Crown Defoliation
Crown
defoliation is one of the main indices monitored for tree
condition of both forest and urban trees. It usually indicates
serious problems with trees of either a physiological or
pathological nature. Defoliation is the term used to describe
a situation where part of the leaf
mass is missing and bare branches and twigs remain. Dieback
(death of shoot and branches, generally from the tip to
base) falls into this category as well.
Bare twigs or dead branches in the
inner crown are not considered crown defoliation. Similarly
if a large tree has one
or two small branches without leaves it is considered
to be healthy.
Three classes of crown defoliation
are identified using the following rating: