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Prosopis juliflora Boon or bane for dryland agroforestry?
March 2004
Prosopis juliflora is a perennial deciduous thorny shrub or small tree that can grow up to 10 m tall, with a trunk up to 1.2 meters in
diameter. Prosopis juliflora, P. pallida,
P. chilensis, P. alba, P. pubescens and
P. tamarugo are all species that are native
to The Americas, but have now become established
in arid and semiarid Australia, Africa and Asia.
Prosopis cineraria is native to India, whilst
Prosopis africana is native to the Sahelian belt
of Africa. Common English names for Prosopis
juliflora are mesquite and honey mesquite.
Prosopis are fast growing, salt-tolerant and
drought-tolerant trees that can grow in areas
receiving as little as 50 mm of rainfall per
year. There is great controversy surrounding
Prosopis juliflora: unmanaged, it often colonizes
disturbed, eroded and over-grazed
lands, forming dense impenetrable thickets.
Thickets of Prosopis juliflora have become
established in grazing lands, crop lands and
along river courses, alarming pastoralists,
farmers and conservationists. There is
concern on the impacts of the tree on
biodiversity of native plants and on the
amount of water in dryland streams.
Prosopis species have been declared noxious
weeds in many countries, including Argentina,
Australia, South Africa, Pakistan and
Sudan. On the other hand, Prosopis juliflora
has proved useful in restoring degraded and
saline lands, producing a variety of useful
products for the local populations. Prosopis
juliflora has potential as a source of
fuelwood, timber, honey and animal forage.
Prosopis was first introduced in Africa in
1822 in Senegal, followed by South Africa
(1880) and Egypt (1900). The first documented
introduction of the tree in Kenya was in 1973,
when seeds were imported from Brazil and Hawaii for
rehabilitation of quarries in the saline soils near
the city of Mombasa. In the early 1970s, prosopis
was introduced further inland in the Hola Irrigation
Scheme in Tana River to control soil erosion.
The main species introduced in Kenya were
Prosopis juliflora, P. chilensis, P. pallida,
P. alba, P. pubenscenes and P. tamarugo. The
districts with the greatest prosopis populations
are Garissa, Wajir, Mandera, Baringo, Turkana,
Taita Taveta and Tana River Districts.
Twenty to thirty years after its introduction
in Kenya’s drylands, there is now growing
concern—and debate—on the negative impacts of
Prosopis juliflora and on its control or
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| Prosopis juliflora at Lake Baringo,
Kenya (Girma Hailu) |
eradication. The Kenya Forestry Research
Institute (KEFRI) and the Forestry Department
and the Food and Agricultural Organization
(FAO) organized an information sharing
workshop on prosopis in October 2003 at which
a number of complaints were received from the
residents of Baringo, Tana River and Turkana
Districts. Local residents complain about the
species’ thorns, its aggressive colonization of
useful habitats such as pastures and irrigation,
farming and fishing areas, its negative effects
on animal and human health, and its use as a
hideout by cattle rustlers and wild animals.
Many people in the drylands are calling for its
eradication. Yet the experience from other
countries shows that Prosopis is extremely
difficult and costly to eradicate once it takes
root. A more sustainable option might be better
management through collective use and harvesting
of marketable products. Fast-growing,
drought- and salt-tolerant, and with remarkable
coppicing power, prosopis is a natural fuelwood
that can meet the energy requirements of the arid
and semi-arid lands (ASALs). With specific gravity
0.70 or higher, the wood has been termed “wooden
anthracite”, because of its high heat content: it
burns slowly and evenly, holding heat well.
Prosopis meets as much as 75% of the fuelwood
needs of rural people in arid and semi-arid India.
The Indian Forestry Department produces and markets
prosopis charcoal through special development
corporations.
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Energy from prosopis can be
a useful complement to
other potential off-grid
options in the ASALs of
Kenya like solar and wind
energy. For Kenyans to
garner more of the potential
energy benefits of Prosopis
juliflora, policies and bureaucratic
procedures that govern
the production and marketing
of charcoal will need to
be changed.
Prosopis wood has
excellent structural stability,
making it ideal for furniture
and handles of agricultural
implements. The pods of
prosopis are sweet, nutritious
and are consumed by
mammals, birds, insects and
reptiles. In Kenya though,
there are unconfirmed reports
that goats that regularly
feed on Prosopis juliflora
pods suffer from having their
teeth fall out. A rich, nutritious
flour can be made from
pulverized pods with the
seeds removed.
Prosopis flowers are an
important source of nectar
and pollen, producing high
quality honey. They exudate
gums from the trunk and
branches of its trees are
used in various sectors such
as food, pharmaceutical,
chemical and manufacturing
industries. Other prosopis
products include tannins,
dyes, medicine, live fencing,
shade and environmental
benefits such as soil
stabilisation and carbon
sequestration.
Prosopis has potential
uses in the wood carving
industry (high-quality carvings),
flooring parquettes/
tiles, high-value furniture,
fibre boards and railway
cross-beams. Prosopis is a
folk remedy in some arid
zones of the world for catarrh,
colds, diarrhoea,
dysentery, excrescences,eyes, flu, colds, hoarseness,
inflammation, itch, measles,
pinkeye, stomach ache, sore
throat and wounds.
Quite clearly, therefore,
Prosopis juliflora is a species
with significant potential for
commercial exploitation and
for enhancing livelihoods in
the world’s drylands. However,
its environmental
benefits and economic potential
are increasingly
overshadowed by some of its
undesirable properties. In
the late 1990s, the Forestry
Research Programme of the
UK Department for International
Development supported
a project by HDRA
(Henry Doubleday Research
Association) in the UK, and
CAZRI (Central Arid Zone
Research Institute) in India,
to collate information on the
most common prosopis
species. The results of this
project are summarized into
monographs and policy briefs
that are available on the
internet here. The
three main conclusions of
that effort are: (1) that
Prosopis juliflora can be a
very valuable resource for
the drylands; (2) that efforts
to completely eradicate
Prosopis juliflora are overly
expensive and likely to be
ineffective; and, (3) that
Prosopis juliflora, when
managed, can be a very
valuable source of commercial
products and livelihoods
in the drylands.
Experiences from India
are particularly instructive.
Prosopis is acknowledged as
an important source of
fuelwood and income for lowincome
earners in Tamil
Nadu. Its value for reclaiming
degraded saline soils has
also been widely acknowledged.
Most importantly, its value for woodfuel, charcoal,
timber, furniture construction,
animal feed, human
food, and medicinal products
have been documented and
increasingly exploited. The
Planning Commission of
India’s Action Plan for
Greening India identifies
Prosopis juliflora as one of
the most promising
agroforestry options for
problematic and saline soils.
Other regions of the world
have much to learn from
these experiences.
ICRAF, together with its
national collaborators such
as KEFRI, is at the starting
phase of a study to investigate
the effects of markets
and institutions in structuring
local community perceptions
towards Prosopis
juliflora in Kenya and India.
Lessons from this comparative
case study are intended
to inform the design of a
mega research and management
strategy for the wider
Eastern Africa region.
At the same time,
ICRAF is aware of the dangers
of introductions of
potentially invasive alien
species. ICRAF is working
with the Global Invasive
Species Programme (GISP)
and others to help inform
and contribute to more
cautious decisions on
transboundary movements of
potentially dangerous weedy
trees.
Additional information
on Prosopis juliflora and
ICRAF’s policy on invasive
species is available on our
webpage. More information on
global experiences with
Prosopis juliflora can also be
found here.
For more information, contact c.ong@cgiar.org
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