At a Glance

Quick response along with an integrated management–treatment system has significantly reduced non-native invasive weed recruitment on more than 65,000 acres of the San Juan National Forest lands.

Project Description

For two months beginning in June 2002 fires burned over 70,000 acres of Missionary Ridge and surrounding lands within the San Juan National Forest. The U.S. Forest Service, concerned about the spread of noxious weed species, retained Biohabitats to identify, inventory, and treat noxious weeds over a 65,000-acre area for a period of three years. Noxious weeds of concern include the musk thistle (Carduus nutans), houndstongue (Cynoglossum officinale), bull thistle (Cirsium vulgare), yellow toadflax (Linaria vulgaris), oxeye daisy (Chrysanthemum leucanthemum), and spotted knapweed, (Centaurea maculosa) among others. Using an adaptive management approach, Biohabitats first focused inventory and treatment efforts on disturbed areas that are likely sites for noxious weed recruitment. 

Field data for both the weed inventory and weed treatment phases of the project were collected and recorded on Trimble XP GPS units using a customized data dictionary that greatly facilitates the acquisition and analysis of the data. This data was electronically transmitted to the Biohabitats office in Maryland, where the data was reviewed and checked for quality assurance. The data was then entered into a Geographic Information System and mapped to illustrate the extent and severity of the noxious weed infestations. This mapping then allowed the team to prioritize and select areas for on-the-ground treatment. 

Working with Southwest Weed Control, selected weed infestations were then treated with approved herbicides. With Forest Service concurrence, herbicides were applied from the ground using various types of equipment such as an ATV, backpack sprayer, and horse-mounted sprayers.



Southern Rocky Mountain

Physiographic Province

Southern Rocky Mountain


Colorado River

Expertise Areas



U.S. Forest Service


Durango, Colorado, United States

Project Team
  • Southwest Weed Control