urban lumberjack
n. A logger who works in an urban environment collecting and selling wood retrieved from demolished buildings or downed trees.
Examples
2005
But no logs are falling. Instead, a crew from Portland's DeConstruction Services is dismantling a home built in the 1920s piece by old-growth piece. Its flooring, joists and paneling come from a time when old-growth wood was a construction staple, as easy to come by as the local lumberyard.

Today it's part of a long-forgotten forest emerging from floors and walls of buildings across Portland and the nation. It's being retrieved by a growing industry of urban lumberjacks and quickly bought up, often at bargain prices, by builders who prize its unmatched beauty, durability and history.
—Michael Milstein, “Better with age,” The Sunday Oregonian, January 23, 2005
1998
The sun has not risen as Jon Hoffman and Kurt Skinner begin their work day. The two men wearing heavy coveralls and protective gloves use muscle and machines to load huge timbers onto flatbed trucks for the journey to the sawmill.

Hoffman and Skinner are loggers, but their workplace is not a national forest or the wilderness of the great Northwest.

They are urban lumberjacks who harvest wood during the demolition of old buildings, then recycle it for use by remodelers and in new timber-frame homes.
—William Recktenwald, “Old Wood's Second Life,” The Chicago Tribune, January 04, 1998
1985 (earliest)
Baker, a retired lawyer for the Veterans Administration, began chopping down dead and dying trees on his property and elsewhere several years ago after he and his wife added a fireplace to their home at 308 North Walnut Street, which is within walking distance of the park.

When he noticed some dead and dying trees in the park, he asked park officials if he could clear them, in exchange for the wood, and they agreed. …

He has learned, too, that wood is a highly sought-after commodity, especially in the city. Once when he went home on a break from his work, he returned to find the logs he ahd left on the ground stolen. It taught the urban lumberjack a lesson. " I"ve learned to haul it as I've cut it,' he said.
—William Green, “Urban Lumberjack, 75, Cuts Dead Trees In LR Park in Exchange for the Firewood,” Arkansas Democrat-Gazette, January 16, 1985