Swaying in 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 consumers

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

808-640-3588

neil@rnl3.net

Version 1.1

 

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.

 

Section III: Management Guide including Puakō Site and Economic Analysis

Section IV: Global Implications, About the Author, Summary, Appendix, Citations

 

Introduction

           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!”

 

Background on Kiawe

 “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 human hands.       

. 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 the way....

 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).

Overgrowth

If kiawe

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.