“Bite-Size Bits of Local, National, and Global History”
“Bite-Size Bits of Local, National, and Global History”
Greybull in Big Horn County, Wyoming — The American West (Mountains)

Agents of Change

Agents of Change Marker image. Click for full size.
By Bill Coughlin, July 24, 2015
1. Agents of Change Marker
Douglas Fir Bark Beetle
The Douglas fir bark beetle enters the bark where it introduces a fungi and creates galleries in the phloem – the layer under the bark that transports nutrients from the leaves throughout the tree. The galleries serve as habitat for the beetle larvae which feeds on the phloem. When mature the beetles exit the trees to find a new “host” tree.

When a region is not in a drought a healthy tree can “pitch-out” an attacking bark beetle with sap. The beetles can be successful when a tree is stressed by drought, disease, or old age, or when the beetle population overwhelms a tree. In many cases, the fungi introduced by the beetle clogs the phloem and kills the tree.

The Forest Service Response
This hillside of dead trees was considered to be a wildfire hazard. Public campgrounds, private cabins, and the watershed were at risk. To reduce the wildfire risk, the Forest Service cuts a “fuel break” beginning where the trees regenerated after the 1959 tornado. Commercial trees were harvested and smaller trees and underbrush were removed by small prescribed fires.

To protect the Shell Falls Visitor Center the Forest Service used “anti-aggregative” pheromones to deter bark beetles. Beetles normally use pheromones
Agents of Change Marker image. Click for full size.
By Bill Coughlin, July 24, 2015
2. Agents of Change Marker
to attract mates or send messages. The man-made pheromones reduce beetle attacks by sending the message, “this tree is full – go someplace else,” thereby protecting the trees near the visitor center.

Many of the majestic Douglas fir trees in Shell Canyon were killed between 2002 and 2006 from the Douglas fir bark beetle.

After years of drought many of the 150-200 year old Douglas fir trees became less resistant to the relentless attack from the bark beetles.
Erected by US Forest Service.
Location. 44° 34.346′ N, 107° 33.046′ W. Marker is in Greybull, Wyoming, in Big Horn County. Marker is on U.S. 14, on the left when traveling west. Click for map. Marker is located in Bighorn National Forest. Marker is in this post office area: Greybull WY 82426, United States of America.
Other nearby markers. At least 8 other markers are within 4 miles of this marker, measured as the crow flies. Nature's Destruction (here, next to this marker); Moving Mountains (approx. 3.3 miles away); A 4,000 Mile Journey (approx. 3.3 miles away); Forming Waterfalls (approx. 3.3 miles away); Hummingbirds (approx. 3.3 miles away); Shaping a Canyon (approx. 3.3 miles away); Lifeblood of the West (approx. 3.3 miles away); Oasis in the Desert (approx. 3.3 miles away).
More about this marker.
Marker in Bighorn National Forest image. Click for full size.
By Bill Coughlin, July 24, 2015
3. Marker in Bighorn National Forest
Several photographs of Douglas firs appear on the marker. On the left is a photo of some Douglas fir trees with a caption of “These Douglas fir trees show signs of stress.” On the upper right is a photo of “Douglas fir bark beetle gallery with larvae.” Next to this is a photo of a beetle with a caption of “Douglas fir bark beetles are 4-6 mm in length – about the size of a pin head.” Two photos at the bottom right of the marker have captions of “Cutting fuel breaks in Shell Canyon protects cabins, campground, and the watershed from a catastrophic wildfire.” and “The Forest Service used man-made, “anti-aggregative” pheromones to protect Douglas fir trees near Shell Falls Visitor Center.”
Categories. Horticulture & Forestry
Credits. This page originally submitted on , by Bill Coughlin of North Arlington, New Jersey. This page has been viewed 136 times since then and 44 times this year. Photos:   1, 2, 3. submitted on , by Bill Coughlin of North Arlington, New Jersey. This page was last revised on June 16, 2016.
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