Observe annual growth rings using this Tree Cookie Cross Section of a 102-year-old ponderosa pine from northwest Nebraska to learn about the many changes in a tree’s lifetime. Early on, the ring widths show average growth for a tree in arid northwest Nebraska but they began to narrow considerably when the tree was about 20 years old. Too many trees in this area of forest were competing for the same limited supply of resources. A timber harvest in 1927 removed some of the trees, reducing competition, and this ponderosa pine increased its growth as a result. When the drought of the 1930s struck, this once again reduced the available resources for this tree, as evidenced in the reduced ring widths.
Also check out what a delegation of Girl Scouts from Poland discovered when asked “What happened around 1917 that might have changed the way this tree grew?” when they looked at this Western Red Cedar tree cookie at the World Scout Jamboree.
