WASHINGTON (AP) — President Donald Trump has signed legislation into law that will devote nearly $3 billion annually to conservation projects, outdoor recreation and maintenance of national parks and other public lands.

The Great American Outdoors Act authorizes spending about $900 million a year, double current spending, on the popular Land and Water Conservation Fund.

It would authorize another $1.9 billion a year to be spent to make improvements at national parks, forests, wildlife refuges and range lands.

Supporters call it the most significant conservation legislation in nearly half a century.

Opponents say the spending is not enough to erase an estimated $20 billion maintenance backlog.