Example of Impact in HemlockAmabilis Types
In moist/cool areas, wind has a major influence on stand structure and
the distribution of stands across the landscape.
HA (hemlockamabilis) and CH (cedarhemlock) are two well
known coastal types. HA stands have a history of windthrow. Some stands
have historically been repeatedly blown down. CH stands lose individual
trees while veteran redcedar is very windfirm.
HA types are predisposed to windthrow because of high density and uniformity;
also due to frequency of trees growing on rootwads/logs. Stands become
more unstable as they grow taller, eventually failing.