the Breeze: A Comprehensive Guide to the Management of Kiawe (Prosopis
pallida) in Hawaii
Audience: Socially Responsible Investors,
Land Managers, Extension Agents, Private Landholders, and Health Conscious
Topics: Ecosystem Restoration,
Ethnobotany, Hawaiian Studies, Living Systems Design, Honey Production,
Bio-energy, and Agriculture
Integrated Living Systems Design
By: Neil Logan © 2007
PO Box 2683
Kamuela, HI 9743
Section I: Overview; Introduction to kiawe, (prosopis pallida);
origins in Hawaii, origins worldwide; botanical differentiation, entomology,
mycology, interactions with native plants/ecosystems, manual statement of goals
Section II: Products, chemistry,
medicinal potential, physical properties and lumber, marketing – pods, leaves,
wood, api-products, gum, et al.
Management Guide including Puakō Site and Economic Analysis
IV: Global Implications, About the Author, Summary,
In today's complex world, to create
innovative wealth-building and quality-of-life improving “living” systems, it
is necessary to bring together experts and resources from diverse fields of
specialization. As you will read in this work, I have stood on the sturdy
shoulders of many of the world's foremost scientific researchers whose areas of
expertise are based on lifetimes of real-world experience.
I have presented exhaustive scientific evidence as well
as my own field research supporting the
economic feasibility and multiple benefits of the under-utilized kiawe tree,
its ecological contribution as a species as well as the commercial value of
kiawe by-products—as a source of food, bio-fuel, lumber, honey, etc.
It is my hope a careful perusal of this work will make its
implications self-evident: kiawe is a valuable resource which, if intelligently
groomed and managed, is the “right choice” for sustainable, prosperous
long-term regional land-use in West Hawaii.
I invite you to contact me. Let's “make the desert bloom!”
“The algarroba, or kiawe, is commonly recognized as
the most valuable tree which has thus far been introduced to the territory of
Hawaii” (Esbenshade 1980).
“In the opinion of the retired Deputy State Forester,
Colonel L.W. Bryan, the kiawe is still the most valuable tree ever introduced
into the Hawaiian Islands” (Esbenshade 1980).
“Prosopis juliflora and Prosopis pallida (kiawe) are two of the most economically and
ecologically important tree species in arid and semi-arid zones of the world”
(Pasiecznik et. al. 2001).
“Kiawe has potential for cultivation in arid coastal
environments with saline soils and rainfall that may not exceed 254 mm per
annum. Thus two of the kiawe’s principal values are tolerance of brackish water
and ability to survive in arid environments” (Esbenshade 1980).
Kiawe has incredible medicinal potential that can
especially benefit those of native Hawaiian ancestry who suffer from diabetes,
heart disease and colon cancer.
Kiawe's honey is of pharmaceutical value and its pods may
be crucial components to modern sustainable food and energy systems.
The dense wood makes excellent
bio-fuel, post and lumber material.
“The development of a multiple-use management program for the remaining
woodlands would be very attractive economically” (Esbenshade 1980).
The leeward coasts of the 7 human-populated, “major”
islands in the state of Hawaii (Oahu, Kauai, Hawaii, Maui, Lanai, Molokai'i, Ko'olave,) tend to be arid to
semi-arid, subtropical/tropical climates.
“The leeward sides of the islands typically receive less
than 1,250 mm (50”) of annual precipitation, and some areas have less than
250mm (10”) per year.” (Cuddihy and Stone 1990) Due to the lack of
water and intense sun, native trees have grown and evolved slowly. The leeward
coast is home to the rarest, most endangered of Hawaiian ecosystems. Unique
plants have been slow to develop in harsh conditions, often on bare lava with
little moisture. When the trees in this ecosystem are cut, recovery tends
to be slow. Lack of moisture and soil makes the leeward coast ecosystems
exceptionally fragile and vulnerable to irrecoverable damage. Most of the lower
elevation (below 2000’) leeward coast ecosystem has already been destroyed.
With many billions of dollars in development slated for the leeward coast,
these already fragile ecosystems will need all the help they can get.
To demonstrate the vulnerability of native species, the
“Willi Willi” (Erythrina sandwichensis)
trees is a case in point, rapidly declining in numbers due to a gall wasp that
has plagued the Pacific and all species in the genus, native and non-native
alike. Efforts are being made to preserve this genus by use of systemic
treatments injected into the base of the trunk. Along with Koaia, Uhi Uhi and
Mamane, this tree was the major pioneering legume species of the leeward coast.
Loss of the genus means a gap in its eco-niche, which needs to be filled.
At one time, Sandalwood, Curley Koa, Naio, Willi Willi,
Hala Pepe, and other native trees, covered much of the leeward coast. The
unsustainable harvesting of Sandalwood led to nearly complete deforestation and
major changes to the hydrology. A picture of what this ecosystem looked like
before the arrival of humans is quite fuzzy. “Perhaps because of a history of
human disturbance, the vegetation of the dry leeward zone is more fragmented
and difficult to characterize than that of wet windward zones.” (Cuddihy and
Stone 1990) There are reference sites scattered amongst the islands that can
offer clues and direction for rehabilitation.
In 1962, there were 60,730 hectares
(~150,000 acres) of kiawe in the state of Hawaii. That figure has most
certainly been reduced due to leeward coast development of commercial resorts
and residential homes. The leeward coast ecosystem has also been ravaged by
lava even before the arrival of the first Hawaiians from Polynesia. For this
reason, the reduction of the number of kiawe trees cannot be pinned on western
contact and human encroachment alone.
Creating a picture of what the former
ecosystem was like is difficult now. The original pioneering species may have
been Acacias of the lowland Koa varieties, types of Ohia, Sandalwoods, and
possibly other trees, shrubs and vines. Many of those trees are not thriving in
the lowland coastal ecosystems today due to insect predation and human
disruption. Native pioneering, nitrogen-fixing species such as the “Willi
Willi” are seriously threatened at the time of this writing by a gal wasp that
is a virulent predator of all members of the genus Erythrina.
In any case, as cited above, due to the attrition of other native
trees, kiawe is now the dominant species in this low moisture, largely barren
habitat. At present, there are “little to no” competing plants and trees in
this eco-niche—they simply cannot grow in this austere environment. From an
evolutionary perspective, Kiawe's functions as a first-forest pioneer: breaking
cracks in hard soil and barren lava, building soil, creating shade and humidity
for secondary growth forests.
Given the opportunity, kiawe is a rapid
colonizer of hot, dry, open areas, especially when there are few competitor
plants, and especially after the loss of Erythrina.
One of kiawe's strengths is that it can live where few other trees can,
colonizing barren land, lava, sand dunes, or any other harsh, arid, conditions
it may find itself in—as long as there
is a source of subterranean water.
Kiawe has a “determined” taproot which
can widen existing cracks in lava and hard compacted dirt, reaching for water
deep below. By literally breaking ground, kiawe pioneers the ecosystem, grabbing
hold of water tables that have sunk deep into the earth. This makes it possible
for young plants to penetrate the soil, take root and uptake nutrients
efficiently, despite the harsh climactic conditions.
Most productive from 1000’ or less
elevation, Kiawe is gradually covering the surface of the leeward coasts even
up to 2000’. Kiawe will even grow with its roots in the ocean or as a high as
2,000 feet elevation. Its spread has actually slowed with the decrease in
cattle ranching. Kiawe is technically not native to Hawaii, being introduced by
. Kiawe's propagation, or at least
“non-interference,” can therefore be
seen as a value-added benefit, especially in the case of leeward Hawaii, where
the indigenous competing inhabitants of
the niche which once were there are no longer there due to the ravages of both
human and natural forces (cited above).
__________________Setting the Record Straight--Correcting
Unjustified Prejudices Against Kiawe
Merge negatives in one section: eradication efforts, overgrowth, allelophath
and allelophathic etc in one place and get it handled and out of
paragragh with eradication efforts to put negative aspects all in
one place. “Public Relations” Repair The allelophathic potential of
Kiawe does exist although it is low and can be mitigated by cutting a furrow
around the drip line to contain the roots, by harvesting the fruits and by
regular pruning (Pasiecznik et. al. 2001).
is allowed to grow wild, If well-managed in forests, gardens and
orchards, Kiawe is not a problem. In fact, regenerating native ecosystems with
the aid of Kiawe may be possible, if done correctly. If left alone and with
access to resources Kiawe will form dense thickets, which will shade out almost
anything below. This over-growth can be reversed, however. The forest is in a
state of flux and will eventually fall apart, rot, and create soil that other
species may use for growth, leaving behind some large trees and a potential
seed bank in the soil. In the case of fire, the forest will burn and the seeds
in the soil can regenerate or seeds from trees not burned will regenerate. In
this way the building and conservation of soil occurs. Tall kiawe trees have a
propensity for being blown over by strong winds. Once trees taller than kiawe
emerge, or if the kiawe is kept pruned and allowed to be overtaken by other
trees the shade from those trees will begin to weaken the kiawe. The
accumulation of a thick, rich hummus-like soil layer and the presence of shade
from newly emerging trees through the kiawe canopy heralds the end of Kiawe
primacy and the beginning of a long-term, more diverse and stable forest.
Working with Kiawe is made more
difficult by the presence of cultural sites and historical trails common in the
leeward coast of the state. Many of these sites are degraded by the large kiawe
root systems cracking rock art and walls. When Kiawe doesn’t successfully tap
water they may die back or die completely leaving behind standing, dry dead
wood. Pieces like these make perfect ladder fuels standing amongst dry buffel
and fountain grasses. What may begin only as a grass fire grabs hold of the
dead wood and moves into the crown of nearby trees. Crown fires are rapidly
spreading fires, often quite difficult to stop unless they have completely
exhausted their fuel source. For this reason Kiawe contributes to fire danger
along the developing leeward coasts and needs to be addressed. Making kiawe
fire safe is a simple matter of pruning and removing fuels from the ground. By
removing or reducing the wood lying on the ground, pruning all low lying
branches up to 10’ and by selecting, when possible, for a single trunk will
make a kiawe tree relatively fire safe. This is because ground fires will not
tend to kill a large kiawe tree as long as there are no hot burning fuels
around the trunk and no way to get into the crown of the tree. Small trees will
be lost but replaced soon there after by the surviving trees.
Native plants have demonstrated fire resistance. Native plant
restoration amongst kiawe is promoted here in as a first option. There are many
places where kiawe has arrived that can take advantage of its presence as a
shade/nurse tree, nitrogen fixer, and fruit-bearing tree. Below will be
discussed options that caring land stewards in Hawaii can choose for how to
manage kiawe as a non-competing nurse tree for native plants, or an
agra-forestry crop and landscape shade tree.
We can choose to
accept the gift of kiawe to help restore our threatened ecosystems and heal our
people. This guide is written so that we may be better equipped to work
with the kiawe tree, understand what it is doing here and what it’s gifts are
for the people of Hawaii. Sometimes in this guide references will be made to a
closely related species to kiawe, as there may not be data available specific
to Kiawe. As a genus Prosopis has
been generally found to be very similar in its properties. This guide aims to
be as specific to Kiawe in Hawaii as possible.