Over the last two years, an outbreak has affected more than 500,000 acres of forest.

The latest tally of beetle kill shows more than 550,000 acres of forest with dead spruce from the ongoing infestation this year alone, much of it in Mat-Su.

Dead, red trees signal an increasingly dire outbreak driven by warm summers and plentiful spruce, especially in the Susitna Valley.

The closures of the campgrounds, facing the threat of falling trees, likely will last through summer, the state parks division said.