Many of the birches are susceptible to damage from two
insect pests. The
birch leaf miner will eat between the layers of
the leaves causing the leaves to turn brown and, in
severe cases, defoliate the tree early in the
In itself, leaf miner
damage stresses the tree but rarely kills it.
However, the weakened tree is then more attractive
to a much more serious pest called the
bronze birch borer. This critter will bore into
the wood and kill the tree starting from the top and
working its way down the trunk.