Category Archives: Land Development

Alan, Tree Cutting Rock Star!

Trees In Seattle

Can you cut down a tree in Seattle?  Safe answer is always no.  But in actuality it depends.

We just went through this exercise on a tree covered lot in West Seattle.

On Developed Lots:
  • You cannot remove any “exceptional trees.”
  • You cannot cut down more than 3 non-exceptional trees 6 inches or greater in diameter each year.
  • You can remove trees determined to be hazardous through a hazard tree assessment by a certified tree risk professional.

First you need to determine if any of the trees are “Exceptional Trees” meaning: “a tree or group of trees that because of its unique historical, ecological, or aesthetic value constitutes an important community resource, and is determined as such by the Director according to standards and procedures promulgated by the Department of Planning and Development.”

I am happy we cleared that up.  Any questions on what an exceptional tree is?

First place I look is the “Heritage Tree List”   If your tree is on this list, you are pretty much done. Unless it presents a hazard.

The next place to look is Director’s Rule 16-2008.  This directors rule gives species of trees and DBH (Diameter at Breast Height) trees need to qualify for Exceptional Tree designation.

If your tree is an exceptional tree, it can still be cut down, if it is a hazard. To have a tree blessed as a hazard you will need a Tree Risk Assessment Form filled out by a “qualified” professional.  Which is defined in Tip 331 b.

Qualified Professional – A qualified professional shall have a minimum of three years of experience in tree evaluation and hold a current Tree Risk Assessment Qualification (TRAQ), as established by the International Society of Arboriculture (ISA).

After your tree has been deemed hazardous you get to fill out a “Hazard Tree Removal Application.”  You can file your hazard tree removal application the Public Resource Center (PRC), located on the 20th floor of the Seattle Municipal Tower at 700 Fifth Ave.

OR, call me.  I have a few phone numbers of excellent tree removal specialists.




75/80 Rule

Seattle’s 75/80 Rule for Lot Subdivision


As Platted Now

We just tried to purchase a 12,000 square foot lot zoned SF 5000, one house per 5000 square feet of land.  When it was originally platted in the 1930’s it was platted as three 4000 square foot lots.  But, somebody built a house straddling two of the lots in the 1960’s.  We had a meeting with DPD, took all the neighbors lot sizes to the meeting, and the decision was made since the house is straddling two lots, the two 4000 square foot lots have been combined.  So we are left with one 4000 square foot lot, and one 8000 square foot lot.  The question is, can we re-subdivide the lots back to the original 4000 square foot lots?  Answer, No.  See below.


Original Plat Map showing all 4000 square foot lots.

DPD has a 75/80 rule that will allow  you to short plat lots into parcels less then 5000 square feet.   (SMC 23.44.010 B.1.a)

1)      The new lot/lots created must be 75 percent of the general minimum lot area for the zone.

2)      At least 80 percent of the mean area of the lots on the same block face and within the same zone.

5000 square foot lot x 75% = 3750 square foot lot is the smallest allowed.
IF 80 percent the mean of the neighbors lots is 3750 or less.

Neighbors lots: 5000, 4400, 4000, 6000, 5300, 5500, 4000 = 34,200/ 7 lots = 5520 * 80% = 4,886 square feet is the smallest allowed on this block.

Steep Slope Exemption

Steep Slope exemption.

DPD has a handy “Tip”, they use to be called, “CAM”, client Assist Memo, I guess that sounds too official, now it is called a Tip.  In this case Tip 327a.

Seattle has designated certain areas as Environmentally Critical Areas, ECA,s.  They even created Seattle Municipal Codes to regulate their development.  SMC Chapter 25.09

Before and After Grading Profiles Picture

Before and after grading profiles are kept in the SDOT Vault

In-short to develop an area is designated by the city as a Geological Hazard you will need approval from the director. In the case of Steep Slopes you can get an exemption per SMC 25.09.180 A, and B2.  The easiest exemption to receive is 25.09.180 B.2.d.  Which to paraphrase states: if the steep slope was created by “right of way improvements” (when a road was built) you should get a steep slope exemption.  SDOT even keeps records of slopes before and after roads were constructed in their “Vault”.

What is meant by “right of way improvements”? Think of a gentle slope and a road is built across the slope, some dirt is piled on the high side of the road, and some dirt is pushed down hill.  Now both sides of the road have a steep slope, created by “right of way improvements”

Below is an excerpt of 25.09.180:

B. Impacts on steep slope areas

1. Development is prohibited on steep slope areas, unless the applicant demonstrates that the provisions of subsections 25.09.180.B.2 or 25.09.180.E apply.

2. Provided that all the provisions of this Chapter 25.09 and all applicable provisions of Title 23 and Chapters 22.800 through 22.808 are met, subsection 25.09.180.B.1 does not apply when the applicant demonstrates the development meets one of the following criteria. In determining whether these criteria are met, the Director may require a geotechnical report to verify site conditions and to evaluate the impacts of the development in the steep slope area and shall require such a report for criteria in subsections 25.09.180.B.2.c and 25.09.180.B.2.d. The geotechnical report is subject to the provisions for third party review in subsection 25.09.080.C.

a. Development is located where existing development is located, if the impact on the steep slope area is not altered or increased; or

b. Development is located on steep slope areas that have been created through previous legal grading activities, including rockeries or retaining walls resulting from rights of way improvements, if no adverse impact on the steep slope area will result; or

c. Development is located on steep slope areas that are less than 20 feet in vertical rise and that are 30 feet or more from other steep slope areas, if no adverse impact on the steep slope area will result; or

d. Development is located on steep slope areas where the Director determines that application of subsection 25.09.180.B.1 would prevent necessary stabilization of a landslide-prone area.


Links useful for research:

List of DPD Tips:

Entire Seattle Municipal Code can be found here: