Anne Roster, age 10, of North Brunswick, New Jersey, for her question:
How old is the ginkgo tree?
The ginkgo tree in Andy's garden is ten years old and stands almost five feet tall. Its ancient family once shared the world with the dinosaurs. But only a few survivors remain, so some people call them living fossils. The ginkgo's ancestors arrived on earth about 250 million years ago. Later, wide ginkgo forests clothed parts of Asia, Europe and North America. Nowadays, the only survivors are tended as ornamental trees in our parks and gardens.
Our layers of buried coal were pressed from plants that grew 300 million years ago. In these strange, swampy forests grew giant tree ferns and tree sized horsetails. Later came the redwoods and other evergreen cone trees, also cycads that looked like pineapples with feathery top knots. About the same time, the earliest known ancestors of the ginkgo tree joined the earth's greenery.
This was late in the Permian Period that ended about 250 million years ago. Those early forests were populated with scorpions and a few strange insects. Huge salamanders wallowed in the soggy swamps. In a few million years, the first small reptiles began branching out to become the stupendous dinosaur clan. Through 100 million years, while the giant reptiles came to power, the ginkgos thrived in vast forests. They were still thriving, after the dinosaurs departed.
Meantime flowering plants arrived and when Alaska was much warmer, magnolias grew alongside the ginkgos. About 60 million years ago, beside the western Columbia River, ginkgos shared the forests with birch and beech trees, locust trees and towering redwoods. Later, the rising western mountain buried this region under lava and volcanic ashes. The old ginkgo trunks were changed to petrified wood, made of opal type minerals. Their seeds and fan shaped leaves formed fossil imprints in the cindery rocks.
In the past million years, the glaciers of four ice ages crushed over the old ginkgo territory. Most of the trees were destroyed. Only a few were left, maybe where the thick ice left certain hillsides high and dry. Perhaps this was in China, because this is where our surviving, trees were rescued. Ages ago, the Chinese adopted the handsome, ferny ginkgo as a sacred tree. They tended it around their temples, where some of the living trees are said to be 1,000 years old.
Our first ornamental ginkgos were brought from China, several generations ago. Some people call them maidenhair trees because their pale green foliage resembles the dainty, little maidenhair fern. Our ginkgos grow slowly, though they need little care and bugs do not bother them. After all, a tree family would have to be very sturdy to survive unchanged through 250 million years.