As we formed our Carbon Offset Program we looked at over 20 of programs all over the world and over fifty references.  It was amazing to see how much they varied!  After all that looking we looked at ourselves.  TreeFolks, Inc. has a long, strong relationship with our Central Texas community.  We felt that we owed you the best, most reliable set of numbers we could find for our calculations.  Here's where we got them:

Our numbers for carbon emitted from Gasoline and Natural Gas came from the United States Department of Energy.  You can see those numbers at the at this link.

Our numbers for carbon emitted for air travel were an average from a study run by Tufts University.  It's really interesting because it also compares different carbon offset programs around the world.  You can see that paper here.

Our numbers for carbon emitted from electricity come from the exact fuel mix used by Austin Energy.

Our numbers for how many trees it will take come from a conservative average .66 tons of carbon dioxide per mature tree (from American Forests) adjusted for mortality figures (documented minimum average 80% survival) from our 18 years of tree survival surveys in Central Texas.