By Sheril Kirshenbaum and Chris Mooney

NASA satellites made possible for Nalini Nadkarni at Evergreen State College in Washington to estimate the number of trees on planet earth. Because they reflect sunshine in particular patterns, it’s possible for biologists to determine coverage and look at numbers. The result? Approximately 400,246,300,201 trees in the world.

But what does that mean? Well, using the latest estimates for our human population, Nadkarni calculated we ‘have‘ roughly 61 trees each. Is that adequate? Hard to say. How many trees do we each ‘use‘ in our lifetime? Just consider your dependence on paper, construction materials, firewood, toothpicks, and so on. We also likely consume more per person here in the US than in places like India and Africa.

Now keep in mind trees are pretty important. They soak up excess carbon we emit and provide habitat for much of the world’s biodiversity. Seventy percent of the Earth’s land animals and plants live in forests and The World Resources Institute reports that over 80 percent of these areas have already been destroyed.

That said, the good thing about this story is that trees are a renewable resource. So let’s make sure we continue planting them and do a better job of preserving the forests we have. Otherwise, it will play out as the classic situation where we won’t know what we’ve got til it’s gone…