Typically, cones mature on the redwood branches in autumn. They turn slightly yellow as the cone scales separate, exposing the seeds hidden within to the elements. Rain then washes away tannic crystals that hold the seeds inside the cones and releases the seeds to fall down onto the forest floor. This year, something else is happening and many green cones are falling onto the forest floor before they ripen. Probably a drought response, the falling green cone crop means fewer redwood seeds will land in the woods this year.
While this is not great for the seed bank, the green cones are fun to play with and I recommend dropping a few into a glass of water to see what happens. The tannic crystals inside the cones will dissolve and you’ll see the water turn a beautiful red color. Check it out!