sensitive and can be susceptible to both "sunburn" and
"frostbite". If a tree that has grown for many years in deep
shade is suddenly exposed to hot sun (when all the trees around
it are cut down, for example), the bark may become red and flake
off, injuring the tree. In northern regions, a frost too late in
the spring or too early in the fall can kill new bark tissue, as
well as leaves and Why is there such variation in the color and
texture of bark? Certain characteristics have obvious advantages
in certain habitats. The thick, rough bark of pine trees
withstands fire far better than the bark of oak trees, and
therefore more pines survive the frequent fires in temperate
coniferous forests. In other cases, the advantage of one type of
bark over another is less well understood. Smooth bark might
take less energy to produce, or it might help to discourage the
growth of moss and lichen. Rough bark might be more effective in
keeping wood-boring insects out. No one knows quite why the
types of bark have evolved t