A few rare giant sequoias (Sequoiadendron giganteum) have grown taller than 300 feet; the tallest known giant sequoia is 314 feet tall. 2 However, it is the sequoia's giant girth that sets it apart. They are usually more than 20 feet in diameter, and at least one has a diameter of 35 feet.

Several species of trees can reach heights exceeding 300 feet, with the Coast Redwood (Sequoia sempervirens) being the most prominent. The world's tallest known living tree, Hyperion, stands at approximately 380 feet in California's Redwood National Park. Other redwoods like Helios (376 ft) and Icarus (371 ft) also far exceed the 300-foot mark. Outside of the redwood family, the Coast Douglas Fir is a notable giant, with the "Doerner Fir" in Oregon reaching 327 feet. In Australia, the Mountain Ash (Eucalyptus regnans) can also surpass this threshold; "Centurion" in Tasmania is measured at roughly 330 feet. Additionally, the "Menara" tree in Malaysia, a Yellow Meranti, became the world's tallest known tropical tree in 2019, standing at 331 feet. These sky-touching giants are often 600 to 800 years old and are frequently located in secret or protected areas to safeguard their fragile ecosystems from human traffic.