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Saguaro National Park Resumes Aerial Treatments
to Control Buffelgrass
Tucson, AZ - Possibly beginning as soon as Wednesday, Aug. 15, Saguaro National Park plans to begin this year’s aerial spraying treatments to control the spread of buffelgrass in the Rincon Mountain District (east side). The start date will depend on when we receive rain.
A helicopter with a spray boom is used in areas of the park inaccessible to ground crews. This is the fifth year that the park has used a helicopter to treat dense patches of buffelgrass with glyphosate during the monsoon. The park considers weather conditions before beginning treatment each day, including wind direction and wind speed, to ensure that the rain-sized droplets reach only their intended target areas. The exact starting date and time will depend upon these conditions, and it will last 5 to 8 days, mostly depending on the weather.
“The monsoon is difficult to predict, so we wait for the buffelgrass to show when it is at the optimal time to spray," according to Ray O’Neil, Acting Superintendent of Saguaro National Park. “The treatment is most effective generally in the middle of the monsoon season and when the grass has greened up and is actively growing. We also spray with only very light winds."
During treatment, the Tanque Verde Ridge Trail and Rincon Creek Trail in the Rincon Mountain District (east) will be temporarily closed, for 1-2 days in each area. Due to success in killing buffelgrass at Panther Peak, aerial spraying with the boom is not needed in the Tucson Mountain District (west side) of the park.
The accompanying map shows the general locations of helicopter boom-spraying treatments. Updates providing locations of closures due to aerial spraying will be available on the park’s website: www.nps.gov/sagu. Later in the monsoon, a helicopter with a spot-sprayer may be used for a few days for smaller patches in both districts.
The prescribed treatment of buffelgrass is within guidelines approved by the National Park Service in 2014 as part of a Restoration Plan and Environmental Assessment. That document includes aerial application of herbicide to control invasive, non-native plants in places that are unsafe or too remote for control by ground crews. Ground-based crews and volunteers will continue to control undesirable plants in accessible areas with manual pulling and herbicide from backpack sprayers.
Buffelgrass spreads exponentially, and significant efforts are required to reverse its expansion. It crowds out native plants and can pose a serious fire threat, not only to desert plants like the saguaro, but also to homes and property. In 2012 when the park was last mapped for buffelgrass infestation, there were approximately 2,000 acres of parkland with the invasive grass. Last year, about 540 acres of buffelgrass-infested park lands were aerially treated with herbicide, and follow-up monitoring has indicated a significant decrease in buffelgrass in treated areas.
Additional information on buffelgrass and the threat it poses to the park, as well as the park’s Restoration Plan and Environmental Assessment, are also available at: https://www.nps.gov/sagu/learn/management/restoration-plan.htm andhttps://www.nps.gov/sagu/learn/nature/buffelgrass.htm.
To help the park by joining us in digging up buffelgrass, visit: https://www.nps.gov/sagu/getinvolved/supportyourpark/monthly-buffelgrass-pull.htm
Source: U.S. Department of the Interior, National Park Service
