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- Info
Logging and fragmentation of broadleaved deciduous forests: Are we asking the right ecological questions?
| Author: |
Bratton, Susan P. |
| Date: |
1994 |
| Periodical: |
Conservation Biology |
| Abstract: |
Contemporary logging practices: (1) change the scale of disturbance in eastern forests, generally increasing the size of openings; (2) change the rotation of disturbance in eastern forests, generally increasing the frequency of large canopy opening; (3) remove woody debris; (4) change soil structure via compaction and erosion by loggers and equipment; and (5) have direct impacts on understory species, such as intensive trampling near the bases of felled trees. We should, therefore, expect some differences between herbaceous species survival in logged stands and those subject to gap phase succession, whether the logging is historic or contemporary. The differences in the size of the openings alone will have a major impact on the microclimate on the forest floor; very small openings will cause less change in radiation, temperature, and humidity than larger ones. Many vernal herbs are confined to mesic sites and, therefore, may indeed be sensitive to microclimatic changes caused by large canopy disturbances. Since both foresters and ecologists could probably agree that skidder logging in the first half of the 20th century was "brutal" from the point of view of your average Trillium grandiflorum, the most interesting question is not, Do Duffy and Meier's (1992) results apply primarily to older clear cuts? but rather, What is the effect of the scale of the opening on K-selected species or those found largely in closed canopy forests? Is there a threshold size where larger openings are more likely to result in understory species loss? Conversely, is there a minimum area of old growth that will retain its species diversity? How does understory diversity in small woodlots compare with that of more extensive forested stands? Will small fragments of mature or old growth stands slowly lose small patches of K-selected herbs? |
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