Today on “Post Reports,” we join The Post’s Lillian Cunningham on her journey through the messy past and uncertain future of America’s most awe-inspiring places: the national parks. First stop? Yosemite.Read more: California’s Sierra Nevada is home to a very special kind of tree, found nowhere else on Earth: the giant sequoia. For thousands of years, these towering trees withstood the trials of the world around them, including wildfire. Low-intensity fires frequently swept through groves of sequoias, leaving their cinnamon-red bark scarred but strengthened, and opening their cones to allow new seeds to take root.But in the era of catastrophic wildfires fueled by climate change, these ancient trees are in jeopardy. And Yosemite National Park is on the front lines of the fight to protect them.In the first episode of “Field Trip,” Washington Post reporter Lillian Cunningham takes listeners inside this fabled landscape — from the hush of the Mariposa Grove to the rush of the Merced River — to explore one of America’s oldest and most-visited national parks.We’ll hear from Yosemite forest ecologist Garrett Dickman on the extreme measures he’s taken to protect iconic trees; from members of the Southern Sierra Miwuk working to restore Native American fire practices to the park; and from Yosemite Superintendent Cicely Muldoon about the tough choices it takes to manage a place like this.We’ll also examine the complicated legacies that conservationist John Muir, President Abraham Lincoln and President Theodore Roosevelt left on this land.The giant trees of Yosemite kick-started the whole idea of public land preservation in America. Join us as we visit the place where the idea of the national parks began — and ask what the next chapter might look like. You can see incredible photos of Yosemite and find more on the national parks here. Subscribe to The Washington Post with a special deal for podcast listeners. Your first four weeks are free when you sign up here.