"Recent research on seasonal effects on tree rings in other trees in the same genus, the plantation pine Pinus radiata, has revealed that up to five rings per year can be produced and extra rings are often indistinguishable, even under the microscope, from annual rings...
Considering that the immediate post-Flood world would have been wetter with less contrasting seasons until the Ice Age waned…many extra growth rings would have been produced in the Bristlecone pines (even though extra rings are not produced today because of the seasonal extremes)..."
See online article below for more information from CMI.
( Note pix by jgl.)