David C. Shaw

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Content by David C. Shaw

Yuletide kissers, smooch without guilt: Research suggests your mistletoe didn’t harm its tree host

If mistletoe’s status as a nutrient-stealing freeloader has been cooling your holiday ardor, new research led by an Oregon State University scientist may help relight the fire.

Steve Lundeberg | Dec 15, 2025 | News story

Emerald ash borer in Oregon: what to do now — and what to plant next

Don’t remove healthy ash preemptively, learn the symptoms and start planning resilient replacements.

Kym Pokorny | Sep 23, 2025 | News story

Monitoring Oregon ash forests in the face of the emerald ash borer: A guide for small woodland owners and managers

The emerald ash borer threatens Oregon ash forests. This guide offers methods for long-term monitoring, helping landowners track changes and assess impacts on their trees and landscape over time.

David C. Shaw, Katie Hill, Karen Ripley, Dan Stark, Wyatt Williams | Feb 2025 | OSU Extension Catalog

OSU study identifies causes of Douglas-fir decline in southwest Oregon

The research findings were disseminated to landowner and professional audiences via presentations and field tours and a daylong workshop, reaching a total of about 700 participants at local, state and national levels.

David C. Shaw, Max Bennett | Jan 2025 | Impact story

What is this fungus and could it indicate internal decay in my Douglas-fir?

P: A large fungus is growing at the base of a large Douglas-fir tree in my backyard. There are several fungi that can cause root rot in Douglas-fir, so I don't want to lose the tree, and I also don't want it to fall ...

R: View answer | View all featured questions

Workshop helps Oregonians care for iconic madrone trees

Extension foresters explain how to recognize disease, manage Arbutus menziesii and choose good sites.

Kym Pokorny | Nov 28, 2023 | News story

Is my maple firewood safe to burn?

P: I’m ready to burn the wood in my woodstove and expected it would still be on the green side. However, its color has changed and seems as though it could be diseased. Is it safe to burn? If not, can it be turned into compost?

R: View answer | View all featured questions

Grow Oregon’s iconic madrone with care and patience

Madrones resist fussing — but thrive when planted wisely.

Kym Pokorny | Oct 19, 2023 | News story

Tree Health Webinar Series: Douglas-fir (in English)

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: 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

Should we treat ash trees for emerald ash borer?

P: I just read about the emerald ash borer (EAB) appearing in Oregon. We have two large very nice ash trees that we don't want to cut down, no signs of infestation at this time. Would you recommend we go ahead and treat these with the pesticide injection that treats for the borer, just in case?

R: View answer | View all featured questions

Multiple stressors drive Douglas-fir decline in the Klamath Mountains

OSU study finds Douglas-fir in Klamath Mountains in decline; risk tool helps landowners.

Steve Lundeberg | Mar 21, 2023 | News story

Alternatives to Ash in Western Oregon: With a Critical Tree Under Threat, These Options Can Help Fill Habitat Niche

Oregon ash thrives in many areas of western Oregon, from floodplains to foothills. But this key tree is threatened by the spread of an invasive beetle known as the emerald ash borer, which kills ash. This ...

George Kral, David C. Shaw | Mar 2023 | OSU Extension Catalog

True fir and Douglas-fir mortality in Oregon

Lack of fire has profoundly changed forest structure across the region, significantly increasing true fir occurrence and density. The recent drought and bark beetles have led to a large mortality event.

David C. Shaw | Jan 2023 | OSU Extension Catalog

Oregon ash: Insects, pathogens and tree health

Oregon ash grows along the streams and wetlands of western Oregon and Northern California, where it provides important wildlife habitat. But these trees are threatened by the emerald ash borer, an insect pest that...

David C. Shaw, Jay W. Pscheidt, Alexander Gorman | Jan 2023 | OSU Extension Catalog

Episode 24: Swiss Needle Cast (in English)

In this episode, Jacob Putney invites Dave Shaw and Gabriela Ritokova on the podcast to discuss Swiss Needle Cast's impact on Douglas fir populations. Dave Shaw is an OSU extension forest health specialist and Gabriela Ritokova is an ODF forest pathologist.

Jacob Putney, David C. Shaw, Gabriela Ritokova | Aug 2022 | Podcast episode

How should our community respond to emerald ash borer?

P: I am chair of our city tree commission, and have a couple of questions about emerald ash borer (EAB). We have many planted ash trees in city parks and on rights-of-way, although the tree is now on the list of prohibited...

R: View answer | View all featured questions

Are traps available to monitor and check for emerald ash borers?

P: Can I use traps to capture and minimize the damage done by emerald ash borers if my ash trees become infected?

R: View answer | View all featured questions

Recognizing ash trees in Oregon, Washington and Northern California

How to identify our native and common landscaping ash trees, including look-alikes. All ash trees are susceptible to emerald ash borer, an invasive pest first sighted in Oregon in June 2022.

David C. Shaw | Jul 2022 | Educational gallery

What do I do if I suspect an emerald ash borer infestation?

P: We have at least one ash tree that is showing top dieback. What should we do to try to confirm whether or not we have the beetle?

R: View answer | View all featured questions

Silvicultural Decision Guide for Swiss Needle Cast in Coastal Oregon and Washington

Swiss needle cast is a significant disease for Douglas-fir trees in the coastal Pacific Northwest. The disease turns foliage yellow, reduces needle retention, thins crowns and reduces tree growth. Options for forest ...

Gabriela Ritóková, David C. Shaw, Doug Mainwaring | May 2022 | OSU Extension Catalog

Episode 4: Forest Health (in English)

In this episode, Jacob Putney is joined by Oregon State University Extension Forest Health Specialist, Dave Shaw. They discuss a wide variety of forest health topics such as drought, insects, and disease, and the influences these agents have on individual tree and forest growth.

Jacob Putney, David C. Shaw | Mar 2022 | Podcast episode

Preventing Phytophthora infestations in restoration nurseries

Phytophthora species are water molds that can kill plants. They can spread undetected in container plants and equipment. Once they are introduced to an ecosystem, it's difficult or impossible to eradicate them. ...

Norma Kline, Marianne Elliott, Jennifer Parke, Dan Stark, David C. Shaw, Alicia Christiansen | Jan 2022 | OSU Extension Catalog

The madrones look troubled, how can I help?

P: Do madrones have a short life cycle? Is something killing them? What can I do to help them thrive?

R: View answer | View all featured questions

Sudden Oak Death: Prevention, Recognition, Restoration

A guide for homeowners, small woodland owners, resource managers, and conservation groups to recognize, prevent, and manage Sudden Oak Death. This publication can be downloaded in two different formats. The "PDF" ...

Norma Kline, Sarah Navarro, David C. Shaw | Mar 2023 | OSU Extension Catalog

Managing Insects and Diseases of Oregon Conifers

Discusses options for managing major insect pests and diseases of conifers in Oregon forests: bark beetles, wood borers, and ambrosia beetles; defoliators; aphids, adelgids, and scale insects; terminal and branch ...

Paul T. Oester, David C. Shaw, Gregory M. Filip | Jun 2023 | OSU Extension Catalog

The hidden threat In firewood: Invasive forest pests

Invasive forest pests are being transported throughout the continent in untreated firewood. Learn about the threat of introducing or dispersing invasive forest pests.

David C. Shaw, Amy Grotta, Wyatt Williams, Raini Rippy, Steve Bowers | Jul 2025 | OSU Extension Catalog

Common Insect Pests and Diseases of Sitka Spruce on the Oregon Coast

Sitka spruce is among the world's fast-growing trees and the largest of the world's spruces. It's a valuable commercial timber. Its range extends from Alaska to northern California, but it faces unique problems ...

Jim Reeb, David C. Shaw | Mar 2023 | OSU Extension Catalog

Common Insect Pests and Diseases of Shore Pine on the Oregon Coast

Shore pine is a subspecies of lodgepole pine that inhabits the coastal strip in Oregon. Insect pests, diseases, and nonbiological (abiotic) factors may have an impact on growth, visual appearance, and productivity ...

James E. Reeb, David C. Shaw | Mar 2023 | OSU Extension Catalog

Forest Health Fact Sheet: Diseases and Insect Pests of Pacific Madrone

Discusses three major types of madrone diseases--foliage, branch dieback and trunk canker, and root--and ways to minimize and manage. Discusses insect pests of madrone: fall webworm, western tent caterpillar, aphids, and leaf miners. Color photos. Sources of further information.

Max Bennett, David C. Shaw | Mar 2023 | OSU Extension Catalog

Forest Health Fact Sheet: Sudden Oak Death (Phytophthora ramorum)

Gives basic facts about a serious plant disease called Sudden Oak Death, caused by the pathogen Phytophthora ramorum. Describes risk of disease to forest health and to commercial nursery industry. Shows disease ...

David C. Shaw | Mar 2023 | OSU Extension Catalog