Mesquite (of the genus Prosopis) consists of about 45 species of leguminous spiny trees and shrubs found in subtropical and tropical regions of the Americas, Africa and southwest Asia.

There are three common species of mesquite in North America: Honey Mesquite (Prosopis glandulosa), Screwbean Mesquite (Prosopis pubescens), and Velvet Mesquite (Prosopis velutina). The Honey Mesquite is distinguished by smooth (rather than hairy) leaflets. It grows primarily in the Chihuahuan Desert east of the Continental Divide, but its outer range extends across the Sonoran Desert as well. The Screwbean Mesquite with its distinctive tightly spiraled bean pods grows in the northern Sonoran Desert up into the Mojave Desert. The Velvet Mesquite is the largest and most common of the three species. It has velvet-surfaced leaflets and grows primarily in the Sonoran Desert, west of the Continental Divide. Where the species overlap, the plants hybridize, often making identification difficult. Most of the following information is specific to the Velvet Mesquite, but all three species have similar characteristics.

Common Names (North American species):

Algaroba, bilayati kikar, common mesquite, cuji, honey locust, honey mesquite, honey-pod, ibapiguazu, inesquirte, ironwood, mescrew, mesquite, screwbean, screwbean mesquite, screw-pod mesquite, scrub mesquite, tornillo, Torrey mesquite, velvet mesquite, wawahi, western honey mesquite

Range:

Velvet mesquite grows from central and southern Arizona to extreme southwestern New Mexico and adjacent northern Mexico. It can be found in the Chihuahua, Sonoran, and Mojave deserts. The only desert it doesn't occur in is the Great Basin Desert because the temperatures are too cold.

History:

During the Ice Ages, which lasted from about 1.8 million to 10,000 years ago, mesquite trees evolved along with large herbivores, such as mastodons and ground sloths, which ate the pods and then dispersed them. Over time, mesquite expanded it's range to correspond largely with the herbivores’ range, which extended from the flood plains and washes up into prairies, mesas and mountain slopes. When the Ice Ages ended and the large herbivores died out, mesquite lost it's primary method of distribution and with lower rainfall amounts, more frequent wildfires and greater competition from grasses and other plants at higher elevations, mesquite was confined primarily to the flood plains and washes.

When Europeans moved into the desert southwest, mesquite expanded it's range again, being spread by domestic livestock, especially cattle. The new herbivores not only ate and dispersed the pods, the large livestock herds stripped away the desert grasses, eliminating competition and wildfire fuel. In many areas, mesquite moved in to displace grasses and reclaimed much of it's Ice Age range, expanding from the flood plains and washes again up into prairies, mesas and mountain slopes. Mesquites grew up along the historic cattle trails and in some areas, can still be seem today made visible by the mesquite growing along the routes. Mesquites have also become established in borrow ditches along modern desert roadways traveled by cattle trucks.

Habitat:

Mesquite is the most common tree of the desert southwest. It grows at elevations below 5,500 feet primarily in desert washes and grasslands. It is the dominant tree species along streams and river beds. In these areas, mesquite forms dense thickets and and open parklike woodlands called mesquite bosques. During the settlement of Arizona, bosques were cleared for firewood, lumber, and agricultural use. Today, bosque destruction occurs due to fuelwood cutting, land conversion to housing developments and agricultural use, and by the lowering of the water table by groundwater pumping for agriculture. Bosque destruction results in the decline of nesting bird species and other animals that depend on the mesquite for shelter and as a food source.

                                                                   Mesquite Bosques

Mesquite is essential to the survival of wildlife in the desert. Birds, insects, and mammals eat the beans, seek shelter under its canopy, and benefit from the leaf litter and nutrient rich soil under the tree. Mesquite, along with desert ironwoods are considered to be "nurse trees" to other desert plants like the saguaro cactus, organ pipe cactus, and many succulents and grasses. Its nitrogen rich soil feeds young seedlings while the canopy provides shelter and shade. Its foliage provides cover for large animals like javelinas and mule deer as well. Many species of rodents dig their burrows under mesquite trees. The temperature under the tree can be 15° F cooler than the surrounding desert.

Description:

Velvet mesquite is a low-branched thorny, deciduous tree or large shrub with a broad spreading crown. Height varies greatly depending on growing conditions. It may grow to less than 5 feet height and 6 inches in diameter in desert grasslands where there is very limited water and nutrients. In floodplains and along major water courses and their tributaries, where the roots have access to water, it may grow to more than 50 feet in height and 48 inches in diameter. Velvet mesquite has a massive root system which can grow down as far as 50 to 100 feet to reach the water table. The taproot can be as large in diameter as the trunk itself. A second lateral root system spreads out beyond the crown 6 to 12 inches below the soil surface to catch and absorb any rain that may fall.

The bark of the velvet mesquite is reddish to gray brown to nearly black, rough, thick, and shredded into long, narrow strips. Young, green branches grow in a zig-zag pattern and may be photosynthetic. On young branches, two inch long thorns grow in pairs at the base of each leaf discouraging browsing animals. The fernlike compound leaves are 3 to 6 inches long and dark to grayish green. The flowers are yellow green, growing in drooping catkins about 2 to 3 inches long. The flowers are tiny, but there are hundreds in each catkin. The velvet mesquite is pollinated by bees and other insects and the flowers are used as a source of bee food in the honey industry. The seeds are contained seed pods that are 3 to 8 inches long, growing singly or in drooping clusters that mature 7 to 9 weeks after flowering. The beans are sweet to the taste and are a nutritious food source for livestock and wildlife including wild turkeys, quail, many songbirds, ground squirrels, jackrabbits, woodrats, javelinas, coyotes and mule deer.

                    Bark                                       Leaves                                       Flowers                                       Pods          

Cattlemen regard mesquite trees as range weeds and millions of dollars have been spent in the Southwest to eradicate the tree, but much of the invasion of mesquite into former grasslands - where it did not grow a century ago, is due to overgrazing. Mesquite trees have largely thwarted any attempt at control, including planned burns, herbicides and physical removal - all methods that have a high cost and potential environmental damage. In many cases these methods have actually indirectly resulted in an increase in the mesquite population.

Ethnobotanical Uses:

Mesquite pods provided a staple food to the Maricopa, Pima, and other tribes of the Southwest and are still very important today. The pods or the seeds alone are ground or the seeds are sometimes parched and afterwards ground into a meal that is very nourishing. The meal, called pinole, is eaten as is or is used to sweeten other seed mixtures, or made into bread. Tea and syrup are also prepared from the beans.  The black gum from the mesquite was an important medicine. It was boiled along with a little water and applied to sore lips and gums, chapped fingers, and taken internally to cleanse the system. Mesquite leaves were pounded and boiled and placed on the eyes as a treatment for pink eye. The black gum was also used in a concoction to dye gray hair black. Mesquite bark was also used to make baskets and fabrics.

Wood:

Mesquite is a slow growing tree. The Southwest is covered with mesquite, but much of it is small and too poorly formed for use as lumber. Due to eradication efforts by cattle ranchers, and continued housing and agricultural development, old growth trees that have grown to a size to be of use for lumber are very uncommon. The tendency of mesquite to grow very crooked branches also results in straight sections of lumber usually no more than 48" long. Inclusions, ring shake, checks, bug damage, ingrown bark, mineral stains, splits, and other minor defects are also common. For these reasons, mesquite lumber is priced higher than most other domestic woods. Even in the Southwest where mesquite trees are very common, much of the mesquite lumber available is imported from Mexico and other areas of Latin America.

Sapwood: Cream to yellow in color.

Heartwood: Color varies from a rich pink or reddish brown to dark brown sometimes with dark wavy lines. Color darkens as it is exposed to sunlight.

Weight: specific gravity 0.80 (dry), density 50 lbs/cubic foot

Grain: Straight to slightly wavy or interlocked.

Texture: medium to coarse.

Luster: Not lusterous.

Durability: Sapwood is very suseptible to beetles and borers. Heartwood is very durable and long lasting.

Stiffness: Medium.

Bending strength: High.

Crushing strength: High.

Resistance to shock loads: Medium.

Steam bending: Moderate.

Stability: One of Mesquites major assets is it's dimensional stability. Since the wood expands and contracts nearly equal amounts both radially and tangentially, wood movement is minimal when fully dried.

Workability: Works well with machine and hand tools but has a blunting effect on cutting surfaces.

Staining: Difficult to stain.

Glueing: Takes glue well.

Nailing: Nailing requires pre-boring.

Uses: Used for heavy construction, flooring, joinery, poles, fence posts, construction lumber, railway sleepers, turnery, sculpture, and decorative veneers.

The wood of the mesquite tree burns slowly and is used as firewood, and to make an aromatic charcoal for barbecuing and smoking.

Some of the other more common species of mesquite found outside of North America are listed below.

South American species:
Argentine Mesquite (Prosopis alba) grows to 60 ft. in height and 5 ft. diameter. The sapwood is light yellow, heartwood is reddish brown changing to dark brown. The wood has a pronounced stripe, with spiral to interlocked grain.

Caldén (Prosopis caldenia) grows 25 to 40 ft. in height. The sapwood is yellow ochre and the heartwood is reddish brown, turning chestnut brown after being cut. The wood has pronounced stripes, with a medium texture and wavy, interlocked grain.

Chilean Mesquite (Prosopis chilensis or Prosopis juliflora) reaches height of 40 ft and diameter of 4 ft. It is cultivated as an ornamental and used for reforestation and conservation in dry areas. It is widely planted in the Southwest as an landscape tree and is moderately fast-growing. The sapwood is narrow and pale yellow and the heartwood is yellowish brown to dark brown. The wood has a slight luster, straight to wavy grain, and medium to coarse texture.

Black Mesquite (Prosopis nigra) grows 30 to 50 ft. in height and 1 to 4 ft. in diameter. The sapwood is yellow ochre and the heartwood is chestnut brown, darkening upon exposure, and sometimes has a wavy stripe. The texture is average, with slanted, interlocked grain.
 
African species:
African Mesquite (Prosopis africana) depending on growing conditions, grows to heights of 12 to 100 feet. Sapwood is yellow and heartwood is reddish brown, becoming wine red after drying. Texture is fine.

Asian species:
Khejri (Prosopis cineraria) grows 10 to 30 ft. in height and up to 1 ft. in diameter.