BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Robinia neomexicana | New Mexico Locust 



GENERAL BOTANICAL CHARACTERISTICS : 
New Mexico locust is a native rhizomatous, small tree or shrub that
grows from 3 to 26 feet (4-8 m) tall with a diameter of 4 to 8 inches
(10-20 cm) [29,34,45,53,58].  It has a dense crown and thin bark
[32,34].  New Mexico locust has many stout spiny branches with pinnately
compound leaves that are 6 to 8 inches (15-20 cm) long [11,34].  Flowers
hang in dense clusters [36].  The fruit is a hairy legume about 3 inches
(7.6 cm) long containing several seeds [36,45].


RAUNKIAER LIFE FORM : 
   Phanerophyte
   Geophyte


REGENERATION PROCESSES : 
New Mexico locust reproduces asexually and sexually.  It sprouts from
stumps and root crowns [36,56].  New Mexico locust spreads by rhizomes,
forming dense thickets [49].

New Mexico locust fruits open rapidly when mature [42].  Locust (Robinia
spp.) seeds have impermeable seed coats and must be scarified [42,56].
Olson [42] and Vines [56] outline nursery methods for New Mexico locust
propagation.  Seed stored in a cool dry place remained viable 1 to 4
years, which indicates that a short-lived seedbank could exist [56].


SITE CHARACTERISTICS : 
New Mexico locust is common in canyons, along streams or arroyos, on
terraces, talus slopes, and in coniferous forest understories
[35,36,45,58].  It is found on gentle to relatively steep slopes on all
aspects [24,28,57].  New Mexico locust occurs on a wide variety of
soils, ranging from clays to sandy loams derived from volcanic or
limestone parent materials [5,8,12,23,31].  Across its range, New Mexico
locust is found between 4,000 and 9,150 feet (1,219-2,789 m) in
elevation [23,28,39,48,56].

New Mexico locust occurs in semiarid continental climates with dry warm
springs, hot moist summers, and cold moist winters [14,44].  Across its
range, two major precipitation seasons exist, with 35 to 42 percent of
precipitation falling as rain in July and August [28].  Average annual
precipitation ranges from 15 to 30 inches (381-762 mm) [12,23,28,31,46].

Associated species not mentioned in Distribution and Occurrence are
listed below.  Associated trees are southwestern white pine (Pinus
strobiformis), Chihuahua pine (Pinus leiophylla var. chihuahuana), and
quaking aspen (Populus tremuloides) [17,24,43,57].  Common shrub
associates are Fendler ceanothus (Ceanothus fenderi), manzanita
(Arctostaphylos spp.), silverleaf oak (Quercus hypoleucoides), mountain
snowberry (Symphoricarpos oreophilus), and mountain-mahogany
(Cercocarpus spp.) [6,9,28,52].  Other associated species are Arizona
fescue (Festuca arizonica), mutton bluegrass (Poa fendleriana), and
western yarrow (Achillea lanulosa) [12,23].


SUCCESSIONAL STATUS : 
Facultative Seral Species

New Mexico locust is a seral species after overstory removal in
southwestern coniferous forests [28].  After disturbance in
mixed-conifer stands, New Mexico locust became dominant after 1 to 3
years of forb dominance [28].  New Mexico locust is shaded out when the
conifers overtop it in 15 to 20 years [27,28].


SEASONAL DEVELOPMENT : 
New leaves of New Mexico locust begin growing in the spring.  Flowers
form April to July in the new leaf axils [36,56].  Fruits ripen
September to October, and seeds disperse from September to December
[42,56].  Leaves abscise in autumn [42].

Related categories for Species: Robinia neomexicana | New Mexico Locust