It was found in a stash of plants and fruit in the burrow of an ice age squirrel 125 feet below the present surface of the permafrost. And in the same ice layer were the bones of large mammals, such as mammoth, woolly rhinoceros, bison, horse and deer. And the researchers claim that their success with S. stenophylla shows that tissue can survive in ice for tens of thousands of years and opens “the way to the possible resurrection of ice age mammals.” Carlos’ remark was uncannily prophetic.
I have always loved trees. I remember once, when I was about 6 years old, bursting into tears and frantically hitting an older cousin (with my little hands only) because he was stamping on a small sapling at the bottom of the garden. He told me he hated trees because they “made wind”! Even at 6 years I knew how wrong he was. I have already mentioned the trees in my childhood garden—the most special being a beech tree. I persuaded my grandmother to leave Beech to me in a last will and testament that I drew up, making it look as legal as I could, and she signed it for me on my 11th birthday.
In Gombe, when I walked alone up to the Peak—the observation point from which, using my binoculars, I could usually locate the chimpanzees—I would pause to talk to some of the trees I passed each day. There was the huge old fig tree, with great wide branches, laden with fruit and feasting chimpanzees, monkeys, birds and insects in the summer, and the very tall and upright mvule, or “dudu tree,” which attracted chimpanzees to feed on white galls made by a lace bug in the spring. Then there were the groves of the mgwiza, or “plum tree,” that grew near the streams, and the mbula and msiloti of the open woodlands, all of which provide, in their seasons, plentiful food for the chimpanzees—and other creatures too.
Of all the trees at Gombe it was the gnarled old fig tree that I loved best. How long had he stood there? How many rains had he known and how many wild storms had tossed his branches? With modern technology we could answer those questions. We even know, today, when the first trees appeared on planet Earth.
From the fossil record, it has been suggested that trees appeared about 370 million years ago, about 100 million years after the first plants had gained a foothold on the land. I can well imagine the excitement of the scientists working at a site in Gilboa, New York, who, in 2004, discovered a 400-pound fossil that was the crown of a fernlike tree. The following year they found fragments of a 28-foot-high trunk. And suddenly they realized the significance of the hundreds of upright fossil tree stumps that had been exposed during a flash flood over a century earlier. Those tree stumps were just a few miles away from their site and were estimated to be 385 million years old—the crown and the new trunk fragments were the same age. The newly discovered species Eospermatopteris is commonly known as Wattieza, which actually refers to the type of foliage.
It seems that these treelike plants spread across the land and began the work of sending roots down into the ground, breaking up the hard surface and eventually forming the first forests. And as their numbers increased they played an increasingly important role in removing C02 from the atmosphere and cooling Devonian temperatures. Thus they prepared things for the proliferation of land animals across the barren landscape of the early Devonian.
The Archaeopteris, which flourished in the late Devonian period, 385 to 359 million years ago, is the most likely candidate so far for the ancestor of modern trees. It was a woody tree with a branched trunk, but it reproduced by means of spores, like a fern. It could reach more than 30 feet in height, and trunks have been found with diameters of up to three feet. It seems to have spread rather fast, occupying areas around the globe wherever there were wet soils, and soon became the dominant tree in the spreading early forests, continuing to remove C02 from the atmosphere.
And then there are the “living fossils,” the cycads. They look like palms but are in fact most closely related to the evergreen conifers: pines, firs and spruces. They were widespread throughout the Mesozoic Era, 250 million to 65 million years ago—most commonly referred to as the “Age of the Reptiles,” but some botanists call it the “Age of the Cycads.” I remember Louis Leakey talking about them as we sat around the fire at Olduvai Gorge in the eastern Serengeti Plain, and imagining myself back in that strange prehistoric era. Today there are about 200 species throughout the tropical and semi- tropical zones of the planet.
Once the first forests were established both plant and animal species took off, conquering more and more habitats, adapting to the changing environment through sometimes quite extraordinary adaptations. Throughout the millennia new tree species have appeared, while others have become extinct due to competition or changing environments. Today there are an estimated 100,000 species of trees on planet Earth.