Mandatory Housing Affordability Draft EIS Comments

MHA Draft EIS Comments by Friends of Seattle’s Urban Forest

August 7, 2017

From Steve Zemke – Chair Friends of Seattle’s Urban Forest

To:  Office of Planning and Community Development
PO Box 34019
Seattle, WA 98124-4019

The Friends of Seattle’s Urban Forest appreciates the recognition and analysis that the MHA Draft EIS did in its study, emphasizing the significance and importance of our urban forest in keeping Seattle a livable city and recognizing the many positive ecological, environmental, aesthetic and health benefits a healthy urban forest provides. Seattle is striving to increase its urban forest canopy to 30% by 2037. The longer range goal in the 2035 Comprehensive Plan remains a 40% canopy goal.

It is important to note that the American Forestry Association, which came up with the original 40% recommendation recently stated “According to a national analysis by U.S. Forest Service researchers David Nowak (also on our Science Advisory Board) and Eric Greenfield, a 40-60 percent urban tree canopy is attainable under ideal conditions in forested states.” (

Calculating Total Tree Canopy loss under Scenarios 1, 2 and 3 is necessary to understand impact of MHA additional canopy loss.

Friends of Seattle’s Urban Forest disagrees that the proposed development of additional housing under MHA is not significant. The impact is cumulative, added on top of the projected growth of housing under the 2035 Comprehensive Plan. The draft EIS by not stating the projected canopy loss under existing projections presents a very misleading and incomplete analysis of the changes occurring in this study area through 2025 when the additional affordable housing units will be added.

The baseline for the EIS should start with the current urban forest canopy in the study area as of 2016 when last studied so that the total projected change over time can be calculated under alternative 1 –No action.  Under alternative 1 some 43,631 new units are projected to be built and significant tree canopy will be lost.  The statement on page 3-284 is thus very misleading stating “The resulting change in canopy cover is assumed to be static.” The projected tree loss through 20125 under scenario 1 is nowhere quantified in the draft EIS.   The premise that “This study does not quantify tree loss resulting from current development patterns” is not acceptable because without understanding the total tree canopy change in the area through 2025 it is impossible to put in perspective the impact of the change that would result from the additional development proposed under HALA.

When you add in the additional housing units proposed under alternative 2 (17,709) and alternative 3 (17,479) they comprise about 28% of the total new growth in the area. To evaluate the addition of this growth to the area under study you have to add it to the projected growth already assumed under Scenario 1 through 2025.  If you have not assessed the impact of the growth quantitatively under Scenario 1, it is impossible to then state that this additional growth will have no significant impact.

Scenario 2      17,709/63,070 =28.1%

Scenario 3     17497/62,856 =27.8%

Rounding up to 28% and assuming the tree loss in alternative 1 is at the same rate (not necessarily true) as alternative 2 and 3 you get the following projected canopy acreage loss as

Loss current development under scenario 1 plus additional loss scenario 2:

Scenario 2 – total tree loss through 2025

28% x total tree loss = 5 acres canopy     total tree loss = 17.86 acres low estimate

28% x total tree loss = 11 acres canopy    total tree loss = 39.29 acres high estimate

Scenario 3 – total tree loss through 2025

28% x total tree loss = 8 acres canopy       total tree loss = 28.57 acres low estimate

28% x total tree loss = 16 acres canopy    total tree loss = 57.14 acres high estimate

By way of size comparisons, please note the following city parks and their acreage:

  • Seattle Japanese Garden – 3.5 acres
  • Myrtle Edwards Park – 4.8 acres
  • Freeway Park – 5.2 acres
  • Olympic Sculpture Park – 9 acres
  • Kubota Gardens- 20 acres
  • Northacres Park – 20.7 acres
  • Volunteer Park – 48.4 acres
  • Schmitz Park – 53.1 acres

It is in error for this EIS to not provide any information on the total tree loss in acreage through 2025 that is projected for Alternative 1, 2 and 3 due to the total development projected under each of the scenarios. Please provide the total projected tree loss in scenarios 1, 2 and 3 so that we can understand the total tree and canopy loss in each of the scenarios through 2025 relative to the additional tree loss projected in scenarios 2 and 3 that would be added.

No analysis made of potential acreage lost due to development that could be used for increasing tree canopy to meet city canopy goals.

The city is striving to increase its tree canopy. This means looking for places where no trees exist or where more trees could reasonably be planted. While the EIS evaluates existing canopy that would be lost, no analysis is made of the loss of potential canopy area for planting trees that if planted would help the city reach both its short term and aspirational goals. SDOT for example has looked at potential planting sites to help increase tree canopy. The reality is that as increased intensive development occurs the number of potential planting sites that could be used for planting trees is permanently lost as building density increases and covers more lot area.

What amount of potential planting area is lost due to this increased development under scenarios 1, 2, and 3?

Need to evaluate changes in growth projections and potential housing units over time based on low and high growth in recent history

The development projected under Alternative 1 should really be a range of projected low and high development in housing units.  It is impossible to project development impacts out 8 -10 years with precise accuracy as Seattle has found in other projections when growth has greatly exceeded expectations in recent years.

As the Urbanist noted recently, “The 2010 Census pegged Seattle at just 608,660, meaning we’ve grown by nearly 100,000 new people in just six years … Housing supply tends to lag behind housing demand; it could be in the coming years supply finally approaches demand. About 10,000 apartments are set to open in 2017, and more than 12,000 more are slotted for 2018. At the very least, with record-setting apartment growth expected, we have ample reason to expect the population growth trend to continue. Since King County averages 1.8 people per apartment, we could see growth in excess of 20,000 per year continue a bit longer if those expected apartments are filled.” (

What is the estimated range of housing units under scenarios 1, 2 and 3?

Mitigation Recommendation – To track tree and canopy loss require Urban Forest Canopy Impact Assessment on all development

The Seattle Urban Forestry Commission asked DPD in a letter dated June 25, 2014 and also in a letter dated June 10, 2015 to do an Urban Forest Canopy Impact Assessment on all development so that tree and canopy loss could be tracked. The Seattle Urban Forestry Commission also sent detailed comments on the draft EIS for the Seattle 2015 Comprehensive Plan urging this action. Our recommendation was not included in the final EIS proposed mitigation.   This recommendation should be included as mitigation assessment in this MHA EIS as a condition for proceeding so that canopy and ecological function lost can be more accurately followed and compensated for during development.

From the June 10, 2015 letter of the Seattle Urban Forestry Commission ( :

“The Commission has discussed several ideas to improve submittal documentation and final reporting for projects under DPD’s permitting.

  • Currently, the City, through OSE and the Urban Forestry Interdepartmental Team, keeps track of the number of trees planted and removed on public property every year. The Commission recommends tracking trees lost on private property undergoing development to assist in determining where we are gaining or losing trees and canopy. This would add information to the overall city canopy coverage assessment data. By knowing more about canopy trends on different types of land, we can better direct policy and programming to ensure we are on track to meet our 30% goal.
  • What would help the City better understand what is happening with tree canopy protection and enhancement is to require that all development projects submit an Urban Forest Canopy Impact Assessment prior to any construction project being approved.

The Urban Forest Canopy Impact Assessment would include a map of the property with the trees numbered, canopy area of trees drawn, and trees to be removed clearly labeled. Under current guidelines it would minimally require that all trees 6 inches DBH (diameter at breast height) or larger be inventoried on the property. The suggested data points required would be:

  • 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.”

Please consider and discuss benefits of using Urban Forest Canopy Impact Assessments as part of development process.

Mitigation Recommendation – Update City Tree Ordinance to require replacement on or off site of tree canopy lost or payment into City Tree Replacement and Maintenance Fund

In terms of loss of ecological function due to canopy loss, mitigation options to be explored should include total compensation of both canopy loss and ecological function projected such that trees that are nor replaced on site should be mitigated by compensation into a City Tree Replacement and Maintenance Fund for replacing and maintaining trees elsewhere.  Development should pay for losses to the city’s green infrastructure that transfer development impact costs onto the general public while developers pocket the profits.

It is not acceptable that the costs of mitigating for tree and canopy loss should be picked up by all city taxpayers rather than the developers who are removing existing tree canopy the city is trying to maintain and increase. This EIS should recommend that Seattle update its existing tree ordinance to reverse the ongoing tree and canopy loss by the rapid development occurring in Seattle.

Please consider and discuss creation of a City Tree Replacement and Maintenance Fund for mitigation of projected tree canopy loss.

Reference Links needed

Please provide links to references where they are missing on documents that are not readily available to the public including:

  • City of Seattle. 2017a. Tree Regulations Research Project—Phase II Final Findings and Recommendations. March 27, 2017.
  • Seattle Parks and Recreation (SPR). 2011. Seattle’s Parks and Recreation 2011 Development Plan.
  • Adopted November 28, 2011. Resolution: 31336. Seattle Parks and Recreation (SPR). 2016. 2016 Seattle
  • Recreation Demand Study. Seattle Parks and Recreation (SPR). 2017. 2017 Parks and Open Space Plan, May Draft.


Submitted by Steve Zemke

Chair – Friends of Seattle’s Urban Forest


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