I notice stuff like that on framing lumber. On older homes ill find virgin growth with tight rings. On second growth and current lumber they are spaced apart. I as well notice density difference in lumber. I can recall years back trying to count the growth rings on a red cedar 2x4 and it was over 200!
The lodge pole I cut here is the same way. Old slow growth. I have cut trees that were around 14 to 15" across that were around 140 years old. Dense wood and burns good.
