You have 61 trees... please don't lose them

We humans number about 6.5 billion. How many trees are there? NASA has been taking satellite pictures of the Earth's forests for years and sharing them with ecologists who have figured out an algorithm for calculating worldwide tree totals based on patterns of sunlight. The result of that research is a worldwide tree census, as of 2005, of 400,246,300,201, or 400 billion. Now, do the math -- that's 61 trees per person -- a figure that professor Nalini Nadkarni of the Evergreen State College in Washington seems to have been the first to calculate. Speaking on NPR, Professor Nadkarni said, "This number is one of the interesting things you glom onto, because suddenly you can picture yourself and these trees." That's something I relate to, living in southern Vermont with intimate experience with hundreds if not thousands of trees per person. The figure, which Professor Nadkarni acknowledges is approximate, puts worldwide demand in perspective. Statistics from the North Carolina Forestry Association show that the average American uses over a ton of wood annually. That's equivalent to a single tree measuring 100 feet tall and 18 inches in diameter. Professor Nadkarni emphasizes that the tree census is not a strictly accurate number. Where do you draw the line on infants and the deceased? But, she says, "it is a way to personalize the number of finite trees that we humans can access, and ask is there a way to reduce our consumption." Thanks to David Foley for bringing this item to my notice.