Trench Warfare

Trench warfare occurred when a revolution in firepower was not matched by similar advances in mobility, resulting in a grueling form of warfare in which the defender held the advantage. In World War I, both sides constructed elaborate trench and dugout systems opposing each other along a front, protected from assault by barbed wire. The area between opposing trench lines (known as "no man's land") was fully exposed to artillery fire from both sides. Attacks, even if successful, often sustained severe casualties as a matter of course.

Trench warfare prevailed on the Western Front from 16 September 1914 until the Germans launched their Spring Offensive on 21 March 1918. After the buildup of forces in 1915, the Western Front became a stalemated struggle between equals. Frontal assaults, and their associated casualties, became inevitable because the continuous trench lines had no open flanks. Casualties of the defenders matched those of the attackers, as vast reserves were expended in costly counter-attacks or exposed to the attacker's artillery.

Mortars, which lobbed a shell in a high arc over a relatively short distance, were widely used in trench fighting for harassing the forward trenches, for cutting wire in preparation for a raid or attack, and for destroying dugouts, saps and other entrenchments.

Early trenches were simple. According to pre-war doctrine were to be packed with men fighting shoulder to shoulder, leading to heavy casualties from artillery fire. This, and the length of the front to be defended, soon led to front line trenches being held by fewer men. In addition to the trenches themselves, barbed wire was strung up to impede movement, and wiring parties went out every night to improve these forward defences.

Fighting trenches were usually about 12 feet deep. Trenches were never straight but were dug in a zigzagging or stepped pattern. Later fighting trenches broke the line into firebays connected by traverses. This meant that a soldier could never see more than 10 yards or so along the trench. (If a bomb or shell landed in the trench, the blast could not travel far.)

Dugouts of varying degrees of luxury would be built in the rear of the support trench. British dugouts were usually 8 to 16 feet deep, whereas German dugouts were typically much deeper, usually a minimum of 12 feet deep and sometimes dug three stories down, with concrete staircases to reach the upper level

The banked earth on the lip of the trench facing the enemy was called the parapet and had a fire step. The embanked rear lip of the trench was called the parados. The parados protected the soldier's back from shells falling behind the trench. The sides of the trench were often revetted with sandbags, wooden frames and wire mesh. The floor of the trench was usually covered by wooden duckboards. In later designs the floor might be raised on a wooden frame to provide a drainage channel underneath.

An individual unit's time in the front-line trench was usually brief; from as little as one day to as much as two weeks at a time before being relieved. The 31st Australian Battalion once spent 53 days in the line at Villers-Bretonneux, but such a duration was a rare exception.

On an individual level, a typical British soldier's year could be divided as follows:

15% front line

10% support line

30% reserve line

20% rest

25% other (hospital, traveling, leave, training courses, etc.)

sectors still amassed daily casualties through sniper fire, artillery, disease, and poison gas. About 1 in 2 men would return alive and unwounded from the trenches

During the day, snipers and artillery observers in balloons made movement perilous, so the trenches were mostly quiet. Consequently, trenches were busiest at night, when cover of darkness allowed the movement of troops and supplies, the maintenance and expansion of the barbed wire and trench system, and reconnaissance of the enemy's defences.

The common infantry soldier had only a few weapons to use in the trenches: the rifle, bayonet, and hand grenade.

Chateau Wood, Ypres, 1917

A specialized group of fighters called trench sweepers (Nettoyeurs de Tranchées or Zigouilleurs) evolved to fight within the trenches. They cleared surviving enemy personnel from recently overrun trenches and made clandestine raids into enemy trenches to gather intelligence. Volunteers for this dangerous work were often exempted from participation in frontal assaults over open ground and from routine work like filling sandbags, draining trenches, and repairing barbed wire in no-man's land. When allowed to choose their own weapons, many selected grenades, knives and pistols.

Trench Warfare

Trench Life

Structure

What is it?

The End Result

The intensity of World War I trench warfare meant about 10% of the fighting soldiers were killed. This compared to 5% killed during the Second Boer War and 4.5% killed during World War II. For British and Dominion troops serving on the Western Front, the proportion of troops killed was 12.5%, while the total proportion of troops who became casualties (killed or wounded) was 56%.

Sanitary conditions in the trenches were quite poor, and common infections included dysentery, typhus, and cholera. Many soldiers suffered from parasites and related infections. Poor hygiene also led to fungal conditions, such as trench mouth and trench foot. Another common killer was exposure, since the temperature within a trench in the winter could easily fall below freezing. Burial of the dead was usually a luxury that neither side could easily afford. The bodies would lie in no man's land until the front line moved, by which time the bodies were often unidentifiable.