Resource Management

Noxious Weeds and the Payette NF

Noxious weed infestations pose a serious threat to the diversity, integrity, and health of the plant communities in the Payette National Forest, which in turn can have negative impacts on recreational experiences, timberlands, wildlife/fisheries habitat, and watershed stability. They can create monocultures that eliminate diverse plant communities. Watersheds dominated by noxious weeds tend to be less efficient in absorbing and storing water resulting in increased soil erosion. Noxious weeds can reduce forage production for all classes of herbivores and reduce habitats for small birds and animals. Several noxious weed species can cause physical discomfort or irritation to humans due to barbs, spines and prickles.

The State of Idaho has designated 36 species of weeds as noxious by law, 11 of which are known to exist on the Payette National Forest. Five other invasive weeds are also present and managed in conjunction with the noxious weeds. An estimated 117,000 acres of Payette National Forest lands are infested with weeds, the majority of which are closely associated with roads and other areas of disturbance. The Payette National Forest actively manages noxious weeds by hiring inventory and treatment personnel to work on Forest priorty projects, as well as through Cooperative Weed Management Areas (CWMAs). CWMAs are community-based weed management organizations that have banded together to build coordinated and integrated weed management programs within a given geographical area. The Payette National Forest participates with four CWMAs to improve the efficiency and effectiveness of noxious weed management across the Forest.

The following lists are the State designated noxious and invasive weeds that can be found on the Payette National Forest.

Noxious weeds

  • yellow toadflax
  • dalmation toadflax
  • Canada thistle
  • spotted knapweed
  • diffuse knapweed
  • rush skeletonweed
  • leafy spurge
  • scotch thistle
  • poison hemlock
  • white top

Invasive Species

  • St Johnswort
  • tall larkspur
  • bull thistle
  • houndstongue
  • sulfur cinquefoil

Visit the Web Sites listed below for more information on Weeds