Street Trees

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, as 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 the 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.