Historical Status and Trends
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| Logging white pine early 1900s. (Photo: Archives of Ontario) |
Prior to European settlement, forests dominated by white pine and red pine are estimated to have covered 0.7 per cent of the Lake Abitibi Ecoregion and 17.6 per cent of the Lake Temagami Ecoregion. The area covered by this forest type has since been reduced to about 0.06 per cent in the Lake Abitibi Ecoregion and to 8.5 per cent in the Lake Temagami Ecoregion. Fewer old-growth white pine and red pine forest stands likely exist today than prior to European settlement, but the actual change in the area of old-growth forest stands in Ontario has not been estimated.
The reduction in forests dominated by white pine and red pine is largely due to the following factors:
- From the 1870s until the 1990s, many white pine forests were not managed sustainably due to practices such as cutting the oldest trees first and high-grading that selectively removed only the best quality trees. White pine did not regenerate well in many areas, often because too few trees were retained to provide seed and/or only poor quality trees were left behind.
- For many years, little effort was devoted to regenerating white pine after forest harvesting. In areas where white pine seedlings did establish from seed or, more recently, by being planted, they often did not survive or grow well due to competition from other plants. White pine has also been affected by white pine blister rust, a non-native fungus introduced into North America in the early 1900s.
- During European settlement, repeated human-caused fires occurred in harvested areas and ignited the large amounts of waste wood left behind. Fires in recently cut areas kills young white pines, and repeated or very intense fires can also kill the remaining mature trees.
- Effective fire suppression in recent decades has nearly eliminated slow-spreading, low-intensity surface fires from the landscape. This type of fire is the primary natural disturbance agent required for natural regeneration of white pine.
Current Status
White pine is a component of 0.58 per cent of the total forested area or about 60,000 hectares of forest in the Lake Abitibi Ecoregion. White pine is much more abundant and widespread in the Lake Temagami Ecoregion, where it is a component of 31 per cent of the total forested area or about 1 million hectares of forest. Most of the time, white pine makes up a small part (less than 30 per cent) of those forests. Note that the decreasing amount of white pine from south to north, evident in Figure 5, is a natural pattern, as already described. Almost no forests containing white pine are recorded north of the area shown in Figure 5.
Figure 5. Current distribution of forests containing white pine in the Lake Abitibi and Lake Temagami ecoregions.
In both ecoregions, the area of white pine– and red pine–dominated forests classified as either young stands (with the exception of stands 0 to 20 years old in Lake Abitibi Ecoregion) or old stands is much lower than the area of forest stands of intermediate ages (Figure 6). The small area of younger forest stands is due to poor regeneration and does not support the long-term goal of maintaining white pine on the landscape.The apparent increase in area of 0-to-20-year old forest stands that are in the Lake Abitibi Ecoregion (3E) suggests that recent efforts to regenerate white pine and red pine have been more successful.
Figure 6. The age distribution of forest stands dominated by white pine and red pine in the Lake Abitibi (A) and the Lake Temagami (B) ecoregions in 2001 and 2006.
The small area of older forest stands is related to natural succession and fire suppression. As large, old white pine trees in old-growth forest stands die over time, other tree species replace them and become the dominant trees. The younger trees that replace them are often species that grow better in the shade, such as balsam fir and maples. Historically, low-intensity forest fires periodically reduced the abundance of these tree species, allowing white pine to re-establish. Today, the development and maintenance of old-growth white pine forest stands mainly depends on the successful regeneration and creation of new white pine stands after harvesting.
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Factors currently influencing white pine
