Black Hills National Forest crews plan to thin and burn trees and brush on about 18,000 acres this fall, with one major prescribed burn coming as early as Tuesday near Spear-fish.

About half of the 18,000 acres will be burned with prescribed fire, and the other half will be thinned by machines and by hand, according to Frank Carroll, public affairs officer for the Black Hills National Forest.

"We've got a pretty ambitious target this year," Carroll said. Forest officials hope to treat about 14,000 acres next year.

The thinning and prescribed burns are aimed at reducing fuels for wildfires, Carroll said.

The Griggs prescribed fire southwest of Spearfish is aimed at burning about 1,900 acres. Carroll said that fire could begin as early as Tuesday and will be very visible to Spearfish residents.

"The Griggs fire is especially important because it will be protecting one piece of a flank of Spearfish," he said.

"If we're going to make a difference, we have to light fires close to our communities," Carroll said. "We have to burn so big fires can't get a running and jump at our towns."

Carroll said low-intensity ground fires done with prescribed burning help prevent high-intensity fires that threaten and destroy homes, such as the Alabaugh Fire this year and the East Ridge Fire in 2006.

Prescribed burns can be done in the fall or spring.

Before every prescribed fire, burn personnel use site-specific weather forecasts, including temperatures, humidity, winds and smoke dispersal conditions, to determine whether to burn or not, according to a Forest Service news release.

Other planned fuels treatment areas this fall include:

- The 840-acre West Snugget burn east of Slate Creek dam, about eight miles northwest of Hill City and four miles southwest of Silver City. That burn could begin as early as Tuesday.

- The Horse Nugget burn in the upper Horse Creek drainage in western Pennington County, 165 acres.

- The Buffalo unit near the intersection of S.D. Highway 44 and U.S. Highway 385, 165 acres.

- Bald Hills unit, 689 acres, on the east side of Highway 385 between Sheridan Lake and Pactola Reservoir.

- West Rim Project near Cheyenne Crossing at the intersection of U.S. Highway 85 and U.S. Highway 14A, 53,157 acres. The burn is aimed at reducing hazardous fuels and the risk of mountain pine beetle infestation. Of the 53,157 acres in the project area, 10,000 acres are private land and will not be treated.

- The Picnic/Cavern/Kine prescribed burn about three miles northeast of Steamboat Rock Picnic Ground, 1,300 acres. The burn has a target date of mid-September to Nov. 15 or March 1, 2008, to April 30, 2008.

- Sundance Hazardous Fuels burn, 1,359 acres, three to eight miles northwest of Sundance, Wyo. The target date is September to Nov. 15.

In addition, smoke from slash piles burning will be seen in the Spearfish Canyon area, Beaver Park fuel breaks along Forest Roads 139 and 169, Crook Mountain south of Whitewood, Lawrence County Road 044 south of Deadwood and east of Highway 385, and near the O'Neil Pass area.

The Bearlodge District will be burning slash piles in the Snapper Timber Sale in the Blacktail Drainage, Wish Timber Sale near the Black Buttes - east of Highway 385, and just above the Vista West Subdivision near Reuter Campground.

The slash pile burning will be done only with sufficient snow cover.

For more information, go to www.fs.fed.us/r2/blackhills.

Contact Steve Miller at 394-8417 or steve.miller@rapidcityjournal.com