Interior Secretary Ryan Zinke is conducting an unprecedented review of more than two dozen national monuments to determine whether protections for these public lands should be reduced. One place on his list is California’s Giant Sequoia National Monument, home to an estimated 50 percent of all sequoias on the planet.

Photographer Sam Kweskin has been traveling across the Golden State documenting some of the state’s national monuments that are risk, as well as the groups and individuals who are working to save them. Here are some of his photographs from Giant Sequoia.