BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Celtis reticulata | Netleaf Hackberry 



GENERAL BOTANICAL CHARACTERISTICS : 
Netleaf hackberry is a spreading, scraggly, often stunted tree or large
shrub [44,55,63,75].  It commonly grows from 7 to 20 feet (2-6 m) in
height but can reach up to 53 feet (16 m) in height and 24 inches (60
cm) in diameter on favorable sites [31,53].  Plants generally grow
slowly [64] and live for 100 to 200 years [62].  The trunk is usually
short and crooked [4,44] with thick, warty, reddish-brown to gray bark
[37,44].  Slender twigs are reddish-brown, glabrous or puberulent [53],
and often form a twisting network [4].  Plants are strongly taprooted
but possess many shallow roots as well [62].  Roots are fibrous, wide
spreading, and can reach maximum depths of 15 feet (5 m) or more
[64,80].



RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Flowering and fruiting:  Netleaf hackberry is monoecious [63].  Small,
inconspicuous green flowers are borne singly in the leaf axils on
current year's twigs [33,37,63].  The fruit is an orange to reddish,
purplish, or black drupe that contains a single seed or nutlet [33].
The fruit is sweet with thin, dry pulp [4,76].

Seed:  Netleaf hackberry produces an abundance of persistent seed nearly
every year [8].  The hard, bony seeds are cream-colored and
approximately 0.22 inch (5.5 mm) in diameter [4,63].  Seed is readily
dispersed by a variety of birds and mammals [44].  Seed remains viable
under laboratory conditions for at least several years [8]; seed
longevity under natural conditions has not been documented.

Germination:  Seed dormancy can be broken by stratification for 120 days
at 41 degrees F (5 degrees C) [8].  Germination is also enhanced by
depulping the fruit prior to planting [8].  Germination has averaged 37
to 80 percent in laboratory tests [8,72].  Natural germination occurs in
late winter and spring [80].

Seedling establishment:  Seedlings are commonly observed on moist loamy
drainageway soils, in the sand of ephemeral streambeds, and in saturated
alluvium in waterways with sustained flows [22,80].  Establishment may
be favored on high terraces in riparian zones where floods may disturb
the channels themselves but leave terraces relatively undisturbed [5].

Vegetative regeneration:  Netleaf hackberry sprouts from the root crown
after aboveground portions of the plant are removed or damaged [14].


SITE CHARACTERISTICS : 
Netleaf hackberry commonly grows in bottomlands, washes, ravines,
arroyos, rocky canyons, and along streamcourses, water tanks, and ponds
[31,33,37,55,79].  Netleaf hackberry is particularly abundant in
floodplain forests along large rivers of the Edwards Plateau of Texas
[71,79] and is common in gallery forests along the major canyons of
Snake, Salmon, and Columbia River valleys [18,50,68].  Netleaf hackberry
also occurs as scattered individuals in desert shrubland and in
semidesert grassland communities [9,28].  Scattered individuals often
occur where upper desert grassland communities grade into low savannas
[21].  In Texas, netleaf hackberry is particularly common on rolling
plains and breaks, and as a component of hill and bluff timber
[25,55,62].  Netleaf hackberry occurs in Great Basin montane scrubland,
creosotebush scrub, and wash scrub communities, pinyon-juniper and
Joshua tree woodlands, and mesquite bosques of the Southwest
[10,13,30,52,53].

Plant associates:  Common associates in Southwestern riparian woodland
communities include walnut (Juglans spp.), willow (Salix spp.),
cottonwood (Populus spp), American sycamore (Platanus occidentalis),
Texas mulberry (Morus microphylla), western soapberry (Sapindus
saponaria var. drummondii), live oak (Quercus virginana), cedar elm
(Ulmus crassifolia), ash (Fraxinus spp.), Texas persimmon (Diospyros
texana), and mesquite (Prosopis glandulosa) [52,78,79].  Overstory
codominants in terrace communities include live oak, little walnut
(Juglans microcarpa), and pecan (Carya illinoensis) [79].  Other common
Southwestern associates include Utah juniper (Juniperus osteosperma),
Ashe juniper (J. ashei), live oak (Quercus fusiformis), black cherry
(Prunus serotina), whitethorn acacia (Acacia constricta), fendlerbush
(Fallugia paradoxa) [12,13,81].  Cheatgrass, white alder (Alnus
rhombifolia), water birch (Betula occidentalis), black poplar (Populus
trichocarpa), sand dropseed, bluebunch wheatgrass, and Kentucky
bluegrass (Poa pratensis) occur with netleaf hackberry in gallery
forests of Idaho and Washington [18,50,68].

Soils:  Netleaf hackberry grows on well-drained, dry to moist soils
[64].  It occurs on gravelly or rocky soils, and also on sand and loam
[22,31,72].  Netleaf hackberry grows on alkaline or acidic soils [54],
but pH averages 7.0 to 7.5 [64].  Soils are commonly derived from
limestone, or alluvial or colluvial parent materials [31,39,68].  Near
the Gulf, plants occur on calcareous shell banks [73].  In many areas,
netleaf hackberry develop best on alluvial soils [71].

Climate:  Netleaf hackberry grows well in sun and is tolerant of drought
[38,72].  It occurs in subhumid to semiarid areas characterized by
mesothermal climatic regimes [71].  Average annual precipitation ranges
from 15 to 33 inches (38-84 cm) in parts of Texas [71]; however, netleaf
hackberry can grow where annual precipitation averages only 7 inches (18
cm) [4].  In some areas, summertime temperatures may exceed 110 degrees
F (43 degrees C) [4].  Netleaf hackberry may be restricted by soil
moisture levels [79].  Its distribution may also be largely limited by
flood tolerance.

Elevation:  In many areas, netleaf hackberry is restricted to waterways
and spans a considerable elevational range [32].  It grows at elevations
ranging from 2,500 to 6,000 feet (762-1,829 m) in Arizona [41]; from
2,800 to 5,000 feet (853-1,524 m) in California [53]; and up to 6,000
feet (2,000 m) in Utah [37].


SUCCESSIONAL STATUS : 
Netleaf hackberry can invade many types of newly disturbed sites but can
also persist in a number of climax communities where soil-water regimes
are favorable.

Texas:  On the Edwards Plateau, netleaf hackberry is among the
large-seeded facultative riparian species that invade river terrace
communities [5].  It also increases after prescribed burns in Ashe
juniper communities on toeslopes where water availability is relatively
high [57].  Although it commonly codominates these moister toeslopes
with flameleaf sumac (Rhus lanceolata) and live oak (Quercus
fusiformis), it is often absent on adjacent drier sites [57].

Idaho-eastern Washington:  In the middle Snake and lower Salmon
drainages of west-central Idaho and eastern Washington, netleaf
hackberry occurs as an overstory dominant on lower valley slopes and
alluvial terraces [18,68].  Many of these sites have been disturbed by
domestic livestock.  Current understory dominants on disturbed sites
include annual bromes (cheatgrass, Japanese brome (B. japonicus), and
poverty brome (B. sterilis), and sand dropseed, but evidence suggests
that bluebunch wheatgrass grew as an understory dominant beneath netleaf
hackberry prior to disturbance [68].  Daubenmire [18] identified a
netleaf hackberry/cheatgrass habitat type, although Tisdale [68]
maintained that "designation of a climax community type with an exotic
annual as one of the dominants seems inappropriate, especially when
stands of Celtis douglasii [reticulata]/ bluebunch wheatgrass can be
found on similar habitats in Washington along the Grande Ronde River."

Tallgrass prairie:  Plowing in the tallgrass prairie disturbs the roots
of grasses, reducing their competitive ability and allowing for the
subsequent establishment of weeds and woody invaders.  Woody plants such
as netleaf hackberry tend to increase after annual cultivation in
tallgrass prairies of central Oklahoma [16].  Grass cover typically
increases immediately after plowing stops and peaks 5 years later.
Sumac (Rhus spp.), indian-currant coralberry (Symphoricarpos
orbiculatus), and roughleaf dogwood (Cornus drummondii) soon become
established, and netleaf hackberry and slippery elm (Ulmus rubra)
gradually invade the area.  Although woody plants remain rare during the
first 9 years, these invaders begin to increase dramatically as
grassland vegetation loses dominance.  Netleaf hackberry, indian-currant
coralberry, flameleaf sumac (Rhus copallina), and weedy grasses such as
johnson-grass (Sorghum halepense) dominate some 9- to 32-year-old
stands.  Collins and Adams [16] noted that succession can be both rapid
and unpredictable in the tallgrass prairie, and "even at the
physiognomic level, general successional trends may be difficult to
quantify."


SEASONAL DEVELOPMENT : 
Leaves of netleaf hackberry first appear in early April to late May [23]
and mature in June [74].  Plants flower in spring, with or shortly after
initial leaf development [23].  Fruit ripens in late summer or fall
[64].  Fruit may persist through the winter [62], although some seed is
dispersed during the fall and winter [8,72].  Generalized flowering and
fruiting dates by geographic location are as follows:

Location              Flowering      Fruit ripe      Authority

c Great Plains        late April      August-Sept.   Stephens 1973     
s CA                  April-May         ----         Munz 1974
Great Plains          April-Sept.       ----         Great Plains Flora
                                                     Association 1986

Related categories for Species: Celtis reticulata | Netleaf Hackberry