Bark Beetles Attracted to Storm Damaged Trees

Recent history seems to indicate that we are experiencing more windstorms with greater frequency and intensity. Most of us recall the back-to-back windstorms that occurred in July and August 2014. They resulted in road closures, power outages, building damage and many downed trees, in both urban and wildland forests. Another doozy of a storm blew through the region in November 2015, causing human injuries and fatalities as well as property and forest damage. And sandwiched between these major events, localized minor storms with more winds caused noticeable damage.

As forest owners and foresters we well understand the cause and effect relationship between downed trees and bark beetles. Downed or damaged trees at the wrong time of year will attract bark beetles. This is especially true with ponderosa or lodgepole pine (pine engraver beetle) and Douglas-fir (Douglas-fir beetle). The beetles attack the downed trees, limbs and stems three inches and larger in diameter, go through a life cycle under the bark, and a second generation emerges to attack nearby live trees. In the case of the pine engraver beetle (also referred to as Ips because of its genus name), this second generation flight takes place the same summer as the original attack. For Douglas-fir the follow-up attack on live trees occurs in the next year.

Though tree damage was significant, the 2014 storms were, for the most part, late enough in the summer that bark beetle flights had already occurred for the season. Moreover, the moist tissue underneath the bark that harbors bark beetles had sufficiently dried prior to the flights in the spring and early summer of 2015, so we avoided the double whammy of a bark beetle outbreak.

But this will likely not be the case following the November 2015 windstorm. Downed trees, broken tops and fresh cut logs will likely attract bark beetles when they begin to fly in a month or two. The best advice if you have damaged or downed trees is to clean-up as quickly as possible, especially pine species. Unfortunately, the shortened winter logging season did not provide much of an opportunity for salvage harvesting for those with downed merchantable timber.

Points to keep in mind:
• Pine species should be cleaned up this spring. You have until next spring to clean up Douglas-fir.
• Salvage merchantable timber if possible.
• If you cut firewood, get the individual pieces out in direct sunlight to speed drying.
• If possible, remove some or all of the bark.
• Do not stack firewood against live trees.
• Monitor downed trees for bark beetle attacks when daytime temperatures warm to 70 degrees or above.
• Look for boring frass (small piles of reddish colored sawdust) on logs. This is a sure sign that bark beetles have attacked the tree.
• Pile and burn or chip the unused portions of trees.

Don’t hesitate to contact us if you sustained damage during the latest wind storm or if you have any questions on how to avoid a future problem with bark beetles.  –Bill Love, CF

What Kind of Tree is This?

Can’t tell you how many times I’ve heard: “Hey, you’re a forester; what kind of tree is this?”

For many foresters, we would rather confront a bear in the woods than hear that brief question. We’re fine answering that question in our local forest with native trees, but while looking at a non-native tree we’re quickly reminded that our college Dendrology course came down to a one-question final exam with either a pass or fail grade. No matter if we took this course last semester or 40 years ago, our reputation is on the line.

Every forester, usually as a freshman, takes Dendrology which literally translates as the “study of trees.” And for decades, the Textbook of Dendrology, published by McGraw-Hill Book Company, Inc. in their American Forestry Series, became each student’s bible.

In the introduction, authors Harlow and Harrar begin with, “A knowledge of the names of trees, their habits, and principal botanical features is basic to advanced studies in forestry.” Dendrology teaches not only tree identification, but perhaps more importantly, the knowledge and methods to be able to identify unknown species.

Dendrology lectures focused on basic tree identification characteristics. Since leaves provide important clues to a tree’s identity, students learn about leaf arrangement, leaf composition, leaf shapes, leaf venation, and leaf surface features.

But leaves are not always present. Flowers (yes, trees have flowers), fruits, twigs, buds, and bark all become important identifying characteristics on a leafless tree.

My dendrology course took place in southwest Louisiana where bottomland hardwoods prevailed in any forest not planted with southern yellow pines: loblolly, slash, longleaf or shortleaf. The professor warned us that the deciduous tree we easily identified by its leaves in September would be bare during our field exam in January. Sassafras, for example, has three distinctively shaped leaves on the same tree making it easy to identify. Recognizing this species by its twigs and bark, however, requires some skill. For a real test, try picking out about a dozen different oaks just by their bark.

Going back to that dreaded question, foresters feel comfortable in identifying native trees growing in the forest within their local area. We can usually look from one ridge to the next and easily pick out native conifers just by the shape of their crowns. But we quiver in our boots when asked that same question in someone’s backyard, or especially, on an old farmstead. That’s because there is no way of predicting what non-native species were planted with origins from who knows where. Since many settlers migrated to this area from the mid-west or Lake States, it’s not unusual to find a mid-western hardwood or two transplanted from the old family farm in Indiana or Michigan.
Over the years I’ve been asked to identify northern red oak, bitternut hickory, and American elm growing in North Idaho. In regard to conifers, I’ve seen bristlecone pine and giant sequoia. Who knows how they got here or why they survived. (The sequoia trees did well for several years but eventually succumbed during an extremely cold winter.)

Probably the second most-asked question for a forester: “…can you recommend a good book on tree identification?” The answer, of course, is yes and it’s not just limited to printed publications. A search of the internet becomes a quick source to learn about tree identification. But for those of us who like the feel of a book in our hands, most of the regional plant guides, available from local book stores or on-line sources, have sections on native trees. I especially like a series from Lone Pine Publishing based in Canada.

Although out-of-print, Wild Trees of Idaho, by Frederick D. Johnson is available at but, let me warn you, the few available new copies now bring about $180. Fortunately used copies start at $40. Another source is the University of Idaho website where a PDF version can be viewed online or downloaded to your computer. Regardless of how you obtain a copy, you will learn about trees in Idaho.

Another good source of information on tree and plant identification is “Plants of Southern Interior British Columbia and the Inland Northwest” by Parish, Coupe and Lloyd. This book is a great “take it with you” guide to the flora world.

So next time you see a forester, be sure to ask, “… you’re a forester; what kind of tree is this?”– Bill Love, CF