The emerald ash borer, a metallic green beetle native to Asia has destroyed tens of millions of ash trees in both the U.S. and Canada. Damage is estimated to be billions of dollars. The emerald ash borer was first discovered in Colorado in Boulder in September of 2013.
The Colorado Department of Agriculture estimates that approximately 15% of Colorado’s forests are ash trees and that there is approximately 98,000 in Boulder alone.
To help prevent the spreading to other areas, you are encouraged not to move firewood or ash tree wood out of Boulder County and any surrounding quarantined area. See quarantine map here.
The City of Denver launched a program in May called "Be a Smart Ash". The program is to help educate people on what to look for and what to do. Here is the link for the program at beasmartash.org.