Tumwater GIS: tree canopy declined since 2020; city starts inventory and hires consultant for Garry oak work

City of Tumwater GIS staff told the Tree Board that the city’s tree canopy coverage fell between 2020 and 2025 and presented next steps including a five‑year canopy comparison, a planned street‑tree inventory and a consultant contract to prepare pruning and permitting for a notable Garry oak site. Jennifer Radcliffe, the city’s GIS manager, and Georgiana Hupp, the GIS analyst, presented the 2025 tree canopy assessment and explained the machine‑learning methods behind the results.

The assessment showed losses across most land‑use zones when compared with the 2020 baseline, with small gains in one mixed‑use band. “We train our machine learning classifier to identify six different categories of land cover,” Georgiana Hupp said during the presentation, describing the steps used to classify tree canopy and other surface types from aerial imagery.

Why it matters: The urban forestry management plan, adopted in March 2021, calls for a canopy assessment every five years to measure progress toward zone‑specific canopy goals and to inform code and street‑tree policy changes. City staff said the results will be used to identify neighborhoods with low canopy so future planting and protection efforts can be targeted.

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