Mesquite – a keystone species for desert

restoration

David A. Bainbridge

Mesquite Prosopis glandulosa var. torreyana T.

• A small to medium sized tree • Once widespread in the deserts of California

and the southern San Joaquin Valley• Still some good trees along the Colorado

River• A keystone species with high habitat value • P. glandulosa, P. velutina, P. pubescens also

introduced species P. chilensis etc.

Ecosystem Values

• Nitrogen fixing – soil fertility

• Sugar and protein rich pods

• Blossoms excellent food for bees

• Leaflets are excellent for wind speed reduction

• Fast growing, hardy• Nesting locations

Location, location

• Usually found in areas where soil water reserves are available

• Wash edges• Along rivers• Near playas and

lakes

Soil and roots

• Living roots of velvet mesquite found at greater than 150 feet depth

• Active symbionts (mycorrhizal fungi and nitrogen fixing bacteria also found in deep soil 10-25+ feet)

• High nitrogen levels found in mesquite soils• Soils and mesquite litter formerly used

fertilizer by native Americans

Mesquite Dune

Human utilization

• Pods once a very important food– Mesquite pods still harvested and sold– Mesquite pod cooperative in Tucson

• Pods can be used to make alcohol– Excellent opportunity today, wine, beer or liqueurs

• Firewood high quality– Also excellent charcoal feedstock

• Wood high quality• Windbreak and shelter

Mesquite pods

• High yield per plant• Easy to collect• Easy to store• High sugar and

protein content• Edible raw• Work well in baking

and food production(Meyer 1984)

Mesquite pods

• Discussions with Tohono O’Odham revealed the old timers knew the sweetest and most productive trees

Animal use

• Important food for rabbits, rodents, birds, insects

• Pods used to feed animals

• Pods used as critical food for stagecoach horses and mules

• Often found along old routes

Establishing Mesquite

• Collect local source seeds (June)• Dry and protect seeds from beetles• Clip seeds out of pods and scarify• Container plant• Small to large containers successful

with irrigation and tree shelter• Salty conditions - consider P.

pubescens - Screwbean mesquite

Planting mesquite

• Very small to large containers

• Mesquite is tough• Plant while roots are

healthy • Early out for small

containers• Can deep plant

When to plant?

• Growth is limited at lower temperatures• Plant in Spring or Summer if irrigation

systems are reliable• Can be successfully planted from small

containers in air temperatures of 100°F• Fall or winter also possible but slower

response

Options for irrigation

• Deep pipe• Wick• Porous hose• Clay pot• Treeshelter• Drip

Irrigating Mesquite

Wick irrigation

seems like an

ideal system to

link surface

to groundwater

Groundwater

• The goal is to get the mesquite roots to groundwater as quickly as possible

• More research on this is needed

• It may be drilling a hole and deep planting from a tall container

• Wick irrigation or deep pipe irrigation with a very deep pipe may also work

Rainwater catchments

• Rainwater catchments can also speed growth and improve survival

• The low salinity rain water is idea for plant growth

• But in the low desert they cannot be assumed to be enough

Tree shelters

• Herbivory is a major problem

• Jack rabbits a special consideration

• Tree shelters 24-36” tall preferred

• Or tree shelter plus cage 36” tall

• Twin wall Tubex and Treessentials have been best

Tree shelters

• Herbivory has been severe for mesquite

• This treeshelter shows the level of pressure from jack rabbits

• Treeshelters also reduce sandblast and reduce moisture loss

After 12 Years

• After twelve years mesquite has been kept browsed to the height of low treeshelter

• The taller shelter was suppressed for 10 years -- but escaped when it finally rained

Restoration

• Mesquite has suffered a great deal over the last 200 years

• Firewood cutting, conversion of land to agriculture, overgrazing, flooding of the Salton Sea, urbanization, and groundwater withdrawals have all adversely affected mesquite

• Restoration is needed over very large areas

Protection Ongoing Damage

• ORVs are destroying many of the last mesquite mounds

• Protection and education are needed

A Desertwide Program

• It would be good to do a survey of past and present mesquite distribution

• A recovery program could be developed to return mesquite to locations where it is now missing

• This could include research on economic development opportunities (windbreaks, landscaping, food, alcohol, firewood, charcoal, wood)

Production and Planting

• A seed collection program would be a useful start

• Nursery production is well understood and easy

• Plant bands probably the best compromise in cost and performance

• Planting incentives and support could be provided

Mesquite Nursery

Rapid Growth Hywy86

• Seedlings from small conetainers were planted along highway 86 to mitigate losses

• Excellent survival and rapid growth impressed everyone

• Five years old from small containers

Mesquite as a keystone

• Habitat value• Windbreak• Honey• Nitrogen fixer• Food source• Firewood source

Research efforts

• Peter Felker studied growth and performance of a range of mesquites at UC Riverside

• The growth was impressive

The Salton Sea

• Mesquite woodlands and windbreaks should be an integral part of the Salton Sea Restoration Plan

• They offer many benefits at low cost

• Mechanically transplanted windrows could help prevent toxic dust clouds

• And support wildlife

More reading

• Honey Mesquite. NFTA 90-07, 1990

• Papers by Ross Virginia, Wes Jarrell and Phil Rundel

• Daniel Meyer’s PhD on pod utilization as food is excellent

• Books on native American use