The beetle kill epidemic is an obvious problem in the county, and with a clearer understanding of the beetle mosaic of Ouray County, we are now left with the questions: how did this happen, why should we care and what can we do?
While it's difficult to tell how long the beetles have been at work in the Uncompahgre Forest, Ouray resident of more than 20 years Barbara Uhles said she's noticed the severe impact of beetle kill only over the last five years.
"One tree can die up there and you wouldn't notice it," she said. "I think it's probably (been a problem) longer than what we think and it's just a sad situation."
U.S. Forest Service entomologist Tom Eager explained that three factors contributed to beetle infestations across all tree species: stand conditions, weather and critical mass of beetles (large numbers).
The stand conditions near Ouray are largely all trees of an older age class, restarted from tree clearing during the early mining era, he explained. Older trees are much more susceptible to the beetles, as they may not be as healthy as younger, stronger trees.
"Why save a tree that's already so old, if it's going to die anyway?" asked Uhles. "There's only a certain length of time that these firs live and we have to let them live out their cycle. Unfortunately, (their life cycle) is probably being driven by the beetle."
Eager also mentioned that the beetles are cued into warm, dry weather.
"The 2002 drought kicked off a lot of different species," said Eager. "Since then, we've been behind the eight ball."
Dry weather conditions and a lack of precipitation don't bode well for tree health. During a drought season, as soil-water content declines, trees become more stressed and are unable to develop proper resistance to threats such as the bark beetle.
When a beetle's work is done, it quickly moves on to its next target, leaving behind the dead tree. Dead trees become a problem to the forests as well as to populated communities, as the risk of a fire increases.
The dead and dry fuels created by the beetle kill are a concern, said USFS forester Todd Gardiner. He noted that beetle kill trees cause "a bit of an elevated fire risk."
"The fire danger scares me more than the trees dying," said Uhles.
In Ouray, the steep slopes of the hillsides make it difficult to reach and remove the dead trees. City Administrator Patrick Rondinelli recognized the dangers of leaving dead trees in the forests, though he said the terrain surrounding the city makes it nearly impossible to reach every dead tree.
Gardiner did note that natural barriers near Ouray, such as rocky areas, somewhat improved the fire situation.
"So far we've been really lucky that we haven't burned to the ground," said Uhles. "We have to really be thankful for that."
There are a variety of methods for combating the spread of beetle infestations, but they are as specific and nuanced as the beetle species.
A protective, insecticide spray will work against all beetles, but is feasible for only a few trees, said Eager.
According to Rondinelli, the city sprayed and will continue to spray a number of white firs in key areas of the city. He mentioned that trees in town are watered regularly so they are not as subject to drought conditions as firs in the open areas.
Carbaryl and permethrine are two commonly used insecticides, applied to trees with a spray gun or wand on an annual basis. Eager said these treatments would need to be repeated each year as long as the risk was high.
On Douglas-fir trees, the MCH anti-aggregation pheromone packets fool Douglas-fir beetles into thinking the trees have already been infected. Earlier this spring, the City of Ouray purchased and sold MCH packets for residents to place on trees on their private properties. The city, with help from the Ouray Trail Group, was also able to hang the packets on a number of Douglas-firs on city property.
"It's only effective for Douglas-fir beetles," Eager clarified.
Effective treatment of white fir trees requires an especially detailed inspection of the trees, according to Eager, as the white fir engraver doesn't have a "good signature" and can be overlooked by the untrained eye.
On a larger scale, sanitation, or removing infected trees, works; however, with most beetle species, preventative measures are the most effective, explained Eager.
"We're not going to stop the beetles," he said.
As changing the weather is not a possibility, Eager said controlling stand conditions was the most effective way to limit the beetles.
Diversity on the landscape, in terms of age classes, tree density and tree species can afford some degree of risk management in response to the ongoing beetle outbreaks, according to Eager.
Uhles encouraged residents to consider planting different tree species on their property to promote diversity. She also urged property owners to water their trees regularly to keep them healthy and resistant to beetle infestation. She hopes residents will take advantage of information about tree spraying and removal services available on the city of Ouray's website, under the community affairs tab.
Gardiner explained that the service has removed several hundred dead and infested trees near the Amphitheater in Ouray over the past two years.
"It's very difficult, the beetle population is so great around these areas," he said.
Gardiner noted that root disease had also deteriorated the health of white fir stands near Ouray. Treatment or removal of trees on the wall above Ouray is limited by two factors, he said, topography and a mix of USFS, city, county and private ownership, including mining claims.
On the Grand Mesa, Uncompahgre and Gunnison National Forests, the Spruce Beetle Epidemic and Aspen Decline Management Response (SBEADMR) project will prioritize and accelerate clearing of trees affected by beetles and address the deteriorating stand conditions; but this will only treat approximately four percent of the forest, Eager estimated.
SBEADMR excludes wilderness and roadless areas, contributing to its limited scope.
On the Uncompaghre Plateau, Gardiner said thinning could bring the forest closer to historic stand conditions.
"We can have success at endemic (area specific outbreak) levels," said Gardiner.
In addition, the USFS may also treat a number of stands for to fulfill stewardship and public safety objectives, such as trees adjacent to campgrounds and roadways.
"These insect outbreaks are part of a natural cycle," Gardiner said. "Our recorded history is a small snapshot in time."
For residents like Uhles, while the death of trees may be the natural progression of life in Ouray's forests, that doesn't make it any easier to witness.
"It's not something we want to look at or watch, but maybe it's better for our forests as long as we can keep Ouray from burning to the ground," she said.