Robinia neomexicana A. Gray

New Mexico locust
New Mexican locust
southwestern locust
hojalito
Una de Gato

More info for the term: cover

In Arizona, New Mexico locust as a minor species with Gambel oak
noticeably contributed to elk summer thermal cover in a ponderosa pine
(Pinus ponderosa)-white fir overstory [7]. The cover value of New
Mexico locust in Utah is rated as poor for pronghorn, elk, and
waterfowl; fair for mule deer and upland game birds; and good for small
mammals and small nongame birds [18].

More info for the terms: fruit, shrub, tree

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].

New Mexico locust is found from the mountains of Trans-Pecos Texas north
to southern Colorado and west to southern Nevada [29,36,42]. Its range
extends from southeastern California to New Mexico and northern Mexico
[3,11,53,56].

More info for the terms: fire regime, litter, rhizome, root crown, severity

Thin bark and moderate litter production probably make New Mexico locust
susceptible to fire [32]. Horton [32] stated that the succulent foliage
during the summer decreases the severity of fires in New Mexico locust
communities. Postburn regeneration probably occurs via root crown and
rhizome sprouting.

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the term: shrubs

The use of fire to control New Mexico locust and improve conifer
regeneration has not been tested [26]. Potentially, fires occurring
more frequently than every 10 years would favor sprouting shrubs, such
as New Mexico locust, over nonsprouting shrubs [59].

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More info for the terms: geophyte, phanerophyte

Phanerophyte
Geophyte

More info for the terms: forest, shrub

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].

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

206 Engelmann spruce - subalpine fir
211 White fir
216 Blue spruce
217 Aspen
237 Interior ponderosa pine
238 Western juniper
239 Pinyon - juniper
240 Arizona cypress
241 Western live oak

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub

FRES21 Ponderosa pine
FRES23 Fir - spruce
FRES34 Chaparral - mountain shrub
FRES35 Pinyon - juniper

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: forest, woodland

K018 Pine - Douglas-fir forest
K019 Arizona pine forest
K020 Spruce - fir - Douglas-fir forest
K021 Southwestern spruce - fir forest
K023 Juniper - pinyon woodland
K031 Oak - juniper woodlands
K032 Transition between K031 and K037

More info for the term: root crown

Fire probably kills New Mexico locust aerial stems and seedlings.
However, the root crown can survive low- to moderate-severity fires
[44].

More info for the term: cover

On disturbed sites, New Mexico locust offers good forage and cover for
livestock and wildlife [39,45]. New Mexico locust is eaten by mule
deer, bighorn sheep, Gambel's quail, chipmunk, and porcupine [56].

More info for the terms: association, codominant, forest, woodland

New Mexico locust grows in pure stands or as an understory species [26].
New Mexico locust is an understory dominant or codominant with Gambel
oak (Quercus gambelii) under spruce-fir (Picea engelmannii-Abies
lasiocarpa), white fir (A. concolor), and mixed-conifer forests
[1,16,20,24,37,40]. It is a minor component in most riparian forest and
scrubland community types within its range, and in one chaparral
association (Arizona oak-yellowleaf silktassel-Emory oak [Q.
arizonica-Garrya flavescens-Q. emoryi]) [8,51,52].

New Mexico locust is an indicator for habitat types or plant
associations in the following publications:

(1) Classification of the forest vegetation on the National Forests of
Arizona and New Mexico [2]
(2) A vegetation classification system for New Mexico, U.S.A. [19]
(3) Forest habitat types in the Apache, Gila, and part of the Cibola
National Forests, Arizona and New Mexico [24]
(4) Forest and woodland habitat types (plant associations) of northern
New Mexico and northern Arizona [39]
(5) A classification of spruce-fir and mixed conifer habitat types of
Arizona and New Mexico [40]

More info for the terms: shrub, tree

Tree, Shrub

More info for the terms: competition, cover, forest, tree

New Mexico locust competes with conifer seedlings and saplings for
moisture and light [26]. Because of its rapid growth and prolific
sprouting, efforts are made to suppress New Mexico locust, especially
after timber harvest [13,14,39]. Brush competition is usually
detrimental to seedling or juvenile tree growth [10,26,30]. However,
Coffman [10] showed that under adverse planting conditions, the highest
establishment rates of planted Douglas-fir (Pseudotsuga menziesii)
seedlings occurred under moderate or heavy cover of New Mexico locust
and Gambel oak.

Mechanical methods alone do not successfully control New Mexico locust
[26]. Gottfried [26] tested combinations of mechanical and chemical
control methods on New Mexico locust in central Arizona. There was no
significant difference among the various treatments after 1 year.
However, 4 years after the combination treatment of (1) cutting stems
during dormancy, (2) painting stumps with 2,4-D, and (3) spraying
sprouts with 2,4,5-T, stems were reduced from 104 to 9.

Within 8 years of an 80-acre (32.4 ha) harvest of mixed-conifer forest
in Arizona, 20 acres (8.1 ha) were covered by New Mexico locust. The
New Mexico locust plants were treated with picloram; 86 percent of the
plants were dead after 2 years [13]. Single applications of soil
herbicides may not eliminate New Mexico locust due to delayed recovery of
plants and establishment of seedlings. Therefore, follow-up spot
treatment is recommended [13].

In open ponderosa pine stands in northern Arizona, production values for
New Mexico locust were 3 pounds per acre (3.4 kg/ha) [9]. Ffolliott
[22] has developed models for predicting understory production in
ponderosa pine or mixed conifer forests of which New Mexico locust is a
component.

New Mexico locust has fair energy value but usually has poor protein
value (however, see below) [18]. New Mexico locust leaves comprised 0.8
percent of the total diet of mule deer in Arizona in June [54]. Protein
and acid-detergent fiber were each 25 percent of the leafy material.
Digestible dry matter was 39 percent of the leaves.

AZ CA CO NV NM TX UT MEXICO

New Mexico locust is cultivated as an ornamental [34,36,56].

The Hopi Indians have used it as an emetic and for treating rheumatism
[36,56].

Both the flowers and foliage are preferred by cattle and deer [33,36].
Palatability of New Mexico locust in Utah is fair for cattle and horses
and good for sheep [18].

More info on this topic.

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].

More info for the terms: density, shrubs, woodland

Surviving New Mexico locust root crowns and rhizomes sprout following
fire [8]. From information about the rate of growth, it is probable
that postfire recovery via sprouting is good [32]. Two years after a
fire in north-central New Mexico, New Mexico locust, at a density of 240
plants per acre (593 plants/ha), had 295 sprouts per acre (729
sprouts/ha) with an average height of 15 inches (38 cm) [44].

Hanks and Dick-Peddie [28] evaluated the effects of elevation and
exposure on 11 burns aged 3 to 80 years in south-central New Mexico.
There was no trend in size or number of trees for New Mexico locust.
New Mexico locust was nearly ubiquitous on burned sites below 10,000
feet (3,048 m) by postfire year 2 or 3.

Potter and Foxx [44] looked at sprouting on a low-severity burn at
postfire year 2; a moderate-severity burn at postfire year 17; and a
high-severity burn at postfire year 100. New Mexico locust had the
greatest number of sprouts per acre on the moderate-severity burn area
at postfire year 17.

In a pinyon-Utah juniper (Juniperus osteosperma) woodland in
northwestern Arizona, shrubs were assessed at postfire year 20. The
area had been seeded to introduced grasses. New Mexico locust occurred
infrequently; the plants were assumed to be on-site survivors that had
sprouted [15].

Tree with adventitious-bud root crown/root sucker

More info for the terms: seed, vines

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].

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

6 Upper Basin and Range
7 Lower Basin and Range
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont

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More info for the term: forb

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].

Robinia luxurians (Dieck) Schneid.
Robinia subvelutina Rydb.
Robinia breviloba Rydb.
Robinia neomexicana var. subvelutina (Rydb.) Kearney & Peebles

The currently accepted scientific name of New Mexico locust is Robinia
neomexicana Gray. It is a member of the pea family (Fabaceae). Several
varieties may be encountered in the literature; however, the maintenance
of varieties is questionable due to intergradation of all forms [3,36].

More info for the term: forest

New Mexico locust is cultivated for erosion control [32,34,36,45,56].
Caution is advised when using New Mexico locust in recreation areas
because of its stout spines [32].

In San Dimas Experimental Forest, California, at an elevation of 500
feet (152 m), New Mexico locust bareroot stock was planted on road
fills. Survival was 52 percent. New Mexico locust made the most rapid
growth compared to all other species planted. It has been fully tested
and is recommended for erosion control on sites at 500 to 6,000 feet
(152-1,829 m) in elevation with deep soil and in full sun[32].

More info for the term: fuel

New Mexico locust wood is hard, heavy, and durable. It has been used
for fence posts and fuel [34,36]. It is of little use as lumber due to
its small size and limited distribution [34].