Zion National Park officials hope to interrupt the life cycle of cheatgrass, a highly flammable, invasive plant that fuels wildfires, by spraying herbicide over thousands of burned acres within the park.

"Cheatgrass is a cool season plant. It emerges earlier than other grasses and eliminates diversity," said Kelly Fuhrmann, a fire ecologist with Zion National Park. "Following a fire, one of the main concerns is the ability of native plants to recover, and cheatgrass doesn't allow anything else to compete with it."

In July, the Dakota Hill fire complex included two lightning-caused fires that burned nearly 5,900 acres within the park. Another 10,000 acres were consumed in the Kolob fire last year, searing the land of its native vegetation and giving cheatgrass a chance to take over.

Flash flooding that occurred downstream from the Dakota and Kolob fires this year destroyed several homes and vehicles and damaged roads. Killing the cheatgrass that helped fuel those fires is a top priority since the grass tends to muscle out native plants and shorten the time between wildfires.

Park officials want to use helicopters to spray herbicides over the targeted area. If the herbicides are applied at the right time, said Fuhrmann, the grass-fire cycle that feeds cheatgrass can be slowed down enough for native plants to have a chance at making a comeback.

"If we had not reseeded some areas of Kolob last year, the growth of cheatgrass in the area would have been worse," he said.

Using cattle to graze the area can help, although cattle will eat cheatgrass only when it is supple and green. Once it dries, goats may be used to reduce the amount of cheatgrass, but it still requires herbicides to really make a difference, Fuhrmann said.

"We really need to get this treatment on the ground by fall or next spring," he said. Following a fire, cheatgrass tends to grow back more quickly and densely. Native shrubs and trees such as juniper are slower to re-establish after a fire, and some need years between fires to complete their life cycles, he said.

The National Park Service proposal includes using two herbicides, Plateau and Roundup, to treat the burned areas. Both herbicides have shown a low toxicity to humans, fish and wildlife, according to a park news release. A no-spray buffer zone will be included along all streams within the targeted area.

The park is preparing an environmental assessment to consider the impacts of the proposed aerial application of the herbicides. Send comments on the Dakota Hill fire rehabilitation plan to Zion National Park, Springdale, UT 84767. Comments will be accepted through Thursday.

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