An industrial Tree Farm plantation
is not a healthy self-perpetuating Forest
Western Canada Wilderness Committee
Educational Report - Victoria Chapter
Volume 20, No. 1, Summer 2001
"We replant three trees for every one we cut down!" boast the big
logging companies. Everyone has heard this. Assuming that replanting is
successful, what's wrong with cutting down all, or almost all, of our remaining
oldgrowth forests, like the big-treed forest of the Upper Walbran [in British
Columbia]? The primary problem is that second growth tree plantations and
old-growth forests provide very different habitats. Here are some of the ways
they differ.
Trees in second-growth plantations are even-aged and closely spaced, blocking
out the sunlight. In the wild oldgrowth forest, the trees are of different ages.
As the giant trees die and topple over, they leave gaps for light to penetrate
onto the ground, allowing seedlings a chance to perpetuate an uneven-aged
forest. The different living spaces support more kinds of plants and animals,
creating more diversity in the oldgrowth forests.
Even-aged tree plantations contain few, if any, large dead trees, called
"snags," and no giant rotting logs on the forest floor that are so
common in oldgrowth forests. This rotting wood is home to numerous species of
birds, bats, salamanders, voles, insects and fungi. In times of drought, rotting
oldgrowth logs act as giant water sponges that gradually release their store of
moisture for wildlife and plants and to help retard fires.
Second-growth forests have "single-layered" canopies while
oldgrowth forests have "multi-layered" canopies. The single-layered
canopies have only one vertical level of needles and branches, because most of
the trees are roughly the same age and height. In contrast, the wide range of
tree ages and heights in oldgrowth forests create "multi-layered"
canopies. Different species, including birds, live in different canopy layers.
The gradual release of rainwater through the multi-layered canopies prolongs the
time period before moisture is absorbed by the soil, reducing the chance of
flooding and landslides.
Second-growth forests that are cut on short rotations do not have the time to
develop layers of lichens, ferns and mosses (called the "epiphyte"
layer) which grow on the trunks and branches of trees and which are a distinct
feature of oldgrowth forests. This is because many of these epiphyte species
take hundreds of years to become established and grow. Thick mats of suspended
soil build up from centuries of decay on branches. New species are constantly
being discovered in this epiphyte soil layer
University of Victoria entomologist Dr. Neville Winchester's research in the
oldgrowth canopy of the Carmanah Valley [in British Columbia] has so far
discovered over 70 new species of insects and spiders previously unknown to
science. He expects to discover another 600 new species from the thousands of
samples that have yet to be examined by taxonomy experts Undoubtedly the Upper
Walbran Valley's lush canopy, located just a few kilometers from Carmanah, will
also yield hundreds of new species -- if logging does not obliterate them before
they're discovered! Some biologists believe that the amazing complexity of the
oldgrowth temperate rainforest (the most complex of all the temperate
ecosystems) and its multitude of species contribute to this ecosystem's
heartiness, stability and longevity.
BC's oldgrowth coastal forests support many species that require or prefer
ancient forest habitat. Olgrowth-dependent species living in the Walbran include
nesting marbled murrelets, Vaux's swifts and Keen's long-eared myotis (a species
of bats). Unfortunately, the goal of BCs forest management system is to replace
the oldgrowth forests which are not protected in parks -- including the wild
forests of the Upper Walbran -- with tree farms that are clear-cut on short
rotation, long before they acquire oldgrowth features.
The rate of cut in BC is currently 71 million cubic meters a year, despite
the Ministry of Forests' own calculations that the long-term sustainable harvest
level (which itself is still based on the current short rotation/plantation
system of forestry and does not consider more ecologically sound forestry) is 59
million cubic meters a year. It is essential that the BC government drastically
reduce BC's rate of cut and mandate selection logging practices to stop the
forests of the province from being transformed into biologically impoverished
unsustainable tree plantations. |
