In a perfect world, perhaps pulling invasive weeds by hand would make sense. But when you’re dealing with such things as knapweed, as the U.S. Forest Service is in its current spray program in Central Oregon forests, hand pulling is no solution at all.
Thus, despite challenges from the Blue Mountains Biodiversity Project, the agency is right to go ahead and spray.
Knapweed, one of the targeted weeds, is difficult to pull correctly, and failure to do the job right only serves to spread the pest. This time of year, seed heads must be bagged and the plants destroyed. Earlier, before knapweed flowers, improper pulling can break the taproot and fail to kill the plant.
Most animals, meanwhile, won’t eat knapweed and the plant itself chokes out native plants they will eat. It fuels fires, prevents native plants from germinating and lessens biodiversity in part by forcing native animals to look elsewhere for their food.
Cheatgrass, commonly a range plant that is beginning to move into relatively low-elevation forests, also wreaks havoc on the land it invades and on the animals that live on that land. On rangeland, meanwhile, cheat is in part responsible for loss of sage grouse habitat which, if it continues, will force the listing of that bird under the Endangered Species Act. It also provides excellent fuel for range fires.
As for pulling such weeds, experts say knapweed can be controlled in small areas — one-quarter acre or less — by hand pulling, but the process must be repeated over a period of years to be successful. Neither does cheat lend itself to control by pulling.
That leaves the Forest Service with two options. One, let the plants invade, forcing out animals and native plants. Be prepared, however, for the nearly certain damage by fire, loss of native plants and animals, loss of recreation opportunities and all the rest.
Or, the Forest Service can, as it is doing in the Deschutes forest, spray and hope to control invasive weeds that way. If healthy forests, populated by the plants and animals that make up the natural ecosystem is the goal, however, spraying is surely the best option.