Missoula Managers Diversify City Tree Canopy

The city is updating its urban forestry strategy to ensure long-term canopy health through strict biodiversity limits.

Updated on Oct. 26, 2026 in Asthma

Bold vector editorial illustration of a single young tree in a city park, with autumn-colored leaves against a clean background. — Missoula urban foresters are diversifying the city's 40,000-tree canopy to build resilience against environmental shifts and future disease outbreaks. AI Illustration. Upload story photo >

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Should your local government prioritize planting diverse tree species over native flora in public spaces?

As Missoula experiences its peak autumn foliage, local urban foresters are emphasizing the importance of a diverse tree canopy to protect against future disease and environmental shifts. The city manages an inventory of up to 40,000 trees across more than 175 varieties.

Why it matters

Prioritizing biodiversity helps the city avoid the massive canopy losses previously seen during the Dutch Elm disease outbreaks of the 1950s and 1960s. By balancing tree families and species, managers aim to ensure the urban forest remains resilient against pests like the Emerald ash borer.

The city maintains an inventory of 29,000 to 40,000 trees following a 30-20-10 diversity rule for families, genera, and species. Norway maples currently account for up to 7,000 trees, while other areas like McLeod Avenue show high density with 80% sugar maples.

The players

Missoula Urban Forestry Program

This department oversees the maintenance and selection of tree species in public spaces across the city.

The details

City foresters evaluate specific soil types and local microclimates to select species that can withstand temperature swings. This approach follows lessons learned from past population collapses and currently targets the management of over 175 varieties in public spaces.

Late 1800s to early 1900s: Community leaders began the city's tree planting efforts.
1950s and 1960s: Dutch Elm disease eliminated American elm populations.
October 2026: Autumn colors arrive in Missoula.

Health Landscape

Missoula manages its tree canopy using the 30-20-10 urban forestry management rule to prevent monoculture-related failures. This strategy positions the city to mitigate risks from invasive pests and climate shifts that threaten historical tree populations.

A diverse and healthy tree canopy helps regulate local air quality and mitigate urban heat island effects, which directly benefits residents with respiratory sensitivities. Maintaining these green spaces ensures that public areas remain accessible and comfortable for all community members.

The takeaway

Maintaining a balanced urban forest is a long-term commitment that protects city infrastructure against unpredictable climate trends. Residents can support these efforts by planting diverse, drought-tolerant species on their own properties to extend the benefits of the city canopy.