The removal of trees along U.S. Highway 20 that were poisoned by an improperly applied herbicide is scheduled to start Monday.

The Oregon Department of Transportation announced Thursday that crews will begin removing hazardous trees along a stretch of Highway 20 west of Sisters. The process will involve felling trees that have been identified as dangerous to motorists, either due to natural causes, or to use of the weedkiller Perspective. The weedkiller, which was applied along a roadside west of Sisters from 2013 through 2015, has been linked to the deaths of hundreds of ponderosa pines and other trees in the area.

The state transportation department identified as many as 87 trees in the area that present a danger to motorists and need to be removed, according to a news release from the agency.

Crews will leave the downed trees in the immediate vicinity, pending a more complete removal of dead and dying trees next year, according to the release. Motorists can expect to see equipment and personnel near the highway, and should anticipate some slowing or stopping during the operation.