BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Fraxinus americana | White Ash 



GENERAL BOTANICAL CHARACTERISTICS : 
White ash is a native, deciduous, long-lived tree [30].  Leaves are
compound, 8 to 15 inches (20-38 cm) in length, and usually have seven
oval, entire leaflets [17].  White ash is dioecious.  The male flowers
bloom first, before the leaf buds break.  The pollen is already airborne
during the 7 to 10 days when the female flowers are receptive [10,32].
The flowers are borne in panicles near branch tips.  White ash will
start to flower when it is 3 to 4 inches (8-10 cm) in d.b.h., but
abundant flowering does not occur until the tree is 8 to 10 inches
(20-25 cm) [10].

White ash obtains heights of 60 to 70 feet (18-21 m).  The bole is long,
straight and free of branches for most of its length, and the crown is
narrow and pyramidal when grown in a mixed stand.  Open-grown specimens
have a short bole with a rounded crown [17].


RAUNKIAER LIFE FORM : 
   Undisturbed State:  Phanerophyte (megophanerophyte)
   Undisturbed State:  Chamaephyte
   Burned or Clipped State:  Chamaephyte
   Burned or Clipped State:  Cryptophyte (geophyte)


REGENERATION PROCESSES : 
Sexual:  White ash samaras remain viable on the forest floor for 3 to 4
years [5].  The samaras require cold stratification; in the laboratory
stratification at 41 to 14 degrees F (5 to -10 degrees C) for 2 to 3
months resulted in a mean germination of 54 percent.  Germination is
epigeal and can occur on mineral soil, humus, or leaf litter, but the
substrate must be moist [27].

Vegetative:  White ash resprouts from the root crown after logging or
fire.  Sprouting ability decreases with age [27].

Silviculture:  Young stands (5 to 10 years) respond to the addition of
nitrogen and thinning by increasing the number of stems per acre and
increasing in height growth by 1 to 2 feet (0.3-0.6 m) [15], whereas
older stands (35 to 85 years) do not exhibit increased growth from
fertilization or release [8].

White ash responds well to shelterwood cutting.  Advanced regeneration
grows best with 60 percent of the overstory removed [14].


SITE CHARACTERISTICS : 
White ash grows best on deep, well-drained, moist soils with other
hardwoods [17].  In the Northeast white ash occurs on middle mesophytic
slopes, and it is reduced or lacking on dry, cold ridges and
mountaintops.  White ash occurs on slightly elevated ridges in the
floodplains of major streams in the Coastal Plain and on slopes along
major streams in the Central States [27].

Soil:  White ash has a strong affinity for soils high in nitrogen and
calcium [27]. 

Climate:  Climate varies widely within white ash's range.  The
frost-free period ranges from 90 to 270 days.  Annual precipitation
ranges from 30 to 60 inches (76-152 cm) per year.  Snow depths vary from
0 to more than 100 inches (254 cm) [27].

Elevation:  White ash grows from near sea level on the Coastal Plain to
3,450 feet (1,050 m) in the Cumberland Mountains [27].

Associates:  White ash's primary associates are eastern white pine
(Pinus strobus), northern red oak (Quercus rubra), white oak (Q. alba),
sugar maple (Acer saccharum), red maple (A. rubrum), yellow birch
(Betula alleghaniensis), American beech (Fagus grandifolia), black
cherry (Prunus serotina), eastern hemlock (Tsuga canadensis), and yellow
poplar (Liriodendron tulipifera) [27].

Understory associates are downy serviceberry (Amelanchier arborea),
pawpaw (Asimina triloba), American hornbeam (Carpinus caroliniana),
flowering dogwood (Cornus florida), and eastern hophornbeam (Ostrya
virginiana) [27].


SUCCESSIONAL STATUS : 
White ash is a pioneer species.  It is characteristic of early and
intermediate stages of succession.  Although mature white ash is
classified as shade intolerant, the seedlings are shade tolerant.  A
seedling can survive at less than 3 percent of full sunlight for a few
years.  This attribute allows the species to regenerate in gaps [27].


SEASONAL DEVELOPMENT : 
White ash flower buds break dormancy from April to May, with the
vegetative buds breaking immediately after the flowers [27,30].  The
fruit ripens from August to October [24], and seeds are dispersed from
August to November [2].

Related categories for Species: Fraxinus americana | White Ash