Trolls stand guard over the nature haven of Morton Arboretum in Illinois, USA

Danish artist Thomas Dambo stands beside his creation, Joe the Guardian, one of the six larger-than-life-trolls in Morton Arboretum in Lisle, Illinois, the United States, overlooking Highway 53. Dambo and his team created the trolls using hundreds of pieces of reclaimed wood, battered boards, fallen trees and branches.

The troll dubbed Joe peers out over the Ronald Reagan Memorial Tollway and the suburban sprawl beyond, one hand shielding his brow as he scans the horizon, the other holding a giant spear.

He is a handmade, deliberately secondhand thing, his body pieced together from discarded shipping pallets, his hair a tangle of trimmed branches, the spear a ramrod-straight trunk of a conifer that had to be chopped down.