Due to a combination of ground saturation and heavy winds, these microbursts produced extensive
windthrow in relatively discrete patches of damage with adjacent undamaged areas.
Periodic burns and associated droughts may have caused widespread overstory mortality either directly or indirectly (predisposing trees to
windthrow, disease, or insect attacks).
In the East, the major factor in local disturbance regimes," to use the elegant ecological term, was
windthrow. Fire was second.
For example, infected stands have been observed to be more susceptible to
windthrow (Papaik et al., 2005).
Uprooted Tsuga canadensis demonstrate little survival after
windthrow, and the subsequent forest may consist of distinct age and size cohorts of very different species: older, extremely shade-tolerant species (e.g., Tsuga canadensis and Fagus grandifolia) that were present in the original understory, and younger, less shade-tolerant, wind-dispersed species that established after the disturbance (e.g.
Evidence of disturbance, including
windthrow mounds, cutting, fire scars, stem charring, and soil charcoal, was recorded at each plot.
Individuals that die leave single tree gaps; we do not include severe disturbances such as
windthrow or fire in runs described in this paper.
Mortality of overstory trees and
windthrow created many gaps in the forest canopy at the time of the study.
Of note is that treefall often created a pit and mound soil microtopography not unlike that usually attributed to
windthrow (see Wardle 1984).
Thus, it may be possible to treat wind speed in much the same fashion as wave height has been dealt with here, and by measuring the drag coefficients and strength of trees, to predict the rate of
windthrow in forests.
(2002) found that the amount of light was only significant for their smallest size class (similar in height to our large seedlings), our results are not surprising because northern white cedar is known to have a plastic growth response when canopy gaps are created by small-scale logging,
windthrow or other disturbances (Scott and Murphy, 1987; Heitzman et al., 1997).
The purpose of the model is to simulate species-level forest dynamics in combination with fire,
windthrow, and harvesting, with adequate mechanistic realism for a range of spatial scales.