BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Sassafras albidum | Sassafras 



GENERAL BOTANICAL CHARACTERISTICS : 
Sassafras is a native, deciduous, aromatic tree or large shrub, with a
flattened, oblong crown [41,83].  On the best sites, height ranges up to
98 feet (30 m) [41].  In the northern parts of its range, sassafras
tends to be shrubby, especially on dry, sandy sites, and reaches a
maximum of 40 feet (12 m) [49].  The bark of older stems is deeply
furrowed, or irregularly broken into broad, flat ridges [38,83].  The
variety of leaf shapes to be found on one individual is a distinctive
trait of the species.  Leaves can be entire, one-lobed, or two-lobed.
The fruit is a drupe [41].  The root system is shallow, with prominent
lateral roots.  Root depth ranges from 6 to 20 inches (15-50 cm).


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Sexual reproduction:  Sassafras is sexually mature by 10 years of age,
and best seed production occurs between 25 and 50 years of age.  Good
seed crops are produced every 1 to 2 years.  Seeds are dispersed by
birds, water, and small mammals.  Sassafras seeds are usually dormant
until spring, but some germination occurs in the fall immediately
following dispersal [41].  Stratification in sand for 30 days at 41
degrees Fahrenheit (5 deg C) breaks the natural dormancy.  Average
germination rate is around 85 percent [83].  Since sassafras seeds are
relatively large, initial establishment is not highly dependent on
available soil nutrients.  Other factors appear to play a greater role.
Seedling establishment occurred at higher than randomly expected
frequencies on microsites with greater ground cover, less light, or
deeper litter than other microsites [14].  Sassafras seeds were found in
seedbanks under red pine (Pinus resinosa), eastern white pine (P.
strobus), and Virginia pine (P. virginiana) stands [6].  Sassafras
seedling reproduction is usually sparse and erratic in wooded areas.  In
these areas, reproduction is usually vegetative [32,41].

Asexual reproduction:  Sassafras forms dense thickets of root sprouts,
and young trees sprout from the stump [41].  After clearcutting in
upland hardwood stands (Indiana), 86.5 percent of sassafras regeneration
was of seedling or seedling sprout origin; the remainder was of stump
sprout origin [36].


SITE CHARACTERISTICS : 
Sassafras occurs on nearly all soil types within its range, but is best
developed on moist, well-drained sandy loams in open woodlands [41].
Optimum soil pH ranges from 6.0 to 7.0, but sassafras also occurs on
acid sands in eastern Texas [41,75].  It is intolerant of poorly drained
soils [32].  Sassafras occurs along fence rows and on dry ridges and
upper slopes, particularly following fire [41].  Sassafras occurs at
elevations ranging from Mississippi River bottomlands up to 4,000 feet
(1,220 m) in the southern Appalachian Mountains, occasionally up to
4,900 feet (1,500 m) [24,41].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Sassafras is a frequent pioneer in old fields, and is a member of seral
stands in the Southeast [41].  In oldfield succession in Tennessee,
sassafras was a dominant member of a 15-year-old stand, and was not
present in a 48-year-old stand [11].  In Virginia, sassafras persists to
mid-successional stages with black locust, Virginia pine, pitch pine,
eastern white pine, scarlet oak, blackjack oak, and post oak [86].  It
also occurs in the canopy of old-growth forests in Illinois and Michigan
[45,71].  In the Michigan stands sassafras decreased in relative density
during a 20-year study [45].  The persistence of sassafras into later
seres and climax stands may be a result of gap capture; in an old-growth
forest in Massachussetts, older sassafras trees appear to be associated
with hurricane and/or windthrow gaps.  There was no evidence of fire
disturbance in this forest [25].  Human activities and disturbance can
foster sassafras establishment in old-growth stands.  The relatively
high abundance of sassafras under Virginia pine stands is associated
with a greater frequency of tree-fall gaps under Virginia pine than
under red pine or eastern white pine [6].  Sassafras seedlings in Table
Mountain pine (Pinus pungens) stands are able to exploit canopy gaps at
the expense of Table Mountain pine [87].

A detailed study of age structure in mixed forests in Virginia reveals
another role for sassafras.  In 45- to 80-year-old mixed hardwoods and
mixed pine stands, sassafras seedlings and saplings occur in large
numbers.  They rarely survive more than 30 years except on moist sites.
On relatively dry sites, sassafras does not survive long enough to
occupy upper canopy positions.  But since sassafras sprouts
prolifically, there is a constant turnover of sassafras stems; older
stems die back and are replaced by new ramets.  Sassafras in the
understory produces fruit under these conditions.  In these stands,
sassafras is apparently functioning as a dominant shrub [72].

In New Jersey, fragmented mixed oak forests were compared with forests
that were continuous.  Sassafras was present in 63 percent of the
fragments, compared to 25 percent of the continuous stands [37].

Sassafras exhibits a positive response to overstory removal; overstory
defoliation by gypsy moths results in an increase in the number of
sassafras stems [1].

An unusual pure stand of sassfras was reported by Lamb [59] in 1923.
This stand appeared to have remained essentially pure and intact for
over 100 years.  The trees were described as fully mature, slow growing,
and the soil was very fertile.  It is possible that the persistence of
this stand, and the competitive success of sassafras in pioneer
communities are related to the presence of terpenoid allelopathic
substances in sassafras leaves .  These substances affect, among other
species, American elm (Ulmus americana) and box elder (Acer negundo).
The susceptibility of these species appears to be related to their habit
of germination immediately following dispersal.  The toxic terpenes are
washed off of summer leaves and are less concentrated in winter and
spring when no fresh leaves are present [31,34].


SEASONAL DEVELOPMENT : 
Depending upon latitude, sassafras flowers from March to May [24], and
fruits ripen from June to September [68,76,77].

Related categories for Species: Sassafras albidum | Sassafras