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The Poconos of eastern Pennsylvania encompass an area of moderate topographic relief, with thin rocky soils and a climate with both continental and maritime influences. This outline relief map of Pennsylvania shows the location (white dot) of the Blooming Grove Hunting and Fishing Club, one of my study sites. The natural forest vegetation of this area is transitional between the mixed oak forests further south along the Piedmont, and the northern hardwoods further north and west in Pennsylvania and New York. |
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On May 31, 1998, two tornadoes, rated F2 in intensity, moved across the property of the Blooming Grove Hunting and Fishing Club, located about 20 miles east of Scranton. This image shows the hand-drawn paths of the two tornadoes as they moved from west to east across the Club property. Of the roughly 20,000 acres in Club ownership, about 800 acres were damaged by the two storms. Most of the damaged area in the northern path was subsequently salvage-logged, and about half of the southern path. |
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This image shows the view of the Taylor Swamp area in the southern
tornado path. This roughly 4-hectare area is separated from the damage path
further west by a road, and from the damage path further east by a swamp;
therefore it was not salvaged. The photo shows that damage was very severe;
nearly complete canopy destruction. The forest here is comprised of red and
white oaks, red and sugar maple, yellow and black birch, white ash, several
species of hickory, and in the lower spots, hemlock. Less common species
include yellow poplar, white pine, and bigtooth aspen.
Note the row of young aspen stems coming up through a fallen tree in the foreground. This is an example of a potentially important influence on regeneration in wind-damaged forests: the fallen trees, as woody debris, may often provide protection from browsers for small seedlings, thus facilitating establishment. As a consequence, if browser activity is high, the protection offered by debris could strongly influence the location and abundance of regeneration by determining which new stems survive. |
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This image shows the view from the same point as the previous photo, but looking in a different direction. While it is clear that essentially all of the pre-storm canopy trees were toppled, it is also apparent that regeneration is abundant. This 2001 photo was taken 3 years after the storm, showing that new seedlings, root sprouts, sucker sprouts, and surviving advance regeneration combine with non-woody species to form a dense vegetation in this area, despite the absence of an overhead tree canopy. Note also the presence of obvious soil microtopography (pits and mounds) created by uprooted trees. The role of this microtopography in influencing regeneration is poorly known, and the subject of much interest from me and my students. |
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Another view of the Taylor Swamp area shows an additional phenomenon. In the background you can see intact trees that escaped wind damage; the boundary between severely damaged forest and forest with little or no damage can be surprisingly sharp after tornado disturbances, offering the opportunity to compare neighboring areas that are essentially identical in every way except for the amount of damage experienced. |