Changes in understory vegetation including invasive weeds following mountain pine beetle outbreaks

•Bark beetle outbreaks open forest canopies which can affect understory plants.•Forb cover increased after recent mountain pine beetle outbreaks in lodgepole pine forests but cover of shrubs and graminoids didn't change.•Invasive plants increased after outbreaks and were associated with tip up sites created when beetle-killed trees fell.•A literature review revealed that outbreaks usually result in short-term increases in understory plants but varies with beetle species/forest type.