Pre-commercial thinning is a silvicultural treatment
or type of cut in which young crop trees are selected and released
by removing any less promising neighbouring trees hindering their
growth. The trees that are kept are usually free of deformities,
harmful insects and disease. The end result is a much healthier
and better quality forest with a much faster diameter growth rate.
Where is pre-commercial thinning carried out?
Pre-commercial thinning is best suited to young,
very dense stands where more space is required between the trees.
It is performed only in forests that are around 15 years old, where
all the trees are more or less the same age. Such forests are known
as “even-aged forests”. They can be composed of softwoods,
hardwoods or a mixture of the two.
Pre-commercial thinning releases the healthier trees and allows
them to grow more quickly
This type of cut cannot be used to harvest timber
because the trees that are removed are too small to be of use to
the mills – hence the “pre-commercial” descriptor.
||Pre-commercial thinning is always performed mechanically with
a brush saw or chain saw.
The trees that are cut should always be left on
site, since their decomposition enriches the soil.
The features of pre-commercial thinning
Although species diversity usually remains more
or less unchanged, pre-commercial thinning can be used to shape
the final composition of a forest intended for wildlife, recreational
or other uses.
The treatment produces an environment that is well
suited to certain animal species, including the white-tailed deer,
which feeds on the branches in newly cut areas and finds shelter
in the thinned forest. The same applies to the hare and partridge,
which hide in the cutting waste. For other wildlife species, however,
it is important to ensure that certain types of trees – fruit
trees, for example – are left standing.