I had never seen anything like that. An image of radial rings of a Ponderosa Pine up to and after 1950. An image showing much thicker growth rings after 1950.
That image projected from a slide onto a wall screen at the Lee Metcalf National Wildlife Refuge on Thursday night, 11/9/17. Where I heard again that CO2 emissions started a steep rise after 1950.
Next day I entered these words into Google search:
graph co2 1900
My favorite graph option to those search terms has four colors.
Observing that graph motivates me to hear about Forest Management history at the North Valley Public Library, Wednesday, 11/16/17.
Bob Williams
Stevensville