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.

Key findings and limits - The new canopy map used 19‑inch‑resolution Maxar imagery captured in April; the 2020 baseline used higher resolution imagery (about 6‑inch pixels) captured in July and included lidar support. City staff warned those technical differences can exaggerate apparent loss. Georgiana Hupp said earlier leaf‑out in the April imagery and the coarser pixel size likely contributed to some of the measured decline. - Lidar data that helped distinguish tree tops from other vegetation in 2020 were not available for 2025; staff said state lidar programs have faced budget cuts and the city could not obtain updated lidar for the current assessment. - Staff called out specific development as contributors to canopy loss on the maps, citing a large warehouse and residential subdivisions in areas shown in red on the change map. The Port of Olympia area and airport sector showed little change.

Staff direction and contracts - The city has a contract with Todd Prager & Associates to develop a detailed scope of work and to assist with permitting for pruning and long‑term management at the Davis‑Meeker Garry oak site. “We have a contract with Todd Prager and Associates to develop a detailed scope of work for us to then go to bid,” a staff member reported. The contract amount to develop specifications and assist with permitting was cited as $30,000. - City council previously allocated up to $55,000 for tree work; staff said the council will determine the final funding source because the $30,000 contract and any physical work were not fully budgeted in a specific account. - Staff also reported that an approved street‑tree list is now posted on the city website and that staff are using it to respond to public requests for planting and replacement guidance.

Inventory and next steps City staff said they are beginning a multi‑year, detailed inventory of trees that the city is responsible for — counting species and locations on city rights‑of‑way so future work can be scheduled and tracked. Brian (staff member) described early inventory work and distribution of seedlings to local organizations; he said about 20 saplings remained from a recent distribution and that the city is seeking partner organizations to plant or steward them.

Public comment and context Charlotte Parsons, who identified herself as representing the conservation committee of the group now called South Sound Bird Alliance, urged continued attention to tree protections and cited recent state action on Wildland‑Urban Interface rules. “We’re very excited that you’re back on schedule,” Parsons said, referring to resumed work on tree codes.

What was not decided The presentation was informational. The board did not adopt new code or planting requirements during the meeting. Staff described work already contracted and budgeted by the council and said additional funding sources and permits remain to be resolved. Staff also noted zoning changes and parcel‑level data differences complicate direct comparisons between the 2020 and 2025 canopy figures.

Looking ahead Staff said the inventory and canopy data will inform the Tree Board’s annual update on Urban Forestry Management Plan implementation at a future meeting and will be included in the city’s comprehensive plan package. The board set its next meeting and will review staff work plans that council must later approve.

Speakers quoted in this story came from the meeting record and were: Jennifer Radcliffe, GIS manager, City of Tumwater; Georgiana Hupp, GIS analyst, City of Tumwater; Charlotte Parsons, conservation committee, South Sound Bird Alliance (citizen); and a city staff member identified in the record as Brian.