A lot in this story — about climate change without even mentioning it — fires, drought, tree/forest succession, mitigation efforts (which as the story makes clear, are too expensive and labor intensive to implement at scale). The "pest" isn't invasive; it's a native species in a rapidly changing ecosystem — result of #ClimateChange. Not everyplace is as lucky/wealthy as #Aspen.
https://www.aspendailynews.com/news/squatters-invade-aspen-mountain/article_d479e99e-0e76-11ee-802e-bbe90b21b2a9.html
As @bud_t (h/t — because credit where due) says, this is an interesting read.