing traffic in corridors lined with trees.  To maximize these benefits, larger trees are ideal.

To avoid a disease or pest wiping out a significant portion of the street trees in Cornelius, like the Dutch Elm Disease did in the early 20th century in the Midwest, the City promotes tree diversity in its street-side plantings.  In new developments, planting plans must follow the 10-20-30 rule where no more than 10% of the trees are of any one species, 20% of any one genus, or 30% of any family.

Cornelius does not have regulations governing management of street trees.  However, new street trees require a Public Works Permit and City Engineer approval.  The purpose of this approval is to help property owners select trees that are appropriate for the location along the right-of-way.  In other words, trees with a low risk of invading sewer lines or cracking sidewalks and ones that will not cause problems for pedestrians or vehicles.

As a guideline for appropriate street trees, Cornelius uses the street tree list from the city of Portland.  A link to this list is provided below: