Friends of Seattle’s Urban Forest Response to Seattle City Council’s Passage of Tree Ordinance Update –


Friends of Seattle’s Urban Forest Response to Seattle City Council’s Passage of Tree Ordinance Update 


The passage by the Seattle City Council of CB 120534 on May 24, 2023 culminates a 14-year effort to update Seattle’s Tree Protection Ordinance. While there are many good provisions in the new ordinance, it has evolved with the assistance of the Master Builder of King and Snohomish County with a focus on tree removal and replacement over increased protection of Seattle’s trees on private property as Seattle builds more housing.

Missing from CB 120534  is any sincere effort to maximize the retention of our existing trees during development, especially large mature trees. While the ordinance greatly reduces the removal of trees outside of development; besides saving a few heritage trees, it allows developers to continue their clear cutting of lots to maximize their building potential and profits.

Without increased efforts to maximize the retention of existing trees across the city during development, all areas will see a significant decrease in tree canopy, increased adverse health impacts, a decrease in climate resiliency and increased heat island impacts. Areas currently with low canopy and environmental inequity will only get worse as they will also lose trees during development.  

The Council bill now guarantees developers an 85% guaranteed lot development area in Low Rise zones and 100% in Mid Rise, Seattle Mixed and Commercial Zones. This will leave no space for trees in most cases. It will result in significant new tree loss. For example, the 2021 Seattle Canopy Study noted that the Seattle Mixed Zone currently has a 12% canopy cover.

People need trees where they live for healthy communities and healthy houses. The new ordinance prioritizes a policy that will create housing without requiring trees. Living close to trees dramatically improves our health. Lower rates of asthma, cardiovascular disease and cancer, improved pregnancy outcomes, better mental/emotional health and improved cognitive function are all correlated with living near trees.

While replacement trees during development can be planted on site if there is space, most will be planted off site in public areas like parks and along streets through paying the city an in-lieu fee. Few trees if any will be retained in multifamily zones. New trees will need decades to provide the benefits our existing trees provide now.

There is no requirement for developers in Seattle to have a tree retention and planting area like Portland, Oregon passed last year. They did this after complying with Oregon’s legislation in 2020 that said Portland had to allow 4-plexes in single family zones.  Portland provides an option to save a 20% tree retention and planting area in multifamily zones and 40% in their family residential zone. New trees are expensive to plant and maintain for 5 years. The Seattle Parks Dept. says it would need to spend $4000 to plant, maintain and water a replacement tree for 5 years. Replacement trees also have low survival rates—our existing trees are already established.

Large trees shading housing and the immediate area can be the difference between life and death during heat waves, but this ordinance promotes the removal of trees near homes being built.    Summer heat events are coming more frequent and are expected to increase with climate change. According to The New York Times, some 600 people died during the Northwest’s 2021 heat dome event.

Areas with large trees can lower temperatures 10 degrees or more as shown by numerous studies. Seattle did not investigate the impacts of tree loss on lots guaranteed 100% development areas in their 2022 DNS and 2023 Addendum. They did not consider the potential impacts of the state passing legislation like HB 1110 even though “middle housing” legislation came close to passing the previous year and was introduced in this year’s legislative session. HB 1110’s passage requires middle housing of 4-plexes and up to 6-plexes near frequent transit across Seattle including in the Neighborhood Residential zone.

Current development practices result in significant tree loss, which will worsen as new housing is built without space for trees on lots. Seattle’s 2021 canopy study showed a 50% decline in tree canopy on multifamily lots that were developed. Multifamily zones currently only have a 23% canopy cover. Washington state’s new middle housing bill, HB 1110, will expand multifamily housing throughout the city. Seattle has a 30% canopy goal by 2037 but has never produced a plan on how to reach that goal.

Most middle housing currently being built in Seattle (mostly townhouses) already exceeds the 85% low rise guaranteed development area and has at most a few small trees in the street planting area.  Seattle’s 2021 canopy study showed a 50% decline in tree canopy on multifamily lots that were developed. Washington state’s new middle housing bill, HB 1110, will expand multifamily housing throughout Seattle.

New housing CAN be built WITH trees: Many of Seattle’s trees grow on the edges of lots that tear down existing housing and should not be an obstacle to development. Other trees on the lot can be worked around in many cases by repositioning new buildings.

Last year, developers in the Master Builders Association  of King and Snohomish County Hearing Examiner appeal of Mayor Harrell’s 2022 draft ordinance presented no evidence that building added significantly to the cost of housing. This was the conclusion of the Hearing Examiner in the 2022 Master Builders of King and Snohomish Counties’ legal action after three days of testimony and considering the evidence, the Hearing Examiner concluded that the “Appellants’ arguments that the Proposal will increase the costs of development and will have negative impacts on the City housing supply were based on speculation, not any actual quantitative analysis that was introduced into evidence.”

Frontline communities, including South Seattle, will bear the brunt of a tree ordinance which misses the mark. Frontline communities already have low tree canopy and has lost more trees, faster, than other parts of Seattle. While the new ordinance focuses tree re-planting on these communities, which is a good start, it will also promote inequitable and unsustainable building practices by allowing the removal of the few large trees left in these areas.

Polls show that two-thirds of Seattle voters are concerned about tree loss as housing density increases and believe that Seattle needs to BOTH build new housing and do a better job of protecting its existing trees.

Seattle can do better and that is why more work is needed to address tree loss by maintaining more existing trees where people live as Seattle increases its housing supply. The city needs to seriously consider adding provisions to the tree ordinance like “maximizing the retention of existing trees” and “requiring a Tree Inventory (Arborists Report) and Tree Plan up front before building permits are issued” like  Portland Oregon does.

We appreciate that the city has a goal to collect more data to make better decisions as asked for by Mayor Harrell to help it respond to the impacts of tree loss, climate change and increased housing over time. Requiring developers to file tree retention, tree loss and tree replacement information online prior to a building permit being issued as Portland does is critical to obtaining accurate information. Permits to remove trees as many other cities require will also help. We need a stronger Tree Protection Ordinance that also increases retention of existing trees, not one that mainly emphasizes tree removal and then replacement on public lands during development. Trees where people live are vital for healthy communities and healthy living.

For more information contact: Steve Zemke



Friends of Seattle’s Urban Forest Response to Seattle City Council’s Passage of Tree Ordinance Update – — 1 Comment

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