The night was very dark and it rained heavily, the roads were so bad that the troops had to cut trees and corduroy the road a part of the way, to get through.
1988, James McPherson, Battle Cry of Freedom, Oxford 2004, pp. 827-8:
But Sherman organized “pioneer battalions” of soldiers and freedmen ... to cut saplings and trees to corduroy the roads, build bridges, and construct causeways.