Sequoiadendron Giganteum
Giant redwoods are the only surviving member of the genus sequoiadendron. There are 3 members of the redwood family, the coastal redwood (sequoia sempervirens), the dawn redwood (metasequoia glyptostroboides), and the giant redwood. They are all part of the cupressaceae botanical family (cypress).
This giant tree is also commonly known as the giant sequoia tree, the Sierra Redwood, and the Wellingtonia tree. They are the absolute most massive tree species on the planet, and they are also some of the oldest known tree species, with the oldest specimen being an estimated 3266 years old.
These trees will only grow in groves on the western slopes of the Sierra Nevada mountains in California, and are protected by the national parks association.
The etymology of the word sequoia derives from Sequoyah, who was a First Nations polymath who was the first person to actually transcribe the Cherokee language.
101 Types of Trees is a huge article we’ve compiled of trees from all around the world. In here we cover different redwood species, fruit tree species, and many more kinds of our endlessly interesting woody plant friends.
Related: Dawn Redwood Tree | Redwood Tree
What do Giant Redwood Trees Look Like?
Root System
Considering their enormous size, giant redwood tree roots don’t actually grow all that deep in the soil. Their roots will usually on grow within the top 36 inches of soil, but will spread way beyond the width of their crown.
The reason for this is that redwood trees only grow in locations that are extremely moist, and the soil is perpetually saturated. Trees do not need to direct their roots towards moisture reserves, and so they can remain in the top soil.
Dimensions
Giant redwood trees, indicated by their name, are some of the tallest living specimens on this planet. Though their average height usually occurs between 50-85 meters and trunk diameter is between 6-8 meters, they are capable of far greater heights. The largest tree is 94.8 meters tall, with a trunk diameter of 17 meters.
Growth Pattern
The giant redwood tree has a very straight, thick, and upright trunk. Older trees will have pruned away its lower most branches, and their crown will occur within the top third of the trunk height.
Branches are heavy and emerge from the trunk horizontally or slightly upward ascending. Branches grow like the spokes on a bike wheel. The redwood canopy is very thick, and creates intense shade cover.
Bark
Another very easily identifiable character of the giant redwood, other than its extreme height, is its bark.
Bark is very fibrous and furrowed, and it a mature tree is may be upwards of 30 inches thick near the base of the trunk.
Sap within the bark contains high tannic acid, which helps the tree against fire damage, along with the thick bark.
Foliage
Redwoods are an evergreen species, meaning that they have leaves that remain green and persist all year long.
Giant redwood leaves are needle-like, but are not nearly as sharp of needles as say a pine or spruce tree. They are more like scales.They are green in color, awl shaped, and 3-6mm long.
These leaves are high in number and extending. Redwoods need to have a high number of leaves to help the tree absorb moisture from the air, mostly through fog.
How do Giant Redwoods Reproduce?
Cones
Redwood trees are conifers, meaning that they possess cones as reproductive characteristics rather than flowers.
A redwood seed cone is 1-3 inches long, and has 30-50 spirally arranged scales with several seeds on each scale. That makes an average of 230 seeds per cone.
Typically when a seed cone is fertilized, it will mature in 18-20 months after pollination, though there are many cones that will remain green and remain closed for up to 20 years!
Seeds
This is because redwood seeds have very specific germination requirements. Seeds will only grow in full sun, and in soil that is very rich in minerals.
These conditions don’t usually come about until there has been a wildfire which clears out all competing vegetation. This is another way in which redwoods have adapt to forest fire damage.
Cones will either immediately open after a fire to release seeds, or a cone will shrink during hot weather, or they will be released from insect damage.
A giant redwood seed is dark brown in color and has two yellow/brown papery wings on either side to help with seed dispersal.
Sexual Maturity
Some giant redwood trees will start to produce cones when they are about 12 years of age, though most will start when they are closer to 20.
Considering how long this tree species lives, that is an incredible number of seed crops in one lifetime! A large tree may hold up to as many as 11,000 cones, but seeds growing into a young tree is a slightly rare occurrence, as birds will quickly eat seedlings.
What are Some Other Redwood Species?
The redwood family only contains 3 different tree species that are all part of different subspecies. Whereas the giant sequoia is alone in the subspecies sequoiadendron, the following two trees are their very own subspecies. All three members are part of the cupressaceae botanical family.
The Coast Redwood Tree (Sequoia Sempervirens)
The coast redwood is the sole living species of the genus sequoia, and is commonly known as the coastal redwood or the California redwood.
This tree species includes both the oldest living tree species, and the tallest living tree species. The oldest specimen is 3266 years old, and the tallest specimen is 115.5 meters tall.
These trees are unfortunately endangered due to extreme commercial logging in the 18th century, and now they only occur in small corners of coastal Oregon and southwestern California.
The Dawn Redwood Tree (Metasequoia Glyptostroboides)
The dawn redwood is the sole living species of the genus metasequoia. Though the shortest of the redwood trees, they still obtain an average height of 35 meters.
This is a living fossil species, meaning that they are nearly genetically identical to tree fossil findings. They only grow in the wet lower slopes of certain parts of China.
Where do Giant Redwood Trees Grow?
The redwood forest has a very restricted growing range. They are completely limited to specific areas of the western Sierra Nevada mountains in northern California. However, their growing range was historically for more widely distributed, and they were a common species all of North America and Eurasia.
These trees occur in 68 different scattered groves, which end up spanning over 35,620 acres. In their northern range, they will grow at elevations of 1400-2000 meters in altitude, and in their southern range, they will grow at elevations of 1700-2150 in altitude.
They commonly occur on the south facing side of northern mountains, and the north facing side of southern slopes. They growing site is characterized by a very humid climate, and ample annual precipitation.
A redwood grove is not a pure stand, and will always be surrounded by a great number of other plant species and tree species.
What are the Growing Conditions of Giant Redwood Trees?
Soil
Redwood trees prefer to grow in soil that is very high in organic matter. Soil is usually either granite based or an alluvial soil. Soil should also be consistently moist.
Sun Exposure
Redwood trees are very sun loving trees, and prefer to live in full sun conditions, as indicated by their incredible heights. Redwood tree seeds also require full sunlight in order to successfully germinate.
Water Level
Redwood trees are also water loving. Not only does soil have to be consistently moist, but the air needs to have high water content through humidity or fog.
Why? Because water that is taken up from the roots is actually not able to travel that far up the trunk, and so leaves need to obtain water another way.
Redwood leaves are filled with water tubules that actually absorb water through fog, humidity, or rain, and that is the only way that redwood leaves are able to access moisture.
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