BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Cercis canadensis | Eastern Redbud 



GENERAL BOTANICAL CHARACTERISTICS : 
Eastern redbud is a native, deciduous, small tree or shrub.  Mature
height ranges from 25 to 50 feet (7.6-15.2 m); the smaller figure is
probably closer to average [15,16].  The crown is flat to rounded [53].
The trunk us usually straight, branching about 5 to 9 feet (1.5-2 m)
above the ground [56].  The 0.5-inch- (1.2-cm) thick bark becomes scaly
on older stems [11,16].  The root system of eastern redbud is long and
coarse with a relatively small number of fine feeder roots near the
surface [29]. The fruit is a flat, thin-walled legume (pod) 1.5 to 3.9
inches (4-10 cm) long and 0.32 to 0.72 inches (8-18 mm) broad, with
several hard, shiny seeds [11].

The national champion (1976) eastern redbud from Springfield, Missouri,
measured 47 feet tall (14.3 m), 8.17 inches (20.75 cm) in circumference,
and had a crown spread 36 feet (10.9 m) in diameter [23].

Unlike most other members of the Fabaceae, eastern redbud does not form
root nodules and does not appear to fix nitrogen [37].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Eastern redbud reproduces by bird dispersed seeds [47].  On average,
first reproduction occurs when an individual is about 15 feet tall (4.5
m), although sometimes blooming begins when trees are 5 to 7 feet
(1.5-2.1 m) in height [14].  Pods may be borne by 5-year-old eastern
redbud, with a maximum reproductive age of 75 years.  Good seed crops
usually occur in alternate years [56].  The seeds exhibit combined
dormancy:  internal dormancy plus a hard, impermeable seedcoat [46].  In
nursery practice, both scarification and cold, moist stratification are
required for germination [59].

Eastern redbud sprouts from the roots or root crown following topkill [5].

Eastern redbud can be propagated by softwood cuttings [17].


SITE CHARACTERISTICS : 
Eastern redbud grows on almost any site that is not excessively wet,
excessively dry, or strongly acidic [11,14,18].  Within its natural
range, eastern redbud exhibits a strong preference for, and can be used
as an indicator of, alkaline soils.  Eastern redbud occurs in eastern
redcedar communities on calcareous soils [12].  In Virginia, eastern
redbud tends to occur on alkaline soils high in calcium and magnesium
[20].  Collier and Longenecker [15] recommend a soil pH range of 6.0 to
8.0.  Best growth of eastern redbud occurs on rich, moist soils, usually
in partial shade [11].  It is usually not considered drought tolerant
[18]; however, its ability to tolerate dry conditions is decreased in
full full sun [14].  Probst [42] reported that eastern redbud is less
common in oak forests on poor sites than in oak forests on good sites
(defined by oak site indices).  The upper elevational limit of eastern
redbud is about 2,200 feet (670 m) in the southeastern portion of its
range [18].  In Trans-Pecos Texas, eastern redbud ranges from 2,300 to
5,000 feet (701-1524 m) in elevation [41].

In Trans-Pecos Texas, Mexican redbud occurs in brushy arroyos, canyons,
and limestone hillsides [41].  In the Konza Prairie of Kansas, eastern
redbud occurs on rocky breaks in the grassland [45].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Eastern redbud is moderately tolerant of shade and grows well in full
sun.  Flower and fruit production is best in full sun, but eastern
redbud's tolerance of full sunlight decreases in hot and dry areas
[50,54].  It has been hypothesized that eastern redbud and similar
midstory trees such as flowering dogwood attain a midstory canopy height
that maximizes interception of sunflecks (transitory periods of full sun
created by gaps in the canopy and the angle of the sun).  If this is the
case, eastern redbud requires at least short periods of sunlight for
growth [54].

Eastern redbud apparently establishes in middle seres, forming a
midstory layer, often with flowering dogwood.  In North Carolina,
eastern redbud and flowering dogwood developed as a distinct midstory
under an oldfield shortleaf pine (Pinus echinata) canopy as the stand
approached middle age (85 years) [7].  In western Tennessee, eastern
redbud was recorded on 28-year-old abandoned agricultural fields, but
not recorded on 3- and 12-year-old sites [48].  In Texas, primary
succession in gravel pit excavations did not include eastern redbud even
on the 47-year-old site, although eastern redbud was present in adjacent
undisturbed forest [60].  Eastern redbud is a characteristic midstory
species in mesic southern mixed hardwood forests which succeed
pine-hardwood mixtures, and could therefore be classed as a
late-successional species [43].  It occurs, for example, in an
old-growth oak forest in northwestern Ohio [61] and it is present as
seedlings, saplings and mature trees in southern mixed hardwood forest
in north-central Florida [38].  It may not, however, be stable in some
climax communities:  eastern redbud was reported as decreasing in
importance and relative dominance in an oldgrowth oak (Quercus
spp.)-hickory (Carya spp.) forest in Illinois [49].

Although eastern redbud is not usually described as a pioneer species it
often increases in dominance on sites experiencing disturbance.  It is
common on cutover or windthrown areas on calcareous soils [35].  In
Indiana, a tornado caused severe windthrow in a sugar maple (Acer
saccharum)-Ohio buckeye (Aesculus glabra) stand.  Prior to the tornado,
eastern redbud was a minor component in the stand.  The most severely
damaged portion of the forest was still mostly open 7 years after the
disturbance and was dominated by sugar maple, elms (Ulmus spp.), Ohio
buckeye, and eastern redbud.  Eastern redbud, which increased
dramatically in the first years after the tornado, will probably decline
in importance as taller species begin to close the canopy [35].


SEASONAL DEVELOPMENT : 
Eastern redbud flowers appear before the leaves from as early as
February in the southeastern United States to May [11,16,56].  In the
southern part of its range, eastern redbud pods are fully grown by the
end of May and ripen by September or October [16,56].  The pods split
open in late autumn to winter, sometimes persisting on the tree through
the winter [18,56].

Related categories for Species: Cercis canadensis | Eastern Redbud