Mike Siaperas, a wealthy software executive, was looking for a change. He found it 10,000 feet above sea level in Utah, buying a ranch that he would turn into a luxury hunting retreat. But there was a problem.

“You couldn’t see 10 feet in front of you, the trees were so overgrown,” he recalled in an interview for a podcast in 2021. “I wanted to see wildlife.”

So he bulldozed swaths of forest on his property and an adjacent state reserve. Then he patented a technique that could strip as much as 100 acres of woodland in a day and tested it at a nearby ranch owned by one of America’s wealthiest families. He has since started a tree removal company, created a charity for veterans and opened a pricey lodge at his ranch, hosting retired Navy SEALs, former football stars and other guests to ride ATVs, shoot firearms, hunt and bond.

Those ambitions have been significantly aided by Utah taxpayers, an investigation by The New York Times and The Salt Lake Tribune has found.

Since 2019, state lawmakers have appropriated more than $5 million to support Mr. Siaperas’s forestry work, although less than half of it has been paid out. His proposals have been backed by influential allies, met with little to no competition and relied on unproven or disputed scientific claims.

The funding is part of a pattern of questionable contracts the state — led by a Republican governor and a legislature with a Republican supermajority — has awarded over the last decade to politically connected people pushing moneymaking projects they claimed had ecological benefits.