NEW ORLEANS (AP) — More than 8,000 bundled Christmas trees are to be airdropped Wednesday into a wildlife refuge in New Orleans as a way to slow erosion.

The bundles will create breakwaters to slow wave and water movement, trap silt, and encourage the growth of marsh grasses in the Bayou Sauvage National Wildlife Refuge, the U.S. Fish and Wildlife Service said in a news release Tuesday.

To avoid contamination, the project uses only real trees which have never been sprayed with any flocking, paint or chemical. Last year's collection totaled more than 6,000 trees.

Christmas tree breakwaters and other work have brought back nearly 100 acres (40 hectares) in an area called Blind Lagoon, Refuge Manager Shelley Stiaes said in a phone interview Tuesday. For about five years, she said, trees and plantings have been going on in an area called the Joe Madere Unit.

"We're watching it slowly come back," she said.

The Louisiana Army National Guard hauls and drops the trees as a helicopter training exercise. New Orleans' Office of Resilience and Sustainability provides money and collaborates with the Department of Sanitation for this effort. Last year Orleans Parish residents put more than 6,000 trees into the recycling program giving them an important role in coastal restoration.