SURVIVAL OF THE FITTEST: Why eucalyptus, sycamore, birch, crape myrtle, madrone, and our western manzanita, as well as many other trees, shed their bark. Obviously, there must be an evolutionary reason for frequent shedding in some tree species. The rainbow eucalyptus and some other gum trees that shed frequently are a source of delight for me because I am always on the lookout for things in nature that are beautiful or unusual or both. Darwin wasn’t interested in the eucalyptus because they make pretty pictures. He and other botanists looking for evidence to reinforce the theory of evolution, actually no longer just a theory, cite the trees that shed their bark as good examples. Frequent shedding reduces the chances that sheltered insects will stay long enough to damage a tree. The green blotches in these pictures are photosynthetic patches. The trees can photosynthesize along their trunks and branches as well as in their leaves, creating an increased growing season.

To some extent all trees shed older bark the way we humans shed our skin, but the trees I like best are the species that produce beautiful shedding patterns. With the small camera I usually take along on a bike trip, I took some pictures and posted them a couple of weeks ago of a special eucalyptus I found down by the yacht harbor. I went back to the same tree to see if the shedding had changed it further. Wow! The tree is like a kaleidoscope. I took these pictures especially for my brother.