Tree Tumors

Everyone knows that humans can get tumors. However, fewer people realize that trees can acquire tumors, too. Here are some photographs that I took of such tree tumors:

Fetus-Shaped Tree Tumor by B.Held

Teratoma Tree by B.Held

From what I've read, it seems as if most tree tumors are benign growths. If a twig bud fails to grow into a tree limb, then this bud can keep growing and growing. The end result is the protrusions on the trees (i.e., tree tumors or tree teratomas).

You can check out more of my photos at flickr.