Why do River Birches have peeling bark? What biological advantage does that give them?
The river birch isn’t the only tree that exfoliates its bark. I found a general article that talks about why some trees may do this: The bark is brittle and can’t accommodate the fast growth and annual diameter accruals of the trunk and branches, so it cracks and exfoliates. “This is not an issue that has received much attention,” says Dr. Marc Abrams, Professor of Forest Ecology at Penn State University. “The only explanation I have ever heard for exfoliating bark, in general and not specific to sycamore, is the rapid growth idea. On the other hand, shagbark hickory is not particularly fast growing.” Exceptions abound. One hypothesis is that thin bark is an adaptation to the floodplain environment. Water conservation, an advantage that thick bark offers, is not necessary with the continual availability of moisture. Thin bark may conversely allow for increased transpiration of water through and out of the tree’s system, speeding growth and ultimately leading to exfoliation. Additionall
