  Epicormic branches arise from dormant buds patterned during the growth of
previous years. Dormant epicormic buds remain on the surface of trees, pushed
outward from the pith during secondary growth, but maintaining vascular
connections. Epicormic buds can be reactivated, either through natural
processes or intentionally, to rejuvenate orchards and control tree
architecture. Because epicormic structures are embedded within secondary
growth, tomographic approaches are a useful method to study them and understand
their development.
  We apply techniques from image processing to determine the locations of
epicormic vascular traces embedded within secondary growth of sweet cherry
(Prunus avium L.), revealing the juvenile phyllotactic pattern in the trunk of
an adult tree. Techniques include breadth-first search to find the pith of the
tree, edge detection to approximate the radius, and a conversion to polar
coordinates to threshold and segment phyllotactic features. Intensity values
from Magnetic Resonance Imaging (MRI) of the trunk are projected onto the
surface of a perfect cylinder to find the locations of traces in the "boundary
image". Mathematical phyllotaxy provides a means to capture the patterns in the
boundary image by modeling phyllotactic parameters. Our cherry tree specimen
has the conspicuous parastichy pair $(2,3)$, phyllotactic fraction 2/5, and
divergence angle of approximately 143 degrees.
  The methods described not only provide a framework to study phyllotaxy, but
for image processing of volumetric image data in plants. Our results have
practical implications for orchard rejuvenation and directed approaches to
influence tree architecture. The study of epicormic structures, which are
hidden within secondary growth, using tomographic methods also opens the
possibility of studying the genetic and environmental basis of such structures.
