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. Here in Lake Oswego, we celebrate the entire month of April as Lake Oswego Arbor Month. Click here to read the City’s proclamation.

For 36 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 its eighth TCUSA 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: adopting the 2024 Urban and Community Forestry Plan Update; planting more trees than were removed on City owned and managed properties, including 92 trees removed and 12,154 trees planted; and, by working to implement the City’s Natural Areas Habitat Management Plan by performing environmental restoration in multiple natural areas owned and managed by the City including control of noxious weeds, removal of invasive tree species and excess woody debris along property lines to reduce wildfire hazards, and replanting with fire-resistant plants for a resilient native understory.

Checkout the 2025 Urban & Community Forestry Newsletter and find fun ways to celebrate trees this Arbor Month, and throughout the year, below. 

Urban & Community Forestry Events:

TREE PRUNING WORKSHOP
Saturday, April 5, 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 Rick Till. Pre-registration is required and capacity is limited to 40 participants. Visit https://www.ci.oswego.or.us/formslf/PlanningWorkshops or call 503-635-0290 to register.

OAK WOODLAND RESTORATION
Saturday, April 5, 10 a.m. to 12 p.m., park at the church at 14903 Westlake DriveJoin Oswego Lake Watershed Council for a morning of land tending and restoration at Westlake HOA Oak Woodland. This beautiful habitat is home to centuries old Oregon white oaks and a diversity of wildlife. Volunteers will learn about Oregon white oak ecology, land tending and preserving oak ecosystems, and help remove invasive species and plant natives. For additional information and free registration, visit https://docs.google.com/forms/d/e/1FAIpQLSe3wvUE-Kn4HPqs0I3YNdEZnrBM8j_IuM3Nq7rhDyZIR5Qbog/viewform

TRYON TRILLIUM FESTIVAL
Saturday, April 5, 9 a.m. to 2 p.m., Tryon Creek State Natural Area, 11321 S. Terwilliger Boulevard
Join Friends of Tryon Creek for the 45th Annual Trillium Festival, a festive day in the woods to celebrate the return of the Trillium, an early season perennial native to our local forests. In addition to the Native Plant Sale, this family-friendly event includes a Gardening Resources Fair and free educational stations around the Nature Center and trails offering hands-on presentations, crafts and nature activities. More event details are available at www.tryonfriends.org/calendar.

SUSTAINABILITY RESOURCE FAIR
Sunday, April 6, 11 a.m. to 2 p.m., River Grove Elementary School, 5850 SW McEwan 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 4th Annual Lake Oswego Sustainability Resource Fair. This year’s fair will feature resources on sustainable landscaping and gardening, including information on native plants and pollinators and an opportunity to try out electric yard tools. Plus, take a guided tour of the River Grove Elementary School, learn about sustainability classes and activities for students, take home some sporting gear from Shifting Gears/Gifting Gear’s equipment exchange, and learn about topics from recycling to rooftop solar. More details at: https://www.ci.oswego.or.us/sustainability/sustainability-resource-fair-2025?date=0.

YEAR OF THE OAK: ARBORIST WORKSHOP & FILM SCREENING
Thursday, April 10th, 6 to 8 p.m., Lake Theater & Cafe, 106 N. State Street
Join us for an evening of learning and discussion on Oregon white oaks! This event explores a wide range of topics essential for oak tree health and maintenance with a short film screening and an informative presentation led by ISA Certified Arborist Brian French who brings over 24 years of experience and a passion for tree preservation. Learn how to recognize signs of oak tree health issues, structural problems, and identifying common threats like pests and diseases. You'll learn best practices for watering, mulching, and planting around oaks, as well as how to protect them from storm damage. Brian will also share valuable pruning techniques for healthy growth and discuss the vital role oaks play in supporting local ecosystems. Bring your oak tree questions for the closing Q&A. Proactive oak tree care can enhance safety and save you money in the long run. This program is offered by Oswego Lake Watershed Council in cooperation with the Lake Theater & Café and funded by the Oregon Watershed Enhancement Board. Admission is free, but preregistration is required and food and drink purchases are encouraged to help offset costs to the Lake Theater & Cafe. Doors open at 5:45. For more details and registration, visit https://events.humanitix.com/year-of-the-oak-arborist-workshop-and-film-screening and click “get tickets” in the upper right corner.

PAPER MAKING CRAFT FOR KIDS
Friday, April 11, 11 a.m., Lake Oswego Public Library (lower level), 706 4th Street
Celebrate Arbor Month AND Lake Oswego Reads by making your own handmade paper. All materials will be provided. This program is sponsored by the Friends of Lake Oswego Public Library and admission is free. For more information, contact the Children’s desk at 503-697-6580 or visit www.lopl.org/kids.

TREE PLANTING WORKSHOP
Saturday, April 12, 10 a.m. to 12 p.m., Foothills Park Pavilion, 199 Foothills
Learn what the City is doing to prepare for the arrival of Emerald ash borer, an invasive insect pest that threatens all ash tree species, and practice proper tree planting techniques while we install a variety of native tree species to help replace the inevitable loss of the ash tree canopy in Foothills Park. Dress for the weather and wear closed-toed shoes. This workshop is led by Parks and Recreation staff. Pre-registration is required and capacity is limited to 25 participants. Contact stewardship@lakeoswego.city with questions and visit https://www.ci.oswego.or.us/formslf/PlanningWorkshops or call 503-635-0290 for free registration.

MOUNTAIN PARK STREAM RESTORATION
Wednesday, April 16, 9 to 11 a.m., Elizabeth M. Gress Park, parking is available on side streets, access the park from McNary Parkway
The common spaces in Mountain Park are home to a diverse forest that provides a valuable wildlife corridor. Invasive species, especially English ivy, have taken over the forest and Oswego Lake Watershed Council needs your help! We will be pulling invasive ivy and other invasive species to prepare native groundcover recovery. Pulling ivy requires volunteers to be able to bend over or kneel, but we can arrange alternate projects for those with different abilities or mobility issues. For additional information and free registration, visit https://forms.gle/Mfs6bYawuTRJUCLz9.

OREGON WHITE OAK TREE SURVEY TRAINING
Saturday, April 19, 10 a.m. to 12 p.m., East Waluga Park Picnic Shelter, 15505 Quarry Road
If you like Oregon white oaks, don’t miss this chance to participate in a community science project! The Oswego Lake Watershed Council (OLWC) has developed a simple tool for trained participants to survey Oregon white oaks throughout the City. Locating trees and collecting data on their size, condition and overall health helps to inform management decisions. While the City is undertaking an inventory of trees on City owned and managed properties, residents can work with OLWC to help us all develop a better understanding of the urban forest. Participants will gather at the picnic shelter for a brief introduction and follow along as the workshop hosts demonstrate how to use the survey tool and collect tree data, then set out to survey oaks throughout East Waluga Park with the hosts there to assist and answer questions. After the workshop, you’ll be trained to survey oaks on your own property or your neighbors’ with their permission and a signed agreement provided by OLWC. This workshop is led by OLWC Project Coordinator, Rio Hybert, with assistance from the City’s contract arborist. Pre-registration is required and capacity is limited to 30 participants. Registered participants will receive an e-mail a few days prior to the event with background information to review and instructions for downloading the survey tool to your phone or tablet. Please bring your charged device and wear close-toed shoes. Register here: https://forms.gle/fCpwpQFzPQyPR3Mg6.

SPRINGBROOK PARK PRESCHOOL NATURE WALK
Wednesday, April 23, 10:30 to 11:30 a.m., Springbrook Park, park at Uplands Elementary School or along the street, 2055 Wembley Park Road, meet at the Park kiosk behind the playground
Preschoolers can join Friends of Springbrook Park for 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. Contact Anne Lider anne.lider@gmail.com with questions.

OAK WOODLAND ECOLOGY WALK
Saturday, April 26, 10 to 11:30 a.m., Park at 14903 Westlake Drive in the church parking lot
Join Oswego Lake Watershed Council on an oak woodland walking tour. Explore native understory plants and flowers, discover a variety of birds, and see the progress being made to restore and enhance this valuable habitat, all while enjoying good company. Gloves and light refreshments will be provided. Sturdy close-toed shoes are recommended. This event is free and family-friendly. Visit this link for registration: https://forms.gle/Bok1QiLr5iKCCKYK7.

SOIL YOUR UNDIES FOR SCIENCE
Life underground is just as complex and vital as the plants above. Oswego Lake Watershed Council (OLWC) invites you to participate in the “Soil Your Undies” challenge to measure and nurture this hidden world. Simply bury a pair of cotton undies for 60 days and see how soil organisms break them down. The more they decompose, the healthier your soil is! Here’s how to participate:

1. Visit https://forms.gle/aM4eSMoUWqXZMX32A today to register for a free challenge kit.
2. Pick up your challenge kit on Saturday, April 5 from 9 a.m. to 2 p.m. at Tryon Creek State Natural Area during the Trillium Festival or on Sunday, April 6 from 11 a.m. to 2 p.m. at River Grove Elementary School during the Lake Oswego Sustainability Resource Fair. For alternative pick-up locations, contact Megan Hill at megan@oswegowatershed.org.     
3. Bury the new pair of cotton underwear included in your challenge kit on Saturday, April 22.
4. Dig up the underwear on Tuesday, June 24 and take a photo to share with OLCW.
5. Join OLWC on Saturday, June 28 for a virtual reveal event to learn more about soil health.

STEWARDSHIP WORK PARTIES
Over 500 acres of park natural areas and open spaces in the City contribute to important habitat for plants and animals, watershed and stormwater management and health. These park natural areas also provide places for the community to connect with nature. Join a Friends of the Parks volunteer habitat restoration work party to help keep our park natural areas and open spaces healthy and beautiful:

Sunday, April 6, 1 to 3 p.m., Friends of Luscher Farm Invasive Removal, 125 S Rosemont Road
Join the Friends of Luscher Farm in restoring a 300-square-foot natural area near the northeast corner of the Luscher Community Gardens. This rehabilitated space is used as an outdoor learning area for summer youth camps and classes. Contact Kaleb Simpson at stewardship@lakeoswego.city for additional information.

Sunday, April 27, 1 to 3 p.m., Investigate the Forest at Freepons Park, 1399 Bickner Street (street parking only)
Gather the whole family for a fun-filled Nature Treasure Hunt hosted by the Friends of Hallinan Woods in beautiful Freepons Park! Explore the park's natural wonders as you search for hidden treasures. This event is open to adventurers of all ages and all materials will be provided. Contact Debbie Craig at 650-380-4179 or kbrizgys@gmail.com for additional information.

Saturday, May 3, 9 to 11 a.m., Pull Together at West Waluga Park, 15775 Waluga Drive
Join the Friends of Waluga Park in removing teasel overtaking the wetlands next to the West Waluga paved path. The new friends group aims to restore the sprawling wetlands surrounding both West and East Waluga Parks and build community focused volunteerism. Contact Lindsey Boccia at 503-943-0480 or LakeForestChair@gmail.com for additional information.

Volunteers must sign the Stewardship Waiver form upon arrival to the work party site. Dress for weather and wear close-toed shoes. Bring gloves and water to drink. Restrooms may not be available. For additional information, visit www.LO-STEWARDSHIP.org or contact Kaleb Simpson, Natural Resource & Stewardship Coordinator at stewardship@lakeoswego.city. 

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. At 11 a.m. on Friday, April 11, stop by the Children’s library on the lower level to make handmade paper to celebrate both Arbor Month and LO Reads! 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.

GNOMES & BEES IN NATURE
The wily Stewardship Gnomes, Blossom, Greenie and Oak, and their bee buddy, Polli will be hiding 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 the forest friends in three different natural area parks each month. In April, they will be hiding in Cooks Butte, George Rogers, and Bryant Woods.
• Scan the QR code and take a photo of you, your dog, or anything else by a Gnome and/or the Bee.
• With your participation, you may be selected to win your very own garden gnome in October. 
• Visit lo-stewardship.org each month to learn where the Gnomes and Bee have moved and discover fun facts about native plants, wildlife, and the City’s 500-acres of park natural areas.

Explore these related links:

• Arbor Month Art Contest
• Tree of the Week
• Stewardship Opportunities
• Workshop Series
• Forestry at the Farmers Market
• The BUZZ on Bumblebees 
• Heritage Trees 
• State of the Urban Forest 
• Tree Care and Maintenance