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Over the next several days, crews in the Santa Catalina Mountains will be burning wood gathered in a forest thinning operation.

About 20 acres of wood will be burned on Mount Bigelow and in Spencer Canyon over several days, according to the Coronado National Forest.

"Mount Bigelow and Spencer Canyon are between mile posts 20 and 25 on the Catalina Highway. They are in an area that is facing Tucson, so when smoke starts to rise, there's a very good possibility that it will be visible to folks here in town," said Coronado National Forest's Heidi Schewel.

The thinning project is part of an effort to create a healthier forest.

Three Republican senators, including U.S. Sen. John McCain, introduced a proposal this week to have 2009's FLAME Act include funding to aggressively thing forests, among other wildfire prevention programs and fighting methods.

Officials also say they had been waiting for sufficient rain to begin burning the wood.