“Thank goodness for a wet spring”. Obviously these
are the words of an arborist and not a travel agent.
After months of below average rainfall, our weather
pattern has shifted. We received above average rainfall
in March, April, May and the first portion of June.
According to the U. S. Geologic Survey, surface water
levels in Massachusetts have returned to normal levels,
as have 6 of 8 ground water monitoring wells. It seems
the drought is over. What implication does this return
to abundance have for our trees?
In almost all cases, consistent moisture during the
active growing season is extremely beneficial. Water
is necessary for photosynthesis and plant growth. In
fact, moisture is the key determinate in shoot elongation.
Shoot growth takes place from preformed initials called
buds. Buds form during the previous growing season
and contain all the cells, which will expand into new
leaves and shoots; it can be compared to a not yet
inflated balloon.
As growth starts in the spring, the buds begin to expand.
The amount of water available during expansion is the
primary factor that influences the amount of annual
growth. This is especially true in determining the
amount of xylem, or wood trees that produce to thicken
their trunks each year. This direct connection between
water supply and annual wood production is the basis
for the science of dendrochronology.
Dendrochronology is the science of studying the width
of tree rings, in order to establish ages of trees
or wood, or the years in which they grew. What are
the implications for your property? There are two distinct
issues of which to be conscious. One issue is vigor,
which is important for older or previously watered
stressed trees, the second is crown density or structural
integrity.
Older trees or trees which have suffered from drought
over the past few years cannot recover their vigor
in one season. Several years of below normal precipitation
can weaken trees, and they will require several years
to recover. It is important to continue to take any
required effort to rebuild their health. This spring’s
rain alone is not adequate. On the other hand, healthy
trees and shrubs have grown an extraordinary amount
this season. It appears to be the best year for growth
in a decade.
Because of the unusual amount of growth, it will be
important to check your trees’ structures and
insure that an over full crown does not put too much
weight on weak limbs or decayed areas. Further, this
year’s profuse growth may require a few additional
hours of work, when we perform summer shrub or ornamental
tree pruning. In short, we can be grateful for a wonderful
growing season, which will help our plants begin to
recover from several challenging dry years.
