why do  us forces wear black
However, since June 14, 2001, the black beret is worn by all United States Army troops unless the soldier is approved to wear a different distinctive beret. The Rangers now wear tan berets in reverence to the buckskins worn by Rogers' Rangers during the French and Indian War.
A black beret was authorized for wear by women soldiers in 1975. On January 30, 1975, it was officially assigned as part of the newly created battalions of United States Army Rangers who had worn it unofficially during the Vietnam War.