Glenn Ahrens

he/him/his

Forestry

503-655-8631
[email protected]

Expertise: Cutting and selling trees , Forest health and management , Riparian areas , Water management and conservation

Programs: Oregon Season Tracker

Locations: Clackamas County , Hood River County , Marion County

Links: Clackamas Extension Forestry

Biography

Glenn Ahrens is Extension Forester, Oregon State University Extension Service, Clackamas, Marion, and Hood River Counties, and Director, OSU Hardwood Silviculture Cooperative. His general mission for OSU Extension is to improve our knowledge of forest resources and options for sustaining and expanding benefits from forests. Glenn has a B.S. in Forestry from Humboldt State University (1982) and an M.S. in Forest Science from Oregon State University (1990). He has over 30 years of experience in research, Extension, and private consulting. Glenn’s areas of specialty include forest ecology, silviculture, vegetation management, and hardwood management.

Content by Glenn Ahrens

Episode 46: Storm Damage

In this episode, Lauren Grand is joined by Glenn Ahrens and Scott Altenhoff to discuss the impact of storms on Oregon's forests and preventative measures that can be taken to mitigate tree damage caused by storms.

Lauren Grand, Glenn Ahrens, Scott Altenhoff | Mar 2024 | Podcast episode

The intriguing life of coho salmon and a conservation opportunity for landowners

What makes salmon unique? Oregon is home to many wonders, including one that swims upstream. Coho salmon are one of seven salmon species native to the Pacific Ocean, all of which share an incredibly unique lifecycle. Salmon ...

Sarah Cameron, David Bugni, Glenn Ahrens | Dec 2023 | Article

Tree Health Webinar Series: True Firs

As part of the Tree Health Webinar Series, Laura Lowrey discusses the forest health outlook for true fir trees, future projections in Oregon, and actions that landowners and managers can take for their trees.

Glenn Ahrens, Laura Lowrey | Aug 2023 | Video

Tree Health Webinar Series: Why Are My Trees Dying?

As more trees die each year, these 30-minute webinars address current health issues impacting some of our common species, what it means for the trees, and what you can do.

Glenn Ahrens, Sarah Cameron, David C. Shaw, Christine Buhl, Laura Lowrey | Aug 2023 | Collection

Tree Health Webinar Series: Douglas-fir

As part of the Tree Health Webinar Series, Dave Shaw discusses the forest health outlook for Douglas-fir, future projections in Oregon, and actions that landowners and managers can take for their trees.

Glenn Ahrens, David C. Shaw | Aug 2023 | Video

Tree Health Webinar Series: Alder and Broadleaf Trees

As part of the Tree Health Webinar Series, Glenn Ahrens discusses the forest health outlook for alder and broadleaf trees, future projections in Oregon, and actions that landowners and managers can take for their trees.

Glenn Ahrens | Aug 2023 | Video

Tree Health Webinar Series: Western Redcedar

As part of the Tree Health Webinar Series, Christine Buhl discusses the forest health outlook for western redcedar, future projections in Oregon, and actions that landowners and managers can take for their trees.

Glenn Ahrens, Christine Buhl | Aug 2023 | Video

Treatments for bronze birch borer?

Q: I had an arborist out because one of my birch trees had died and needed removal. He said it was the bronze birch beetle and that it was beginning to affect a second birch. He said it could be treated with a ...

A: View answer | View all featured questions

Episode 32: Tree School

In this episode, Scott Leavengood visits the 33rd annual Clackamas Tree School to interview Sarah Cameron and Glenn Ahrens about what the event is and why it's so beneficial.

Scott Leavengood, Sarah Cameron, Glenn Ahrens | Apr 2023 | Podcast episode

Healthy streams: a family’s journey toward fish habitat restoration

This class will cover how a small woodland family northeast of Estacada embarked on a ten-year effort (ongoing) to restore their creek to improve fish habitat and allow for fish passage. Topics covered include planning, ...

David Bugni, Glenn Ahrens, Dan Stark | Apr 2022 | Video

Episode 13: Woodland Management

In this episode, Jacob Putney discusses the importance of managing forests with Glenn Ahrens. Ahrens is an assistant professor for Oregon State University's College of Forestry and extension agent for Clackamas, Marion, and Hood River Counties.

Jacob Putney, Glenn Ahrens | Mar 2022 | Podcast episode

Using nature as a model for forest management

Most small woodland owners want to manage their forests for a wide range of benefits, including wildlife habitat, aesthetics, long-term income and carbon sequestration. This class will introduce you to basic principles of forest ...

Kirk Hanson, Glenn Ahrens | Mar 2022 | Video

Prescribed fire in Oregon

Prescribed fire is an age-old tool first used by indigenous peoples, for a variety of reasons from fuels management to favoring desired plant species. The use of prescribed fire has been limited in Oregon and there have been...

Amanda Rau, Glenn Ahrens | Feb 2022 | Video

Online Tree School Reaches Statewide and Beyond

A major goal for OSU Extension’s Forestry and Natural Resources program is to help forest owners learn about and manage their forests. Started in Clackamas County, Online Tree School now reaches statewide and beyond. Topics ...

Glenn Ahrens | Jan 2022 | Video

June 2021 heat impacts on trees explained

The June 2021 heat wave caused significant damage to trees in Oregon. Learn some key findings on causes, types of damage, physiological "thermotolerance" of trees, and possible forest management implications.

Glenn Ahrens | Jan 2022 | Article

Overcoming Reforestation Challenges

This class will provide an update on current reforestation challenges and a discussion of ways to overcome them. Shortages of seedlings and services are making it hard to get trees in the ground, particularly with the increase...

Glenn Ahrens | Oct 2021 | Video

Reforestation considerations after wildfire (Recorded)

This webinar covered key considerations in reforestation following wildfire including legal requirements, planting vs. natural regeneration, site preparation, selecting and finding seedlings, tree planting, and post-planting care. Originally ...

Glenn Ahrens, Max Bennett | Oct 2021 | Video

Wildfires, climate create challenges for establishing new trees

In the aftermath of disastrous wildfire seasons, it is harder than ever to find seedlings and workers for reforestation efforts. But there's help out there. Here's a look at what's available for reforestation efforts.

Glenn Ahrens | Oct 2021 | Article Peer reviewed (Gray level)

Wildfire preparedness in Hood River County

In this video, you will learn from representatives of OSU Extension Forestry & Natural Resources, Hood River County Emergency Management, Oregon Department of Forestry, and Mosier Fire. This webinar provides local information about...

Glenn Ahrens | Sep 2021 | Video

Fire Preparedness in Marion County

In this video, you will hear from representatives from OSU Extension Forestry & Natural Resources, Marion Soil & Water Conservation District, City of Salem Fire, Marion County Emergency Management, and more to learn about ...

Amanda Brenner, Glenn Ahrens | Jul 2021 | Video

Western Oregon forest health update, July 2021

Aside from wildfire, bark beetles and other insects are the most common cause of dying trees across Oregon. Landowners and others in charge of tree care should take special precautions to prevent bark beetle outbreaks.

Glenn Ahrens | Jun 2021 | Article

Treatment options for young forest stands damaged by fire or ice

Fires and ice storms in recent years have done serious damage to young forest stands in the Willamette Valley. Without much salvageable timber, landowners must decide how to restore the stands. Here are some options.

Glenn Ahrens | Jun 2021 | Article

Why some trees can stand up to ice storms

The ice storm in 2021 in Clackamas and Marion counties provided lots of lessons about the kinds of trees that are vulnerable to weather damage. It also showed that well-spaced trees are stronger in the face of adversity.

Glenn Ahrens | Apr 2021 | Article

Ongoing recovery from wildfire and ice damage

Oregon State Extension Service and other agencies are working together to help landowners recover from wildfires. The effort includes assessing reforestation needs, acquiring seedlings and facilitating restoration.

Glenn Ahrens | Mar 2021 | Article

Reforestation assistance for landowners who need to replant after wildfire

Due to recent wildfire losses, the demand for tree seedlings and tree planters is expected to far exceed supply for years to come. OSU Extension is working to assess the need and provide help for replanting efforts.

Glenn Ahrens | Dec 2020 | Article

Managing Your Forest with Fire in Mind

The fires of September 2020 were a brutal reminder that western Oregon is a fire-driven landscape, like southern Oregon and the East Side. Part of the new reality is a greater awareness that we need to manage forests and ...

Brad Withrow-Robinson, Glenn Ahrens, Amanda Rau | Dec 2020 | Video

Is my cedar dying?

Q: My beautiful cedars are now showing some dying branches. I’d like to send a photo to confirm if it has that fungus or beetle that’s killing lots of trees. And whether I need to cut them down before it gets dangerous to do so.

A: View answer | View all featured questions

Post-fire revegetation overview

Basic options for post-fire reforestation.

Glenn Ahrens, Max Bennett | Nov 2020 | Fact Sheet

Assessing post-fire survivability of trees

Extensive research on the fate of fire damaged trees provides guidance for assessing survival based on post-fire observations of crown scorch, bark char, and root damage.

Glenn Ahrens | Nov 2020 | Fact Sheet

Assessing post-fire survivability of trees and potential for salvage harvesting (Recorded)

This webinar will cover a visual method for assessing survival of trees that have been injured by wildfire. We will also discuss specifically how salvage operations are conducted, equipment used, wildlife considerations, economics, ...

Glenn Ahrens, Stephen Fitzgerald | Oct 2020 | Video

Wildfires leave behind lessons for how to prepare for the next one

Amid all the work involved in recovering from wildfires, there are lessons to be learned about how to reduce the severity of future fires. Here's a look at what a recent fire teaches us about prevention and mitigation.

Glenn Ahrens | Oct 2020 | Article

Managing to Keep Your Forest Healthy

Is something wrong with your trees? How do you keep your forest healthy? How might climate change affect your trees? When something goes wrong people tend to look for specific causal agents such as bark beetles or root ...

Glenn Ahrens | Apr 2020 | Video

Strategies for maintaining healthy forests in western Oregon

While relatively healthy, forests in western Oregon face threats from climate stress, insects and disease. Here's a look at forest management strategies to cope with those threats and keep the state's forests healthy.

Glenn Ahrens | Apr 2020 | Article

Selecting and Buying Quality Tree Seedlings

Selecting trees adapted for long-term growth under your local conditions and how to choose nursery stock that has a high probability of surviving and showing good initial growth. Focuses on trees suitable for long-term timber production in Oregon.

Amy Grotta, Glenn Ahrens, Max Bennett | Jun 2019 | Extension Catalog publication Peer reviewed (Orange level)

Thinning and selective management of maturing Douglas-fir forests (part 1)

While it can be challenging to find the balance, there is much that we can do to meet our objectives for wildlife while controlling weeds and reducing fuels. Recent research at OSU can help us make informed decisions about some of the tradeoffs.

Glenn Ahrens | May 2019 | Article

Identifying and Managing Mountain Beaver Damage to Forest Resources

The mountain beaver is a medium-sized rodent of the western Pacific Northwest. Mountain beavers cause damage to forest regeneration by clipping or girdling seedlings or saplings or both, and undermining roots. Methods...

Jimmy Taylor, Donivan Sphar, Glenn Ahrens | Jul 2013 | Extension Catalog publication Peer reviewed (Orange level)

A Guide to Riparian Tree and Shrub Planting in the Willamette Valley: Steps to Success

A step-by-step guide to riparian tree and shrub planting in the Willamette Valley. Provides information on project planning, plant materials, site preparation, planting techniques, site maintenance, and monitoring and ...

Brad Withrow-Robinson, Max Bennett, Glenn Ahrens | Oct 2011 | Extension Catalog publication Peer reviewed (Orange level)

Tree School Online helps woodland owners during COVID-19

Tree School events were provided online in a series of 35 webinars hosted by OSU Extension in Clackamas County in collaboration with the Oregon Forest Resources Institute and the Oregon Partnership for Forestry Education.

Glenn Ahrens | Mar 2021 | Impact story

Extension helps deliver critical reforesting information and seedlings to woodland owners affected by 2020 wildfires

Landowners needed help learning about reforestation and getting the resources they needed, and there was a critical need for tree seedlings to replace the trees lost to the fires, especially for private landowners who have less access to large-scale nurseries.

Alicia Christiansen, Kara Baylog, Glenn Ahrens | Mar 2023 | Impact story

OSU Extension helps Oregon’s woodland owners manage their land

More than 600 volunteers have been trained through the Master Woodland Manager program.

Alicia Christiansen, Glenn Ahrens | May 2023 | Impact story

After COVID-19 cuts down in-person Tree School, event re-grows online

The first Tree School Online session debuted with 300 registered participants. Since then, the live classes have rolled out with anywhere from 50 to 100 participants.

Jim Sloan | Jun 30, 2020 | News story

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