Intensive Forest Management
I believe that we are missing out on the advantages of more
intensive forest management. In other parts of our country and
the world, significant investments are made – including site
preparation, planting, thinning, and protection – decades before
trees are harvested. Perhaps because we live in a part of the world
where forests come back on their own, we’ve adopted the mentality
that little or no investment is needed to grow trees.
In an “intensive forest management” regimen, the goal is to
grow quality trees of desired species rapidly. The timeframe is
still multigenerational, but areas that would have been avoided in
hunter-gatherer forestry are actively managed.
If the objective is growing quality sawlogs, foresters concentrate
on growing high-value species with clear lower trunks. If the goal is
to promote wildlife species that depend on mast crops, then beech
and oaks are favored. Diversity is an important consideration in
determining desired species, as diverse forests are more resilient in
the face of threats than are monocultures. Another tenet of intensive
forest management is to grow species that are well adapted to
the soils, water conditions, and microclimate on a given site; for
instance, sugar maple and cherry like well-drained soil, and eastern
hemlock does well in deep ravines and on north-facing slopes.
Climate change is a new factor to consider in deciding on the
desired species. Given that trees can live for 100 years or more,
it behooves us to think of the climate they will experience in the
coming decades. Climate models for the Northeast predict that
we’ll experience warmer temperatures and more precipitation but
with greater variability, so this may include more droughts. For
southern Vermont, this suggests that white pine and red oak are
species to favor, as they are relatively drought- and heat-tolerant
compared to sugar maple and yellow birch.
As we identify our quality trees, it’s important to assess their
growth, since rapidly growing trees have several distinct advantages
over slowly growing ones. They are better able to defend against
insects, disease, and decay organisms. When they are injured,
they grow over wounds more quickly, decreasing the chance of
infection. They produce more seeds – generally at an earlier age
– which benefits both wildlife and forest regeneration. And fast-growing trees yield valuable forest products much sooner than do
trees that grow slowly.
Of course, most trees do not grow in diameter at a uniform
rate throughout their lives. It is not uncommon for a tree to grow
rapidly in its early years before slowing as it becomes crowded by
neighbors. Similarly, a crowded tree may respond to release from
the competition of neighboring trees by growing more rapidly,
with growth rates doubling or tripling within the space of a few
This potential increase in growth rates in trees following their
release from competition is a very important consideration. In
general, young trees are far better at responding to release than
older ones. As trees grow older (as a percentage of their species’
typical lifespan), they generally are less able to respond to release.
(A possible exception is eastern hemlock, which seems to respond
at any age.) So early intervention is preferable.