The fire and oak hypothesis: incorporating the influence of deer browsing and canopy gaps

A century of fire suppression has altered tree species composition and is a commonly cited cause for the region-wide decline in oak abundance (the fire and oak hypothesis). Other explanations include alterations in canopy gap regimes and deer browsing that operate in conjunction with fire suppression. We examined the interactions among these processes by manipulating fire, deer browsing, and canopy gaps, in a fully factorial design. Fire lowered survival of small canopy trees (10-19.9 cm DBH) but had no effect on large canopy trees (>20 cm DBH). Fire increased and deer browsing decreased the proportion of top-killed saplings that sprouted. Gaps, however, had no significant effect on sprouting. Deer browsing, after fire, reduced diversity in the sprouting community, created understories dominated by striped maple. Northern red oak saplings were not fire tolerant and did not produce tall sprouts following fire. These results cast doubt on the ubiquitous application of the fire and oak hypothesis to explain the dominance of oak in some mixed hardwood forests. 2003
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The fire and oak hypothesis: incorporating the influence of deer browsing and canopy gaps   (2003)

A century of fire suppression has altered tree species composition and is a commonly cited cause for the region-wide decline in oak abundance (the fire and oak hypothesis). Other explanations include alterations in canopy gap regimes and deer browsing that operate in conjunction with fire suppression. We examined the interactions among these processes by manipulating fire, deer browsing, and canopy gaps, in a fully factorial design. Fire lowered survival of small canopy trees (10-19.9 cm DBH) but had no effect on large canopy trees (>20 cm DBH). Fire increased and deer browsing decreased the proportion of top-killed saplings that sprouted. Gaps, however, had no significant effect on sprouting. Deer browsing, after fire, reduced diversity in the sprouting community, created understories dominated by striped maple. Northern red oak saplings were not fire tolerant and did not produce tall sprouts following fire. These results cast doubt on the ubiquitous application of the fire and oak hypothesis to explain the dominance of oak in some mixed hardwood forests.

Author: Collins, Rachel J.; Carson, Walter P.


Source: General Technical Report NC-234. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Research Station

Citation: Collins, Rachel J.; Carson, Walter P.  2003.  The fire and oak hypothesis: incorporating the influence of deer browsing and canopy gaps  General Technical Report NC-234. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Research Station.