[moondoggie]

Forest fire will cause lodgepole seeds to sprout and renew the forest. Fire opens the cones to release the seeds.

The Mason Gulch Fire got within 3 miles of us, but we were smokey for several days with embers blowing in.

There was seedlings EVERYWHERE the following year.

[BIGLOOK]

Seems the area of infestation is climax forest and as such is susceptible to predation by the beetles as well as fire from the deadwood the beetles create. Warmer than average winters can be blamed for the beetle problem but old growth is also a factor.
The climax forest denies its successors space and light and unless there's a fire or weather event (or a logging company) to reduce the old growth population, it will go on its own with time. Doesn't matter if it Lodgepole pines in the west or White oaks in the east.....or Ohias in Hawaii; they all go through the cycle.