Chapter 13. Tree Protection during Construction/Trees and Building Foundations

Tree Protection during Construction/Trees and Building Foundations

Experts agree that tree protection during construction is more important (and less expensive) than tree expansion programs (see Species Selection and Planting section) after the fact. Construction activities such as paving, sidewalk installations, excavation, and road widening can severely affect existing trees. Some areas of impact are root cutting, branch abrasions and trunk fractures, these injuries can lead to rot and decay, structural damage, canopy loss, or tree death. Properly valuing green space and implementing a strategy to monitor, sample, measure, and protect vegetation is critical to urban development preceding construction to effectively preserve the urban forest and maintain its integrity. A professional arborist can recommend how to protect and preserve trees near construction projects. Additionally, many municipalities have tree protection guidelines or by-laws, which often include measures like erecting barriers around the tree, limiting access to the construction site, and posting signs describing what work may not be done near the tree.

Similarly, there exists a wealth of information on the complex relationship between trees and building foundations as they relate to soil types, surface drainage practices, and the variation between species of trees.

Canadian online resources:

• City of Burnaby: Tree Guidelines 
• City of Calgary: Protecting trees during construction and development
• City of Calgary: Tree Protection Plans
• Esquimalt Parks and Recreation: Avoiding Tree Damage During Construction
• City of Halifax: By-Law Protecting Trees on Public Lands
• City of Ottawa: Tree Protection By-law
• City of Toronto: Tree Protection Policy and Specifications for Construction Near Trees (PDF)
• City of Thunder Bay: Tree Protection Standards
• City of Vancouver: Protection of Trees Bylaw

Non-Canadian online resources:

• Colorado State University: Protecting Trees During Construction
• International Society of Arboriculture: Avoiding Tree Damage during Construction (PDF)
• Iowa State University: Preventing Construction Damage to Trees (PDF)
• City of Seattle: Tree & Codes
• Penn State College of Agricultural Sciences: A Guide to Preserving Trees in Development Projects (PDF)
• City of Pleasanton, California: Tree Preservation Ordinance

Further reading:

Despot, D., Gerhold, H. (2003). Preserving trees in construction projects: Identifying incentives and barriers. Journal of Arboriculture, 29(5), 267-275. https://auf.isa-arbor.com/content/29/5/267

Grahn, P., Stigsdotter, U. (2003). Landscape Planning and Stress. Urban Forestry and Urban Greening, 2, 1-18. https://www.sciencedirect.com/science/article/abs/pii/S1618866704700199

Matheny, Nelda and Clark, James. (1998). Trees and Development: A Technical Guide to Preservation of Trees during Land Development. International Society of Arboriculture. https://books.google.ca/books/about/Trees_and_Development.html?id=Ns0sAQAAMAAJ&redir_esc=y

Sorvig, K. & Thompson, J. W. (2018). Sustainable Landscape Construction: A Guide to Green Building Outdoors (3^rd ed.). Washington, DC: Island Press. https://link.springer.com/book/10.5822/978-1-61091-811-4

Watson, G., Neely, D. (1995). Trees and Building Sites: Proceedings of an International Conference Held in the Interest of Developing a Scientific Basis for Managing Trees in Proximity to Buildings. International Society of Arboriculture, Champaign, IL.