BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Quercus lyrata | Overcup Oak 



GENERAL BOTANICAL CHARACTERISTICS : 
Overcup oak is a deciduous, native tree [12].  Mature trees usually
range from 60 to 90 feet (18-27 m), and 24 to 30 inches (61-76 cm)
d.b.h.  Maximum height is rarely over 100 feet (30 m) [34,39].  The bark
has thick, irregular plates or ridges covered with inner scales.  The
root system is usually shallow and saucer shaped.  Seedling taproots are
usually replaced by a lateral root system [39].  Mature crown leaves
range from 5 to 8.5 inches (13-21.5 cm) in length and are usually five-
to nine-lobed [12].  The acorns range from 0.48 to 1 inch (12-25 mm) in
length, and are nearly globose to broadly ovoid.  The acorn cup
covers two-thirds to nearly all of the acorn, with acute scales [7].

Oaks usually grow slowly for the first 10 to 15 years; growth rates
become more rapid thereafter [21].  The national champion overcup oak
for 1976 was in South Carolina; it measured 22 feet (6.7 m) in
circumference, was 123 feet (37 m) tall, and had a 48-foot (14.6-m)
crown spread [12].  The largest overcup oak (ranked by point system in
1990) was found in Texas.  It was 51.1 inches (129.8 cm) in diameter,
160.53 inches (13.37 m) in circumference, and 114 feet tall (34.7 m)
[29].  Overcup oaks can live to 400 years of age [39].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Overcup oak becomes sexually mature around 25 to 30 years of age.  Good
seed crops are produced approximately every 3 or 4 years, although yield
is relatively low compared to other oaks [39,43].  Overcup oak acorns
have a unique spongy shell that renders them buoyant [26].  They are
disseminated by water and, to a lesser extent, animals [39].  Acorns can
be carried long distances by streams.  Overcup oak acorns have been
found on the beach of a northwestern Florida island, miles from any
apparent seed source [4].  Overcup oak acorns are dormant only over the
winter and germinate in the spring after flood waters recede [39].  One
study reported that submergence reduces germination [16].  Another study,
however, found soaking overcup oak acorns strongly retarded germination,
but did not appreciably reduce germination rates.  The first-mentioned
study may be based on shorter test times, and not have allowed for the
ability of overcup oak to germinate after a long period.  Delayed
germination may be an adaptive trait that increases the likelihood that
young seedlings will germinate after spring floods recede.  Partial
shade is beneficial for oak germination [34]. Good germination occurs on
moist surface soils when acorns are covered by leaves [21].

Natural reproduction is usually prolific, but mortality rates are high,
probably due to flooding.  Successful regeneration is dependent on the
an adequate seed source and complete absence of fire [39].

Stumps of small trees sprout vigorously but not consistently [39].


SITE CHARACTERISTICS : 
Overcup oak occurs on low, wet soils in floodplain forests, bottomlands,
streambanks, and bayous, and sometimes on adjacent lower slopes [7,12].
It occurs most often on soils with a moderate water table depth.  Sites
are commonly flooded for 29 to 40 percent of the growing season
[15,16,39].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Overcup oak forms climax stands on low, backwater flats and is usually
subclimax on better sites.  It is relatively intolerant of shade [39].
It usually succeeds black willow during very slow succession on shallow
swamps or on slough margins [36].  Disturbance results in a strong
release response from suppressed overcup oaks [38].


SEASONAL DEVELOPMENT : 
Overcup oak is late to leaf out in the spring, sometimes as long as a
month behind sympatric species.  This late emergence probably
contributes to its flood tolerance [36,39].  Overcup oak flowers from
March to May as its new leaves appear [7,39].  Acorns ripen the same
year, from September to October, and are disseminated shortly thereafter [1].

Related categories for Species: Quercus lyrata | Overcup Oak