There were five hundred men from the Sixth Division detailed to go out and cut down the timber in front of the fortifications around the camp. The trees are cut so as to make them fall outward toward the approach of an enemy; the branches are then sharpened, making what is called an abatis.
The trees in a space six hundred feet wide and twenty miles long are being felled. We had company inspection at 5 o'clock in the evening.
Source: Alexander G. Downing, Edited by Olynthus B., Clark, Downing’s Civil War Diary, p. 53-4