Glenn Ahrens

Photo: Peter Matzka (Cropped from original)
he/him/his

Forestry

503-655-8631
[email protected]

Expertise: Cutting and Selling Trees , Forest Health and Management , Riparian Areas , Water Management and Conservation

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

June 2021 heat impacts on trees explained

The June 2021 heat wave (the heat dome) caused significant damage to trees in Oregon. A mini-symposium on heat dome impacts on trees was organized by Chris Still and other scientists at Oregon State University. This article ...

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

Challenges for establishing new trees

If you are planning to plant trees for reforestation, restoration, Christmas trees or other purposes, you probably already know that this is a very challenging time for establishing new trees. Acquiring tree seedlings and getting ...

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

Dying or declining trees stand out in contrast to the lush green of a new growing season in the forest. Forest Health Highlights based on the statewide aerial survey, provides a good annual update on major tree problems and...

Glenn Ahrens | Jun 2021 | Article

Treatment options for young forest stands damaged by fire or ice

Learn and share with others options for managing the high volume of debris when damaged young forest stands do not have much salvageable (merchantable) material.

Glenn Ahrens | Jun 2021 | Article

Lessons learned from the ice storm

The ice damage across Clackamas and Marion Counties provides plenty of object lessons illustrating what kinds of trees are vulnerable to weather damage vs. those that emerge more intact. It also reinforces some basic forest stand...

Glenn Ahrens | Apr 2021 | Article

Ongoing recovery from wildfire and ice damage

As noted previously, OSU Extension is working with Oregon Small Woodlands Association, Oregon Department of Forestry, US Forest Service and other partners to assess the reforestation need, develop extra capacity to produce tree ...

Glenn Ahrens | Mar 2021 | Article

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

OSU Extension Christmas Tree Specialist Chal Landgren Retires After 42 Years of Service

Prior to his work as Christmas Tree Specialist, Chal Landgren had a 30-year career as a forester, best known for his work as Extension Forester for Columbia and Washington Counties. But Christmas Trees have long been an ...

Glenn Ahrens | Dec 2020 | Article

Continuing Recovery After Wildfire

In the aftermath of the Labor Day Fires of 2020, OSU Extension and our partners are continuing to assess the damage and help landowners move forward with recovery efforts. A key part of this is mapping the area that ...

Glenn Ahrens | Dec 2020 | Article

Reforestation Assistance for Landowners Who Need to Replant After Wildfire

Because of the huge wildfire losses, the availability of tree seedlings and tree planters is expected to be far short of what is needed over the next few years. OSU Extension is working with Oregon Small Woodlands ...

Glenn Ahrens | Dec 2020 | Article

Clackamas Woodland Farmer of the Year 2020

There is something fishy about the Clackamas Woodland Farmer of the Year 2020. Literally, the return of coho salmon to spawn in Suter Creek is a major highlight of their story. Trees of all sizes do feature prominently in ...

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

Can you help assess my trees after the fire?

Q: I have 20 acres on the edge of the Beachie Creek fire. I lost my barn and quite a few trees. I just need help in assessing which I should save and those that I should have harvested...if at all possible. Can you point me in the right direction? Several areas were involved.

A: View answer | View all featured questions

After the Fire

Now that the smoke has cleared after the wildfires, the full extent of the damage is becoming apparent. Estimates are that over 400,000 acres burned just in Clackamas and Marion Counties, including almost 100,000 acres of ...

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

30 Years of Learning New Ways to Grow: Tree School 2020

Clackamas Tree School, set for March 21, 2020, would have marked our 30th anniversary. Since 1991, the Clackamas County Extension office has been organizing this forestry education event for anyone interested in learning about ...

Amanda Brenner, Glenn Ahrens | Apr 2020 | Article

Managing for Healthy Forests in the Future

The recent biennial conference on Forest Health in Oregon State of the State 2020 (February 26-27, OSU Corvallis) provided an important update on forest health issues. Overall, forests are still relatively healthy in western ...

Glenn Ahrens | Apr 2020 | Article

Tree Seedling Availability

Are you planning to plant trees? Here's an update for 2021. Availability of tree seedlings for reforestation and Christmas tree plantings are often limited. The information below is from the 2020 newsletter article (so supplies ...

Glenn Ahrens, Amanda Brenner | Jan 2020 | Article

Clackamas woodland farmer of the year 2019

Buser family Lazy B Timber Farm recognized as Clackamas Woodland Farmer of the year 2019

Glenn Ahrens | Jan 2020 | Article

New Oregon State Wildland Fire Extension program

This new program will add capacity for up to six new OSU Extension Wildfire Specialists to work with agency and industry partners, communities, landowners, and land managers. The work to be done is too big for any one ...

Glenn Ahrens | Aug 2019 | 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 | OSU Extension Catalog 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

Tree School Clackamas teaches love for the land

Educational event draws hundreds from woodland community in Clackamas County and beyond.

Glenn Ahrens, Rose Clarke, Michael Bondi, Kimberly Jacobsen Nelson | Apr 2019 | Article

Are there insect issues with birch trees?

Q: Is it true that white paper birch in the Willamette Valley have been infested with insect like beetle? I wanted to plant one this spring and my yard maintenance service told me I should consider a different type due to the insect problem.

A: View answer | View all featured questions

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 to control ...

Glenn Ahrens | Jul 2013 | OSU Extension Catalog 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 evaluation. Intended...

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

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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