Chapter 5
The Ecological Basis
for Oak Silviculture
in Eastern North America
DANIEL DEY
Quercus is a dominant genus throughout North America and has been
for the past 10,000 years or more (see Chapters 2 and 3). Oak distribu-
tion has shifted in response to changes in climate, disturbance regime,
and human population and culture. Oak dominance has increased
throughout the Holocene period. However, a recent successional trend
is the replacement of oak-dominated ecosystems throughout the range
of oak.
The inability of oak reproduction to compete with either large shade-
tolerant advance reproduction or aggressive pioneer species is the fun-
damental cause of problems in oak regeneration and sustainability
(Lorimer 1993). Oak regeneration problems and reductions in oak stock-
ing are most likely on higher-quality mesic sites (site index > 60 feet,
base age 50). Oaks appear to be successionally most stable on xeric
sites, under current disturbance regimes, which are typified by frequent
small-scale disturbances that cause isolated mortality to overstory trees
and the absence of fire (Johnson 1993a). However, increased competi-
tion from shade-tolerant trees and shrubs threatens oak regeneration
potential even on these drier sites.
Oaks are adapted to environments characterized by disturbance and
stress. The primary factor leading to the successional displacement of
oak in eastern North America has been a change in the historic distur-
bance regime that has altered the competitive relationship between oak
and its associates. The widespread distribution and dominance of oak is
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