Tree Replacement Requirements - Pittsburgh

By Carolyn Ristau

Introduction

Trees are an often overlooked component of real estate development projects, despite the important role they play in health and equity for urban residents. When trees aren’t considered until after an application is submitted for zoning review, delays often result.

Pittsburgh’s tree replacement requirements are an example of this. While only a small paragraph, this section can have a large impact on projects.

Code Section

915.01.B   Applicability

No structure or land use shall be located, erected, constructed, reconstructed, moved, altered, demolished, converted, enlarged or designed to be so, except in conformance the provisions of this Section.

915.02.D   Tree Protection and Replacement

The Zoning Administrator shall require the protection and preservation of trees with a diameter of twelve (12) inches or more, measured at a point four (4) feet above grade. If said trees are removed during site preparation or development, they shall be replaced, at a minimum, equal to the combined total diameter of removed trees. Diameter measurements shall be taken at a point four (4) feet above grade.

What does this mean?

Applicability

The applicability of this section is extremely broad. As worded, almost any project that removes a mature tree is subject to the tree replacement requirements. This includes, but is not limited to, projects that are a partial or total demolition only, are just laying concrete for a patio or parking, or are building a new structure or addition.

While the online zoning application asks if trees will be removed, it is not a required question and it is not feasible for staff to check the site conditions and scope of work to verify if trees may be removed on every application. This is more likely to happen for projects going through site plan review or planning commission review.

For example, the project pictured above appears to have a demolition only scope of work. Though multiple trees of 12” or more DBH (diameter at breast height aka 4’ above grade) were removed, it is unlikely that the tree replacement standards were applied.

Requirements

When trees of 12” or more DBH are removed, the requirement is that the total inches removed be replaced on site.

For example, estimating the size of the two trees that were removed in the photos above at 12” and 16”, this means that if the requirement were applied to this project, 28” of trees would have to be added back to the site. As new trees typically come in sizes of 2-3”, up to 14 trees would need to be planted. On a 30’ x 100’ lot, that doesn’t leave much room for a building.

Challenges

The inch for inch replacement requirement often results in more trees being required than can reasonably fit on a site. Some projects on densely wooded sites or on multiple sites can easily reach a required number of replacement inches in the 100-200” range.

Alternatives

As with other zoning code regulations, there is a path for moving forward when the requirement creates an infeasible challenge. For tree replacement, this path is often an alternative landscaping plan put together by a landscape architect. This plan typically proposes a balance between what can reasonably fit on a site and what can replicate the benefits lost from the removed trees. The design of and negotiations over an alternative landscaping plan can take a significant amount of time.

Conclusion

Plan for additional cost and review time for projects that involve removing trees of 12” or more DBH.