The long-term impacts of clear cutting can significantly affect the balance of life in the rainforest. More than 50 years after a Malaysian rainforest had been clear cut and some of the trees had grown back, U of T researchers found that many plant and animal species had drastically declined in numbers, and some had not even returned at all. Could these findings be relevant to the Canadian logging industry?
Canada’s Pacific coast boasts one of the world’s most extensive rain forests. British Columbia, Canada’s forestry giant, is a world leader in exports of wood and paper products. Heated debate exists between environmental groups and the logging industry. The 1999 agreement over Clayoquot Sound, between the main logging company and First Nations and environmentalists, aims to move away from clear cutting towards sustainable logging based on forest conservation. However, Canada’s forest industry can still benefit from the experiences of other countries.
From 1955 to 1958, the Pasoh Forest Reserve in Malaysia underwent the Malaysian Uniform System, or MUS style of logging. A form of clear-cutting, MUS removes all commercially viable trees at chest level in a single cutting. All stems unlikely to grow into marketable trees are poisoned. A second crop may not be recovered for 70 years.
The best-studied forest in Southeast Asia, Pasoh affords a clear look into the long-term effects of clear cutting. Dr. Sean Thomas, Assistant Professor at U of T’s Faculty of Forestry and one of the head researchers of a study conducted on the Pasoh forest, recently shared his findings here at U of T. His study, begun over 20 years ago, asks whether native floral and faunal species from a clear-cut forest can rebound to previous levels of population density.
They found that some native species function as “environmental gauges,” indicating if the environment is imbalanced. If after the forest has regrown, a certain species is not as abundant as it once was, that species is said to be “sensitive” to logging. For instance, after the Pasoh forest had regrown, trees and bushes growing beneath the canopy layer had declined in numbers. Mosses also demonstrated significantly reduced numbers and varieties. Among animal life, small mammals (shrews and red spiny rats), ants and termites, woodpeckers, and bats especially, demonstrated sensitivity to logging. Geckos and geckos were the most drastically affected-researchers found none in the new forest even after fifty years of regrowth.
The Pasoh study did produce some surprises however, which may well apply to Canadian forests. Some plant and animal species presumed to be “hardy” did not fare well after logging. Conversely, other species thought to be “weak” rebounded to pre-logging population densities. For example, free-standing and climbing palms suffered catastrophic losses. Yet researchers found a higher abundance of fungi and lichens in the regenerated forest compared to before the logging, and beetle and butterfly populations suffered little.
Why is the Pasoh study significant? The logging industry needs to know the impact of its activities on forest ecosystems. Our appetite for wood products may unwittingly extinguish a source of livelihood for many Canadians, and degrade the land we call home.