"is composed of a number of trees cut down, and arranged on the outside of the ditch along the whole front of the work : they are placed close together, and upon one another; and are so disposed that their branches are presented towards the enemy, and their trunks towards the work. When the branches of the trees are well intermingled, and their trunks either buried obliquely in the earth, or fastened to the ground by means of strong pickets driven across them, they cannot be removed so as to effect a passage through them, without great difficulty." [The first principles of field-fortification. Charles Augustus Struensee. London, 1800.]|
ABATIS, in a military sense, is formed by cutting down many entire trees, the branches of which are turned towards the enemy, and as much as possible entangled one into another. They are made either before redoubts, or other works, to render the attacks difficult, ... [An Universal Military Dictionary, Capt. George Smith. London, 1779.]
[Above] Section and plan of ramparts showing the branches of the abattis embedded in the ground.
[The first principles of field-fortification. Charles Augustus Struensee. London, 1800.]
[Right] An adaptation of the abattis, where a live bush or small tree is partially cut through as in plashing a hedge, to form a living barrier.
[Aide-Memoire to the Military Sciences. Abattis - Contours. Volume I, Part I. London: 1845.]
[Above] An image of a laid hedge showing the plashes.
Essays relating to agriculture and rural affairs. James Anderson. Edinburgh and London, 1777.
|Abattis is derived from the French word abattre meaning 'to knock down'. When used in reference to trees, it has the meaning of 'to cut down or fell'. It also carries the sense of 'to shoot down', 'to demoralize' and 'to exhaust', all which terms are appropriate to describe the function of an abattis.|
Examples of how effective these abattis could be are to be found in the military memoirs of 17th, 18th and 19th century soldiers. For example, William Truman, a Confederate artilleryman in the American Civil War, had witnessed an infantry attack that failed due to the impenetrability of an abbatis:
Nov 30th. 1864
Again, in the American Civil War, William Judkins, a Confederate infantry man, was part of a Confederate force advancing into Virginia near Chancellorville in 1863. He recalls his relief in not having to capture the enemy's position, defended as it was by a strong abattis:
Next morning we were ordered around to attack their position, but before we got in position to advance to the attack we found that the enemy had gone; We were glad of that for we never could have taken their position from the side that we were going to attack- for their breast- works were formed in a square on top of a hill, with a great deal of artillery all around, and an abattis all around for 200 yards an all sides- that is the bushes and saplings were cut down with the tops towards the way that we would have had to come, which we never could have gotten through, for the brush and bushes were piled as high as a man's head, and very thick.; the saplings not cut entirely off the stumps. It formed a labyrinth that was impossible to get through, and the enemy could have killed all of us, and we could have done them no harm.