Abatis in front of the Union trench lines at Petersburg in 1865

An abatis, abattis, or abbattis is a field

fortification A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere'' ...

consisting of an obstacle formed (in the modern era) of the branches of trees laid in a row, with the sharpened tops directed outwards, towards the enemy. The trees are usually interlaced or tied with

wire Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm A wire is a flexible strand of metal. Wire is c ...

. Abatis are used alone or in combination with

wire entanglement In the military science of fortification, wire obstacles are defensive obstacles made from barbed wire, barbed tape or concertina wire. They are designed to disrupt, delay and generally slow down an attacking enemy. During the time that the at ...

s and other obstacles. In Slavic languages it is known as ''zaseka'', a position behind sharpened objects.

History

There is evidence it was used as early as the

Roman Imperial The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Roman Republic, Republican period of ancient Rome. As a polity, it included large territorial holdings aro ...

period, and as recently as the

American Civil War The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states th ...

and the

Anglo-Zulu War The Anglo-Zulu War was fought in 1879 between the British Empire and the Zulu Kingdom. Following the passing of the British North America Act of 1867 forming a federation in Canada, Lord Carnarvon thought that a similar political effort, coupl ...

of 1879. A classic use of an abatis was at the

Battle of Carillon The Battle of Carillon, also known as the 1758 Battle of Ticonderoga, Chartrand (2000), p. 57 was fought on July 8, 1758, during the French and Indian War (which was part of the global Seven Years' War). It was fought near Fort Carillon (now k ...

(1758) during the Seven Years' War. The 3,600 French troops defeated a massive army of 16,000 British and Colonial troops by fronting their defensive positions with an extremely dense abatis. The British found the defences almost impossible to breach and were forced to withdraw with some 2,600 casualties. Other uses of an abatis can be found at the

Battle of the Chateauguay The Battle of the Chateauguay was an engagement of the War of 1812. On 26 October 1813, a combined British and Canadian force consisting of 1,530 regulars, volunteers, militia and Mohawk warriors from Lower Canada, commanded by Charles de Sal ...

, 26 October 1813, when approximately 1,300

Canadian Voltigeurs The Canadian Voltigeurs were a light infantry unit, raised in Lower Canada (the present-day Province of Quebec) in 1812, that fought in the War of 1812 between Britain and the United States. History Formation As war with the United States threate ...

, under the command of Charles-Michel de Salaberry, defeated an American corps of approximately 4,000 men, or at the

Battle of Plattsburgh The Battle of Plattsburgh, also known as the Battle of Lake Champlain, ended the final British invasion of the northern states of the United States during the War of 1812. An army under Lieutenant General Sir George Prévost and a naval squadro ...

Construction

An important weakness of abatis, in contrast to

barbed wire A close-up view of a barbed wire Roll of modern agricultural barbed wire Barbed wire, also known as barb wire, is a type of steel fencing wire constructed with sharp edges or points arranged at intervals along the strands. Its primary use is t ...

, is that it can be destroyed by

fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition ...

. Also, if laced together with

rope A rope is a group of yarns, plies, fibres, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting. Rope is thicker and stronger than similarly ...

instead of

, the rope can be very quickly destroyed by such fires, after which the abatis can be quickly pulled apart by

grappling hook A grappling hook or grapnel is a device that typically has multiple hooks (known as ''claws'' or ''flukes'') attached to a rope; it is thrown, dropped, sunk, projected, or fastened directly by hand to where at least one hook may catch and hol ...

s thrown from a safe distance. An important advantage is that an improvised abatis can be quickly formed in forested areas. This can be done by simply cutting down a row of trees so that they fall with their tops toward the enemy. An alternative is to place explosives so as to blow the trees down.

Modern use

Abatis are rarely seen nowadays, having been largely replaced by

wire obstacle In the military science of fortification, wire obstacles are defensive obstacles made from barbed wire, barbed tape or concertina wire. They are designed to disrupt, delay and generally slow down an attacking enemy. During the time that the atta ...

s. However, it may be used as a replacement or supplement when

is in short supply. A form of giant abatis, using whole trees instead of branches, can be used as an improvised anti-

tank A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engin ...

obstacle. Though rarely used by modern conventional military units, abatises are still officially maintained in

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

and

Marine Corps Marines, or naval infantry, are typically a military force trained to operate in littoral zones in support of naval operations. Historically, tasks undertaken by marines have included helping maintain discipline and order aboard the ship (refle ...

training. Current US training instructs engineers or other constructors of such obstacles to fell trees, leaving a stump, in such a manner as the trees fall interlocked pointing at a 45-degree angle towards the direction of approach of the enemy. Furthermore, it is recommended that the trees remain connected to the stumps and the length of roadway covered be at least . US military maps record an abatis by use of an inverted "V" with a short line extending from it to the right.

and

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through combi ...

, ''FM 101-5-1/MCRP 5-2A Operational Terms and Graphics'', 30 September 1997

Notes

References

External links