WASHINGTON -- One hundred years after the U.S. entry into World War I, many of the logistics and strategies developed during that era still have an impact on Army operations today -- including the use of the division as a stand-alone unit, the employment of tactical armored vehicles, and the use of aircraft on the battlefield. Here are seven ways that the First World War still influences the Army today.

AIRPOWER

The major European armies possessed airplanes prior to August 1914, but no one believed they would play a major role during World War I. As with most technological advances in wartime, military aircraft proved to be a more vital tool in the war than anyone originally envisioned.

By mid-1915, European combatants sought to produce a new generation of superior warplanes every year. Aircraft development in the United States, however, remained stagnant because of limited funding and the Wright Brothers' efforts to monopolize the U.S aviation industry.

The American Expeditionary Forces Air Service was airborne over the Western Front in early 1918, using French and British planes. The American pilots faced experienced opponents that were equipped with the most capable combat aircraft at that time -- underscoring the necessity for the American forces to develop capable air resources of their own. Today, an entire military service, the Air Force, is dedicated to airpower.

CHEMICAL WEAPONS

Extensive chemical operations had been in place on the Western Front since April 1915, using phosgene, chlorine, and mustard gas. Although the German Army was the first to use chemicals, all nations were soon using chemical weapons.

The United States, however, entered the war unprepared for this particular weapon. The U.S. Army and Marine Corps had to rely on French and British expertise for chemical training, doctrine, and materiel. The Army eventually established a separate Chemical Warfare Service to coordinate the offensive, defensive, and supply problems inherent in chemical weapons.

Gas was responsible over a quarter of all American Expeditionary Forces casualties. While the U.S. military and most militaries no longer use chemical weapons in warfare in accordance with the Geneva Protocol, the Army's modern Chemical Corps still works to protect Soldiers against chemical and biological attacks.

COMMUNICATIONS

Electronic communication made tremendous advancements during World War I. Using transoceanic telegraph wires, American forces in Europe were able to maintain communication with their leaders back home.

American Signal Corps Soldiers built a large-scale communication network in France that included telephone and telegraph lines. In combat zones, telephone lines ran from divisional headquarters to the battalion level, and also between battalions. The Signal Corps used both earth telegraphy and field telephones.

Radio enabled air-to-air and air-to-ground communication for the first time. While much of this technology was initially limited, it created the first real-time communication network within a combat zone.

DIVISIONS

With the Army Service Regulations of 1914, the Army established the division as "a self-contained unit made up of all necessary arms and services, and complete in itself with every requirement for independent action incident to its operations."

The National Defense Act of 1916 called for permanent division headquarters in the Regular Army and National Guard. The summer of 1917 saw the creation of the first of these divisions, in response to the U.S. declaration of war in April of that year.

An American division in the First World War was organized in a "square" formation, consisting of two brigades, each with two infantry regiments, and any additional units (engineers, artillery, and signal) that the division needed to operate independently.

By Armistice Day, November 1918, the Army had fielded 63 infantry divisions, 43 of which had deployed to Europe.

DOCUMENTING COMBAT

During World War I, the Signal Corps undertook the mission to photograph military operations and collect photographs that would support a pictorial history of the war. In the AEF, the Signal Corps took about 35,000 still images and 900,000 feet of moving picture film.

The Signal Corps also served as the only archival repository for film images taken in France, and developed films and plates in Signal Corps facilities. Between the Army and civilians, over 400,000 images came out of the war. The Army War College became the home for this photographic archive in 1919.

THE 'G' SYSTEM

The American Expeditionary Forces General Headquarters was the first to implement what is now known as the "G" system in terms of its staff structure. The AEF General Staff was led by a chief of staff and divided into five sections. The sections were given a specific "G" designation (G--1 for administration, G--2 for intelligence, G--3 for operations, G--4 for coordination, and G--5 for training).

The system was disseminated throughout the AEF and later incorporated into the U.S. Army General Staff in the early 1920s. It has remained the basis for the Army's staff structure since that time. It was the model for the "J" system for joint forces and the "S" system for staffs below the division level.

TANKS

After two years of stalemate on the Western Front, the Allies started searching for technological solutions to break the deadlock. France and Britain independently began producing an armored chassis on caterpillar tracks, armed with cannon and machine guns that could break through German defensive lines. The British initially used a small number of these vehicles with limited results in September 1916.

The Germans developed countermeasures in time to blunt the first use of massed armor by the French in April 1917. Although these early tanks were mechanically unreliable, demand for additional vehicles remained high.

Neither French, American, nor British industry could supply vehicles in large numbers. Only a limited number of tanks were available for American use in late 1918. The Armor Branch was eventually created in 1940 to oversee this vital component of Army equipment. Armored vehicles remain a central part of the Army today.