Giant sequoia (*Sequoiadendron giganteum*) is a tree species that is very well known for being the largest tree on Earth. It is a redwood tree native to the Sierra Nevada and California in the United States. The oldest documented trees of this species are older than 3,000 years.
I. Appearance and Characteristics
Sequoiadendron giganteum, also known as the giant sequoia, giant redwood or Sierra redwood is a coniferous tree, classified in the family Cupressaceae in the subfamily Sequoioideae. Giant sequoia specimens are the most massive trees on Earth. They are native to the groves on the western slopes of the Sierra Nevada mountain range of California but are grown around the world.
The giant sequoia is listed as an endangered species by the IUCN with fewer than 80,000 remaining in its native California. The tree was introduced to the U.K in 1853 and now there are around 5,000 mature trees.
Giant sequoia specimens are the most massive individual trees in the world. They grow to an average height of 50–85 m (164–279 ft) with trunk diameters ranging from 6–8 m (20–26 ft). Record trees have been measured at 94.8 m (311 ft) tall. Trunk diameters of 17 m (56 ft) have been claimed via research figures taken out of context. The specimen known to have the greatest diameter at breast height is the General Grant tree at 8.8 m (28.9 ft). Between 2014 and 2016, it is claimed that specimens of coast redwood were found to have greater trunk diameters than all known giant sequoias – though this has not been independently verified or affirmed in any academic literature. The trunks of coast redwoods taper at lower heights than those of giant sequoias which have more columnar trunks that maintain larger diameters to greater heights.
The oldest known giant sequoia is 3,200–3,266 years old based on dendrochronology. That tree has been verified to have the fourth-largest lifespan of any tree, after individuals of Great Basin bristlecone pine and alerce. Giant sequoia bark is fibrous, furrowed, and may be 90 cm (3 ft) thick at the base of the columnar trunk. The sap contains tannic acid, which provides significant protection from fire damage. The leaves are evergreen, awl-shaped, 3–6 mm (1⁄8–1⁄4 in) long, and arranged spirally on the shoots.
The giant sequoia regenerates by seed. The seed cones are 4–7 cm (1+1⁄2–3 in) long and mature in 18–20 months, though they typically remain green and closed for as long as 20 years. Each cone has 30–50 spirally arranged scales, with several seeds on each scale, giving an average of 230 seeds per cone. Seeds are dark brown, 4–5 mm (0.16–0.20 in) long, and 1 mm (0.04 in) broad, with a 1-millimeter (0.04 in) wide, yellow-brown wing along each side. Some seeds shed when the cone scales shrink during hot weather in late summer, but most are liberated by insect damage or when the cone dries from the heat of fire. Young trees start to bear cones after 12 years.
Trees may produce sprouts from their stumps subsequent to injury, until about 20 years old; however, shoots do not form on the stumps of mature trees as they do on coast redwoods. Giant sequoias of all ages may sprout from their boles when branches are lost to fire or breakage.
A large tree may have as many as 11,000 cones. Cone production is greatest in the upper portion of the canopy. A mature giant sequoia disperses an estimated 300–400 thousand seeds annually. The winged seeds may fly as far as 180 m (590 ft) from the parent tree.
Lower branches die readily from being shaded, but trees younger than 100 years retain most of their dead branches. Trunks of mature trees in groves are generally free of branches to a height of 20–50 m (70–160 ft), but solitary trees retain lower branches.
II. How to Grow and Care
Sunlight
Giant sequoia thrives in full sun conditions, which is vital for its growth and overall health. It prefers long hours of direct light to ensure vigorous growth and maintain robust health. While giant sequoia displays a fair tolerance to partial sun, an extended lack of optimal light can lead to stunted growth and a reduced capacity for photosynthesis. As a highly adaptable species, giant sequoia may endure some variance in light exposure but achieves its best performance with consistent, intense light. These trees are not suited for indoor environments and should be planted outdoors, ideally in open areas where they receive unfiltered sunlight for the majority of the day. Their extraordinary height and massive canopy reflect their adaptation to these light conditions over time.
Temperature
If the weather in your region is severely hot or cold, you’ll need to pay special attention to your tree — especially when it’s small. Do not let your seedling burn in extreme heat, nor freeze in harsh, cold weather. Generally speaking, keep your tree indoors during times of freezing and sub-freezing temperatures. In the spring, after your last freeze, place the tree outdoors once again in a sunny location.
Watering
Giant sequoia thrives in environments that mimic its native habitat of moist, well-drained soils. This species is known for its moderate drought tolerance and a preference for consistent moisture without waterlogging. Its watering schedule should follow a rhythm of once every 1-2 weeks, ensuring the soil has time to dry slightly between waterings. Typically grown outdoors due to its massive size, giant sequoia benefits from natural rainfall patterns and requires less frequent irrigation during the rainy season, aligning with its growth cycles.
Fertilizing
For giant sequoia, balanced nutrition fertilizers with equal parts nitrogen, phosphorous, and potassium (N-P-K) are ideal. Apply annually in early spring, before new growth begins, using a moderate amount per label directions, to boost vigor and health. Carefully distribute the fertilizer around the drip line, avoiding direct contact with the trunk to prevent damage. As giant sequoia matures, its need for fertilization may decrease. Always water thoroughly post-application to help nutrients reach the roots, fostering robust growth. Precise application ensures better uptake, minimal runoff, and environmental protection.
Transplanting
The perfect time to transplant giant sequoia is during the rejuvenating season of early spring. Choose a sunny, well-drained location to ensure healthy growth. Remember, a little extra care during transplanting can help giant sequoia flourish beautifully.
Repotting
Repot giant sequoia every 2-3 years, during early spring to support its seasonal growth spurt. This majestic tree requires a spacious container that allows its extensive root system to expand. After repotting, ensure giant sequoia receives ample sunlight and moderate watering to recover and thrive. Use well-draining soil and avoid over-watering to prevent root rot, as this species demands careful attention post-transplant.
III. Uses and Benefits
- Ornamental uses
The enormous giant sequoia grows quickly, making it a worthwhile and attractive tree as a windbreak or privacy screen at the edge of large garden sites. In addition, this tree creates a habitat for many wildlife species, including owls, squirrels, and woodpeckers. When planted in groves on large properties, these trees can also create shelter for deer, bears, and several species of bats.
- Other uses
Wood from mature giant sequoias is highly resistant to decay, but due to being fibrous and brittle, it is generally unsuitable for construction. From the 1880s through the 1920s, logging took place in many groves in spite of marginal commercial returns. The Hume-Bennett Lumber Company was the last to harvest giant sequoia, going out of business in 1924. Due to their weight and brittleness, trees would often shatter when they hit the ground, wasting much of the wood. Loggers attempted to cushion the impact by digging trenches and filling them with branches. Still, as little as 50% of the timber is estimated to have made it from groves to the mill. The wood was used mainly for shingles and fence posts, or even for matchsticks.
Pictures of the once majestic trees broken and abandoned in formerly pristine groves, and the thought of the giants put to such modest use, spurred the public outcry that caused most of the groves to be preserved as protected land. The public can visit an example of 1880s clear-cutting at Big Stump Grove near General Grant Grove. As late as the 1980s, some immature trees were logged in Sequoia National Forest, publicity of which helped lead to the creation of Giant Sequoia National Monument.
The wood from immature trees is less brittle, with recent tests on young plantation-grown trees showing it similar to coast redwood wood in quality. This is resulting in some interest in cultivating giant sequoia as a very high-yielding timber crop tree, both in California and also in parts of western Europe, where it may grow more efficiently than coastal redwoods. In the northwest United States, some entrepreneurs have also begun growing giant sequoias for Christmas trees. Besides these attempts at tree farming, the principal economic uses for giant sequoia today are tourism and horticulture.
