This amazing tree is the giant sequoia (Sequoiadendron gigantea). Though fossils have been found of similar trees all across the Northern Hemisphere, the modern giant sequoia is found in 75 groves in the middle elevations on the western side of the Sierra Nevada.
Mature sequoias are massive. The largest of all is the General Sherman Tree. It is 274.9 feet tall and 36.5 feet in diameter at the base. The diameter of the largest branch is 6.8 feet. The lowest branch is 130 feet from the ground. This tree is 2,500 to 3,000 years old and is still growing, at least in girth. The tree adds 40 cubic feet of wood per year. This is equivalent to one tree 50 feet tall and a foot in diameter. The General Grant Tree is almost as big. It is 267.4 feet tall and 40.3 feet in diameter at the base.
A mature giant sequoia, even one much smaller than the General Sherman Tree, will produce countless millions of seeds in its lifetime but only the smallest fraction will live on to become mature giant sequoias. Maybe this is the reason why the trees are not more widespread. The seeds are shed from the cones when the cones open, obviously, but the cones do not open every year. Some are opened by a type of squirrel called a chickaree gnawing on them. The chickaree does not eat the seeds but is after the green cone. However most of these seeds will not make it to good germination sites. The greatest opener of cones is heat from a fire. Fire also prepares the ground in the best way possible for seeds. A fire clears away debris to allow the seed to touch the soil. It also cracks and disturbs the soil so that the seed can get buried. Even with all that, things are still iffy for the sequoia seedling. Under a natural fire regimen , fire rarely outright kills a mature giant sequoia. Seedlings on the north side of the tree will be shaded, which is fatal for the seedlings, which need full sun. However, seedlings getting full sun may get too hot and perish. Sequoia seedlings are fussy.
It was bound to happen that a tree as large as the giant sequoia was looked upon as a new and fabulous source of lumber. However, sequoia wood is brittle and the trees shattered when they hit the ground. That didn't stop the lumbering and the pieces were used for fence posts, grapevines stakes, shingles, and pencils. Eventually there was enough protest and protection that logging of giant sequoias has ceased.
Giant sequoias have been planted around the world and they do particularly well in northwest Europe. However, no instance has been recorded of a giant sequoia naturally reproducing outside of its native zone.
The giant sequoia can be grown or at least attempted in any zone outside of the desert and tropics. The young trees are pyramidal in shape. However, this is a tree for parks and large estates. A young tree can reach 60 to 100 feet tall and 30 to 50 feet wide. The root system is extensive but shallow. More mature giant sequoias die from falling over than from any other natural cause. Outside of its natural range, the tree is prone to fungal diseases. There is a weeping sequoia called 'Pendulum'. It is of irregular form and can be trained in to a pillar about 25 feet tall and 4 feet wide.
The giant sequoia is a remarkable tree but generally not suited for the average homeowner. Perhaps a trip to California to see this beauty in its natural state is in order. If, not enjoy the pictures in this article.