By Bill Tiedje
It's no surprise to many residents that beetle infestations have been damaging and killing trees in Ouray County, but the high degree of diversity in both tree species and beetle pests requires a nuanced response.
"Every tree species has its own beetle and its own problem," said forester Austin Shelby of the Colorado State Forest Service.
Shelby explained that for five evergreen tree species present in the county, there is a different insect pest affecting each of those species.
In Ouray, the fir engraver beetle is killing white fir trees.
"While it looks bad, and it is kind of bad, we're not going to see total devastation," he said.
Unlike forests on the Front Range which are dominated by one tree species, the lodgepole pine, the forest surrounding Ouray is a diverse mix of species.
"There are going to be other trees that fill in, even younger white fir," said Shelby, noting the presence of Engelmann spruce, ponderosa pine, Colorado blue spruce and subalpine fir near Ouray.
In the last three years, Shelby noted the presence of a spruce budworm near Ouray and believes that the loss of leaves caused by the budworm may have made the trees more susceptible to beetle damage.
Shelby said the trees most susceptible to the fir engraver beetle were older growth white fir trees, commonly located at lower elevations.
This could mean for some, as Shelby pointed out, the loss of a favorite tree that has been on a family's property for generations.
"Anybody who has a white fir in their yard needs to do something about it," commented Ouray resident Barbara Uhles.
Uhles explained the city of Ouray's website, under the community affairs tab, has information for residents about tree spraying and other services.
In Elk Meadows Estates, a homeowners' association located southwest of Ridgway, homeowners are taking an active approach to combat the Douglas-fir beetle.
Elk Meadows resident David Mullings said he first noticed a few beetle hits on four older Douglas-fir trees last spring and had the trees removed.
However, by August 2013, Mullings said the beetle infestation had already expanded across his nine acre property.
To limit the spread, he had four truckloads of infested trees removed by a logging service.
"You hate to do it, but it's the right thing to do and you have to do it," said Mullings, equating the loss of the beautiful, large trees to euthanizing a beloved dog.
Shelby said the size of the Douglas-fir beetle infestation was doubling each year in stands where it was present in the Elk Meadows area.
The Douglas-fir beetle broods in blown-down trees, Shelby explained, adding that removal of trees damaged by wind was important to limit the beetle's expansion.
Several landowners in the area have had infested trees removed, but a heavy-handed mitigation response was complicated by an issue of cross boundary management, according to Shelby.
Also the case near Ouray, working with dozens of private landowners plus U.S. Forest Service lands has made a coordinated response difficult, he explained.
Ponderosa pine stands, located at higher elevations on Miller Mesa to the south of Elk Meadows and west on the Top of the Pines property, have been affected by the mountain pine beetle for the past several years, as well as a parasitic plant that grows on trees, known as dwarf mistletoe.
"Anything that stresses the trees can make the beetle more active," Shelby explained, describing how the mistletoe increases the pine trees' vulnerability to beetles.
Near Log Hill, Shelby also noted the presence of the piñon ips beetle in the piñon pine stands, although this beetle is currently present at low levels.
Despite the presence of these beetle species, the spruce beetle, which is devastating spruce-fir forest in the Weminuche Wilderness of the San Juan Mountains, has yet to reach Ouray County.
This beetle infestation has grown to epidemic proportions throughout the western San Juans but prefers older trees.
Shelby remained optimistic that the younger trees on Red Mountain Pass, once logged by early settlers, would be more resilient to the spruce beetle.
For continuing coverage of mitigation actions, potential threats and a look at the future of the forest's health in Ouray County, see the story in next week's Plaindealer.