Two California redwoods
You can't get much more American than California's redwood forests, mentioned in the chorus of Woody Guthrie's famous folk song, "This Land Is Your Land." But two redwood species — coast redwoods (Sequoia sempervirens) and giant sequoias (Sequoiadendron giganteum) — are listed as endangered on the IUCN Red List.
Though many of the trees are in protected areas, such as Redwood National Park, the populations continue to decline due to "inadequate regeneration and natural death of (over)mature trees, which are being replaced by other, competing conifers," according to IUCN.
The fast-growing coast redwood is the world's tallest tree species, according to the Global Trees Campaign, and the oldest one on record is 2,200 years old. And though giant sequoias, which can grow to over 250 feet tall, still number in the tens of thousands, they were logged extensively in the past and their numbers continue to decline today.