Community and Historical Analysis of Northern Red Oak Along a Moisture Gradient in North-Central Wisconsin
File(s)
Date
1988-08Author
Nowacki, Gregory Jay
Publisher
University of Wisconsin-Stevens Point, College of Natural Resources
Metadata
Show full item recordAbstract
Forty-six relatively undisturbed northern red oak
(Quercus rubra L.) stands in north-central Wisconsin were
surveyed using the point-quarter method during the summers of
1986 and 1987. Using detrended correspondence analysis (DCA)
and overstory importance values, stands were separated into
four groups. Stand position along DCA axis 1 was
significantly correlated with soil texture, which was
interpreted as a moisture gradient from mesic to dry mesic.
All groups were dominated by overstory northern red oak,
however changes in understory dominance from sugar maple
(Acer saccharum Marsh.) to red maple (Acer rubrum L.)
occurred from mesic to dry mesic groups. Decreases in basal
area and age and increases in shrub cover from mesic to dry
mesic were also found. Historical data suggest that northern
red oak was relatively unimportant in most presettlement
forests in the area. Most of north-central Wisconsin was
completely logged and physical evidence of fire was found
within or near two-thirds of the stands. These disturbances
are thought to have created conditions favorable for northern
red oak establishment. leading to its increased frequency in
the region. Age and diameter data indicated that northern
red oak were consistently the oldest and largest individuals
in all stands, forming an even-aged canopy. Substantial
northern red oak recruitment into the tree size class seemed
to last only for 25-30 years after disturbance (conceivably
until canopy closure), and thereafter only shade tolerant
species were successful in the understory. Under today's low
disturbance regime, northern red oak may be restricted to a
single generation with a strong likelihood of being replaced
by sugar maple on mesic sites, a combination of sugar and red
maple on transitional sites and red maple on dry mesic sites.