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|Yosemite National Park (11)|
Some of the most remarkable natural resources to be found in Yosemite National Park are the giant sequoia trees. In the park these trees are found in three separate groves. The largest group of these trees is located in the Mariposa Grove.
Perhaps the most remarkable sequoia in the grove, and indeed the park, is the Grizzly Giant, originally known as the "Grizzled Giant." This enormous tree is believed to be 2700 years old, the oldest known sequoia tree. Sequoias are among the oldest know organisms on earth, surpassed only by the venerable bristlecone pines.
The Grizzly Giant is not only old--"grizzly"--but it is also enormous--a "giant." The tree is 100 feet around at the base with a diameter of 29 feet (sometimes quotes as 31), and is 209 feet high, although it presently has a snag top and once was much higher. It is the largest tree in Yosemite and is believed to be the 5th largest tree on earth, weighing an astounding 2 million pounds and comprising 30,000 cubic feet of lumber, enough to build some 20 homes. Its lowest limbs are 6 feet across.
As can be seen below, the Grizzly Giant leans slightly, approximately 17 degrees out of plumb. It is able to remain standing because of compensation with root development and additional growth. These giants are often targets of lightning; the Grizzly Giant was once hit 6 times in a single storm!
The Mariposa Trail leads though this astounding grove of sequoias. There are over 200 trees with a diameter of 10 feet or more in this grove. The Tuolumne Grove was first seen by a white man in 1833, when the Joseph Walker party traveled through the area. The Mariposa Grove was probably first seen by non-Indians in 1870. It was discovered by Galen Clark, who explored it, later publicized it, and watched over it as the new national park's caretaker.
The sequoia tends to live at an altitude of 4000 to 8500 feet. They are protected by a sturdy layer of bark, which is 1 to 2 feet thick. The achilles heel of the giant, however, is its shallow root ball, which makes it somewhat vulnerable to uprooting and falling.
One tree which has in fact fallen and can be seen today is The Fallen Monarch, shown below. It is not known when this tree fell, although it was already on the ground when Galen Clark explored the grove in 1857. Even while lying on the ground, the fallen sequoia could resist decay for twenty centuries or more.
One famous tree which used to be found in the Mariposa Grove was the Wawona, or Tunnel, Tree. This was a giant sequoia through which an 8 foot opening at its base was cut, enlarging a burn scar, originally in 1881. Driving through the tree was a famous and much photographed activity. The tree fell in the heavy snows of the winter of 1968-9.
Sequoia's Big Trees were discovered by Joseph P. Walker in 1833. Although the trees were interesting to loggers and lumberman, their enormous size provided a measure of protection, as felling a sequoia requires a great deal of time and effort. Sequoia wood is actually very brittle, and tends to shatter when it falls, a fact which also made the trees less attractive to loggers.
Another group of noteworthy denizens of the Mariposa Grove is the Bachelor and Three Graces, shown below.
The role of fire in the development of the giant trees was once poorly understood, but the occurrence of period burns is essential to the health of these great trees. Fire on the floor of the forest burned duff and creates the soil conditions--bare, mineralized soil--which are necessary for the germination of the sequoia seeds. Old photos show a more open forest than what is seen today. Many of the trunks of the trees show the scars of encounters with fire, as for example the Grizzly Giant above.
These giant trees--sequoiadendron giganteum--are, by volume, the largest living things which have ever existed on the planet. The large sequoias are not only large but also ancient. A sequoia may live 3000 years, making them among the oldest living things on earth. The oldest trees in Yosemite were seedlings at around 1000 to 1500 BC.
Thomas Starr King called the magnificent sequoias "vegetable titans."
The thick, convoluted bark is characteristic of the sequoia. Standing in front of one of these leviathans in the Mariposa Grove is a humbling experience.
It is difficult to even see the top of these giant trees.
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