Dan Stark, Forestry & Natural Resources Extension for Clackamas, Tillamook and Lincoln Counties.

Amid ongoing and expanding interest in redwoods among landowners in western Oregon, OSU Forestry & Natural Resources (FNR) Extension convened Growing Redwoods in Oregon Science Meeting in October 2021.  Over 70 participants met virtually over two half-days, to discuss the potential of redwoods in Oregon.  Participants included researchers, public land managers, private landowners, geneticists, nursery specialists and other practitioners from Oregon and beyond.

Photo by Norma Kline

Information gathered at this meeting will be used to help FNR Extension develop a resources guide  for Western Oregon woodland owners and forestland managers that are interested in growing coast redwood and/or giant sequoia.

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Are you seeing foliage scorch or other damage (as described in earlier post) and want to help increase our understanding of the impacts of our recent heat wave?  If so, you can report those effects to help foresters and researchers studying the longer-term impacts of this event. 

A group of scientists and forest managers at OSU and the USFS is asking people who observed these effects to report their observations by responding to this survey (link is also below). You will be using a website created by the Oregon Department of Forestry to survey drought impacts on forests.

Since this webpage was originally set up to report drought impacts on trees, you need to clarify that you are reporting about the recent heat wave. 

You will be asked to upload a photo of the injury.  Below that you are asked to provide a description or caption for the image.  In that description please note there  that you are reporting ‘impacts of the June 2021 heat wave and also include the phrase foliage scorch so they can retrieve these observations later for mapping and analysis of this extreme event. For example:

Impacts of June 2021 heat wave. Foliage scorch. Douglas-fir at day use area, Cascadia OR.
Impacts of June 2021 heat wave. Foliage scorch. Western redcedar at day use area, Cascadia OR.

Link to survey: https://tinyurl.com/heat-wave-foliage-scorch

Thank you for your help! If you have any questions, please contact Chris Still at chris.still@oregonstate.edu or (541) 737-4086. You will be using a website

Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension agent for Benton, Linn and Polk Counties. 

Mature Douglas-fir showing foliage scorch alng Hwy 20, East of Cascadia. Photo B Withrow-Robinson

People driving in and out of the valley have been alarmed by the damage to trees caused by the recent heat wave and wondering what it means.  They are not alone.

I have been asking around to try to get a clearer sense of the severity and extent of the effects of the heat wave around western Oregon.  What I have heard from within forestry and Extension circles is that the effects seem wide spread, but variable around the Coast Range and Cascades.  Hotspots I’ve heard about include areas along Hwy 20 near Toledo, and also above Sweet Home.  Hwy 58 around Lowell and Oak Ridge looks rough.  Damage seems less evident in the Valley.

A common symptom seen is foliage scorch/sunscald of new growth, sometimes first or second year needles too, generally on southwest exposures, and the southwest side of the tree.  This can be quite dramatic along roads and other exposed areas, with scorched needles visible from base to crown, particularly in Douglas-fir and grand fir, whose needles turn bright red.   Western redcedar and western hemlock are also affected, although the symptoms may be less dramatic, since the color change is more muted. 

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Christin Buhl, Oregon Department of Forestry Entomologist

Western redcedar bark and fronds

From Oregon through western Canada, western redcedar (Thuja plicata, WRC) has been dying in areas where it should be thriving, such as along streams and within closed canopies. The cause for this sometimes sudden and expanding dieback is currently unknown. Insects and diseases of WRC are typically secondary, meaning that they are not direct tree killers but are opportunistic pests and can only attack dead and dying trees. Redcedar can even tolerate endemic levels of bark beetles and stem decay for many years. These known pests have not always been found in dieback pockets nor have novel pests been observed.

The predominant theory for sudden mortality is that trees may be impacted by a changing climate, including increasing average temperatures and drought stress in the form of reduced and inconsistent precipitation. Even shaded sites along streams are at risk due to higher than usual average temperatures and reduced stream flow. Western redcedar is a species more sensitive to slight changes in abiotic conditions and may be crossing the lower limits of where they can thrive in some areas.

Looking for the cause

A team including Oregon Department of Forestry (ODF), Washington Department of Natural Resources (WADNR), the U.S. Forest Service (USFS), various university researchers and natural resource agencies are collaborating to collect locations to determine the distribution and possible cause(s) of dieback. We are mapping locations of dieback and monitoring some of these sites over the long-term.

We are now asking for your help in identifying sites of where dieback and tree decline is occurring. We are looking for pockets of dieback containing at least two mature trees with any of the following symptoms:

Do not report sites where the cause of dieback is known (e.g., mechanical damage, single sun-exposed trees, decadent old growth candelabra crowns or symptomatic trees in known root disease pockets) or trees with normal, seasonal dieback of older needles rather than whole-branch mortality.

Lastly, western redcedar may be confused with the other two species that we call “cedar”: incense cedar and Port Orford cedar (none are true cedar, which do not occur naturally in the PNW).The easiest way to identify western redcedar is by looking at the cones.

Western redcedar produces cones that look like woody roses, incense cedar has larger cones that split open like duck bills, and Port Orford cedar has cones that resemble soccer balls. Assist us in this effort to understand what is happening with this majestic staple of Pacific Northwest forests and urban areas.

Are you seeing these symptoms on western redcedar in your area? We need your help locating and reporting dying and symptomatic WRC across the species distribution!

Please submit GPS locations of western redcedar dieback: Christine Buhl, ODF Entomologist in Oregon (christine.j.buhl@oregon.gov)

By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington and Yamhill Counties

Insects – they can get a bad rap.  Many of our humankind categorically view them as pests – agents of uncleanliness, nuisance, or destruction. Sure, it’s hard to appreciate houseflies, ticks, mosquitos and yellow jackets, but the vast majority of them – nearly 100,000 known insect species in the U.S. alone –are simply going about their business and doing no harm to us. Many are even providing services that we take for granted such as disposing of detritus and cycling nutrients.

Larval galleries of wood boring insects in a dead ponderosa pine tree

The same goes for insects in the forest. We in Extension receive many photos and samples brought to us from people who suspect that insects are killing their trees. However, I’m here to tell you that if you have a dead or dying tree, then chances are that even though it is full of insects and their tunnels, it’s usually a case of correlation, not causation. Continue reading

By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington & Yamhill Counties

I’ve been taking part in an OSU Extension program called Oregon Season Tracker (OST) for about five years.  OST is a citizen science program where volunteers keep track of rainfall and plant phenology (seasonal growth patterns) and submit their records to national databases.  OST also connects natural resources managers, landowners, educators, and others in the community with researchers and their science.  At our office in St. Helens, we have an approved rain gauge which we try to check each morning, and a phenology “garden” consisting of two large Douglas-fir trees and some native shrubs.

When I first got involved in OST, my motivation was practical. I thought that having some consistent record of weather and phenology patterns would ultimately be useful in my work in Forestry & Natural Resources Extension.  I wasn’t quite sure exactly how it would be useful. But I figured that since weather affects trees in many ways, something would come of it; and even if not, I would be helping scientists with THEIR research questions. Continue reading

Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent for Benton, Linn and Polk Counties

In my previous post, I summarized what I think we know about this ecological whodunit. In this post, I look at what it might mean for landowners in the area.

Now What?

Pouch fungus commonly appear one year after trees are attached by beetles like flatheaded fir borer or fir engraver. Phot by Dave Shaw, OSU Forestry & Natural Resources Extension

We seem poised for another stressful summer. May 2018 has turned out to be one of the driest on record, and we are unlikely to catch up in June. Long term forecasts are for another warm dry summer. We will just have to wait and see how it unfolds. But whatever happens this summer, I think we can expect to continue to see more sick, dying and dead trees. There are several reasons for this.

First, many trees are already stressed or injured by the past hot drought events and are in a vulnerable condition. While not yet lost, this stress makes them less resistant and more susceptible to the insects and diseases that are lurking about. A mild summer, or several mild summers would help. But even then they will not recover immediately. Their earlier stress and injuries also hamper their ability to recover and rebuild their resistance, even under good conditions.

An analogy might be of me falling off a ladder. The injuries I suffered when I hit the ground continued to affect my health and recovery long after I stopped falling (it is harder to exercise with a broken leg). It will take a while to recover, even if I stay out of trouble. It will take longer (or could kill me) if I keep falling off the ladder. For the trees, each of these summers is like another fall from my ladder.

Second, some trees are already lost. It may not be obvious, and they may still have needles, but they have been mortally wounded or have already been attacked by insects and will not recover, however our summer turns out. It is just a matter of time before those losses become apparent. Continue reading

Drought-damaged trees have become a common site in the Willamette

Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent for Benton, Linn and Polk Counties


Many of our readers have been tracking this issue over the last several years through the articles on this site. But I imagine many of you are wondering what to expect next, or are being asked by friends and neighbors who are concerned about your trees or theirs. Or just wondering what is going on. What to say?

So, here is a synopsis of what I generally see going on, and the consequences. A bit risky to do, given the role of individual sites and specific conditions. But this is such a widespread phenomenon, it warrants some interpretation, even at the risk of over-generalizing. But I provide the antidote at the end: links to more detailed information.


It is hard to miss all the dead and dying trees in the area. I have been getting dozens of calls about them. So what is going on, and what is to blame? It seems time to revisit this sylvan whodunit: What is killing all these Willamette Valley trees?

Who is involved? Douglas-fir is by far the most frequent casualty, along with other conifers such as grand fir and some ponderosa pine. But trees of many sorts are being affected –

Drought symptoms may include dead branches, dead tops and low vigor. Or all of the above. Photo by Dave Shaw, OSU Forestry & Natural Resources Extension.

hardwoods as well as conifers, both native and non-native. Many of the usual suspects – different beetles and fungi- can be found at the scene too.

What is happening? Symptoms often include dying branches and dead tops, low growth and vigor, sparse crowns, what we have called the “Willamette Valley crud”. It is now often progressing to the death of the tree. This may be happening to individual trees or groups of trees. The younger trees are usually the first involved at a site, eventually joined by older trees.

Where is it happening? This is certainly a Valley-wide phenomenon. But within the Valley, we are seeing the most significant damage in certain situations more than others. Sites with seasonally wet, poorly drained soils, or sites with rocky or shallow soils, exposed south facing aspects tend to be most hard-hit. These are places that we think of as marginal sites for most conifer trees. Our conifers are well adapted to the area, but not every site. Continue reading

By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington, & Yamhill Counties

Last week I attended Forest Health: State of the State, a biannual conference put on by OSU College of Forestry. A packed agenda covered insects, diseases, fire, drought, invasive species, climate change, and other topics. I always look forward to this meeting as an opportunity to brush up on my knowledge of these issues. The speakers came from various backgrounds, representing the many forest ecosystems and ownership types we have across the state, and the audience was equally diverse. With that in mind, I’ve tried to distill the takeaways from the conference that seem most relevant to small woodland ownerships in northwest Oregon.

ODF conducts an annual insect and disease aerial survey. Click on the image to be taken to a short video from the air.

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Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension agent, Benton, Linn and Polk Counties.

We have been dedicating a fair amount of screen space and class time lately to the idea that many family forest landowners would benefit from thinning their young stands. We explored the reasons to consider young stand thinning (YST) as well as some approaches in a series of posts on YST .  YST is consistent with the situation and goals of many family forest landowners, which often include growing older and more diverse forests.

That said, like many other well-grounded activities, YST is not without some potential drawbacks.

Few of them are significant enough to justify not thinning at all, but each requires some thought and consideration to avoid unintended consequences. We present some of those potential drawbacks that you need to consider when planning a YST, along with some links to other information, below. Continue reading