Giant Sequoia – Sequoiadendron giganteum
Other Names: Giant Redwood, Sierra Redwood, Wawona (Miwok), Toos-pung-ish (Tule River Tribe), and Hea-mi-withic (Tule River Tribe).
Distinctive Characteristics: Giant Sequoia is the most massive tree on Earth in terms of wood volume. Sequoiadendron is also one of the oldest-aged tree genera—its ancestors have been on the planet for 200 million years. Giant Sequoia is also one of the longest living trees in the world. Its longevity is in part due to its rot resistance, much like that of its Coast Redwood relative. Sequoia's rich, rusty-colored bark is fibrous, furrowed, and in mature trees it can be up to 3 ft. (1 m) thick. The insulating bark does not become covered by mosses, lichens, or other epiphytes found on other trees, and its thickness, as well as the lack of flammable terpenes in its sap (such is found in pine trees), provide significant fire resistance for protecting the trees. Fire is a necessary element for the Giant Sequoias' survival; they are dependent upon it for germination of the seeds. Also, in the absence of fire, other shade-loving tree species will crowd out young Giant Sequoia seedlings. Although a tree can reach hundreds of feet tall, its roots are shallow, only 4–5 ft. (1.5 m) deep, covering an area of 200–300 ft. (60–90 m) in diameter. Also, like Coast Redwoods, their rate of wood production increases as the tree ages (until near death), meaning, the oldest trees are making the most wood (because they have more leaves).
Distribution: Endemic to western slopes of Sierra Nevada range in California. There are between 65–75 groves (public and private). Elevation: 2,800–8,600 ft. (850–2,600 m), but typically 4,600–7,000 ft. (1,400–2,100 m).
Ecosystem: Usually in groves or mixed with Sugar Pine, White Fir, Incense Cedar, California Black Oak, Ponderosa Pine, and Pacific Dogwood, in a climate characterized by dry summers and wet, snowy winters. They do not grow solitary. Old growth Giant Sequoias are also ecosystems of themselves, with epiphytic plants and trees growing in the tops of canopies.
Maximum Age: Approximately 3,200 years.
Maximum Height and Girth: The current tallest Giant Sequoia is 315.91 ft. (96.29 m) in height. Historically, claims have been made as high as 321 ft. (97.8 m) and 341 ft. (104 m). The current largest girthed tree, the General Grant tree, is 91.1 ft. (27.7 m) in circumference. Since Giant Sequoias are buttressed at their base, and sometimes grow on slopes, their base diameters can be much larger, the current widest being an unnamed tree at 57 ft. (17.7 m). The General Sherman tree, although not the largest in terms of height or girth, is currently the largest living Giant Sequoia and largest living tree on Earth in terms of total wood volume, which was estimated at over 55,000 cu ft. (1,557 m3).
Animal Community: In addition to fire, two animal agents, the longhorn beetle and the Douglas squirrel, assist in the Giant Sequoia's seed release. The beetle's larvae bore holes in the seeds, allowing the cones to dry and open for the seeds to fall, while the Douglas squirrel dislodges and drops seeds as the green cones are eaten. Otherwise, the cones may stay on the tree for up to twenty years before falling.
Modern Uses: Even though their brittle wood usually shattered upon falling, making much of it unusable as timber, the trees were logged to make shingles, fence posts, and, horrifyingly, matchsticks! Giant Sequoia has since become a popular horticultural tree in landscapes and botanical gardens in many parts of the world.
Threats and Conservation: Upon their discovery in the 1800s, Giant Sequoias were logged nearly to extinction. Giant Sequoias are currently classified as a Threatened species by the U.S. Endangered Species List and classified as Endangered by the IUCN Red List. Although most of the ancient trees are protected from logging, preserved in Yosemite, Sequoia and Kings Canyon National Parks, as well as a few state parks and on private land, they are still at risk on National Forest lands. The historical absence of wildfires has contributed greatly to their slow regeneration.