the different textures in tree bark result from changes in the cork cambium and the stretching of the bark as the tree increases in circumference.
in the beech tree the cambium remains close to the surface, expanding when necesary and producing a smooth gray cork that appears tightly stretched over the trunk.
in most species,however,successive cork cambium are formed beneath the original one: the new layer of cork that forms cuts off amd kills the outer cambium under pressure from the expanding trunk.
some tree, such as pines and sysamores, have secondary cork cambium the occur in pathes.
with time have patches result in layer of scales, easily seen in fragment of pine bark.
like pines, ash trees have patches of secondary cork cambium , but these from within phlome tissue containing long fibers.
as the trunk expands, the fibers pull apart, creating a net of dimond-shaped furrows, but the bark does not flake off in scales