ARTIFICIAL REGENERATION OF THE GIANT SEQUOIAS
THE GIANT SEQUOIA is being grown successfully from seed in many places outside its natural range; indeed, several trees more than 50 years of age and showing rapid growth are to be found in the warmer parts of the United States and in many places in southern and central Europe. This indicates that the species is able to adapt itself to a rather wide range of climatic conditions.
It is relatively easy to raise seedlings of the giant sequoia, although the fertility of the seed is low, being only about 10 percent, the seed should be sown about one-fourth inch deep in well-drained but moist mineral soil to which a little wood ash has been added. Although germination requires several weeks and seedlings develop slowly during the first year, growth is rapid thereafter under good conditions.
The requirements for successful growth of the giant sequoia outside its natural range appear to be moderate winter temperatures and relatively low summer humidities. In its normal habitat temperatures range from a minimum of about 10° F. in winter to a maximum of 85° F. in summer. The annual precipitation in the groves is about 25 to 30 inches, and winter snows accumulate to depths of 12 feet. Summer rains are rare, however, and less than 1 inch falls between June and September. The Sequoias are only found in places where ample underground moisture is available in summer.
Attempts to grow these trees in Northern States and other cold or wet climates have generally failed. Several attempts have been made to grow the species in the Arnold Arboretum of Harvard University in Boston, Mass., where the trees grew slowly to heights of 3 to 6 feet, but died during the first severe winter. One of the longest lived giant Sequoias in the Northeast was located in Aurora, N. Y., on the shore of Lake Cayuga. This tree was more than 70 feet tall and 20 inches in diameter and was supposed to have been 70 years old. It was killed, however, by the severe winter of 1933-34. In Washington, D. C., several attempts have been made to grow giant sequoias but, perhaps because of the high summer humidity, they have invariably weakened and died.
A notable exception to the general rule of failure in the Eastern United States is the relatively large Sequoia gigantea growing on the grounds of the Tyler Arboretum near Lima, Pa. This specimen, when examined in November 1941, was 25-1/2 inches in diameter at breast height and was estimated to be approximately 52 feet in height.
Many fine specimens, some at least 50 years old, are to be found in arboretums and city parks in England and southern Europe.
Last Updated: 02-Feb-2007