Agents of change
in Alberta's forest ecosystems can originate from natural sources, as well as
human activities. Some years, the overall area affected by forest fires, insects
and disease is extensive. But these natural processes, active in virtually all
of Alberta's forests, are natural agents of change for forest ecosystems. Forest
size, shape, distribution pattern and mix of tree species are all affected over
time by a combination of climate, landform, and the frequency of fire and other
harvesting can also disturb forest ecosystems. As with fire, the changes can be
abrupt. Harvesting's potential effects include habitat alteration and
fragmentation, a reduction in biological diversity, and soil compaction and
erosion. Overall, timber harvesting, fire suppression, and related forest
management activities affect the forest ecosystem. In some areas of the
province, however, clearing for agriculture and petroleum exploration and
development are more significant human disturbances than timber harvesting.
Department of the Environment. State of the Environment Report, Terrestrial Ecosystems. Edmonton: n.p., 2001. With permission from Alberta Environment.