Abstract:The trunk of Broussonetia payrifera (L.) Vent. following an extensive length of completegirdling could regenerate new bark in the entire growing season after bud-sprouting. Severaldays after girdling, most of ray cells near the surface dilated and proliferated outward to formcallus. Then, other immature xylem cells rehabilitated the ability of cell division and tookpart in the formation of callus Later, a cork cambium developed near the surface of thecallus and a cambium near the middle part of the callus. The newly formed cambium cannormally produce phloem outward and xylem inward. However, when the girdled trunk waswrapped up with a transparent plastic shee during the growing period from late May to earlyAugust causing high temperature and humidity inside the wrapping sheet, the surface of peridem often produced loose sloughy cell layers that could regain it’s normal structure after unwrapping the sheet.