Old Trees & New Growth in Sequoia National Forest

Old Trees & New Growth in Sequoia National Forest

January 31, 2013
Photo by: Michael Nichols, National Geographic. The canopy of General Sherman, an aging individual in the Sequoia National Forest


Last month's National Geographic magazine included a fold-out spread (below) that will be adored by anyone who has ever loved a tree. The lush pin-up, a composite of 126 images shot by magazine photographer Michael "Nick" Nichols, is a full-length portrait of a 3,200 year old and 247-feet-tall sequoia. It cuts an impressive figure in the forest, to say the least, and the poster is about the only way you can see the whole expanse. The tree, respectfully called the President, is the subject of a new study that has changed the way we think about trees. 

The President is also the second largest tree on Earth, a title awarded by a team of tree-climbing scientists who conducted the study in the Sequoia National Forest. Stephen Sillett, of Humboldt State University, and his team, were there there to assess the potential of California's trees to absorb the carbon dioxide of a warming planet. They studied the forest like no ecologist had done before—by climbing the big trees and taking detailed measurements, including age, height, and volume. 

The President's extraordinary numbers made it a good specimen for the study, and was a critical subject for a surprising discovery: As a tree ages, its rate of growth increases, not just its total height or volume. The aging President actually produces more new wood per year than a younger tree. It might be because older trees are generally larger, and have more leaves (the President has nearly two billion), and can thereby produce more sugars through photosynthesis. 

Their discovery refutes a previously accepted assumption that wood production decreases as the tree ages, and could change short-rotation forestry practices. It may not hold true for all species of trees, but Sillett and his team proved that it holds true to giant sequoias and coast redwoods.

Photos © Michael Nichols, National Geographic