Douglas fir old growth at risk
With less than one percent of the original area remaining, coastal old-growth Douglas fir forest is
the most threatened of all in British Columbia. Greater Victoria Water District lands contain the
largest stands of old-growth Douglas fir left on southern Vancouver Island, with a total area of
approximately 45 square kilometers. As owners of this ecological treasure, the people of Greater
Victoria have in their control a biologically unique legacy on southern Vancouver Island that
will, if kept as undisturbed as possible, play a crucial role in maintaining a source of quality
drinking water for generations to come.
In the past, much emphasis has been placed on the diversity of the tropical rainforests, but we are
now learning that our old growth forests are far more complex that we originally imagined.
According to Dr. Michael Amaranthus, a leading soil scientist in the Pacific Northwest, if we
include both above and below ground zones then our temperate forests are as diverse as any.
This complexity and diversity make the old growth forests invaluable in providing quality water
and very dynamic in dealing with pests and diseases. The more we disturb this complex natural
balance the more we encourage problems and enter into a vicious cycle of managing our
management. Dr. Michael Feller, associate professor at the University of British Columbia’s
Forestry Faculty, comments: “Thousands of years of natural evolution have given us the old-
growth forests of our watersheds which generally do an excellent job providing high quality
water.”
Scapegoats: Logging for pests, disease and fire
PESTS, a term associated with naturally occurring plant-eating insects, are a part of any diverse system. From an industrial forester’s perspective, these insects are viewed as competitors for valuable timber and thereby made out to be villains.
This is the common approach when trees are viewed in terms of dollars and cents. In the case of our watersheds, we must view the forests as an ecosystem made up of incredibly complex and diverse elements that function together, maintaining the ecological conditions of the old growth forests, which result in high quality drinking water.
Dr. Tim Schowalter, one of the Pacific Northwest’s foremost experts on forest insects, speaking on pests in old-growth: “Contrary to numerous assertions, old-growth forests are highly productive and remarkably resistant to potential pests. The resistance of these forests may be due largely to the diversity of plant and animal predator species.”
On our watershed lands, logging interests constantly disregard and downplay the ecological approach because logging would then not have a dominant role. In turn, logging on our watershed lands is being touted as crucial to deal with pests and disease. Areas where insects have made impacts are not extensive in old-growth forests. These small areas can produce snags, or standing dead trees. But these trees are far from being void of life. They are home to a myriad of species, from birds through to insects and are part of the natural process that makes for a healthy ecosystem. These areas encourage and promote further diversity of plants and animals and are among the many attributes in an old growth forest that make it remarkably resilient.
DISEASE is another word being used to promote logging our watershed lands. “Phellinus weirri’ is a naturally occurring native fungus which causes laminated root rot in Douglas fir.
Again, to the forester who is looking for the greatest volume of timber as quickly as possible, this is regarded as a threat to timber production, and must be eradicated or controlled. Our watershed lands are not tree farms and this approach is counterproductive to maintaining the natural diversity that makes our watersheds ecologically healthy. In old growth forests this fungus is not a threat at all. In fact, it is part of the complex system that acts to encourage diversity. In the small areas that are affected, shrubs and younger trees of perhaps alder or red cedar, which are immune to this fungus, establish and provide a new habitat and a new level of complexity. Snags and down logs are actually crucial in perpetuating the complex natural ecosystem. So this fungus acts as an agent to promote overall forest health. It just depends which perspective you look at the forests from; Timber production for maximum dollars, or a healthy ecosystem for quality water. It is on the heavily managed areas of plantations that root rot spread over extensive areas. A joint federal and provincial forestry report found that, ‘Young second growth forests are particularly vulnerable to root disease.’ UBC’s Dr. Michael Feller from the Faculty of Forestry sums it up this way:
“On balance, the undisturbed old-growth forests of our watersheds are not particularly susceptible to insect or disease attack as evidenced by the fact that we never find extensive areas of such forests killed by insects or disease.”
FIRE is a risk to the forests of our watershed lands, but again the forest type that is most resistant to its spread is the old-growth forest. Gaps and holes that exist naturally in the old- growth act as a retardant to the spread of fires.
The closed nature of a managed young forest presents a high risk for fast spreading and more severe crown fires. Dr. Feller, an expert on the subject, states: “Old growth usually presents much less a fire hazard than managed forests unless extreme forms of management occur, and this is generally not done.” It is widely recognized that logging and related activities actually increase risk of fire. Dr. Feller goes on to say: “Unequivocally, the net effect of forest management in the watersheds is to increase the risk of fire caused by people and logging related activities.”
