The Sequoia and General Grant National Parks have more than a million Big Trees. Of these, more than twelve thousand are ten or more feet in diameter. A few of these trees are upwards of three hundred feet high, but the majority are about two hundred and fifty feet. Galen Clark, who made a long and careful study of the Big Trees, expressed the opinion that the Grizzly Giant was at least six thousand years old. A number may be four thousand or more years of age, but the majority probably are less than three thousand. Careful counts of the annual rings of trees that have been felled show that a number of these had lived more than three thousand years. One had more than four thousand annual rings. W. L. Jepson, author of "The Trees of California," believes that the general tendency is to exaggerate the age of the living Big Trees. These trees bear seeds each year. In a fruitful year a Big Tree may produce one million seeds. These are exceedingly small and light. The tree blooms in late winter, while the earth is still covered with snow. The flowers are pale green and pale yellow. The cones are bright green and are about two and one-half inches in length. They shed their seeds as soon as they are ripened, but the cones sometimes cling to the trees for months. If the seeds alight on freshly upturned soil or soil recently burned over, they usually sprout and grow vigorously. They do best in the sunlight. But if the seeds fall upon a grass- or trash-covered forest floor, they fail to sprout. With branches nearly to the earth, the outline of a young tree is that of a slender pyramid. As the tree ages, the lower branches fall off. In middle-aged trees, the trunk commonly is free of branches from fifty to one hundred and fifty feet above the ground. The tiptop of aged trees usually is a dead snag, surrounded by living, up-curved side branches from the trunk. The original tops of nearly all old trees have been smashed by lightning. Usually in young trees the bark is almost purplish; in old ones it is cinnamon-color. This bark is fire-resisting, is from one to two feet thick, and is good protection to the vitals of the tree. The roots are short, but the base of the trunk is heavily, artistically buttressed. Living or dead, the Big Tree has extraordinary durability. It has exceptional vitality and recuperative power. Its long life probably is due to the fact that it is almost immune from insect pests, the most deadly enemies of all other kinds of trees. Men, fire, and lightning are the worst enemies of the Big Tree. Most of the old ones have had their heads shattered by lightning again and again, but they still insist on living and will produce a new top even though the old one is entirely smashed off. These trees appear to be almost immortal. Unless they starve or meet a violent death, they live on and on.