Theodore Roosevelt

Roosevelt's signing of The Newlands Act in 1902 placed the federal government in an activist role in water management and reclamation. He created the US Forest Service in 1905.
Roosevelt created 150 national forests, 18 national monuments, 5 national parks and 51 wildlife refuges.
He protected 230 million acres of Americas wildlands often ignoring congress and demands from railroad, oil and timber bigwigs.

Lyndon Johnson

President Lyndon Johnson signed the Wilderness Act, establishing the National Wilderness Preservation System and provisions for wilderness use and protection. 1968 President Lyndon Johnson signed the Wild and Scenic Rivers Act, establishing the National Wild and Scenic Rivers System, which protects designated rivers as either wild, scenic, or recreational.

Richard Nixon

established the EPA in 1970. In his letter to congress at the time he said:
"Our national government today is not structured to make a coordinated attack on the pollutants which debase the air we breathe, the water we drink, and the land that grows our food. Indeed, the present governmental structure for dealing with environmental pollution often defies effective and concerted action. Despite its complexity, for pollution control purposes the environment must be perceived as a single, interrelated system. Present assignments of departmental responsibilities do not reflect this interrelatedness."

During his Presidency he signed several eco-acts including the Clean Air Act, the Endangered Species Act, Safe Drinking Water Act, and the Ocean Dumping Act.

Jimmy Carder

President Jimmy Carter signed the Alaska National Interest Lands Conservation Act (ANILCA). The Act expanded the Arctic Range to approximately 18 million acres, renamed it the Arctic National Wildlife Refuge, designated eight million acres as Wilderness, and designated three rivers as Wild

Eisenhower

Both a president and a cattle farmer, he was also keenly aware of the need for sound soil conservation and animal husbandry.
The Secretary of Interior in the Eisenhower administration signed a Public Land Order establishing the 8.9 million acre Arctic National Wildlife Range.
Although it was probably not his intention the creation of the Interstate Highway System increased sprawl and funding and energy moved away from mass transit.

Gerald Ford

During his relatively short tenure in office Ford added 18 new sites to the National Park System including Valley Forge National Historic Park and Tuskegee Institute National Historic Site.

Ronald Regan

Although it has been pointed out that Ronald Reagan (1981-1989) had been pretty solid on the environment as governor of California, he seemed to take a turn for the worse once he got to the White House.
President Reagan signed into law 38 bills that added more than 10.6 million acres of spectacular forests, mountains, deserts, and wetlands to the National Wilderness Preservation System.
Reagan's historic wins for both terms of office was not because voters wanted to see the environment destroyed. It was because he convinced Americans that individual responsibility and stewardship, not government largess, was the best hope for the nation and conserving her environment.
His interior secretary, James Watt, was demonized sometimes unfairly. He once said:
"I do not know how many future generations we can count on before the Lord returns. Whatever it is we have to manage with a skill to leave the resources needed for future generations."

Goerge Bush 41

The revision of the Clean Air Act was deemed to be the most significant environmental legislation ever passed. Elimination of leaded gasoline was just one result. Through the implementation of the CAAA (Clean Air Act Amendments) at the federal and state level, dozens of highly polluted cities saw remarkable improvements in air quality.

Although the Antiquities Act remained on the books, since 1950 presidents have been more cautious in creating national monuments. Generally, the chief executive has consulted the House Interior and Insular Affairs Committee prior to issuing the proclamation. Unsanctioned monuments could go unfunded by Congress. Thus, the need for cooperation in achieving conservation goals combined with the "power of the purse" has meant a general reluctance to use the full power of the Antiquities Act in the manner of either Roosevelt. [51]

One is quick to add, however, that the Antiquities Act was not discarded. It remained (and remains) the law, and Presidents Eisenhower, Kennedy, Johnson, and Carter have all proclaimed monuments, usually with the prior approval of Congress, but sometimes in defiance of it.

Books:

Links:
The Best and Worst Green Presidents
Republican Presidents in Conservation
The 10 Greenest Presidents in U.S. History