The tiny seeds that eventually produce these awesome trees resemble the flakes in uncooked oatmeal. It would take 91,000 of them to make a pound. The seeds are held within cones, which are about the size of hens’ eggs. A mature tree produces some 2,000 cones a year and may hold as many as 40,000 cones, bearing 500,000 seeds.
Some trees–such as the giant sequoia’s cousin, the coast redwood–can regenerate from root or stump. The giant sequoia grows only from a seed. To do this, it needs help. Seeds thrive only in bare, mineral-rich soil. Although cones eventually release seeds, the seeds cannot grow on forest debris. Therefore, it’s best if fire has cleared debris off the ground. A giant sequoia will survive most fires because of its dense bark–as much as 18 inches thick. Meanwhile, burnt cones will plummet to the forest floor, spilling their seeds onto compatible soil.
Giant sequoias grow naturally only in 75 groves on the western slopes of the Sierra Nevada, where moisture and high elevations (5,000 to 7,000 feet) combine to produce favorable conditions. Douglas squirrels, or chickarees, sometimes play a role in the birth process, because they bury seeds as they forage.
These fire-resistant trees also survive insects and rot because of their high tannin content.
Mature trees continue to grow, even past their 2,500th birthday. Their only fatal flaw is a shallow root system, which provides a shaky foundation. High winds or unstable soil conditions may cause a tree to lose its balance and topple to the ground.