It will take years, even decades, to see the full impact of their work, but local volunteers this weekend are winding up an effort to plant 15,000 trees in the Shanksville, Pa., area where United Airlines Flight 93 crashed during the terrorist attacks of Sept. 11, 2001.


More than two dozen employees of Davey Tree Expert Co. and their families have spent the last two weekends participating in the Flight 93 National Memorial Reforestation Project, which is hoping to return a lush landscape to the abandoned strip mine that has become a focal point of mourning and inspiration.


The 40 people aboard that Boeing 757 flight died after trying to wrest control of the plane from four al-Qaeda hijackers who it was presumed were planning to crash the plane into a Washington, D.C., target.


A 2,000-acre memorial park is being created in their honor. A plaza and a 3.5-mile road through the park have been completed; other features have yet to be constructed.


But reclaiming the land for the park is a challenge because of the stripped and rocky soil.


“It’s also very windy on the site, so the trees are going to have a tough battle ahead,” said Karen Wise, manager of Davey’s Natural Resources Consulting group who spent Friday planting pine trees, hardwoods and shrubs.


Davey consulted with the National Park Service to determine which species have the best chance of surviving on the barren landscape, then donated 10,000 seedlings from 8 inches to 18 inches high.


Davey volunteers — 10 from the Kent headquarters and 14 from the Pittsburgh and various mid-Atlantic offices — were among 600 people working to plant the trees last weekend and this weekend.


Elaine Mattern, Davey Tree’s project manager, said as part of Arbor Day this month, Davey also donated 10,000 seedlings to efforts in Joplin, Mo., and northern Alabama to restore areas ravaged by last spring’s tornadoes, and another 5,000 to the Angeles National Forest Wildfire Relief Project in California.


Mattern said it was easy finding Davey Tree employees to give their time to the project in Pennsylvania.


“They were honored to be a part of it. They thought it was a fitting way to honor the heroes,” she said.


Wise said she has been helping with the Flight 93 project for four years, both as a volunteer and as a Davey employee during some contracted work, so this weekend’s effort “was a no-brainer for me. I wanted to be a part of it.”


While it will take decades for the trees to look like a forest, the 15-year Davey employee said, “I think in 15 years, you’ll certainly see a difference.”


Paula Schleis can be reached at 330-996-3741 or pschleis@thebeaconjournal.com. Follow her on Twitter at http://twitter.com/paulaschleis.