As the trees shed their fall colors, municipalities gear up for their annual battle: cleaning up the leaves that carpet lawns, sidewalks and streets.

It’s a task each municipality tackles differently, but with the same goal in mind — keeping their residents happy and their properties looking well-kept.

Butler City Councilman Richard Schontz Jr., who directs the city Streets Department, said workers on leaf detail roll with the season.

“It’s kind of dictated by how long it takes the leaves to fall,” Schontz said.

The city runs a crew of five who use a vehicle-mounted vacuuming system and leaf blowers to remove leaves that residents collect and pile near their property.

This year the city’s program formally began Wednesday, though workers have been vacuuming up leaves for weeks as individual residents call in with requests. The city tries to respond to all requests within a day or two, Schontz said.

“The public, they really like the program,” he said. “It saves them a lot of work.”

City residents can also bag up leaves themselves and haul them to a collection site at the former city dump near Butler Memorial Park, Schontz said.

He said there’s no way to quantify the debris the city cleans up each fall.

“All I know is that it’s a heck of a lot of leaves,” Schontz said.

If you think you know why leaves blanket the ground this time of year — colder temperatures that kill them off; wind and rain blow or knock them down — you’re probably wrong.

The real reason is actually much more interesting. Instead of the wind pulling leaves off trees or rain knocking them off, the trees themselves actually actively throw their leaves off.

The phenomenon starts when colder, shorter days trigger the production of a hormone in the trees that primes certain cells in each leaf’s stem to push the leaf away from its connection to the tree.

The microscopic process primes the leaves, which are left hanging by a literal thread, to be finished off and dropped by a breeze or a spat of rain.

The result is tons of compost-ready material and weeks of work for municipalities such as Slippery Rock, which like Butler uses a truck-mounted vacuum system to suck up fallen leaves along curbs.

Borough administrator Lucinda Litko said the borough’s program runs from Oct. 19 through Dec. 4, and it produces more leaf debris than she can track.

“I could not even begin to give you an idea how much (is collected),” Litko said. “There’s a lot, and we get a lot of people who participate,” in the program.

Once the leaves are vacuumed up, Litko said, the borough hauls them to Harmony House on Harmony Road where they’re composted and used for mulch.

Other municipalities, like Center and Butler townships, contract with companies to dispose of residents’ leaves.

Both municipalities sell biodegradable bags to residents and have designated days or periods when leaf pickup or drop-off can take place.

Center Township, where workers collect curbside leaf bags on a daily basis, collected 213 tons of leaf debris last year, said secretary-treasurer Anthony Amendolea.

The township takes the debris to a drop off site on Hendricks Road and contracts with a Summit Township company that hauls it off to be recycled.

Butler Township manager Ed Kirkwood said the township doesn’t track the weight of leaf collections, but does provide 8,000 to 10,000 leaf bags to residents.

Residents can pack the bags and set them out for pickup by Vogel Disposal Service, which hauls the debris to a composting site.