BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Carya illinoensis | Pecan 



GENERAL BOTANICAL CHARACTERISTICS : 
Pecan is a long-lived, medium to large, native, deciduous tree ranging
from 100 to 150 feet (30-45 m) in height and 6 to 7 feet (1.8-2.1 m) in
diameter [5].  The gray trunk is shallowly furrowed and flat-ridged with
ascending branches forming an irregular, rounded crown.  The twigs are
gray brown and hairy when young but become rough and furrowed on mature
trees.  Flowers are borne in staminate and pistillate catkins.
Staminate catkins are in threes and bear small green flowers;
seed-bearing flowers occur singly or a few at the end of new growth.
The leaves are narrow, pointed, and curved at the tip with tooth margins
yellow-green above and paler below.  The nut is brown, cylindric,
thin-shelled, and enveloped in a four-winged husk [7,9].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Seed production and dissemination:  Seed production starts when the
trees are about 20 years old, but optimum seed-bearing age is 75 to 225
years.  The trees bear fair to good crops almost every year.  A mature
tree yields about 100 pounds (40 kg) of nuts per year.  The seed is
disseminated by water, squirrels, and birds [12,18].

Seedling development:  Under normal conditions, pecan nuts remain
dormant until germination starts in early April.  Exceptionally dry
weather or heavy competition greatly reduces seedling survival.  Under
favorable condition, pecan seedlings grow 3 feet (0.9 m) per year after
they have been established for several years [18].

Vegetative reproduction:  Small stumps and fire-girdled seedlings and
saplings sprout very rapidly.  Horticultural varieties of pecan are
propagated by budding and stem grafting [18].


SITE CHARACTERISTICS : 
Pecan is most common on well-drained loamy soils not subjected to
prolonged flooding.  Throughout its range it is largely limited to
bottom alluvial soils of relatively recent origin.  Its best development
is on riverfront ridges and well-drained flats [18].  It rarely grows on
low and poorly drained clay flats; it is usually replaced by water
hickory (Carya aquatica) on these sites [1].

In addition to the species listed in the SAF cover types, common tree
associates of pecan include slippery elm (Ulmus rubra), sugarberry
(Celtis laevigata), box elder (Acer negundo), silver maple (A.
saccharinum), roughleaf dogwood (Cornus drummondii), and swamp-privet
(Forestiera acuminata).  Common understory components include pawpaw
(Asimina triloba), giant cane (Arundinaria gigantea), and pokeweed
(Phytolacca americana).  Vines often present are poison-ivy
(Toxicodendron radicans), grape (Vitis spp.), Alabama supplejack
(Berchemia scandens), greenbriers (Smilax spp.), and Japanese
honeysuckle (Lonicera japonica) [4,17,18].


SUCCESSIONAL STATUS : 
Pecan is classified as shade intolerant but is more shade tolerant than
cottonwood or willow.  It responds well to release in all age groups,
provided that the trees have good vigor.  Pecan is a subclimax species
[11,18].


SEASONAL DEVELOPMENT : 
Pecan flowers from March to May about a week after the leaves have
started to open.  The nuts mature from September to October; seedfall
begins in September and ends in December [2,11].

Related categories for Species: Carya illinoensis | Pecan