Recommendations for Updating Seattle’s Tree Ordinance

Recommendations for Updating Seattle’s Tree Ordinance 

The current Seattle Tree Ordinance SMC 25.11 was written in 2001 with a major update in 2009 and some additional amendments since then. It has some good provisions like protecting tree groves and exceptional trees but needs serious updating.  Its main problem is that it does not require significant protection of trees during development and does not require replacement for trees removed during development and by private property owners. While green factor helps some, it does not significantly replace many of the services trees provide in our city – like helping to remove air pollution from our growing city, reducing storm water runoff without creating new infrastructure or providing habitat for birds and other animals.

Other cities both in Washington State and nationally have come up with urban forest ordinances that address many of the problems with Seattle’s current ordinance. Changes needed include:

 Re-instate a policy of no net loss of tree canopy.  Seattle’s previous Comprehensive Plan had a policy of no net loss of tree canopy. This was removed in the 2035 Comprehensive Plan. This needs to be re-stated in an updated tree ordinance.  We cannot reach our goal of increasing tree canopy if we do not replace what is being lost each year through development, by trees dying, by both legal and illegal removals on private property. A complaint-based tree code enforcement process after trees have been cut down is not working to save and replace trees Some cities that have a no net loss policy includes Atlanta, GA and Annapolis, MD; Issaquah, Lake Forest Park; Redmond and Shoreline.

To achieve no net loss of tree canopy requires that tree canopy removed must be replaced on site, off site or a fee in lieu for the city to replace the trees be paid into a Tree Replacement and Maintenance Fund. This should apply to significant trees (over 6 inches DBH) and any exceptional trees removed during development or as hazard trees. For a healthy urban forest Seattle needs both a diversity of tree species and sizes. Replacement trees should be based on the size of a tree removed  (eg, small, medium and large)  to ensure that over time an equivalent canopy volume is replaced.

The fee in lieu value shall be determined based on current arboriculture practices and shall be periodically updated to keep pace with costs of replacement and maintenance. Adjustments reducing fees for property owners may be determined for those that the cost is a hardship.

The Tree Replacement and Maintenance Fund shall also collect funds based on fines for violation of this ordinance.  Fines need to be appropriately large to effectively deter illegal removal of trees. The Fund may also be used to assist individuals that need help to comply with the tree ordinance. Donations by non-profits, corporations and members of the public can be made to the fund to further city goals to maintain and increase the city’s tree canopy.

To track and monitor tree loss and replacement Seattle needs to expand the current tree removal and replacement permit system run by the Seattle Department of Transportation.   Such an expanded system should be comprehensive and require a tree permit to remove any significant or exceptional trees on both public and private property. Tree permit applications and approvals shall be posted on line and data kept and posted on all trees removed and replaced to track compliance. One city website  portal should be used for all tree permits applications to make it easier for people to comply.

As SDOT does, trees to be removed shall be marked with a yellow ribbon and a notice posted that is visible and can be read from the property line for 2 weeks prior to a non-hazard tree being removed.

To help monitor and replace trees lost during development require that an Urban Forest Canopy Impact Assessment be done by a certified arborist – basically a tree survey detailing the impact of the development on the urban forest canopy and trees on site prior to issuing a construction permit. It would be used to determine canopy loss and to quantify replacement trees needed to be replaced on site, off site or a fee-in-lieu value.  The Urban Forest Canopy Impact Assessment Report shall include a map of the property with all trees six inches DBH and larger noted and numbered, canopy area, and trees to be removed clearly labeled.

  • Species: speaks to size of canopy and amount of storm water benefit.
  • DBH: speaks to age of tree and canopy coverage.
  • Tree Height: speaks to canopy volume and amount of environmental benefit.
  • Canopy Width (area): speaks to canopy volume and amount of environmental benefit.
  • Tree Condition: speaks to overall forest health and environmental impacts.
  • Photographs of the trees on the parcel and adjacent properties.
  • Canopy coverage as a percent of area pre- and post-project development.
  • Canopy impact assessment must include a revegetation plan for the site where trees are removed and details on where off site trees will be planted and maintained or whether in lieu fees are proposed to pay the city to replant and maintain trees.

Expand SDOT’s current tree service provider’s registration to cover all tree work done in the city. All tree service providers must register with the city of Seattle to ensure that they comply with city ordinances and regulations to protect and grow the urban canopy. Tree service providers shall include all those who cut down. prune or plant trees in the city. SDCI and other city departments will work with SDOT to establish and maintain one list of approved Tree Service Providers for the City.

Other updates needed:

Expand purpose and intent of ordinance to include “The Tree Protection code is one of the implementation measures of the Seattle Comprehensive Plan and the Seattle Urban Forest Stewardship Plan. Together with education and other initiatives, these regulations protect the health, safety, and general welfare of the citizens of Seattle and are consistent with other plans and policies of the City. In so doing, the appearance of the City is enhanced, and important ecological, cultural, and economic resources are protected for the benefit of the City’s residents and visitors.”

A 5-year Tree Maintenance Bond shall be posted to ensure trees planted or retained on a development project survive as well as for trees planted off site. Any fee in lieu system for trees removed shall be according to standard arboriculture guidelines and shall include costs for planting and survival for 5 years. Any trees dying during the 5-year period must be replaced. Any replacement trees will be considered significant trees by the city to ensure they are not removed without replacement.

The tree ordinance should consider ways to consolidate tree oversight and maintenance into one city department that does not have a conflict of interests in terms of their mission statement.  The Seattle City Auditor in 2009 recommended that the 8 city departments currently overseeing trees should be consolidated and recommended that the Office of Sustainability and Environment was a logical choice.

Remove exemption for lots under 5000 square feet complying with tree ordinance.

Limit the removal of significant non-exceptional trees to no more than 2 in any 3 year period.

Add more definitions including:

          “DBH” means diameter of a tree at breast height – 54 inches above ground

Canopy area” means the area below the tree dripline as viewed from above

Canopy volume” means the 3 dimensional volume of tree foliage branches

Fee-in-lieu” – a fee paid into the Tree Replacement and Canopy Maintenance Fund to replace tree canopy lost on site and not replaced on site or off site either during development or on private property

Hazard tree” a tree that has a structural defect that makes it likely to fail in whole or in part and has the potential to harm people or buildings.

Seattle Comprehensive Plan” – 20 year plan adopted by the Seattle City Council and Mayor to guide future growth in Seattle

Seattle Urban Forestry Stewardship Plan” – Plan adopted every 5 years to guide protection and  enhancement of Seattle’s urban forest

Significant tree” – any tree on a property that is over six inches or more in diameter at DBH.

Tree” – woody vegetation which is 6 inches or greater diameter at breast height (DBH), measured 54” above the ground mid-slope. Multi-stem trees like vine maple use the following formula to determine their DBH = square root of the sum of each stem DBH squared. A Tree does not include any species which appears on the King County Noxious Weeds or Weeds of Concern list. A Tree may be alive or dead.

Tree permit” – permit required for all significant and exceptional trees removed on private property, including during development, and trees removed on public property

Tree protection area” – area denoted on site plan for protection of significant and exceptional trees during development

Tree Replacement and Maintenance Fund” means a fund established to facilitate mitigation and tree replacement when trees cannot be replaced on the site from which they were removed.

Tree Service Providers” – Tree Service contractors who meet the requirements of the city to register to do tree care work

Urban Forest Canopy Impact Assessment” – detailed report on impact of development on urban forest canopy and trees used to determine canopy loss or gain during development and to quantify replacement values.


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