The energy pioneer and philanthropist died of natural causes at his home in Dallas surrounded by friends and family, a spokesman said Wednesday

T. Boone Pickens, the legendary oilman who made his fortune in Texas, died on Wednesday. He was 91.

Pickens, who was born in a small town in Oklahoma but spent his adult life in Texas, died of natural causes at his home in Dallas surrounded by friends and family, according to a statement from spokesman Jay Rosser.

The former wildcatter turned oil executive turned hedge fund manager and philanthropist had suffered a series of strokes and head injuries in recent years but remained active on social media and other mediums. In May, he published an op-ed in TribTalk — the opinion arm of The Texas Tribune — that advocated for the construction of a veterinary school at Texas Tech University.

In a statement, George W. Bush said Pickens, a staunch supporter of and major donor to the former president, became "a household name across the country because he was bold, imaginative and daring."

"He was successful — and more importantly, he generously shared his success with institutions and communities across Texas and Oklahoma," Bush said. "He loved the outdoors, his country, and his friends and family."

Despite Pickens' Oklahoma roots, Dallas Mayor Eric Johnson expressed gratitude in a statement for the magnate's contributions to the city of Dallas.

"While he might have been an Oklahoma boy, he’ll always be remembered as a Texas legend," Johnson said. "He was a larger-than-life figure, a titan in business, and a generous philanthropist."

Pickens did a series of interviews with the Tribune over the years in which he speculated about dicey oil markets and pushed "The Pickens Plan." That novel vision — aimed at reducing the nation's dependence on foreign oil — called for a $1 trillion investment in wind energy.

A statement posted on Pickens' website on Wednesday described that effort as "a self-funded, $100 million, grass-roots campaign aimed at reducing this country’s crippling dependence on OPEC (Organization of Petroleum Exporting Countries) oil."

In a statement, Gov. Greg Abbott considered this initiative a key part of Pickens' legacy.

"He was a passionate man who always stood by his principles on his path to success. T. Boone Pickens’ commitment to establishing American energy independence will have a lasting impact on the state of Texas, and the United States of America," Abbott said.

Plans for memorial services in Dallas and Stillwater, Okla., are pending, the statement said.

Disclosure: T. Boone Pickens was a financial supporter of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune's journalism. Find a complete list of them here.