What we know today as the Civilian Conservation Corps was originally called
Emergency Conservation Work (ECW), established as an independent agency by Executive Order 6101, on April 5, 1933. The program was created under the authority of an emergency employment act of March 3l, 1933 (48 Stat. 22) to relieve unemployment and to restore the country’s natural resources through public works. ECW was superseded by the Civilian Conservation Corps, by act of June 28, 1937 (50 Stat. 319).

This popular program was abolished by the Labor-Federal Security Appropriation Act (56 Stat. 569), July 2, 1942, providing for liquidation by June 30, 1943. Liquidation appropriations continued through June 30, 1948. [Source: National Archives and Records Administration]

Less than a week after taking office, on the morning of March 9, 1933, Franklin Delano Roosevelt ordered some of his senior staff to come up with a way to put 500,000 young men to work on conservation projects by the summer. By that evening, they had a plan that became the focus of more discussions over the next few weeks.
Roosevelt sent a more modest proposal to Congress on March 21, calling for the employment of 250,000 men by early summer. It was quickly approved and signed into law on March 31. The final measure conveyed broad discretionary authority to the President in setting up an “Emergency Conservation Work” program. (ECW was the legal name of the program until the more popularly used CCC became official in 1937.)
—Into the Woods: The First Year of the Civilian Conservation Corps, by Joseph M. Speakman. Prologue Magazine, Fall 2006, Vol. 38, No. 3 (public domain at Archives.gov)