From Bushwalk Australia
Any boards placed in, on, or above the ground as part of a walking track.
Duck boards are used to avoid further damage to the ground by the repeated trampling of bushwalkers and/or to make walking easier than it would otherwise have been. Duck boards are most commonly used in Tasmania over Bogs to prevent the mud getting worse, and to prevent people from walking around the mud which would eventually damage surrounding vegetation.
On Tasmanian walking tracks, duck boards range from rough split logs laid on the ground, through long single sawn logs or long double planks laid end-to-end, to square cut treated pine board walks built as a deck above the ground.
They often have chicken wire nailed on top to provide grip when wet, as duck boards can be very slippery. Other forms of grip that is sometimes added are cross-cut grooves, or bitumen.
Split logs (or cords) laid across the track are also known as cordwood.
Single, double or triple sawn planks laid longitudinally, with "sleepers" at regular intervals, are also know as parallel planking. Both of these techniques are generally laid on or low to the ground.
Elevated techniques are more commonly known as duckboard. These usually consist of sawn bearers and decking, with posts driven alongside the bearers to raise the structure off the ground (generally less than 300mm off the ground or above surrounding vegetation).