29.3.4: Trench Warfare

Trench Warfare in World War I

Trench warfare occurs when a revolution in firepower is not matched by similar advances in mobility, resulting in a grueling form of warfare in which the defender holds the advantage. Military tactics developed before World War I failed to keep pace with advances in technology and became obsolete. These advances had allowed the creation of strong defensive systems, which out-of-date military tactics could not break through for most of the war. Barbed wire was a significant hindrance to massed infantry advances, while artillery vastly more lethal than in the 1870s, coupled with machine guns, made crossing open ground extremely difficult. Commanders on both sides failed to develop tactics for breaching entrenched positions without heavy casualties. In time, however, technology began to produce new offensive weapons, such as gas warfare and the tank.

On the Western Front in 1914–18, both sides constructed elaborate trench and dugout systems opposing each other along a front, protected from assault by barbed wire, mines, and other obstacles. 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.

Just after the First Battle of the Marne (September 5-12, 1914), Entente and German forces repeatedly attempted maneuvering to the north in an effort to outflank each other, a strategy that became known as the “Race to the Sea.” When these outflanking efforts failed, the opposing forces soon found themselves facing an uninterrupted line of entrenched positions from Lorraine to Belgium’s coast Britain. France sought to take the offensive while Germany defended the occupied territories. Consequently, German trenches were much better constructed than those of their enemy; Anglo-French trenches were only intended to be “temporary” before their forces broke through the German defenses.

Trench warfare prevailed on the Western Front from late 1914 until the Germans launched their Spring Offensive on March 21, 1918. After the buildup of forces in 1915, the Western Front became a stalemated struggle between equals to be decided by attrition. The small, improvised trenches of the first few months grew deeper and more complex, gradually becoming vast areas of interlocking defensive works. They resisted both artillery bombardment and mass infantry assault. Shell-proof dugouts became a high priority. 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 massed artillery. There were periods in which rigid trench warfare broke down, such as during the Battle of the Somme, but the lines never moved very far. The war would be won by the side able to commit the last reserves to the Western Front.

Neither side delivered a decisive blow for the next two years. Throughout 1915–17, the British Empire and France suffered more casualties than Germany because of the strategic and tactical stances chosen by the sides. Strategically, while the Germans only mounted one major offensive, the Allies made several attempts to break through the German lines.

In February 1916 the Germans attacked the French defensive positions at Verdun. Lasting until December 1916, the battle saw initial German gains before French counter-attacks returned them near their starting point. Casualties were greater for the French, but the Germans bled heavily as well, with anywhere from 700,000 to 975,000 casualties suffered between the two combatants. Verdun became a symbol of French determination and self-sacrifice.

The Battle of the Somme was an Anglo-French offensive of July to November 1916. The opening of this offensive (July 1, 1916) saw the British Army endure the bloodiest day in its history, suffering 57,470 casualties, including 19,240 dead, on the first day alone. The entire Somme offensive cost the British Army some 420,000 casualties. The French suffered another estimated 200,000 casualties and the Germans an estimated 500,000.

The last large-scale offensive of this period was a British attack (with French support) at Passchendaele (July–November 1917). This offensive opened with great promise for the Allies before bogging down in the October mud. Casualties, though disputed, were roughly equal at some 200,000–400,000 per side.

These years of trench warfare in the West saw no major exchanges of territory and, as a result, are often thought of as static and unchanging. However, throughout this period, British, French, and German tactics constantly evolved to meet new battlefield challenges.

Trench Warfare: Trenches of the 11th Cheshire Regiment at Ovillers-la-Boisselle, on the Somme, July 1916. One sentry keeps watch while the others sleep. Photo by Ernest Brooks.

Development of Advanced Weaponry
Both sides tried to break the trench stalemate using scientific and technological advances. On April 22, 1915, at the Second Battle of Ypres, the Germans (violating the Hague Convention) used chlorine gas for the first time on the Western Front. After a two-day bombardment, the Germans released a cloud of 171 tons of chlorine gas onto the battlefield. Though primarily a powerful irritant, it can asphyxiate in high concentrations or prolonged exposure. The gas crept across no man’s land and drifted into the French trenches. The green-yellow cloud killed some defenders and those in the rear fled in panic, creating an undefended 3.7 mile gap in the Allied line. The Germans were unprepared for the level of their success and lacked sufficient reserves to exploit the opening. Canadian troops on the right drew back their left flank and repelled the German advance.

The success of this attack would not be repeated, as the Allies countered by introducing gas masks and other countermeasures. The British retaliated, developing their own chlorine gas and using it at the Battle of Loos in September 1915. Fickle winds and inexperience led to more British casualties from the gas than German. Several types of gas soon became widely used by both sides, and though it never proved a decisive, battle-winning weapon, poison gas became one of the most-feared and best-remembered horrors of the war. French, British, and German forces all escalated the use of gas attacks through the rest of the war, developing the more deadly phosgene gas in 1915, then the infamous mustard gas in 1917, which could linger for days and kill slowly and painfully. Countermeasures also improved and the stalemate continued.

Tanks were developed by Britain and France, and were first used in combat by the British during the Battle of Flers–Courcelette (part of the Battle of the Somme) on September 15, 1916, with only partial success. However, their effectiveness would grow as the war progressed; the Allies built tanks in large numbers, whilst the Germans employed only a few of their own design supplemented by captured Allied tanks.
Attributions
Trench Warfare

“Trench Warfare.” https://en.wikipedia.org/wiki/Trench_warfare. Wikipedia CC BY-SA 3.0.

“Western Front (World War I).” https://en.wikipedia.org/wiki/Western_Front_(World_War_I). Wikipedia CC BY-SA 3.0.

“World War I.” https://en.wikipedia.org/wiki/World_War_I. Wikipedia CC BY-SA 3.0.

“Cheshire_Regiment_trench_Somme_1916.jpg.” https://commons.wikimedia.org/wiki/File:Cheshire_Regiment_trench_Somme_1916.jpg. Wikimedia Commons Public domain.