An annual 200-acre treatment limit on the U.S. Forest Service's invasive plant management program in the 3.7-million-acre Wrangell-Petersburg district has the agency revamping and possibly expanding its efforts to eradicate foreign weeds that could damage the ecosystem and economy.

Since 2015, the Forest Service has been pulling, digging and spot-spraying plants like knotweed and canarygrass that are not naturally occurring in Southeast. But project managers say it's not enough and they need to increase the acreage and means of killing the plants.

The proposed actions would include no annua...