Sam Samuel Leininger

WeedWise Program Manager

(503) 210-6006

Sam has been the manager of the WeedWise program since its inception in 2009. He is an ecologist specializing in invasive species management. As program manager, Sam oversees the operations and continued development of the WeedWise Program. He also provides technical assistance to local landowners and to the Clackamas SWCD planning staff.

Born and raised in rural eastern Oregon, Sam learned the importance of responsible land management at a young age. Weed management was an important part of his rural upbringing.

Sam attended Oregon State University and earned an Honors Bachelors of Science degree in Environmental Science. He later received a Master’s of Science, in Ecology from the University of California, Davis after specializing in invasive species ecology and management.

Over the course of his career, Sam has worked on a variety of ecological issues, including Willamette Valley prairie restoration, rare plant conservation, production forestry, fish and wildlife habitat enhancement, water quality, population modeling, as well as invasive species management.

While serving as WeedWise program manager, Sam has been very active in Cooperative Weed Management Areas (CWMA) in Oregon and serves a leadership role for the 4-County CWMA and the Columbia Gorge CWMA.  Sam also serves on the Board for the Pacific Northwest Invasive Plants Council, and on the Advisory Committee for the Oregon Invasive Species Council.

Sam lives in Oregon City with his wife and two sons. He enjoys gardening and spending quality time with his family.


Jeff LeshJeff Lesh

WeedWise Specialist

(503) 210-6010

Jeff Lesh is a WeedWise Specialist employed with WeedWise program since 2011. He works on weed survey and control throughout the county and also provides technical assistance to public and private land managers on invasive plant issues. In addition to his fieldwork, Jeff develops and maintains the WeedWise program’s spatial and non-spatial computer databases and mobile data collection solutions and also performs GIS analysis and cartography services for the program. Jeff is currently the chair of the Mapping & Data Subcommittee at the 4-County Cooperative Weed Management Area.

Jeff received a Bachelor’s of Arts from Lewis & Clark College in 2004 with majors in Computer Science/Mathematics and Religious Studies. He pursued a career in software engineering at a large software development company prior to transitioning to work in ecology. He has been working on invasive plant issues in Clackamas County and the region since 2008 in various capacities, including as an AmeriCorps volunteer, at the North Clackamas Parks & Recreation District, as a volunteer with the Tsunami Crew, with an ecological restoration contractor, and at the WeedWise program. Jeff was a board member of the North Clackamas Urban Watersheds Council from its inception in 2009 until 2012 developing its first website and supporting is early growth as an important voice and actor on conservation issues in its watersheds.

Jeff was raised in the wilds of Southeast Alaska as well as in Kansas City, Kansas. Southeast Alaska had a profound impact on Jeff where his family operates a full service inn, restaurant, and small farm focused on vegetables and cut flowers supplying the inn and restaurant. He also harvested wild food frequently in waters, forests, and wetlands largely absent of invasive species, giving him a keen sense of the degree to which these plants have altered some ecosystems in the Pacific Northwest.

Jeff lives with his family in Portland and enjoys renovating his home, growing too many pepper plants in his garden, and harvesting wild foods and playing in our region’s beautiful forests and waters.


Sarah Hamilton

WeedWise Specialist and CWMA Coordinator

(503) 210-6015

Sarah Hamilton joined the WeedWise program in 2014, and splits her time working on invasive species management in the Sandy River watershed, and coordinating both the 4-County and the Columbia Gorge Cooperative Weed Management Areas.

She came to us after working in the field of ecological restoration, first as a contractor and later a crew leader. Prior to delving into restoration, Sarah spent 4 years conducting demographics surveys of northern spotted owls (Strix occidentalis caurina) in the Oregon Coast Range. She has also conducted forest health and research surveys around the west coast for the Forest Service and Oregon State University, interned at West Multnomah SWCD, and spent a winter on a wildlife refuge in Iowa for AmeriCorps.

Sarah’s interests in ecology began early, when her grandfather introduced her to the idea of invasive species during a family fishing trip in the Umatilla National Forest. She has a Bachelor of Science degree from Oregon State University in Environmental Sciences specializing in Forest Ecology, and an Associate of Applied Sciences degree in horticulture, where she set out to learn more about native and invasive plants, and about human interactions with the environment.

Sarah lives in the Sellwood neighborhood of Portland. Her interests include a small backyard native plant nursery, her new touring bicycle, and exploring the natural beauty of the Pacific Northwest.


Lindsey Karr

WeedWise Specialist


Lindsey Karr is our newest WeedWise Specialist, joining the Weedwise program in late 2016. She works on controlling, surveying, and mapping invasive species; conducting outreach to landowners; and also collaborates with many of our partners to carry out the management plan for the Clackamas River Invasive Species Partnership (CRISP).

Lindsey has worked with a variety of natural resource organizations in the Portland metro area, including a year-long internship with the City of Portland controlling invasive plants; a winter with the Tualatin Hills Park and Recreation District maintaining natural areas; and summers with the US Forest Service as a ranger, the Mount St. Helens Institute as a guide, and the National Council for Air and Stream Improvement as a plant ecologist. She has also conducted plant surveys on Mount St. Helens and Mt. Adams, and in timber harvest areas across Oregon and Washington. Before joining our team, she spent her summer controlling invasive plants at the Ridgefield National Wildlife Refuge, where she worked with volunteers and often got around in kayaks or ATVs.

Lindsey grew up in Washington with a thirst for adventure and exploration that was closely tied to a love for nature. She earned her Bachelor’s in Mathematics from Seattle Pacific University, and then taught high school for 9 years, including one year of teaching English in Kathmandu, Nepal. While still working as a teacher, she began guiding outdoor trips in 2005. Her love for the outdoors, desire to protect natural resources, and fascination with plants lead her to pursue a Master’s in Environmental Management from Portland State University, which she completed in 2014. For her thesis, she studied the spread of non-native plants at Mount St. Helens.

Lindsey lives in Portland and loves growing vegetables, cooking tasty food, taking photos of wildflowers, and exploring forests and mountains.

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