"Bill R" wrote: (clip) 2. Do tree branches on the equator have equal size
growth rings above and below the pith?(clip)
^^^^^^^^^^^^^
Only for those branches which lie directly above the equator (pointing east
or west.) As the angle of the branches shifts toward north or south, the
position of the pith moves up or down. Because of statistical uncertainty,
and lack of sufficient data, it is not clear whether the shift is
proportional to the angle, or to the sine of the angle.

Another interesting effect is that trees that grow at the north or south
poles do not grow at all.