An industrial Tree Farm plantation is not a healthy self-perpetuating Forest
A dense, dark, uniform even-aged tree farm plantation blocks out the sunlight impoverishing the forest floor habitat. Photo credit: Chris Darimont
"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? 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 standing 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.
This huge Douglas fir snag in the lush Upper Castle Grove is located within a proposed TimberWest TFL 46 cutblock. Photo credit: Ron Smid.
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 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 kilometres 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. Oldgrowth- 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 BC's 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 clearcut on short rotation, long before they acquire oldgrowth features.
The rate of cut in BC is currently 71 million cubic metres 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 metres 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.
