Older Trees Grow Faster as They Age
Like a fairy-tale beanstalk, a tree can grow and grow until it scrapes the sky.
Instead of slowing down as the centuries add up, old trees speed up their growth, according to a study published today (Jan. 15) in the journal Nature.
“Trees keep growing like crazy throughout their life span,” said Nate Stephenson, lead study author and a forest ecologist with the U.S. Geological Survey (USGS) in Three Rivers, Calif.
The results of the survey of 403 tree species around the world suggest that trees never suffer the ill effects of old age. In animals, cells change and break down over a lifetime, eventually causing death. But trees seem free from this growth limit, called senescence. Instead, only disease, insects, fire or accidents such as lightning will kill a tree, Stephenson said. (He forgot to mention logging, of course.) “They never stop,” he said. “Every year, they are always putting on more weight than before.”
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