Figs. 2.27-2.29. Photographs of normal wound responses during and after wound closure. Fig. 2.27. Callus ribs formed in a distinctive pattern on eastern hemlock with six bands of callus growing over a six-year-old wound. Most of the time, the first callus rib is larger than the ribs produced subsequently. Figs. 2.28-2.29. Completely closed wound on a yellow birch showing external and internal appearance, respectively. (Photographs courtesy of A.L. Shigo).