Dear Dr. Moore: Does logging have a long-term impact on biodiversity?
When people think of biodiversity they usually think of species diversity, which refers to the different animals, plants and insects in a given area.
Harvesting, especially when most of the trees are removed, has a considerable impact on species diversity but only in the short term.
Unless it’s converted for farmland or development, almost any forest will grow back to be as beautiful and diverse as the one it replaces. This has been demonstrated through the ages by the many forests around the world that have regenerated after disturbance, not only from logging but from fire, ice, wind, volcanic eruption and disease.
With or without human intervention, forests are in a constant state of change — and different stages of forest growth appeal to different species. After a disturbance such as fire, a site will attract grasses, berries and grazing animals, which like open areas. As the forest grows, species come and go based on the environment they prefer. In the case of wildlife, this might include the mature, low elevation forests needed by deer and elk during winter or old growth forests with dead trees used by birds and hibernating bears.
However, while a forest will grow back on its own, there is a link between sustainable forestry and biodiversity. Sustainability is governed by legislation, and foresters are required to show how they will maintain habitat for a full range of wildlife species. They also have to ensure landscape diversity — which refers to the different types of ecosystem, such as wetlands or old growth forests. An important part of sustainable forest management is designing harvest patterns in such a way that forests of all ages and all types of ecosystem are included on the landscape.
Some environmentalists promote the idea that a forest cut is an ecosystem gone forever, but, in fact, neither the biodiversity nor the spiritual quality of the original forest need be lost as the new forest grows.
I think that a sensible environmentalist understands that the process of renewal occurs over many years and chooses to see a recently harvested site for what it is — a moment in time.
(Questions may be sent to Dr. Moore at the following e-mail address: Patrick@SensibleEnvironmentalist.com.)
