Seattle SDCI Tip #331 - Environmentally Critical Areas: Tree & Vegetation Overview

www.seattle.gov/sdci

700 5th Avenue, Suite 2000

P.O. Box 34019

Seattle, WA 98124-4019

(206) 684-8600

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Seattle Department of Construction

and Inspections

Environmentally

Critical Areas: Tree & Veg-

etation Overview

Updated August 4, 2022

Trees and other vegetation in environmentally critical

areas (ECAs) are essential for maintenance of a naturally

functioning condition that maintains slope stability and

prevents erosion, protects water quality, and provides

diverse wildlife habitat. Consequently, the City of Seattle

protects trees and vegetation within landslide-prone criti-

cal areas (including steep slopes), steep slope buffers,

riparian corridors, shoreline habitat, shoreline habitat buf-

fers, wetlands and wetland buffers. Within these areas,

the ECA code only allows removal, clearing, or other

actions that may harm trees and vegetation in limited situ-

ations. Before you begin any of these activities, you need

to determine if prior approval from the Seattle Department

of Construction and Inspections (SDCI) is necessary. This

Tip outlines when activities that may impact trees and

vegetation are allowed and how to obtain the appropriate

approvals from SDCI.

SDCI maintains maps of ECAs that you can find on our

website (www.seattle.gov/sdci/resources). Our maps

are advisory and are intended to help you identify critical

areas. The maps do not delineate the exact boundar-

ies of ECAs. Environmentally Critical Areas that are not

identified on the maps are still subject to ECA regulations.

If you are planning development or other regulated activi-

ties in or near an ECA, you should contact us early in your

planning process to determine the extent and impact they

may have on your proposal.

You can find standards for the protection and manage-

ment of trees and vegetation in landslide-prone critical

areas (including steep slopes), steep slope buffers, ripar-

ian corridors, shoreline habitat, shoreline habitat buffers,

wetlands and wetland buffers in section 25.09.320 of the

Environmentally Critical Areas Ordinance in the Seattle

Municipal Code (SMC).

Tree and Vegetation Standards

The City of Seattle’s ECA code allows four types of tree

and vegetation work in vegetation in landslide-prone

critical areas (including steep slopes), steep slope buffers,

riparian corridors, shoreline habitat, shoreline habitat buf-

fers, wetlands and wetland buffers:

 Normal and routine maintenance

 Tree and vegetation removal as part of an issued

building or grading permit

 Tree and vegetation restoration

 Removal or other mitigation of a hazard tree

We provide specific standards for each type of tree and

vegetation work later in this Tip. We have summarized

the submittal requirements for the documentation you

must provide to SDCI in Table 1 on page 2.

Normal and Routine Maintenance

Normal and routine maintenance of trees and vegeta-

tion includes work that is necessary to maintain existing

pathways and landscaping or to ensure the health of

existing vegetation. Maintenance also includes limited

tree and shrub pruning. The removal of trees and non-

invasive vegetation is not considered normal and routine

maintenance.

When you prune trees, you must conform to the ANSI

A300 standards outlined in The American National Stan-

dard for Tree Care Operations - Tree, Shrub and Other

Woody Plant Maintenance - Standard Practices. When

you contract with a company to prune your trees, we

recommend obtaining written confirmation that pruning

will be in accordance with these standards. A basic tree

pruning guide outlining appropriate pruning measures is

available from the Seattle Department of Transportation’s

website (www.seattle.gov/transportation/pruning-

guides.htm).

You do not need a permit from SDCI for conducting

normal and routine maintenance of trees and vegeta-

tion when the area of work is less than 750 square

feet. However, if you are conducing normal and routine

331

SDCI Tip #331—Environmentally Critical Areas: Tree & Vegetation Overview page 2

LEGAL DISCLAIMER: This Tip should not be used as a substitute for codes and regulations. The applicant is responsible for compliance with all

code and rule requirements, whether or not described in this Tip.

Table 1. Summary of Thresholds and Standards of the SMC 25.09.320

Applies to landslide-prone critical areas (including steep slopes), steep slope buffers, riparian

corridors, shoreline habitat, shoreline habitat buffers, wetlands and wetland buffers.

Area of work

Plan

FILED

with SDCI

Plan

REVIEWED

by SDCI

SEPA

Review

Required Plan Type

Normal and Routine Maintenance

Less than 750 sq. ft.

None required

750 sq. ft. or greater yes

Maintenance plan

Approved as Part of an Issued Building or Grading Permit

Less than 1,500 sq. ft. yes

Restoration plan as

part of your plan set

1,500 sq. ft. or greater,

but less than 9,000 sq. ft.

yes

Restoration plan as

part of your plan set

9,000 sq. ft. or greater

for single family residen-

tial development

yes

yes Restoration plan and

SEPA checklist as

part of your plan set

Vegetation Restoration Project

Less than 1,500 sq.ft.

25.09.320A3c(2)(a)

yes

Restoration plan,

ECA Restoration Plan

Application

1,500 sq. ft. or greater yes

yes Restoration plan,

SEPA checklist, ECA

Restoration Plan

Application

Hazard Trees

All yes Hazard Tree Applica-

tion from Tip 331B,

tree risk assessment,

photos, restoration

plan

SMC 25.09.320 B2 & 3

SMC 25.09.320 B1 & 2

We will not require SEPA review due to the tree and vegetation disturbance; however, we may requrie

SEPA review based on other factors. See Tip 208, When Environmental Review is Required in Seattle,

for more details about when SEPA review is required.

SMC 25.09.320 A3c(2)(b)

SMC 25.05.908 B

In landslide-prone and steep slope areas, your vegetation restoration plan for areas between 750 and

1,500 square feet must also be approved by a licensed geotechnical engineer or geologist as per SMC

25.09.320.

SDCI Tip #331—Environmentally Critical Areas: Tree & Vegetation Overview page 3

LEGAL DISCLAIMER: This Tip should not be used as a substitute for codes and regulations. The applicant is responsible for compliance with all

code and rule requirements, whether or not described in this Tip.

maintenance of an area greater than 750 square feet,

we require a maintenance plan prepared by a quali-

fied professional. Certain areas maintained prior to the

2006 ECA Ordinance update may be exempt from this

submittal requirement. See SMC 25.09.320.A.3.a for

details about this exemption.

Your maintenance plan must provide a basic site plan

showing where the work will be conducted, and include

a statement that tree pruning will comply with ANSI

A300 pruning standards. If you are conducting main-

tenance in an area larger than 750 square feet within

a landslide-prone area, your maintenance plan must

be approved by a geotechnical engineer or geologist

licensed in the state of Washington. This approval must

accompany your maintenance plan.

You need to submit your maintenance plan and applica-

tion online at https://cosaccela.seattle.gov/.

Tree and Vegetation Removal When Part

of an Issued Building or Grading Permit

You are allowed to remove trees and vegetation and

conduct revegetation activities when it is part of an

issued building or grading permit. During our review

of your proposal we will determine if tree and vegeta-

tion removal is necessary for your building or grading

project. To simplify your preparation of a revegetation

plan, we have produced a Standard Mitigation Plan for

your use (see link below). We recommend you use this

form to submit your revegetation plan. We will accept

an alternative format prepared and signed by a qualified

professional (see Clarification of Terms below) as long

as it meets the guidelines of this Tip and the submittal

requirements outlined below.

Alternative formats for submitted restoration plans must

contain a 11” x 17” site plan with the following information:

 Site address

 Site tax parcel number

 Site configuration

 Area of ECA or ECA buffer delineated

 Location of existing and proposed structures

 Vegetation to be removed due to anticipated ground

disturbance from the proposed construction or grad-

ing activity

 Calculations demonstrating the minimum number of

plants/trees to be replanted

 Specifications for the plant size, species and spacing

of plants to be installed

We may ask for more information during our review.

You can get our Standard Mitigation Plan form on our

website at www.seattle.gov/sdci.

Tip 331A, Environmentally Critical Areas: Vegetation

Restoration, provides helpful resources and guidelines for

vegetation restoration.

Tree and Vegetation Restoration Without a

Building Permit

The ECA code allows disturbance of trees and vegeta-

tion in ECAs when the purpose is to restore or improve

native vegetation and trees to promote a naturally function

condition that prevents erosion, protects water quality, or

provides diverse habitat.

Examples of allowed disturbances include:

 Re-establishing a native ecosystem in human im-

pacted areas, such as paved surfaces, lawns, or

landscaped areas

 Replacing non-native, noxious, and/or invasive spe-

cies such as English ivy, Himalayan blackberry, or

reed canary grass, with native plantings

 Replacing previously topped trees with healthy native

trees

 Replacing monocultural stands of deciduous trees,

such as big leaf maples and red alder, with native

conifers

If your restoration is voluntary and not associated with

a building or grading permit or violation, the following

rules apply:

 If the restoration area that is within an ECA or a

surrounding regulated buffer area is less than 1,500

square feet and you are not using chemical or me-

chanical removal techniques, you must file a vegeta-

tion restoration plan with SDCI at the PRC counter,

along with an ECA Restoration Plan Application.

Applications may also by submitted by mail or email

to the addresses provided above. Tip 331A, Envi-

ronmentally Critical Areas: Vegetation Restoration,

provides helpful resources and guidelines for vegeta-

tion restoration.

SDCI Tip #331—Environmentally Critical Areas: Tree & Vegetation Overview page 4

LEGAL DISCLAIMER: This Tip should not be used as a substitute for codes and regulations. The applicant is responsible for compliance with all

code and rule requirements, whether or not described in this Tip.

 If you are planning to work on a steep slope or as-

sociated buffers in an area between 750 and 1,500

square feet, your vegetation restoration plan must

also be approved by a geotechnical engineer or

geologist licensed in the state of Washington. This is

to ensure that your restoration does not impact slope

stability or cause other adverse impacts.

 If the restoration area that is within an ECA or a sur-

rounding regulated buffer area is greater than 1,500

square feet, or if you plan to use chemical or me-

chanical removal techniques, you must submit your

restoration plan and ECA Restoration Plan Applica-

tion at a scheduled intake appointment. We will re-

quire a State Environmental Policy Act (SEPA) review.

You must complete a SEPA checklist and provide

pertinent supporting documentation (site plan, soils

report, replanting restoration plan, etc.). We will then

conduct the SEPA review and issue a threshold de-

termination. Our review usually takes a minimum of

six weeks to complete. The PRC can provide gen-

eral information on SEPA submittal requirements. You

can schedule an intake appointment by calling the

Applicant Service Center (ASC) at (206) 684-8850.

We recommend using our Standard Mitigation Plan form

to create your restoration plan. We will accept alternative

formats with an equivalent or greater level of detail. Plans

in alternative formats must be prepared and by a qualified

professional, (see Clarification of Terms, below), contain a

11” x 17” site plan, and show the following:

 Site address

 Site tax parcel number

 Site configuration

 Area of ECA or ECA buffer delineated

 Location of existing and proposed structures

 Vegetation to be removed due to anticipated ground

disturbance from the proposed construction or grad-

ing activity

 Calculations demonstrating the minimum number of

plants/trees to be replanted

 Specifications for the plant size, species and spacing

of plants to be installed

We may request additional information during our review.

Tip 331A, Environmentally Critical Areas: Vegetation

Restoration, provides helpful resources and guidelines for

vegetation restoration.

You can get Standard Mitigation Plan forms from our

website, www.seattle.gov/sdci. We will charge a

submittal fee as detailed in the SDCI Fee Subtitle SMC

22.900.

Tip 331A, Environmentally Critical Areas: Vegetation Resto-

ration, provides helpful resources and guidelines for vegeta-

tion restoration.

Hazard Trees

You must submit a hazard tree removal application and

other supporting materials listed in Tip 331B, Hazard

Trees, to request approval to remove a hazardous tree

within landslide-prone critical areas (including steep

slopes), steep slope buffers, riparian corridors, shoreline

habitat, shoreline habitat buffers, wetlands and wetland

buffers. Tip 331B, Hazard Trees, outlines the process

for obtaining approval to remove hazardous trees pro-

tected by the City’s ECA or Tree Protection codes. We

allow the removal of a hazardous tree in these ECAs

when you demonstrate there is a significant risk to prop-

erty or safety. Specifically, a hazard tree must meet all of

these criteria:

 The tree has structural defects and/or other condi-

tions that make it likely to fall or break,

 There is a permanent structure or an area of mod-

erate-to-high use by people, such as sidewalks or

public trails that would be impacted if the tree failed

 The danger cannot be mitigated by pruning the tree

or moving the structure or activity.

In emergency situations, you may remove a tree without

our approval to the minimum extent necessary to elimi-

nate the hazard. However, you are still required to submit

documentation of the hazard tree and the emergency

situation once the situation has been mitigated.

Trees and Vegetation in the Right-of-Way

You must get approval from the Seattle Department of

Transportation (SDOT) before pruning, altering, or removing

a tree or vegetation within the public street right-of-way.

This includes open and unopened street and alley rights-

of-way. The SDOT Urban Forestry Arborist Office issues

these permits. For further information call (206) 684-TREE

(8733) and see www.seattle.gov/transportation/for-

estry.htm.

Priority Habitat & Species Areas

You must comply with all applicable species habitat

management plans when you cut a tree. For informa-

tion on Bald Eagles and Great Blue Heron habitat, you

should consult with ASC staff.

SDCI Tip #331—Environmentally Critical Areas: Tree & Vegetation Overview page 5

LEGAL DISCLAIMER: This Tip should not be used as a substitute for codes and regulations. The applicant is responsible for compliance with all

code and rule requirements, whether or not described in this Tip.

Federal/State Requirements

Your tree cutting must comply with all applicable federal

and state laws, rules, and regulations including the

Endangered Species Act, the Bald Eagle Protection Act,

and the Migratory Bird Treaty Act. For further informa-

tion, contact the Washington State Department of Fish

and Wildlife, http://wdfw.wa.gov/.

Clariﬁcation of Terms

Emergency—A situation, as defined in SMC

25.09.045E, in which there is an immediate danger to life

and property that requires preventive action in a timeframe

too short for you to comply with permit requirements.

Pruning—The pruning of a tree through crown thinning,

crown cleaning, windowing, or crown raising, but not

including topping of trees or any other trimming which is

likely to kill or significantly damage the tree.

Qualiﬁed professional—An expert that has an appro-

priate combination of professional certifications, educa-

tion and training, and experience to plan, implement, and

oversee tree and vegetation maintenance and restoration

750 square feet

30 feet

24.3 feet

10 feet

750 square feet

75 feet

How to Measure the Area of Work

Area of Work: Your area of work consists of the area impacted by your tree and vegetation removal

and/or restoration activities. For trees, the area shall be calculated by measuring around the drip line of

the tree.

Drip-line and area to

calculate disturbance

750 square feet

Area=пR

п = 3.14

R = Radius

R = 15.5 feet

R = 15.5 feet for 750 square foot area

in ECAs. To undertake tree risk assessments, a qualified

professional shall hold a current Tree Risk Assessment

Qualification (TRAQ), as established by the International

Society of Arboriculture (ISA).

Topping—The cutting back of limbs to stubs within the

tree's crown, to such a degree as to remove the normal

canopy and disfigure the tree; or the cutting back of

limbs or branches to lateral branches that are less than

one-half (1/2) of the diameter of the limb or branch that

is cut.

SDCI Tip #331—Environmentally Critical Areas: Tree & Vegetation Overview page 6

LEGAL DISCLAIMER: This Tip should not be used as a substitute for codes and regulations. The applicant is responsible for compliance with all

code and rule requirements, whether or not described in this Tip.

ECA Regulations Related Documents

 Tip 103B, Environmentally Critical Area Site Plan

Requirements

www.seattle.gov/DPD/Publications/CAM/

cam103B.pdf

 Tip 242, Tree Protection Regulations in Seattle

www.seattle.gov/DPD/Publications/CAM/

cam242.pdf

 Tip 331A, Environmentally Critical Areas: Vegetation

Restoration

www.seattle.gov/DPD/Publications/CAM/

cam331a.pdf

Helpful Resources

 King County Native Plan Guide

https://green.kingcounty.gov/GoNative/Index.

aspx

 Slope Stabilization and Erosion Control (Washington

Department of Ecology)

http://www.ecy.wa.gov/programs/sea/pubs/93-

30/index.html

 Releaf

www.seattle.gov/tree

 Pacific Northwest Chapter of the International Society

of Arboriculture

http://pnwisa.org/

 Washington Urban Forestry Program

www.dnr.wa.gov/urbanforestry

 Plant Amnesty

www.plantamnesty.org

Questions?

If you have questions about tree and vegetation removal

permits, contact the ASC at www.seattle.gov/sdci/

about-us/who-we-are/applicant-services-center, or

call (206) 684-8850.

Links to SDCI Tips, Director's Rules, and Forms are

available on our website at www.seattle.gov/sdci.

Access to Information

ECA RESTORATION PLAN APPLICATION

T O B E C O M P L E T E D B Y A P P L I C A N T

Date: _______________________

AP Number: _______________________________________

Owner's Name: ________________________________________________________________________

Address: ___________________________________________________________________________________

Phone: _____________________________________

Email: _____________________________________

Contact Name: ____________________________________________________________

Address: ___________________________________________________________________________________

Phone: _____________________________________

Email: _____________________________________

Site Address: ________________________________________________________________

Legal Description: _____________________________________________________________________________

_____________________________________________________________________________

Tax Parcel Number: ______________________________________________________________

Environmentally Critical Area(s) on/near site:

Geological Hazard Abandoned Landfill

Flood-prone Other ___________________________

Wetlands

Fish & Wildlife Habitat Conservation Area (Creeks, Shorelines, etc.)

Riparian

City of Seattle

Department of Construction and Inspections

700 Fifth Ave., Suite 2000

P.O. Box 34019

Seattle, WA 98104-4019

ECA TREE CUTTING/VEGETATION REMOVAL PERMIT APPLICATION, page 2 of 3

T O B E C O M P L E T E D B Y A P P L I C A N T

Is the project associated with any other construction permit?

Yes

If yes, provide permit number and description:

Permit Number: _______________________

Description of associated construction or other permit:

_________________________________________________________________________

This project is:

Voluntary Restoration

Required Mitigation as part of an enforcement action

Other ________________________________________

Note: An ECA Restoration Plan Application form does not need to be included with landscape or restoration plans

submitted as part of a plan set or a Hazard Tree Removal Application.

Square Footage of Job Site Area = ___________________ square feet

Less than 750 square foot

Between 750 and 1,500 square foot

Between 1,500 and 9,000 square foot

Greater than 9,000 square foot

Are any of the trees proposed for removal designated as heritage trees or protected under

past land use actions? No Yes

Description of work to occur (describe scope of work and objectives; attach any plans)

___________________________________________________________________________________________________

ECA TREE CUTTING/VEGETATION REMOVAL PERMIT APPLICATION, page 3 of 3

T O B E C O M P L E T E D B Y A P P L I C A N T

Is this action the result of a violation?

Yes

If yes, provide case number and description:

Case Number: __________________________

Provide documentation and description of the prior or existing conditions of the site that will be restored or replant-

ed (attach any additional information).

___________________________________________________________________________________________________

T O B E C O M P L E T E D B Y S D C I S T A F F

Application Number: _____________________________ Receipt #: ______________________

Intake Staff: ____________________________________ Fee: ___________________________

Analyst: _______________________________________

Approved: ______________________ Denied: ___________________ Date: _______________

Note: if your project is a wetland mitigation/restoration project you must follow the procedures outlined in Wetland

Mitigation in Washington State Part 2: Developing Mitigation Plans, Version 1, March 2006, Ecology Publication

#06-06-011b