What Seattle could do – Middle Housing using Land Division like Oregon allows to have less scattering of housing units, more space for trees

Posted on January 5, 2025 by Steve Zemke

One Seattle Comprehensive Plan needs to include Middle Housing Land Division on shared common walls like Oregon does.  It would mean less scattering  of housing units on lots being developed, allowing more space for retaining and planting trees and nature in Seattle. We need our trees and urban forests for healthy neighborhoods  where we live.

Here seems to be an option for housing construction alternatives that current city documents have not considered that Oregon allows. Oregon has allowed 4 housing units per city lot since 2020. The concept of “expedited lot splitting” with 4 attached units on a large lot being split into smaller lots based on the common walls seems like a way to free up more land on the site to retain and plant more trees. Also would reduce building costs and heating/cooling costs with a common wall between units.

References below on a couple of ways to open up more space for tree retention and planting.

Oregon bill on middle housing land division:

ORS 92.031 – Middle housing land division – Oregon Laws 92.010 Definitions for ORS 92.010 to 92.192 92.012 Compliance with ORS 92.010 to 92.192 required 92.014 Approval of city or county required for specified divisions of land 92.016 Sale or negotiation to sell lot or parcel prior to approval of tentative plan 92.017 Lawfully created units of land 92.018 Buyer’s remedies for purchase of improperly created unit of land 92.025oregon.public.law

Middle housing land division – Oregon City, Oregon:

Courtyard housing was previously presented as a Seattle option in draft Seattle documents but not in the examples of most recent plans. This could involve the joining of several larger lots and positioning housing units such that a common area could be shared as open space – one way to plant trees or preserve a space for a grove of trees and areas where neighbors  and kids can get together other than public streets.

See Oregon City article below – “Cluster housing formerly known as cottage housing, includes group(s) of 4 to 12 smaller dwellings clustered together around a common green space; more than one such group can be developed on the same site. The dwellings themselves can be individual detached structures-often called cottages; attached structures such as townhouses, duplexes, and 3- to 4-plexes. The dwellings are clustered together facing each other across a courtyard, rather than arranged in a traditional grid along public streets. Dwellings share common amenities such as green space, parking areas, and community buildings.” See picture in article below.

Comments needed on 2024 SDCI Omnibus Ordinance – Seattle City Council Bill 120823   8/29/2024

The SDCI 2024 “Omnibus bill” had a public hearing on Wed. Sept 4, 2024, at 2 PM in the Seattle City Council Land Use Committee.  It is now scheduled for a vote on Wed Sept 18th at 2 PM in the Land Use Committee. You can send comments to Council@Seattle.gov and Bruce.Harrell@Seattle.gov

There are several areas where conflicting statements exist in the omnibus bill that need to be corrected relating to SMC 25.11 Tree Protection Ordinance. 

  Remove all language stating that “the basic tree protection area cannot be modified”.

The most glaring error has to do with having 2 definitions of what a tree protection area is.

• The SDCI 2024 omnibus bill needs to be corrected to remove all language or references that state “The basic tree protection area cannot be modified” including in Section 25.11.070.

The first definition in SMC 25.11.130 of the “tree protection area” is one used by the International Society of Arboriculture as well as the Northwest Society of Arboriculture. It is one that is flexible and designed to help save trees when possible. Its use and implementation are outlined in SMC 25.11.060 – Requirements for trees when development is proposed. 

In SMC 25.11.130 definitions, the “tree protection area” is defined as “means the area surrounding a tree defined by a specific distance, in which excavations and other construction-related activities must be avoided unless approved by the Director. The tree protection area is variable depending on species, age and health of the tree, soil conditions, and proposed construction.”

The Master Builders via their attorneys,  Helsell Fetterman, wrote in their “May 23rd, 2023 letter to the Seattle City Council” urging a second definition – “basic tree protection area” using the radius of the tree protection area as 1 inch diameter of the tree equaling 1 foot of the radius area.” In a separate comment they recommended that “The basic tree protection area cannot be modified” which was incorporated in SMC 25.11.070 – Tree Protection on sites undergoing development in Neighborhood Residential, Lowrise, Midrise, Commercial, and Seattle Mixed Zones.  

The full impact of that statement that “The basic tree protection area cannot be modified” is in contradiction to the Tree Protection Ordinance’s goal to protect as many trees as possible and SMC 25.11.060 which says the tree protection area can be reduced by the Director to save trees. The goal of the Master Builders was to allow developers to decide whether to remove Tier 2 trees rather than the city.

The problem is the language “The basic tree area cannot be modified.”  turns the decision over to the developers as to whether to save Tier 2 trees on developing sites. Modifying the tree protection area as outlined in detail in SMC 25.11.060 would save more Tier 2 trees.  Why is the city not acting in the public interest to save more large trees during development when it is possible by following the recommendations of how to create workable tree protection areas by the International and Pacific NW Society of Arboriculture rather than turning tree removal over to developers to decide?

SDCI actually agrees more trees could be saved when they state in in TIP 242A Seattle permits – Tree Requirements Associated with Development, dated July 8, 2024  that: 

“A Tier 2 tree may be removed if necessary for the construction of new structures, vehicle and pedestrian access, utilities, retaining walls, or other similar improvements associated with development. Tree removal under this scenario will not be authorized if there are viable alternatives to proposed development that would allow retention of the tree including adequate protection of the tree during construction according to SMC 25.11.060.”

In the same tip in their Dec 18, 2023 version they stated:

“The basic tree protection area, delineated using the “trunk diameter method” to determine if Tier 2 tree removal is allowed, is likely larger than necessary to protect most trees during development and is not required during construction.” 

 “The area of the outer half of the tree protection area may be reduced up to 35%”

 “Remember that the actual tree protection needed to protect the tree during development is always smaller than the basic tree protection area, leaving more room to fit your design on site.”

Remove 25.11.020 Exemption D in its entirety

• 25.11.020 Exemptions: D. ((Trees located in an Environmentally Critical Area)) Tree removal as part of an Environmentally Critical Area tree and vegetation plan as provided in 25.09.070 except that tree service providers conducting work on these trees must comply with the tree service provider registry requirements of Section 25.11.100. 

This language “Trees located in Environmentally Critical Areas” was not in the previous ordinance (before the 2023 version) but is in the current version. It creates a whole new exemption to the ordinance. It emerged in one of the draft 2023 versions without public input and needs to be removed which is what the omnibus bill does. The whole Section D exemption should be removed. Why should removing and planting trees as part of a tree and vegetation plan be exempt from SMC 25.11?

Support following amendment in “SDCI Omnibus bill”:

• 25.11.060A.4.b The tree protection area shall not be reduced more than 35% of the outer half of the tree protection radius unless an alternative tree protection area or construction method will provide equal or greater tree protection and result in long-term retention and viability of the tree as determined by a certified arborist.

Remove the following amendment in the “SDCI Omnibus bill”:

• Footnote 1 in Table A for 25.11.050 In all other zones, all trees may be removed when development is proposed.

This is not a minor amendment but covers many other zones not mentioned in the Tree Protection Ordinance, including the Industrial Zone which has an exceptionally low tree canopy. There has been no analysis of the impact of this statement and the exclusion of trees in all other city zones from the requirements of the Tree Protection Ordinance. The fact that the other zones are not mentioned in SMC 25.11 means there is no requirement for tree replacement or in-lieu payments or requiring tree service providers removing trees in these zones being registered with the city.

The following statement in Table A for 25.11.050 Tier 2 trees during development – part of a permit needs to be amended to add SMC 25.11.060:

• “Approval for removal is part of overall development permit consistent with Sections 25.11.060, 25.11.070, or 25.11.080”

Add “trees” to applications for lot boundary adjustments

• SMC 23.28.020 – Application for approval of lot boundary adjustment

1. A plot plan as appropriate showing the location and dimension of existing structures and trees in relation to the proposed lot boundary adjustment.

Steve Zemke – Chair Friends of Seattle’s Urban Forest

Questions regarding One Seattle Comprehensive Plan draft EIS – May 6, 2024

•  What is your estimation of planting needs and time frame to replace canopy lost during development (over 5 year periods as tracked by the city’s canopy study)? The Tree Protection Ordinance refers to “tree replacement required shall be designed to result, upon maturity, in a canopy cover that is at least roughly proportional to the canopy cover prior to tree replacement.” Would you agree that in most cases removing an 80 year old tree will take probably 80 years to replace? 
• Is canopy replacement equivalence even possible with replanting since removed trees, which if not removed, would have increased growing according to scientific articles? It would appear that you’ve lost any canopy growth that would have occurred if the tree had not been removed. 

How many acres are available and suitable for planting trees in each of the following public areas – the city’s right of ways, Natural Areas and Developed Parks?

• How many trees and what size (small, medium and large size) will need to be planted in the city every year to make up for trees and canopy removed during development on lots?
• What is acreage is needed and available to plant trees on private property?
• When will it be possible to reach the 30% citywide goal?
• What potential is there for more than 30% tree canopy in Seattle over time?
• Is up to 40% canopy coverage, over time, as proposed in the previous Comprehensive Plan possible with intense planting? 

•  What is the projected loss in canopy volume over the next 20 years as big conifer trees and others are removed?
• Canopy volume, especially of coniferous trees during our rainy season, is a critical factor in reducing stormwater runoff, particularly in the rainy season in Seattle. Is their loss really possible to replace in a reasonable amount of time?
• What is the projected increase in stormwater runoff and what costs are associated with on site and alternative city water management policies of stormwater and pollutant runoff as a result? 

As to commenting on other tree potential mitigation measures, add:

• Amend the Tree Protection Ordinance to require developers to maximize the retention of existing trees 6″ DSH and larger through the whole development process, not just platting and short platting as required now. Existing trees are the survivors and are providing ecosystem services now. 
• Give the SCCI Director the ability to ask for alternative site designs to save trees.
• Support building higher and building attached units to allow for tree retention and planting areas like Portland, Oregon has with 20% areas for multifamily and 40% for its 1-4 unit family zone. Zones like the industrial zone are allowed to remove all trees during development under the current ordinance.
• Amend the Tree Protection Ordinance to require the ordinance to apply to all city land use zones.
• Remove the “basic tree protection area” loophole in the current Tree Protection Ordinance that allows developers to unnecessarily remove almost all large trees on lots. It is not standard arboriculture practice according to the Northwest Chapter of The American Arboriculture Society. 

Steve Zemke for TreePAC and Friends of Seattle’s Urban Forest