Redwood trees, renowned for their immense stature and longevity, often prompt questions about their reproductive structures. These iconic trees, which include the Coast Redwood (Sequoia sempervirens), Giant Sequoia (Sequoiadendron giganteum), and Dawn Redwood (Metasequoia glyptostroboides), are conifers. A common inquiry concerns whether redwoods produce “pine cones,” and understanding their biology clarifies this aspect of their life cycle.
Redwood Cones Explained
Redwoods are cone-bearing trees, but their cones differ from those typically associated with pine trees.
Coast Redwood cones are small, measuring about 15 to 32 millimeters (0.6 to 1.25 inches) in length and ovoid in shape. These compact cones contain around 15 to 25 spirally arranged scales. They are often compared to the size of an olive or a small tomato.
Giant Sequoia cones are larger than those of the Coast Redwood, ranging from 4 to 9 centimeters (1.5 to 3.5 inches) long and egg-shaped. These woody, brown cones feature 30 to 50 scales, each harboring multiple seeds, averaging about 230 per cone. Giant Sequoia cones can remain on the tree, green and closed, for as long as two decades before releasing their seeds.
The Dawn Redwood, a deciduous conifer, produces small, light brown cones that are 1.5 to 2.5 centimeters (0.6 to 1 inch) in diameter. These cones are distinctive for their four-sided, box-like appearance and hang from long stalks. Unlike their evergreen relatives, Dawn Redwoods shed their needles in the autumn, and their cones mature by late fall.
How Redwood Cones Function
All redwood species are monoecious, meaning individual trees bear both male and female cones. The male cones are smaller and less conspicuous, producing pollen that is carried by wind to the female cones. For Giant Sequoias, pollination occurs between mid-April and mid-May. Fertilization follows in August, with embryos developing over the subsequent summer, with seeds maturing by the end of the second growing season.
Female cones mature and open to release their seeds. Coast Redwood cones mature about 8 to 9 months after pollination, with seed dispersal occurring from early September to late December. Environmental factors, such as low humidity and rainfall, prompt these cones to dry and open, releasing their tiny, winged seeds.
Giant Sequoia cones, in contrast, require external triggers like fire or hot weather to open and release their seeds. Fire prepares the soil for germination, and the winged seeds can be dispersed by wind up to 180 to 400 meters (590 to 1,312 feet) from the parent tree. Squirrels also contribute to seed dispersal by cutting cones from the trees. A single mature Giant Sequoia can disperse an estimated 300,000 to 400,000 seeds annually.