Pruning just makes trees grow bigger and stronger. I think there is another "root" cause, probably too much fiber in the diet.
Epidermodysplasia verruciformis (EV), also known as treeman syndrome, is an extremely rare autosomal recessive hereditary skin disorder associated with a high risk of skin cancer. It is characterized by abnormal susceptibility to human papillomaviruses (HPVs) of the skin. The resulting uncontrolled HPV infections result in the growth of scaly macules and papules resembling tree bark, particularly on the hands and feet. It is typically associated with HPV types 5 and 8, which are found in about 80% of the normal population as asymptomatic infections, although other types may also contribute.
The condition usually has an onset of between the ages of one and 20 but it can occasionally be present in middle age. The condition is also known as Lewandowsky-Lutz dysplasia, named after the physicians who first documented it, Felix Lewandowsky and Wilhelm Lutz.