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

Our Master Woodland Manager trainee class wraps up next week, after sixty-plus hours of learning and sharing together over the past six months. As an instructor, what I’ve enjoyed the most of this experience is that over half of our instructional time has been spent in the field, doing hands-on activities designed to encourage critical thinking about the day’s topic.

Root excavation
Root excavation

For each class session, we’ve tried to hone in on a few key themes. One theme for our forest health session was the importance of being observant in diagnosing a pest or disease. Our instructor, Dave Shaw, had the class look methodically for signs and symptoms at each site we visited. Where on the tree is the problem noticeable? Was there a pattern to the damage across the stand? What’s going on at the ground level? Any signs of chewing, wounding or scraping? What else is going on in the area?

Twice that day, we learned how easy it can be to prematurely jump to conclusions about a forest health problem, without pausing to get the full picture of what’s going on around you. We went to one site where there was extensive mortality of young Douglas-fir trees. Knowing that laminated root rot is the #1 most common disease in the area, when we walked into the stand and saw symptoms consistent with laminated root rot, most of the group who had seen it before agreed that it was the likely cause. But it was not until we started excavating around some of the dead trees that we found signs of two other root diseases, as well.

A sign of black stain root disease
A sign of black stain root disease
A sign of Armillaria root disease
A sign of Armillaria root disease

 

At another site, young trees had dead branches and wilting tops. On our scouting visit before the class, Dave and I had pegged this site to be an example of drought-induced stress, possibly combined with branch cankers, diseases that also are exacerbated by weather stress. So there we were in the class, all standing around, talking on and on about cankers and drought, wondering whether there might be any yellow jackets lurking in the brush, trying to find some meager shade. Not until we were about to leave, one class member thought to look down at the base of the tree.

Girdling by a mountain beaver
Girdling by a mountain beaver

 

That’s no branch canker. Sure enough, we were all standing on a minefield of mountain beaver tunnels. Like we were instructed, be observant. Look at what else is around you. Look at (and under) the ground.

Teaching in the field presents many challenges. Compared to a classroom setting, there are more logistics to contend with. The weather may not cooperate. It is harder to cover as much material as one could with a slideshow. Keys may get locked in the van, 25 miles from town (guilty). Nevertheless, there have been many instances over the MWM training that have affirmed to me that sometimes the best learning happens when one can see, touch, experience, and practice. And as often as not, it doesn’t happen quite as planned.

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2 thoughts on “Pest Scene Investigation

  1. On behalf of the MWM graduating class (today!), thanks for that day and all the other sessions – you worked hard to provide great learning experiences for all of us, and it worked!

    Take Good Care!

  2. It’s the Elk who like to wear my young trees as horn ornaments that is a problem here. I have a couple of Grand Fir that seemed dead for several years from horn rubbing that have come back and are growing again.

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