April 2023 Community ForestryForestryUrban & CommUnityApril 2023
For more information on Arbor Week or Urban and Community
Forestry events, visit www.lakeoswego.city/planning, email
planning@lakeoswego.city, or call 503-635-0290.
Volunteers plant a native Oregon white oak at Luscher Farm.
Continued on page 2
Trillium at Tryon Creek by Jeffery DeWitt, 2022.
April is Arbor Month
Arbor Day is America’s National Tree Holiday, observed on the
last Friday of April to celebrate the role of trees in our lives and
to promote tree planting and care. For the third year in a row,
Mayor Buck has proclaimed the entire month of April Lake Oswego
Arbor Month. Visit www.lakeoswego.city/trees to read the City’s
proclamation.
CheCkout these fun ways to Celebrate:
tree Planting Party
Saturday, April 1, 10 a.m. to 12 p.m., Iron Mountain Park, 2401 Iron
Mountain Boulevard
Kick-off Lake Oswego Arbor Month with a tree planting party at
Iron Mountain City Park! Join Parks & Recreation staff to learn
about tree selection, planting and maintenance, and practice
proper planting techniques by helping to install new trees in the
park. Dress for weather and wear closed toe shoes. Bring gloves,
and water to drink. Pre-registration is required and capacity is
limited to 25 Lake Oswego residents. Parking is limited, carpool
or ride your bike. Visit www.lakeoswego.city/planning/workshop-
series or call 503-635-0290 for free registration.
trillium festival
Saturday, April 1, 10 a.m. to 3 p.m., Tryon Creek State Natural
Area, 11321 S. Terwilliger Boulevard
Join Friends of Tryon Creek to celebrate the return of the Trillium,
an early season perennial native to our local forests, at the 43rd
Annual Trillium Festival at Tyron Creek State Natural Area. In
addition to the native plant sale, this family friendly event offers a
suite of educational stations around the Nature Center and trails.
More event details are available at www.tryonfriends.org/calendar.
CelebrAting 34 YeArs
tree City usa
For 34 years, the City of Lake Oswego has earned Tree City USA (TCUSA) recognition from the
National Arbor Day Foundation for demonstrating a strong commitment to managing and caring
for trees. Cities earn TCUSA status by meeting four standards: maintaining a tree board (the
Parks, Recreation and Natural Resources Advisory Board), having a tree ordinance, spending a
minimum $2 per capita on urban forest management, and proclaiming and celebrating Arbor Day
annually.
This year, the Arbor Day Foundation also presented Lake Oswego with a Tree City USA Growth
Award, which recognizes innovative projects and higher levels of tree care by participating Tree
City USA communities. The Growth Award was awarded to Lake Oswego for developing the 2022
State of the Urban Forest Report, an in-depth analysis of the City’s tree canopy.
Visit www.arborday.org/programs/treecityusa to learn more.
Arbor Month Art Contest
trees! trees! trees!
In celebration of Lake Oswego Arbor Month and in honor of 34 years of Tree City USA status,
the City is hosting a Trees! Trees! Trees! themed art contest for K-5th students residing in Lake
Oswego. The recently published State of the Urban Forest Report describes that Lake Oswego
has 53.4% tree canopy cover citywide, the highest canopy cover in the Portland region among
cities of comparable size. The urban forest tree canopy includes tall trees, short trees, narrow
trees, broad trees, evergreen trees, deciduous trees, old trees, young trees, and all sorts of tree
species, so create a work of art featuring trees in the Lake Oswego urban forest. Entries will be
displayed electronically at City Hall and the Public Library. The contest begins on Saturday, April
1, 2023 and entries must be received by 11:59 p.m. on Sunday, April 23, 2023. Winners will be
notified on National Arbor Day, April 28, 2023, and prizes will be awarded at the Lake Oswego
Farmers’ Market on Saturday, May 20, 2023. For additional information and complete contest
rules, visit www.lakeoswego.city/formslf/ArborMonthArt.
ForestrY At the FArMers’
MArket
saturday, may 20, 8:30 a.m. - 1:30 P.m. at millennium Plaza Park, 200 first street
Join us to celebrate forestry at the Farmers’ Market! Activities include Urban & Community
Forestry booths and activities for children and adults. Spin the prize wheel, do a craft, talk to
an arborist, receive a free tree seedling, answer tree trivia, win raffle prizes and learn about
stewardship opportunities in your neighborhood. Arbor Day Art Contest winners will be
announced and prizes will be awarded.
Workshop series
Each year the City offers a series of free Urban and Community Forestry Workshops for the
public. Pre-registration is required and capacity is limited with preference given to Lake Oswego
residents. Visit www.lakeoswego.city/planning/workshop-series or call 503-635-0290 for
workshop details and free registration. This year’s lineup includes:
• Tree Planting, April 1 from 10 a.m. to 12 p.m. at Iron Mountain Park
• Tree Pruning, April 30 from 10 a.m. to 12 p.m. at Foothills Park
• Landscaping for Pollinators, July 22 from 10 a.m. to 12 p.m., location to be announced soon
• Tree Identification, August 12 from 10 a.m. to 12 p.m. at George Rogers Park
• Tree Removal Permits, August 31 from 1 to 2 p.m. at City Hall
• Tree Protection Plans and Tree Code Violations, September 28 from 1 to 2 p.m.
at City Hall
• Creating Backyard Habitat, September 23 from 10 a.m. to 12 p.m. at Tryon
Creek State Natural Area
WAYs to CelebrAte Continued from page 1
nature Craft workshoP
Friday, April 14, 9 a.m. to 1:00 p.m., Luscher Farm Bunkhouse Classroom, 125
Rosemont Road
Children ages 8 to 12 can mix up plant-based watercolor paints, play with pressed
flowers, and use treasures found in nature to get crafty in this no school day
workshop. Fees apply. Pre-registration is required and capacity is limited. Visit www.
lakeoswego.city/parksrec/parks-recreation-classes-activities and register for activity
#25616.
native bees in your garden
Saturday, April 15, 1 p.m. to 2:30 p.m., Luscher Farm Bunkhouse Classroom, 125
Rosemont Road
Native bees are the most important pollinators of wild plants, helping to maintain
ecosystem diversity and feed the world. Adults and teens 16+ are invited to Luscher
Farm for a hands-on workshop led by Bee Master Carol Yamada of the Lake Grove
Garden Club. Get to know your native northwest bees, discover identification
tools for determining which bees are visiting your garden, and learn tips and tricks
on building native bee populations in your own yard. Fees apply. Pre-registration
is required and capacity is limited. Visit www.lakeoswego.city/parksrec/parks-
recreation-classes-activities and register for activity #25681.
sustainability resourCe fair
Saturday, April 15, 10 a.m. to 1 p.m., Lakeridge Middle School, 4700 Jean Road
In celebration of Earth Day, the City of Lake Oswego Sustainability Advisory Board,
Lake Oswego School District, Lake Oswego Sustainability Network, and Oswego
Lake Watershed Council are holding the second annual Lake Oswego Sustainability
Resource Fair. Come learn what diverse organizations across our community are
doing to advance sustainability, find opportunities to volunteer and participate in
educational programs, connect with neighbors, and learn simple ways you can help
protect the environment, save money, and live well.
sPringbrook Park PresChool nature walk
Tuesday, April 18, 10:45 to 11:45 a.m., Springbrook Park, Park at Uplands
Elementary School, 2055 Wembley Park Road, meet at the park kiosk behind the
playground
Preschoolers can join Friends of Springbrook Park to learn about trees with a fun
and interactive nature walk through Springbrook Park. Exploration buckets will
be provided for hands on discovering! This event is free and no pre-registration is
required. Preschoolers need to be accompanied by an adult. Questions? Anne Lider
503-701-2291 or anne.lider@gmail.com.
oak woodland restoration
Saturday, April 22, 10 a.m. to 12 p.m., Park at 14903 Westlake Drive
Celebrate Earth Day by joining Oswego Lake Watershed Council for a morning of
land tending and restoration at Westlake HOA Oak Woodland. This beautiful oak
woodland habitat is home to majestic Oregon white oaks and a diversity of wildlife.
Volunteers will learn about Oregon white oak ecology, indigenous land tending and
the cultural value of oak ecosystems, and help remove invasive species and plant
natives. For additional information and free registration, visit
www.solveoregon.org/opportunity/a0C8W00000VC2HP/oak-woodland-land-
tending-at-westlake.
farm saturday
Saturday, April 29, 10 a.m. to 2 p.m., Luscher Farm Bunkhouse Classroom, 125
Rosemont Road
Children ages 5 to 12 are invited to spend Saturday morning at Luscher Farm,
creating crafts to celebrate Arbor Month and Earth Day, partake in fun farm
activities, and learn about organic gardening. Fees apply. Pre-registration is required
and capacity is limited. Visit www.lakeoswego.city/parksrec/parks-recreation-
classes-activities and register for activity #25870.
tree Pruning workshoP
Sunday, April 30, 10 a.m. to 12 p.m.,
Foothills Park Pavilion, 199 Foothills
Road
Understand why, what, and how to
prune to develop healthy, strong, and
attractive trees and shrubs. Explore
pruning types, proper cutting tools
and techniques, and tree responses
to pruning. This workshop is led by
ISA Board Certified Master Arborist
Damon Schrosk of Treecology, Inc.
Pre-registration is required and capacity
is limited to 40 Lake Oswego residents. Visit www.
lakeoswego.city/planning/workshop-series or call 503-
635-0290 for free registration.
lake oswego PubliC library
Celebrate Arbor Month with a book and
a kid’s craft! Throughout April, the Lake
Oswego Public Library, located at 706
4th Street, will have tree-themed books
on display and offer a craft for kids using
repurposed puzzle pieces to make a beautiful tree, at the Art Bar on the lower level.
The Art Bar is open anytime the library is open. Arbor Month Art Contest entries will
be on electronic display from mid-April through mid-May. Open daily: 1 to 5 p.m.
Sunday, 10 a.m. to 7 p.m. Monday-Thursday, and 10 a.m. to 5 p.m. Friday-Saturday.
soil your undies for sCienCe
Life underground is just as biodiverse and complex as the plant communities
that live above, and Oswego Lake Watershed Council wants to help residents
measure and nurture that life. It is as easy as burying a pair of cotton undies for 60
days! Celebrate Arbor Month by participating in the 3rd Annual Soil Your Undies
challenge! Sign up to receive your challenge kit, which includes a brand new pair
of cotton undies for you to bury in April and unearth in July. Participants can follow
along with biweekly soil health tips and experiments to try out while the soil
microbes are feasting on all of the buried undies. Learn more about the challenge
and register at: www.oswegowatershed.org/soil-your-undies-2023.
be an lo tree hero
Team up with the Oswego Lake Watershed Council (OLWC) and your neighborhood’s
Urban Forest Committee to be an urban forest hero by removing invasive ivy from
your trees and property. OLWC offers tools, education and leadership. Find out more
at www.oswegowatershed.org/arbormonth23/.
the gnomes in nature
The wily Stewardship Gnomes, Blossom, Greenie and Oak, will hide in three natural
area parks from April to October, moving to different parks on the first of each
month. Come out and find them, you may win a prize! Here’s what to do:
• Find three Gnomes hiding in three different natural area parks each month. In
April, they will be hiding in Foothills Park, River Run Park and Springbrook Park.
• Take a photo of you, your dog or anything else by a gnome.
• Tag #LOparksgnomes and post photos on social media for a chance to win your
very own garden gnome in October.
Visit lo-stewardship.org each month to learn where the Gnomes in Nature have
moved and discover fun facts about the City’s 460-acres of natural park areas, native
plants, wildlife and birds.
Photo by Jerry Winter, 2022.
2022 Sustainability Resource Fair
eMerAld Ash borer
Emerald ash borer (Agrilus planipennis), or EAB, is a metallic wood-boring beetle that
threatens certain trees in the family Oleaceae, including all ash tree species in the Fraxinus
genus as well as olive (Olea species) and white fringetree (Chionanthus virginicus), although
the latter are less preferred by the insect. In its native range in eastern Asia and Russia, EAB
is found at low densities and generally does not cause tree mortality unless trees are already
stressed. However, in North America, this invasive insect is considered the most destructive
forest pest ever seen with the potential to create billions of dollars in damages nationwide.
EAB was first discovered in the United States in Michigan in 2002, likely arriving in wood
packing materials from Asia. EAB has killed hundreds of millions of ash trees across the east
coast and Midwest over the last 20 years. Here in Oregon, loss of our native Oregon ash
(Fraxinus latifolia), a very important riparian and wetland species west of the Cascades, is
of grave concern, as well as the loss of widely planted non-native and cultivated ash trees in
urban landscapes. Unfortunately, EAB was discovered in the City of Forest Grove on June 30,
2022. This is the first time EAB has been identified in Oregon, but the Oregon Department of
Agriculture and Oregon Department of Forestry have been preparing for its arrival for years.
Adult EAB emerges in mid-May through late-June. Adult females lay eggs on both stressed
and healthy ash trees, the eggs hatch in 1-2 weeks and tiny larvae bore through the bark and
burrow into the cambium layer where they feed for several months leaving the tree unable
to transport water and nutrients throughout its tissues. The larvae overwinter in the outer
layer of wood or in the bark, pupate in the spring, and emerge as adults in late spring to
start the life cycle over again. Adult EAB will chew on leaves, but cause little damage relative
to the cambium feeding larvae. EAB can take a few years to kill a tree, with infested trees
appearing healthy but declining rapidly as the insect population builds exponentially. While
adult EAB are poor flyers, studies have shown that mated females can fly an average distance
of nearly 2 miles.
Unfortunately, there are no effective means of eradicating EAB, but here’s what you can do
to help:
• Be on the lookout for EAB. Learn to identify ash trees and EAB (there are many look-
alikes), and report suspected sightings online at the Oregon Invasive Species Council
hotline including the location and a photograph.
• Learn the signs and symptoms of EAB including top-kill, thinning crowns, new branches
sprouting from the lower tree trunk, ~1/8-inch diameter D-shaped exit holes in the bark,
bark splits from separation of wood and bark by feeding tunnels, and patches of light-
colored bark from woodpecker flecking, but know that each of these can be caused by
something other than EAB.
• Don’t actively plant ash trees, but take good care of the ash trees you have. This includes
supplemental watering and mulching during hot and dry summertime drought. Once
EAB is detected in a neighboring county, consider treating high-value ash trees with
systemic insecticides on a two-to-three-year cycle, depending on the product. Treatment
should occur before infestation for optimum protection, but studies have shown that
treatment can be successful in infested trees with less than 20% canopy decline. A
qualified and experienced plant health care specialist can prescribe and implement
appropriate treatments.
• Don’t move firewood to avoid spreading insects and diseases.
• Remove dead and dying ash trees before they become hazardous—at probable risk for
failure in an area near people or property—and replant with another species suitable
for the specific site conditions. A tree removal and replacement plan can help property
owners distribute management costs over time and replace canopy cover and lost
environmental benefits in an on-going, rather than wholesale, way.
• When possible, ash tree pruning and removal should be conducted during EAB’s
dormant period between October 1 and March 31. Dispose of ash wood in accordance
with state mandated protocols in quarantine areas. Currently, only Washington County is
under EAB quarantine in Oregon.
• Share information about EAB with others!
Learn more about EAB online at extension.oregonstate.edu/collection/emerald-ash-borer-
resources.
steWArdship Work
pArties
Over 460 acres of natural area parks and open spaces in the City
contribute to important habitat for plants and animals, watershed and
stormwater management and health. These natural areas also provide
places for the community to connect with nature. Join a friendly Friends
of the Parks volunteer habitat restoration work party during Arbor
Month to help keep our natural area parks and open spaces healthy and
beautiful:
hallinan woods
Sunday, April 16, 1 to 3 p.m.
Join Friends of Hallinan Heights Woods to remove invasive species in the
recently acquired natural area in Hallinan Woods. Parking on Hallinan
Street or Hemlock Street. Questions? Contact Barbara Fisher at 503-888-
2244 or lanefisher108@comcast.net.
Cooks butte Park
Saturday, April 22, 10 a.m. to 12 p.m.
Help Mother Nature with a spring clean-up at this 42-acre natural park.
We’ll remove invasive species and pick up tree debris so native species
can thrive. Parking near 2286 Palisades Crest Drive. Questions? Contact
Radu Stancescu at radu_stancescu@yahoo.com.
sPringbrook Park
Sunday, April 23, 9 to 11 a.m.
Joins Friends of Springbrook Park to remove invasive species and help
restore habitat in this 52-acre natural park. Parking at Uplands Elementary
School, 2055 Wembley Park Road. Meet at the park kiosk behind
the playground. Questions? Contact Laura Tanz at 503-702-7937 or
blmjt2205@gmail.com.
Volunteers MUST fill out and bring the Stewardship Waiver available
online at lo-stewardship.org. Dress for weather and wear closed toe
shoes. Bring gloves, your favorite clippers and water to drink. Restrooms
are not available. Stay home if you have symptoms of any contagious
illness or had recent contact with someone exhibiting symptoms of any
illness. Maintain six feet distance from others. Wash hands before and
after the work party.
noMinAte A heritAge
tree
Do you have a favorite tree or group of trees? If it is of landmark
importance—because of its age, size, species, horticultural quality or
historic significance—you can nominate a tree or group of trees for
Heritage Tree designation with permission from the property owner.
Check out the Heritage Tree Story Map, learn about the City’s Heritage
Tree Preservation Grant Program, and find a nomination form online at
www.lakeoswego.city/planning/heritage-tree-program.
tree CAre &
MAintenAnCe
Visit www.lakeoswego.city/trees for seasonal tree care and
maintenance advice. This webpage is updated quarterly by
an ISA Board Certified Master Arborist. Explore the archives
to learn about best practices for pruning, bird nesting season,
protecting trees from insects and disease, managing storm
damaged trees, soil management, soil mulching, retaining and
creating wildlife snags, and so much more!
Adult EAB is generally 1/3 to 1/2 inch long and 1/8 inch wide, about the size of a grain of cooked rice.
Emerald ash borer, photo by Virginia Tech Department of Forestry.
National Charity League volunteers at Lamont Springs.
Information: 503-635-0290
www.lakeoswego.city
nAturAl AreAs hAbitAt MAnAgeMent plAn
The City’s Parks and Recreation Department (LOPR) manages over 460 acres of
natural area parks to maintain and enhance the natural character and beauty of
Lake Oswego. Protecting and conserving our natural area parks provides important
habitat for plants and animals, watershed and stormwater management, and spaces
for the community to connect with nature.
Since 2011, the City’s Invasive Removal Program and Habitat Enhancement Program
have provided funding for restoration in City natural areas. With the help of
contractors, Friends Groups volunteers and City staff, 370+ acres are in the process
of being restored and stabilized. To enhance these efforts, the Natural Areas Habitat
Management Plan (Plan) was developed and then adopted by City Council in
December 2022.
The Plan focuses on improved ecological resiliency for 27 of the City’s natural areas
already in restoration and provides a framework for the management of other City-
owned natural lands. This Plan seeks to achieve an overarching management goal
to enhance and restore Lake Oswego’s natural areas to provide safe and healthy
ecosystems. The Plan defines “healthy” natural area ecosystems as natural areas
that can support a wide diversity of native plants and animals and can adapt to
change to maintain functionality amidst increased recreation, encroachment by
invasive species, changes to natural water flows, and threats posed by wildfire and
climate change.
The Plan was developed by mapping and classifying seven general habitat types
commonly observed in the City: deciduous forest, conifer forest, mixed-conifer
deciduous forest, Oregon white oak woodland, shrubland, upland grassland and
wetland. Next, habitats were classified based on a unique condition ranking system
for purposes of managing lands based on ecological status (degraded, moderate,
or good quality). Then, Management Objectives were developed based on habitat
conditions and observed factors that constrain healthy ecosystems (e.g., invasive
species, informal trails, and increased drought stress from increasing summer
temperatures):
Objective 1. Enhance Natural Area Health and Resilience by Supporting Natural
Ecological Processes
Objective 2. Noxious Weed Control
Objective 3. Minimize Habitat Fragmentation and Protect Sensitive Lands
Objective 4. Improve Climate Resilience
Objective 5. Reduce Wildfire Hazards
Objective 6. Enhance Hydrologic Function and Resource Protection Districts
Objective 7. Selective Tree Removal to Improve Safe and Healthy Ecosystems
Objective 8. Adaptively Manage Ongoing Public Engagement Opportunities that
Benefit Habitat Protection and Enhancement
The Plan is intended to be a living document that is periodically updated. It includes
success criteria to monitor whether objectives are achieved and inform an adaptive
management approach. Data review and possible plan updates are recommended
every 6 years. The Plan is a useful tool to help guide the City’s restoration efforts
with the adaptability to accommodate change for years to come. To review the
Plan, visit www.lakeoswego.city/parksrec/natural-areas-habitat-management-plan.
Thank you to the following community members and stakeholders who helped
create and review the Plan: AECOM and David Evans and Associates, Plan
consultants; Parks, Recreation & Natural Resources Advisory Board members;
Oswego Lake Watershed Council; Tryon Creek Watershed Council; Mosaic Ecology;
Ash Creek Forest Management; Clackamas Soil & Water Conservation District;
Stewardship Friends Groups; City staff; and, numerous citizens that attended
informational meetings and an open house to provide input.
stAte oF the urbAn Forest
Trees are a defining characteristic of Lake Oswego. Together, trees that line streets,
shade streams, and are scattered throughout neighborhoods, parks, and natural
areas comprise an urban forest that contributes to the environmental, economic,
and social sustainability of Lake Oswego.
The City’s first State of the Urban Forest (SURF) Report, prepared in 2009, contains
baseline data on forest health, including the number of street trees in Lake Oswego
and the community’s overall tree canopy cover, among other metrics. Last year,
at the direction of City Council, Staff and a consultant with Parametrix completed
an update of the SURF Report. The updated Report provides data to help inform
updates to the City’s Urban & Community Forestry Plan (UCFP) consistent with the
Sustainability and Climate Action Plan. The 2022 SURF Report was presented to City
Council in December 2022 and is available online at www.lakeoswego.city/planning.
The 2022 SURF Report provides a qualitative and quantitative analysis of citywide
tree canopy cover based on the most current and available high-resolution aerial
imagery and Lidar for the region. The canopy cover analysis is further assessed
within a series of eight different land classifications and in terms of various tree
height classes. The Report also describes estimated environmental, economic and
social benefits of the City’s tree canopy, identifies a variety of threats to the health
and sustainability of the urban forest, includes data on tree removal permits issued
over time, provides a summary of the City’s various community forestry programs,
and much more. Here is a brief summary of key findings:
• Citywide tree canopy increased from 48.6 percent to 53.4 percent from 2014-
2019, a 4.8% increase.
• Lake Oswego has the highest tree canopy cover in the Portland region among
cities of comparable size.
• Canopy cover is well distributed with all neighborhoods achieving over 40
percent canopy and all having increased canopy during the study period.
• The estimated ecosystem services of Lake Oswego’s urban forest are immense,
including nearly 270,000 pounds of air pollutants removed annually, 155
million gallons of avoided annual stormwater runoff, and storage of 201,732
megagrams of carbon.
• Threats to the City’s urban forest include climate change, extreme weather,
invasive species, insects and disease, urban development and wildfire.
• Lake Oswego has a diverse mix of trees of varying sizes with an abundant stock
of smaller trees, only some of which will eventually replace larger trees based
on species.
• Planting large stature tree species, where appropriate, will help replace
larger trees as they decline or are otherwise removed. The loss of larger trees
negatively impacts carbon storage as well as other important community
benefits.
• Urban forestry policies and practices will need to be balanced with other
community goals including housing, energy conservation, and renewable
energy.
The SURF Report sets the framework for future updates on a 5-year cycle, which
correlates with regional plans to fly high-resolution aerial imagery and Lidar to
aid the assessment. In the meantime, the 2022 analysis will help the City manage
the urban forest, conserve natural resources, and plan for climate resilience by
informing the UCFP update, a 2023 City Council goal. Staff has already begun the
process of selecting a consulting firm to help the City create a comprehensive,
sustainable, and integrated approach to urban forest management
on both public and private property. The update to the UCFP will
include public and stakeholder engagement and will address goals
and actions related to stewardship and education, forest health
and size, tree maintenance, invasive species preparedness and
management, program integration and funding, and will be based
on the best available science. The updated UCFP is tentatively
scheduled to be adopted in early 2024.
Lake Oswego Natural
Area Study Sites
Considered in this Plan