Redwood
Redwood tree (Sequoideae)
Scientific classification
Kingdom:	Plantae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Cupressaceae
Subfamily:	Sequoioideae
Genera
Sequoia Sequoiadendron Metasequoia

The redwoods are a subfamily of conifers, the Sequoioideae. They are in the Cypress family Cupressaceae.^[1]

They are common in the coastal forests of Northern California and are perhaps the largest tree in the world. There are three living genera. There were once more species of redwood trees, but most have become extinct.

These trees are pyrophytes: they have adapted to survive forest fires. Because fire is common where they grow, redwood trees have developed thick, fire-resistant bark. Their cones open only after a fire. Because fire control is better these days, the trees are endangered.

Redwood trees can grow to be very large. The largest species, Sequoiadendron giganteum, can get to 94.8 m tall and 17 m across. The tallest tree in the world is claimed to be a Sequoia sempervirens named Hyperion. The largest tree in the world by volume is claimed to be a Sequoiadendron giganteum named the General Sherman Tree, after William Tecumseh Sherman.

Species

• Sequoiadendron giganteum trees are also called giant sequoias. Their native habitat is only on the western slopes of the Sierra Nevada range of California. They are the largest trees on Earth.^[2]
• Sequoia sempervirens trees are also called coast redwoods. Their native habitat is only in the Northern California coastal forests ecoregion, on the Northern California coast and several miles into Oregon. They are the tallest trees on Earth.^[3]
• Metasequoia glyptostroboides trees are also called dawn redwoods. They are so rare they were thought to be extinct, until rediscovered by a Chinese forester in 1943. They were found on mountainous slopes in remote parts of the Hubei region of China.

However, in principle, they can grow in many other places. [1]