Ponderosa Pines Killed by Western Pine Beetle on the Rise

ponderosa pine killed by western pine beetle
PHOTO 1: Stand of ponderosa pine killed by western pine beetle. Photo: James Everitt, Bugwood.org

The western pine beetle (WPB) is a native bark beetle found in eastern Washington that can kill ponderosa pine, its only host in the state. In typical years, they hang around in low populations attacking weakened, diseased or older ponderosa pines. They are frequently found in trees weakened by root diseases, such as armillaria. When trees experience severe drought stress, as they did in 2015, WPB can more easily overcome the resin flow defenses of water-stressed trees.

High numbers of stressed trees produce more beetle offspring and can lead to large outbreak populations. Aerial surveys in Washington recorded 12,900 acres with WPB-caused mortality in 2016, more than double the amount in 2015, and the highest level since 2008. Typically, there is a year-long delay between beetle attack and visible crown symptoms. Drought damage can also have lasting effects on tree vigor and WPB populations may continue to build, so mortality is likely to increase. The most recent large outbreak in Washington was 2003-2004, with over 120,000 acres affected each year.

The pattern left on the landscape is patchy groups of orange or red ponderosa pines (Photo 1). This “group kill” is a result of pheromones used by the beetles to coordinate mass-attacks and concentrate beetles from the surrounding area.

bluestain fungi
Western pine beetles can introduce bluestain fungi that grow into the sapwood, eventually causing tree death. Photo: US Forest Service.

Female WPB that make it past bark and resin, lay eggs in the sugary phloem layer of the inner bark in the main bole of the tree. Hundreds of their larval offspring mine in the phloem, disrupting the vital flow of sugars and girdle the tree. WPB also introduces bluestain fungi that grow into the sapwood and interrupt flow of water in the xylem layer, hastening tree death. In addition to copious resin flow that might fend off bark beetle attacks, healthy trees are induced by attacks to actively produce high levels of terpenes which can be toxic to bark beetle larvae. This response is reduced in weakened or stressed trees, resulting in higher beetle reproductive success and a larger “brood.” To make matters worse for the trees, WPB can produce up to two overlapping generations per year in Washington.

There are three other species of bark beetles that may aggressively attack and damage ponderosa pine. Mountain pine beetle occupy the same niche as WPB in the main bole, but mountain pine beetle outbreaks in ponderosa pine are more likely to occur in higher elevation areas near lodgepole pine, its preferred host. The red turpentine beetle prefers to attack the lower eight feet of the main bole and ips pine engravers can attack smaller diameter tops and branches. It is possible to find all three species in the same tree. These double- or triple-whammies will certainly decrease chances of tree survival.

Western pine beetle egg galleries
PHOTO 2: Western pine beetle egg galleries. Photo: William M. Ciesla, Bugwood.org

Successful WPB attacks are easy to identify and differentiate from the other bark beetle species. Since WPB is the only one that pupates in the outer bark, their larvae, pupae, and newly developed adults are easily accessible for predators, such as woodpeckers. Look for patches of bright orange bark where woodpeckers have flaked off the darker outer bark, a tell-tale sign of WPB activity. Popcorn-sized pitch tubes may be visible on the bark surface, but these are less common than with mountain pine beetle. The surest way to confirm WPB is to remove a patch of bark and look for the winding, serpentine egg galleries in the layer between bark and sapwood that do not change in width (Photo 2). When new brood adults emerge from the tree, they leave behind perfectly round exit holes a few millimeters across.

Orange crowns will certainly get the attention of landowners who will want to take action to manage the problem. Keep in mind that the crown often dries out the season after beetles killed it, so they may have already moved on. If exit holes are present and numerous, nothing will be gained (in terms of managing beetle numbers) by tree removal. Trees with green crowns that have woodpecker activity or pitch tubes with no exit holes may still contain beetles. Removal of these “green attacked” trees may help reduce beetle populations. During an outbreak, this approach is likely a losing battle since beetles can fly in from nearby areas. The best management practice for bark beetles is to control competing vegetation and increase vigor and resilience of the healthiest trees in a stand.

Direct control methods such as pesticides can be effective in preventing attacks to high value trees but will do nothing to save a tree that’s already infested. There is a commercially available pheromone called verbenone that is marketed as a pine bark beetle repellant. Verbenone can be effective with mountain pine beetle in some situations, but for WPB and ips pine engravers, the current formulation hasn’t worked well in field testing.

Ponderosa pine mortality from WPB may be high in some areas, but keep in mind that due to the patchy attack pattern, landscape level effects will be lower than with mountain pine beetle. Eventually outbreaks will collapse as drought conditions improve and beetles have fewer weak trees to support high populations. In addition, more beetles start dying as they try to survive in healthier hosts.

If you would like assistance with bark beetle identification or ideas for their management, please contact the Washington Department of Natural Resources Forest Health Program at 360-902-1300 or forest_health@dnr.wa.gov.


Events, Workshops and Publications

Forestland Resiliency – Meeting Future Challenges

Saturday, Aug. 5, 2017
72 Tornquist Road, McCleary, WA 98557
No charge to attend but reservations are requested

Tour a small, locally owned forest and learn about the biggest issues for local forests: threat of conversion, climate change, and biodiversity loss–with a focus on what landowners should know and actions they can be taking today to address these issues. Presenters will include Andrea Watts, a local forest landowner, science writer and editor on numerous forestry related issues; and experts in forest pathology, forest genetics and other disciplines from the Washington State Department of Natural Resources.


Forest and Range Owners Field Days

These popular, out-in-the-woods, family-friendly events are designed for small forest landowners. They feature outdoor classes and workshops on tree planting, weed control, thinning, tree diseases, mushroom-growing and much more…


Forest Stewardship Coached Planning

If you own wooded property, our flagship course will teach you how to assess your trees, avoid insect and disease problems, and attract wildlife. Experts will help you develop your own Forest Stewardship Plan to keep your woods on track to provide enjoyment and income for years to come.

  • Preston (King County) starting Sept. 12, 2017
  • Sedro Woolley (Skagit County) starting Sept. 28, 2017
  • Southwest Washington, locations and dates to be announced, Fall 2017. Contact andyp@wsu.edu
  • Stevens County, location and date to be announced, Fall 2017. Contact andyp@wsu.edu


Invasive Forest Weed Control Field Practicums, 2017–2018

These practicums are completely field based and centered around hands-on learning. Learn to identify and control some of the most common invasive weeds that cause economic and environmental damage in forests using chemical (including organic-approved) and non-chemical control options

Practicum 1
Arlington – Saturday, Sept. 30, 2017
9 a.m. to 4 p.m.

Future practicums:


Managing Red Alder

This two-day workshop (which includes a field trip) for property owners will take a comprehensive look at the challenges and opportunities that red alder presents to landowners.

Arlington  Oct. 6-7, 2017


TIES TO THE LAND: A Facilitated Workshop on Succession Planning

Keeping Family Forests, Farms, and Ranches in the Family

Few challenges that family forestland owners, farmers, ranchers, and other land-based family businesses face are more important than the issue of passing the business and its land base on to the following generation. Many small landowners want to preserve their family lands but don’t know how to involve family members in ownership and operation of their small land-based businesses.

This facilitated workshop focuses on ways to maintain family ties to the land from generation to generation, and is a mix of presentations and practical exercises to help families address tough issues. Each family will receive a copy of the Ties to the Land workbook which is designed to help families continue to improve and direct their communications at home. Topics covered will also be relevant to professionals working with landowner families. More information is available on the Ties to the Land website.

Ilwaco – Saturday, Oct. 21  115 Lake St, Ilwaco.

For more information, contact Andy Perleberg, (509) 667-6540, andyp@wsu.edu

Note:  Dates and locations for Ties to the Land workshops are determined by community interest.  Contact Andy Perleberg at WSU Extension, 509-667-6540, or email andyp@wsu.edu for more information (and to campaign for us to schedule a class near you).


Find schedules and information about upcoming education opportunities on the WSU Extension Forestry website: forestry.wsu.edu/


New Publication: Homeowners’ Guide to Landslides

The Washington Geological Survey, in partnership with the Oregon Department of Geology and Mineral industries, has published a Homeowners’ Guide to Landslides. It is available on the Washington Geological Survey’s webpage for download at no charge.

Find out more about landslides in Washington.


Ways to Connect: The Chehalis Basin Partnership and Lead Entity

Chehalis Basin Watershed Management Plan
Two local groups offer helpful information and other resources to Chehalis basin landowners concerned about watershed management, salmon recovery and other issues.

NOTE: The following article by Kirsten Harma, Watershed Coordinator, Chehalis Basin Partnership, was mistakenly attributed to another author when first published. Our apologies for this error.

Clean, abundant water is critical to all residents of the Chehalis River Watershed. Salmon are valued by recreational and tribal fishers and contribute to the local economy. Two local groups have been active over the past two decades ensuring that these natural resources are protected for generations to come. The following article shares information about the history of these groups, and what resources they can offer to small forest landowners.

Chehalis Basin Partnership

The Chehalis Basin Partnership’s founding members recognized that water can cause problems – whether there is too much of it or not enough in the right place at the right time. They also recognized that there were emerging opportunities for local input on managing water throughout an entire landscape. The Chehalis Basin Partnership formed in 1998 to bring people together to find ways to reach shared goals for water management in the lands that compose the Chehalis River Watershed.

The partnership prepared the Chehalis Basin Watershed Management Plan, which was adopted by member cities, counties, ports and the Chehalis Tribe in 2004. Key recommendations were preventing water quality degradation, ensuring that enough water remains in streams for human communities and wildlife, and developing approaches to keep agriculture and forestry on the land.

The plan recommends improving water quality through protecting healthy, high quality waterways so they don’t become impaired, and finding voluntary methods to clean up waterways and the lands that surround them. It recommends making sure there is enough water for people and fish through conducting studies to better understand the connection between water withdrawals from wells and the amount of water available in streams, and developing a ‘toolbox’ with information on flexible strategies for meeting water rights needs, among many other approaches.

The goal of keeping forestry and agriculture on the land was included in the watershed plan because these land uses contribute significant benefits to the basin environment and economy. Forestry and agriculture constitute the least intensive use of land by people within the watershed, and provide benefits to water quality and quantity. For example, forests act as a natural storage facility by helping retain water from rainy seasons into drier ones. The plan recommends developing policies and economic approaches that encourage preservation of forest and agricultural lands, and educating the broader public about the connection between land use and water and the importance of these land uses to our economy.

The plan’s goals and recommendations have become more relevant that ever in the decade since the document was first released. The Chehalis Basin Partnership is working to achieve the vision laid out the Chehalis Basin Watershed Management Plan through member organizations and volunteer efforts around the basin: but there is a lot more still to be done.

The Chehalis Basin Partnership meets monthly to share information about priority water resource topics and to exchange ideas on Plan implementation. Over the past year, the group has hosted presentations on the Department of Ecology’s water rights curtailments issued for the basin in May, DNR’s Forest Practices program, and opportunities and challenges for agriculture in the basin. Interested citizens are always welcome to attend. If you there is a water-related topic you would like to learn more about, feel free to suggest it to the Partnership’s Coordinator for inclusion in a future meeting.

For the meeting schedule and information on speakers and presentation topics, see the “Events” tab on the Chehalis Basin Partnership’s webpage at: www.chehalisbasinpartnership.org

Chehalis Basin Lead Entity

Another priority identified in the Chehalis Basin Watershed Management Plan is making sure conditions exist in our streams and rivers to support sustainable runs of wild salmon. After the state of Washington passed salmon recovery legislation in 1998, a local committee convened to take on the task of writing a plan for salmon habitat restoration and protection, and then finding on-the-ground, voluntary, community supported projects that can best implement that plan. This group, the Chehalis Basin Lead Entity, brings together technical experts that can identify scientifically sound restoration projects, and community members that ensure projects align with local social, cultural and economic values.

Chehalis River Basin Watershed
Private landowners have a number of opportunities to participate in managing and restoring the Chehalis River Basin Watershed .

The Chehalis Basin Lead Entity has the important role of getting salmon recovery funding to public and private landowners to conduct voluntary restoration and protection work on their land. Since 1999, they have helped get funding to 141 projects around the watershed.

Types of projects eligible for funding include:

  • Correcting barriers to salmon migration (e.g., barrier culverts)
  • Planting native shrubs and trees on stream banks
  • Installing large woody material to create habitat in a stream
  • Protecting key habitat areas through property acquisition or easement

The Lead Entity sends out a call for project applications in early February each year, with final funding approval by a state panel occurring in December. If you have an idea for a salmon habitat restoration project on your land, contact the Lead Entity Coordinator for information about how to proceed with developing your project idea.

The committee also is looking for new volunteers who have a passion for protecting salmon and healthy watersheds. Contact the Lead Entity Coordinator if you would like to serve on the project review team.

To learn more about the Chehalis Basin Lead Entity, visit them online at www.chehalisleadentity.org

By Kirsten Harma, Watershed Coordinator, Chehalis Basin Partnership

Reporting Drought Related Tree Damage – Why and How?

Drought damage to hemlock tree.
Drought damage to hemlock tree. Photo by DNR

In the November 2016 issue of the Small Forest Landowner Newsletter, DNR forest entomologist Glenn Kohler reported on the impacts to conifers following the 2015 drought. The drought was the most severe in Washington in several decades and had significant influence on the availability of water, especially the water available for growing trees. This lack of water caused stress and damage in conifers of various ages, sizes and species. Branch and top dieback, foliage loss, entire tree mortality and an increased level of damage caused by secondary bark beetles were observed in both 2015, 2016 and, likely, 2017.

Recently, the State Agency Climate Adaptation Forum held in Lacey, Wash., provided representatives from state agencies and other organizations an opportunity to talk about their experiences and responses associated with the 2015 drought. Representatives from the Washington Department of Natural Resources, Department of Ecology, Department of Fish and Wildlife, Department of Agriculture and several smaller organizations attended. Many resource professionals agreed that the unusually hot and dry weather conditions observed in 2015 are likely to occur with increasing frequency in coming decades.

By documenting the damage observed in our trees during the 2015 drought, we can better learn how to prepare for and guide management fore the future events. If you are interested in reporting drought damage observed on your property, please include as much of the following information as you can:

Minimum information
  • Host/species affected
  • Damage symptoms (branch flagging, top dieback, entire tree mortality, low needle retention, etc.)
  • Location information: GPS reading or address
Additional information
  • Approximate age of tree affected
  • Size of trees affected (diameter and/or height estimate)
  • Other damage agents present (none, Douglas-fir bark beetle, root disease, unknown)
  • How many trees affected (exact number if known, otherwise estimate, few, many)
  • How many acres affected
  • County where damage observed
  • Notes on site characteristics (be as specific as possible; residential property, highway roadside, adjacent to field, forested area, floodplain, forest edge, etc.)
  • Soil characteristics (rocky, well-draining, deep, shallow, poor, etc.)

Please send this information to Amy Ramsey at amy.ramsey@dnr.wa.gov or Washington DNR, 4th Floor, Wildfire Division, PO Box 47037, Olympia, WA, 98501

Many Washington Conifers Hit Hard by Recent Drought

This tree shed its older needles first
This tree shed its older needles first but as the drought continued, the terminal and branch tips died back. Susan K. Hagle, USDA Forest Service, Bugwood.org

The summer drought of 2015 was the most severe in Washington state in the last 16 years. According to the U.S. Drought Monitor, the entire state was under severe or extreme drought conditions from late July through early October. Yet many affected conifers did not show signs of stress until the following year.

Summer months are a critical time for a tree’s water needs. Water lost through needles on hot days is normally replaced by water from the soil. Lack of soil water can result in failures within the tree’s circulatory system. Sometimes, the whole tree dies. Sometimes, all the tissue beyond the point of failure dies, causing a dead top or scattered dead branches. Trees growing in rocky or well-drained soils may experience more drought stress. Young trees and trees with shallow, less-developed root systems are especially vulnerable to damage.

Fortunately, some conifer species are more drought tolerant than others. In general, pines are the most tolerant while Douglas-fir is somewhat tolerant and grand fir, western hemlock and western redcedar are the least tolerant. This tolerance can vary widely depending on the quality of the site.

Damage Reported

Damage and mortality in Douglas-fir, western redcedar and pines was immediately noticeable during the drought in 2015. Symptoms included entirely red crowns, red tops and scattered red branches. But many affected conifers remained green for months as the weather cooled over winter. Then, with record-breaking heat in spring 2016, delayed symptoms became more noticeable and widespread. This was hard to notice in western hemlock, because many dying hemlocks dropped foliage without color change.

At the end of summer 2016, unusual levels of western redcedar mortality were reported. These trees likely had a delayed response to the previous year’s drought conditions. The 2016 annual insect and disease survey showed increases in ponderosa pine killed by western pine beetle, Dendroctonus brevicomis, and grand fir killed by fir engraver, Scolytus ventralis. Attacks by these bark beetle species often increase following drought events.

This sapling exhibits symptoms of chronic drought;
This sapling exhibits symptoms of chronic drought; thin crown, short needles, and short terminal growth. Susan K. Hagle, USDA Forest Service, Bugwood.org

The Washington State Department of Natural Resources (DNR) Forest Health Program examined conifers with drought symptoms at sites throughout the state and many showed little indication of being killed by primary pathogens, insects or other animals. In many cases, there were not even signs of opportunistic wood infesting insects in the lower stem. When galleries were found in the main stem, they were most often wood borers, which only enter conifers that are dead or dying from other causes.

In Douglas-fir and ponderosa pine, secondary bark beetles were rarely seen in the lower stem of mature trees, only in small-diameter trees. In the rare cases where mature trees were felled, they were often found in small-diameter tops and branches. In pines, these were primarily Ips species pine engravers. Evidence of other minor opportunistic bark beetles was also found, such as the so-called “itty bitty pitys”: Pityogenes, Pityokteines or Pityophthorus species.

In northeast Washington and north Idaho, damaged Douglas-firs had high numbers of Scolytus monticolae, a secondary engraver beetle. In western Washington, secondary bark beetles found in Douglas-fir were either Douglas-fir engraver, Scolytus unispinosus, or Douglas-fir pole beetle, Pseudohylesinus nebulosus. Galleries and adults of secondary bark beetles were found in lower stems of western redcedar (cedar bark beetles, Phloeosinus species) and western hemlock (silver fir beetle, Pseudohylesinus sericeus).

Some drought-stressed conifers that survived with compromised defenses may have already been attacked by primary tree-killing bark beetle species in 2016. In normal weather conditions, trees killed by bark beetles often do not turn red until the following summer. So any further increases in bark beetle activity may not be evident until 2017. Trees with root disease already have compromised root systems and drought conditions can exacerbate this, further decreasing water uptake. Drought stress may also increase symptoms of otherwise minor foliar diseases.

Caring for Stressed Trees

If dead trees pose a falling hazard near people or property, they should be removed as soon as possible. Also consider the potential hazard from falling dead tops and large branches. But before removing damaged conifers (those with some green foliage) in areas where hazard is low, monitor for a normal flush of green buds in spring as a sign that the tree may survive. Dead tops and branches will eventually fall and top-killed trees can grow new leaders, but they may become deformed as a result.

Surviving trees should be monitored for evidence of bark beetle attack, such as pitch tubes, pitch streaming or red boring dust. To prevent a build-up of bark beetle populations, remove and destroy any large amounts of freshly killed breeding material or infested logs and slash. Irrigation and mulching around landscape trees during future droughts may reduce damage. Take care not to over-water and avoid fertilizing as this can increase the tree’s foliage growth and need for more water.

2016 Marks 70th Year of Insect and Disease Aerial Survey in Washington

by Glenn Kohler, Entomologist and Aerial Observer, Washington DNR

Every year since 1947, aerial surveyors have reported the location and intensity of damage by forest insects, diseases, and other disturbances across all ownerships of forestland in Washington. Without aerial surveys, it would be impossible to track disturbance conditions over such a large area using ground-based methods. Aerial survey is also an important tool used to detect and map new outbreaks of native and exotic insects and diseases. The Washington Department of Natural Resources and the USDA Forest Service cooperate to conduct the annual aerial detection survey (ADS) and typically cover the majority of Washington’s 22.4 million acres of forested lands. The total area mapped with some type of damage varies each year from a few hundred thousand to nearly two million acres.

Forest health 2015
In 2015, levels of tree mortality, defoliation, or foliar diseases were recorded on approximately 338,000 acres, well below the 543,000 acres reported in 2014.

2015 Aerial Survey Highlights

A very active wildfire season in 2015 posed major challenges for the aerial survey, but crews were still able to complete the survey in all areas unaffected by fire. Approximately one million acres that would have normally been surveyed were not flown in 2015 due to numerous large fires of 2014 and 2015. Because it is difficult to distinguish mortality caused by fire from mortality caused by insects or disease, areas burned by wildfire are not mapped until the second year following the fire. Normally August is the best time to fly aerial survey in eastern Washington because damage signatures are well developed. But heavy smoke, temporary flight restriction areas, and crew and aircraft commitments to fire duty prevented any survey flights the entire month of August. An additional aircraft and crew were used to complete the survey by late September.

In 2015, some level of tree mortality, tree defoliation, or foliar diseases was recorded on approximately 338,000 acres. This is well below the 543,000 acres reported in 2014. Some part of this decrease is due to reduced acres flown in areas of eastern Washington that typically have higher levels of damage. However, downward trends in insect and disease damage were also evident in areas unaffected by wildfires.

Tree mortality was recorded on approximately 241,000 acres, of this 116,000 acres were attributed to bark beetles and 108,000 acres to bear damage or root disease. Relative to 2014, tree mortality decreased for all major bark beetles including mountain pine beetle (58,700 acres), western pine beetle (5,900 acres), Douglas-fir beetle (18,500 acres), fir engraver (11,700 acres), and spruce beetle (16,000 acres). Mountain pine beetle was at the lowest level in the last ten years. The area with conifer defoliation decreased to approximately 99,000 acres, down from 159,000 acres reported in 2014. Almost all defoliation recorded was caused by western spruce budworm (79,000 acres) and balsam woolly adelgid (19,600 acres). Western spruce budworm defoliation was at the lowest level in the last ten years, but similar to 2014. Approximately 9,800 acres had some level of disease damage, primarily bigleaf maple decline (2,700 acres) and needle casts in pines (3,200 acres) and western larch (2,900 acres).

Aerial Surveys Then and Now

Continue reading “2016 Marks 70th Year of Insect and Disease Aerial Survey in Washington”

Seeking Information about Western Cedar Borer, a Significant Pest of Western Red Cedar

Karen Ripley, DNR Forest Entomologist

Western cedar borer tunnels in red cedar branch.  Photo: M. Lloyd
Western cedar borer tunnels in red cedar branch. Photo: M. Lloyd

The Western cedar borer (Trachykele blondeli), or “red powder worm,” is a flat-headed wood boring beetle that causes a problem called “wormy cedar.” A 1928 bulletin describes, “Hundreds of the finest standing trees of the western red cedar … in the Pacific coast region of Oregon, Washington, and British Columbia have a large proportion of their timber riddled by the flattened, oval worm holes. … These holes wind through the sapwood and heartwood of the main trunk of infested trees and render the timber almost worthless for the higher grade uses such as shingles, cooperage, doors, furniture, finishing, cabinetmaking, shipbuilding and other high grade products.” (Burke).

Modern uses for cedar such as utility poles, finished lumber or export wood continue to be compromised due to this insect, even though the strength of the wood is not always significantly reduced. Using infested wood for rough-sawn fencing may be an option, depending on the amount and visibility of the degradation.

Adult cedar borers are between 11 and 17 mm long (roughly 0.5 inches), bright emerald green with a golden sheen, and have several darker spots on the wing covers. While their life cycle is fairly straight forward, the signs of infestation are very difficult to spot. During May and June, adult beetles lay their eggs on the thin-barked upper surfaces of living branches of western red cedar. When the eggs hatch, the slender, grub-like larvae chew into the branches and tunnel toward and into the tree trunk. The larvae mine horizontally and vertically along the annual growth rings, but occasionally cross the grain. The tunnels are packed with wood colored boring dust. Tunnels are usually less than 6 meters (19 feet) long, but can extend as far as 13 meters (42 feet)!

Adult western cedar borer.  Photo: S. Valley
Adult western cedar borer. Photo: S. Valley

Larvae require 2 to 3 plus years to reach maturity, then pupate inside a larger cell they have cut within the wood. Adult beetles chew out of the trees in early spring, feed on cedar foliage for several weeks, mate and lay eggs.

Infested trees appear normal and healthy, but they may have small, oblong exit holes where adult beetles have emerged. The main way to detect western cedar borer infestation is to cut off branches where they meet the trunk. If that part of the tree is infested, dust-packed larval mines may be seen in the exposed knot faces.

Although this insect is reputed to be associated with low elevation western red cedar, information about its specific occurrence is rare. There may be several closely related beetle species or subspecies present in the West, especially in drier forests where cedar gives way to cypress and juniper. Professional cedar log buyers may have key experience and local knowledge about the distribution and impacts of these cedar borers, but overall information is limited. An informal request for information resulted in a number of comments about host selection factors and distributions:

  • “We don’t see them rapidly moving. But once they are in a stand it seems they never leave.”
  • “The greatest infestations occurred where trees had been damaged by previous logging or storms. It was my conjecture that damaged or weakened trees were more susceptible.”
  • “It seems to be an increasing problem…some seem to think the recent below-average precipitation may play a role.”
  • “Eastern Washington and Idaho are essentially worm free in my experience.”
  • “Worm was not a problem on the Mt. Hood National Forest regardless of elevation, but from about Eugene south worms were very prevalent up to 3,000 feet; above 3,000 feet worms were generally not an issue in the Willamette National Forest. Worm on the lower elevation private timber lands in the Willamette Valley was common everywhere from Albany south.”
  • “In general worm has the greatest chance of occurring at low elevation.”
  • “Proximity to salt water was not always a predictor of worm. The Coos Bay area was very wormy, but from Newport north to Astoria worm was generally not a problem.”

I would like to gather as much information as possible in the hope of developing a research proposal or reporting system to better understand both historic and recent activity and infestation locations. If you have experience with “wormy cedar” on your property or through your forestry job, please contact me, Karen Ripley, karen.ripley@dnr.wa.gov, 360 902-1691. Thank you in advance for sharing your knowledge.

For more information see:

The Western Cedar Pole Borer or Powder Worm. H.E. Burke. USDA Technical Bulletin No. 48, February, 1928

Western Cedar Borer. R.W. Duncan. Forest Pest Leaflet No. 66. Pacific Forestry Centre, Canadian Forest Service. April 1995.

The Emerald Ash Borer – Preparing for Battle

Adult emerald ash borer.

The emerald ash borer is an invasive beetle from Asia that has decimated ash populations across New England, the Midwest and Colorado. It’s only a matter of time before it arrives in the Pacific Northwest and infests our native Oregon ash (Fraxinus latifolia) as well as the many ash street and ornamental trees in our communities. Read more at The Battle of the Ash Borer from the Lansing State Journal.