Glenwood Springs’ canopy will need some work

An adult piñon Iips beetle
Kamie Long, Supervisory Forester Colorado State Forest Service

Glenwood Springs hired a city arborist in March, and she already has suggestions for improving the health of the city’s canopy.

Beetle prevention, planting and diversifying are the three priorities Heather Listermann, downtown supervisor and arborist, is focusing on. 

The beetles the city is concerned with are called piñon ips bark beetles (Ips confusus), and they do not go for only piñon pines. Listerman said they attack both pine and spruce trees as well.

“It’s important to get a certified arborist involved if they suspect that there’s some dieback from beetle kill in a pine tree,” Listerman said. 

Ips beetles are native to Colorado and spread rapidly during environmental changes. They are typically attracted to trees under stress, as with drought, transplanting, root damage and over- or underwatering.

Ips beetles can go for healthy trees in the right circumstances. Leaving cut firewood or even wood chips next to healthy trees in the yard can attract them. 

“Don’t cut pine and spruce wood and pile it, because once you cut down one of those healthy trees it sends out a signal to the beetles; it’s like party time for them,” Listerman said.

Recently cut material over 1 inch in diameter, such as green firewood or piles of branches left on the ground after pruning or cutting live piñon trees, attracts beetles. Paying attention to how wood is stored is important when considering beetle life cycles and mitigating risk.

“Don’t be that guy, don’t DIY,” Listerman said. “Please don’t try to just handle this yourself, and cut down your tree and leave wood in your yard. Please just contact a certified arborist to handle it for you.”

Pitch tubes on tree. Photo: Kamie Long, supervisory forester

Signs to look for include: 

  • Fading needles.Much like how most beetle kill looks, the needles will fade to straw or rust color.
  • Entry holes are usually accompanied by saw dust or pitch tubes. 
  • Exit holes are the size of a pinhead and usually mean the mature beetles have left for another tree.  
  • Pitch tubes are small, thumbnail-sized clumps of sap that appear on the bark after a tree tries to flush the beetles out.
  • Galleries are tunnels are made by ips adults and larvae underneath the bark, and usually form a Y or H shape.

When bark is cracking and splitting from the wood, the tree is dry, and beetles have already left. Preventative spraying from a certified arborist is the best option to save noninfested trees. If you think your tree is infested, please report it to the city arborist to keep track of spread. 

“If you suspect something, reach out to either Heather and the city or a certified arborist with a tree care company,” said Bryana Starbuck, the city public information officer.

Piñon ips start the season early when the day temperatures reach 50 degrees and higher. They create tunnels in the wood, under the bark. Ips beetles can produce up to four generations a year. The larvae create small galleries where they take all of the nutrients and water from the tree.

Other trees in the city’s urban canopy are nearing the end of their life, and Listerman is looking to diversify the next generation of trees to prevent infestations or disease from killing large amounts of the canopy at a time. 

“Planting trees this upcoming fall is going to be really important to helping to restore our urban canopy, and we are going to be celebrating Arbor Day and Glenwood Springs on Oct. 20 this year,” Listerman said.

Here is a list of trees that will help diversify the canopy and will also do well in the high altitude high desert climate.

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