Temporary closures in National Park for herbicide applications

Tamarisk trees crowd out native species, trap sediment and consume large amounts of water. Courtesy of NPS.

BIG BEND NATIONAL PARK –– From February 8 to February 10, a team will be cutting down and applying herbicide to invasive salt cedars (Tamarix spp.) in the Hot Springs area. During this time, visitors may encounter a temporary closure along the river from Gravel Pit to Hot Springs Canyon.

Tamarisk, also known as salt cedar, is an aggressive non-native group of closely related trees. These plants crowd out native species, trap sediment, and consume large amounts of water. To remove tamarisk, a resource crew will be cutting tamarisk trees along the Rio Grande from Gravel Pit to Hot Springs Canyon. Stumps will be treated with the herbicide Triclopyr using hand sprayers. Large woody debris will be left in place to provide better growing conditions for native plants and habitat features for native animals.

Hand applications of herbicide have been proven to kill the invasive trees without affecting native plants or animals. Triclopyr is approved by the EPA for use adjacent to aquatic ecosystems. This type of herbicide is a systemic herbicide that moves throughout plant tissue and mimics a hormone that is only found in plants. Treated plants experience uncontrolled growth and eventually die back.

With the removal of these invasive trees, the Rio Grande can better transport sediment downstream, opening up gravel bars and wider floodplains. This in turn benefits native plants, such as willows, and wildlife, such as freshwater mussels, fish, and beaver. Removing dense stands of salt cedar also opens up the banks of the river for recreational use.

This temporary closure and signage will be in place while herbicide is being applied, after which the area will reopen to entry.

This work is NOT expected to affect visitors to the historic Langford Hot Springs.