VALUE AND USE
SPECIES: Prosopis velutina | Velvet Mesquite 



WOOD PRODUCTS VALUE : 
The chief use of velvet mesquite wood is for firewood.  Mesquite
(Prosopis spp.) wood is easily sawed and split, is dry and heavy,
ignites readily, and produces intense heat [54].  During the settlement
of southern Arizona, velvet mesquite provided dimension lumber for
buildings and bridges, walls for corrals, fence posts, tombstones, and
fuel for domestic and industrial uses [92,93].  During the 1880's many
velvet mesquite bosques were clearcut to obtain wood for these purposes.
The wood is still used locally for fence posts and lumber.  In recent
years, mesquites have been increasingly used to produce charcoal
briquets [35].


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Livestock:  Cattle, horses, sheep, goats, hogs, mules, and burros eat
large quantities of ripe velve mesquite fruit when available [29].
Livestock often remove the fruits as high on the tree as they can reach
and eat fallen pods lying on the ground [3,51].  Livestock do not
consume the foliage to any great extent [80].  Foliage consumption by
livestock is greatest during drought years, especially in the early
spring when other forage is lacking [29,49].  Most livestock consume
mesquite (Prosopis spp.) flowers when available [80].  In some areas of
Mexico, mesquite beans are collected, ground, and fed to cattle [31].

Wildlife:  Velvet mesquite annually provides an abundant and nutritious
food source for numerous wildlife species when the pods ripen between
June and late October [51,71].  The beans and seeds form an important
part of the diet of mice, kangaroo rats, woodrats, chipmunks, ground
squirrels, rock squirrels, cottontail rabbits, skunks, quail, doves,
ravens, jackrabbits, the racoon, coyote, collared peccary, white-tailed
deer, mule deer, wild turkey, and mallard [2,9,29,51,52,101,105,122].
Many species of small rodents derive a large portion of their diet from
velvet mesquite seeds.  These animals frequently store seeds and whole
beans in dens or caches [51].  Many species of birds eat flower buds and
young inflorescences of velvet mesquite.  Insectivorous birds feed on
the numerous insects that are attracted to velvet mesquite flowers
[113].  Many species of quail eat mesquite buds and flowers in the
spring, and seeds during the fall and winter [122].  Mesquite seeds
often comprise 10 to 25 percent of the diet of Gambel's and scaled
quails [31].  Collared peccaries in Arizona feed heavily on velvet
mesquite beans from July to September [34].  In south-central Arizona,
velvet mesquite fruits comprised 9 percent of the white-tailed deer's
and 29 percent of the mule deer's summer diet, but use of any velvet
mesquite parts during the rest of the year was minimal [82].  A study in
semidesert grass-shrub habitats of southern Arizona found mule deer use
of velvet mesquite to vary seasonally.  Velvet mesquite leaves comprised
0.3 percent of the mule deer's diet during the spring, 2.9 percent
during the autumn, and 4.9 percent during the winter, while fruits
comprised 24.0 percent of the mule deer's summer diet [110].

Mesquite browse is generally not a very important wildlife food source.
The wild turkey, ground squirrels, cottontails, and woodrats consume
some leaves [9,52].  Jackrabbits often consume large amounts of mesquite
and may crop leaves, buds, and bark as high as they can reach [124].
Velvet mesquite seedlings up to about 2 years old are often eaten by
jackrabbits and cottontails.  Kangaroo rats frequently eat recently
germinated velvet mesquite seedlings [51].  Locally, mule deer consume
large quantities of mesquite foliage, but this may reflect a scarcity of
other browse rather than a preference for mesquite [109].


PALATABILITY : 
The sweet, nutritious seed pods of velvet mesquite are highly palatable
to all classes of livestock and to numerous small and large wildlife
species.  For both livestock and wildlife, the palatability of leaves
and twigs is relatively low.  Livestock browse small amounts of leaves
and twigs as they green up in the spring, but velvet mesquite browse is
otherwise seldom eaten [29].  Leaf consumption may increase during
drought years when other forage is lacking, or following a killing frost
in the fall [49].


NUTRITIONAL VALUE : 
Velvet mesquite's fruits are nutritious.  The thick and spongy pericarp
is high in sugars and the seeds contain large amounts of protein.
Fruits also supply a good source of minerals for herbivores.  Because
plants fix nitrogen, the leaves are high in protein.  

Nutritional information concerning velvet mesquite fruit is presented
below [4]:

                % N    % crude   % fat    % fiber   % ash   % total 
                       protein                               sugars

seed            5.13    29.44    5.68      7.12     3.83      ----
pericarp        1.13     6.88    2.24     23.48     5.52      31.6
whole pod       1.95    11.81    2.36     22.61     4.83      22.2

The mineral composition of velvet mesquite fruit is as follows [4]:

               % Ca   % Mg   % Na   % K   ppm Cu  ppm Zn  ppm Mn  ppm Fe

seed           .26    .18    .06    .68    13.6    49.6    24.2    46.6
pericarp       .63    .09    .04   1.16     6.4     9.6    11.6    48.8
whole pods     .53    .09    .03   1.27     8.3    26.4    14.5    40.4

Nutritional information concerning velvet mesquite leaves and fruits
collected in southern Arizona is presented below [110]:

          season      % protein    % K    P/Ca ratio    % In Vitro
          collected                                     digestibility

leaves    spring        17.6       .23       .28            62.3
fruit     summer        9.5        .16       .23            66.5
leaves    autumn        16.4       .10       .05            44.8
leaves    winter        15.8       .10       .05            44.9


COVER VALUE : 
Velvet mesquite provides needed security cover for large wildlife
species.  Its invasion into grasslands has benefited brush dependent
wildlife species such as the collared peccary and mule deer [2,15].
Southern Arizona studies indicate that velvet-mesquite-dominated
vegetation types are a preferred habitat of desert mule deer, but that
white-tailed deer seldom use velvet mesquite habitats [2,108].  Small
mammals such as antelope jackrabbits, woodrats, and kangaroo rats are
often found in brushy velvet mesquite habitats.  A southern Arizona
study found that 99 percent of available velvet mesquite shrubs housed
Merriam kangaroo rat dens [103].  In fact, many species of rodents place
their burrows under the protection of velvet mesquite plants [76].

Found in desert environments, velvet mesquite provides shade for
livestock and wildlife.  Jackrabbits often use the shade that mesquites
provide to help regulate their heat balance [76].

Brushy velvet mesquite ranges provide excellent habitat for the
zebra-tailed lizard, desert spiny lizard, western whiptail, and tree
lizards.  The desert spiny lizard and tree lizards are primarily
arboreal and are often found in mesquite trees.  Tree lizards may
aggregate in large numbers in the winter, using the underside of
protruding velvet mesquite bark as hibernating sites [47].

Velvet mesquite riparian communities provide important habitat for
numerous nesting bird species during both summer and winter.  Along the
lower Verde River floodplain in Arizona, 19 species and 244 pairs of
breeding birds per 100 acres (40 ha) were found in a velvet mesquite bosque
community [117].  In another velvet mesquite bosque community in
southern Arizona, 476 pairs of nesting birds were found per 100 acres
(40 ha) [46].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Saltcedar (Tamarix ramosissima), an introduced species from Eurasia, has
invaded and replaced many native Southwestern riparian communities.
Since saltcedar communities are much less valuable to wildlife than
native communities, methods have been developed for removing the
saltcedar and revegetating with native species [70].  Along the lower
Colorado River on the border of southern California, nursery-grown
western honey mesquite seedlings have been planted with other native
species to revegetate riparian areas following saltcedar removal
[25,123].  Velvet mesquite can probably be used for these rehabilitation
purposes within its range.

Ninety-day-old nursery grown velvet mesquite seedlings were successfully
transplanted onto 2 feet (0.6 m) of topsoil covering asbestos waste
tailings near Globe, Arizona.  Three years after planting, 96 percent of
the seedlings were alive and showed better growth and vigor than other
shrub species planted [98].  

Stem cuttings of several species of mesquite (Prosopis spp.) have been
successfully rooted in greenhouse experiments when treated with a
rooting compound [41].  Fresh seed that has not been dried will
germinate readily without any pretreatment.  Seed that has been stored
must first have the hard seed coat scarified, which can be done by
knicking individual seeds with a knife or by soaking numerous seeds in
sulfuric acid [81].  Nursery-grown velvet mesquite seedlings have
reached heights of 2.6 inches (6.6 cm) in 7 months, 6.75 inches (17.1
cm) in 12 months, 8.68 inches (22 cm) in 18 months, and 14.8 inches
(37.6 cm) in 21 months [51].

Members of the genus Prosopis are being developed for rehabilitation and
biofuel production in developing countries due to firewood shortages,
erosion, and other problems associated with desertification [39,40].
North American mesquites, however, appear best adapted to their area of
origin.


OTHER USES AND VALUES : 
Velvet mesquite is used as an ornamental shade tree.  It needs little or
no watering and can survive on limited rainfall [1,31].  Velvet mesquite
provides an excellent source of nectar for honey bees and is one of the
most valuable honey plants in Arizona [80].

Mesquite pods have been proposed as a source of food for human
consumption because they are very nutritious.  Velvet mesquite pods
contain large amounts of sugar and the protein content of the seeds is
similar to soy beans.  Flour made from velvet mesquite seeds and pods
mixed in small amounts with wheat flour has been tested in various
recipes including breads and cookies with favorable results [85].
Research suggests that velvet mesquite could be managed as an
agricultural multiple product crop, yielding both nutritious pods and
biomass for fuel.

Mesquites (Prosopis spp.) were probably the most important wild plant
staple of indigenous Southwest peoples [5,37].  The pods were a very
reliable food source because fruiting occurred even during drought
years.  In some places velvet mesquite bosques extended for miles along
river bottoms.  These bosques provided an abundance of beans, allowing
indigenous peoples to harvest selectively from trees producing high
quality fruits [101].  Pods were collected in large quantities and
stored in grainery baskets on the roofs of houses or sheds [5].  The
beans were ground into a flour which was used to prepare cakes and
breads, the main staple of the diet [5,37].  Various refreshing drinks
were made from the sweet pods.  An intoxicating beerlike drink was
sometimes prepared by allowing the juices of the pods to ferment.
Flowers were eaten raw or roasted, formed into balls, and stored in
pottery vessels [37].

Mesquites were not only an important food supply for Southwest peoples
but also provided fuel, shelter, weapons, tools, dyes and paints,
medicines, cosmetics, baskets, furniture, clothing, rope, glue, and many
other everyday items [5,37].


MANAGEMENT CONSIDERATIONS : 
Velvet mesquite infests millions of acres of grazing land in Arizona.
Introduction of livestock in the Southwest resulted in overgrazing,
dispersal of mesquite seed by cattle, and a reduction of range fires due
to insufficient fuels which allowed velvet mesquite to increase in
density and spread into grasslands [66,95].  Today dense velvet
mesquite thickets occur over vast areas that were essentially free of
velvet mesquite 100 years ago.  Velvet mesquite is considered a range pest
or weed because infestations greatly reduce herbaceous forage available
for livestock and makes moving and handling livestock more difficult.

Adaptive features that make control difficult include (1) abundant,
long-lived seed that is disseminated by livestock and wildlife, (2) high
rate of seed germination over a wide range of environmental conditions,
and (3) its ability to resprout following injury [42,95].  Areas which
have been cleared in the past, either by chemical or mechanical methods,
generally were reinfested with seedlings and/or resprouts.  Herbicidal
control attempts often resulted in only low to moderate mortality.  Many
or most plants resprouted after treatment and developed into
multistemmed bushes.

Chemical control:  Aerial application of herbicides generally resulted
in the greatest herbaceous forage production following treatment.
Banned for use on rangelands in the early 1980's, 2,4,5-T was one of the
most commonly used methods of velvet mesquite control in the 1950's,
60's, and 70's.  The most effective herbicide for killing mesquites
(Prosopis spp.) available for use today is clopyralid; however, it is
much more expensive than 2,4,5-T.  Velvet mesquite is probably
susceptible to aerial applications of clopyralid, which often results in
50 to 85 percent mortality of honey mesquite [12,62,63,64].  Recent
research suggests that even greater mesquite mortality, over 90 percent,
can be acheived by mixing clopyralid with picloram or triclopyr [12].
Moderate control has also been achieved with aerial applications of
tebuthiuron pellets [49,129].

Mechanical control:  Mechanical methods devised for controlling
mesquites include tree dozing, cable chaining, roller chopping, root
plowing, tree grubbing, and land imprinting.  For mechanical measures to
be effective, the dormant buds which occur along the underground stem
must be damaged or removed to prevent sprouting.  If only the
aboveground portion of the plant is removed, velvet mesquite will
quickly resprout.  Tree grubbing with blades attached to crawler
tractors which severs roots 6 to 12 inches (15-30 cm) below the soil
surface and root plows which uproot trees are effective control
measures, often achieving over 90 percent mortality [78].  Areas root
plowed or mechanically grubbed are often seeded with native grasses.
Without seeding, serious soil disturbances caused by these control
methods often reduces perennial grass cover for several years.  On areas
with moderate shrub density, an alternative to root plowing, cabling, or
grubbing which disturbs the soil, is land imprinting followed by
seeding.  The land imprinter is a heavy roller, set with pyramid shaped
teeth, 4 to 6 inches (10-15 cm) long, attached in an irregular pattern
and pulled behind a caterpillar tractor.  As the roller passes over the
ground it leaves the area looking like a huge waffle.  The tractor and
roller crush and shred the vegetation and deposit the mulch into the
funnellike depressions [49].

Hand grubbing mesquite seedlings, although very labor intensive, is an
effective preventive measure used for removing mesquites during early
stages of invasion.  When the roots are severed 4 inches (10 cm) below
the soil surface, hand grubbing effectively kills plants under 1 inch
(2.5 cm) in diameter [78].  

Biological control:  Although not used to date, seed, legume, and flower
feeding insects have been proposed as agents for biological control of
mesquites [31].

Grazing:  No matter what method of control is used, it needs to be done
in conjunction with a proper grazing program to ensure maximum benefits.
Due to its reproductive potential and regenerative capabilities, velvet
mesquite will probably never be eliminated from sites where it has
become established [29].  Dahl [29] suggests that a proper rotation
grazing system in coordination with controlled burning promises to be
most effective.

Wildlife:  Control methods which leave selected individuals, scattered
patches, or strips of velvet mesquite can increase forage production for
cattle while retaining enough cover for wildlife.  Aerial applications
of herbicides is often detrimental to collared peccary populations
because prickly pear (Opuntia spp.), an important food source, is
susceptible to spraying.  Root plowing disturbs or kills burrowing
rodents.

Threat to Bosques:  Velvet mesquite bosque communities today cover only
a fraction of the acreage covered in presettlement times.  During the
settlement of southern Arizona, many bosques were cleared for fuelwood,
lumber, and to convert land to agricultural use.  Today, bosque
destruction continues due to fuelwood cutting, clearing for further
agricultural needs and housing developments, and the lowering of
underground water tables [44,86].  Pumping of underground water for
agricultural use, has resulted in the total destruction of entire velvet
mesquite bosques when water tables were lowered below the rooting depth
of the mesquites, about 50 feet (14 m) [67,86].  Remaining bosques are
threatened in areas where pumping of underground water continues.  These
bosques are extremely important avian habitat [46]. [See Cover Value]

Toxicity:  Mesquite pods are normally considered excellent feed for
cattle and horses, however when large amounts of beans are consumed
continuously over a 2-month period serious digestive disturbances or
death may occur [32,116].  The disease known as "jaw and tongue trouble"
is characterized in cattle by profuse salivation, continuous chewing, a
protruding tounge, and a tilted head.  Animals gradually become
emaciated and may lose up to 50 percent of their weight.  If acute
symptoms, such as loss of apetite, rapid weight loss, nervousness, a
wild expression, and bulging eyes, develop, animals usually die within 2
to 4 days [116].  In cattle excessive buildup of mesquite beans in the
rumen apparently destroys the rumen bacteria that digest cellulose and
synthesize B vitamins [32].

Related categories for Species: Prosopis velutina | Velvet Mesquite