Repeat disturbances near old gaps are common and favor growth-suppression alternating species

Evidence

In one study designed to test this hypothesis (Runkle, unpublished data), high rates of repeat disturbance were found. For 273 gaps revisited 6-7 years after originally being sampled, one or more canopy trees surrounding the gap had died or been severely injured in 114 gaps, a former large stump from the tree creating the gap had fallen in 62 gaps, and new gaps were created near but not immediately adjacent to the original gap 35 times. In only 112 gaps did none of these new disturbances occur. Canopy trees surrounding gaps died at about the same rate as canopy trees in general. Multiplying the number of original surrounding canopy trees by a 1%/year disturbance rate by 6 or 7 years gives a predicted number of deaths of 151 trees versus 164 deaths or severe injuries actually recorded. For these forests, therefore, repeat disturbances are common and are a property of the size and age distributions of gaps. The evolutionarily important consequence of this result is that tree species should be favored whose saplings are able to alternate between periods of moderate to rapid growth while in gaps and periods of slow growth during the times between gaps. — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 230

Categorization

• DEFINE: Defines the concept of ‘multiple gap episodes’ quantitatively — a mechanism by which species chain several small gaps to reach the canopy.
• XREF: connects to: Small-edge-rich gap regimes produce repeat disturbance that slows gap closure — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 230; Many shade-tolerant trees reach the canopy through repeated suppression-and-release gap episodes, not one gap — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1342; Species responses to cutting reveal their historical disturbance regime — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 263 (+5 more)

Broader Connections

• Many shade-tolerant trees reach the canopy through repeated suppression-and-release gap episodes, not one gap #exemplifies (0.92) — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1342
• Small-edge-rich gap regimes produce repeat disturbance that slows gap closure #corroborates (0.85) — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 230