Living Fuel Breaks Guide for Leeward Hawaii
by: Neil Logan (Integrated Living Systems Design LLC) İ2008
Ben Kamm, Richard Felger, Yatra Sylviera de Barbosa, Ernst Gosch, Louis Hena, Clayton Brascope, Uluwehi Farm (Tom and Shannon Baldwin) and others who have helped, guided or otherwise supported the development of the living fuelbreak concept and implementation.
Humans are the leading cause of fire. Attempting to address fires when they occur is expensive and often times too late. Therefore, a functional preventative measure is sustainable from the cost/benefit perspective.
The first time this author encountered a living fuel break of succulents, was in the southwest of North America. In 2002 I was privileged to stroll through a remnant Mesquite Bosque outside of Tempe, Arizona on the traditional lands of the Salt River Pima or "Akimel O'odham" (River People) as they refer to themselves. Occasionally, I would find myself in areas devoid of trees and grass; ancient forest camps used for hunting. At the edges of the clearings were succulents bearing fruit. The wall of cacti surrounding the camp not only offered the hunters snacks while they waited, but also some reprieve from the dangers of wildfires that occasionally broke out during times of drought. One year later I traveled to Goias, Brazil to study agroforestry with Ernst Gosch and the Friends of the Forest organization. There I helped to implement a living fuelbreak for the first time. The concept was to protect newly planted agroforestry plots from grass fires set intentionally by local cattle ranchers. Living fuel breaks have been born out of the need for a sustainable solution to wildfire management.
Table of Contents
II. History of Fuel breaks
III. Living Fuel break Concept
IV. Critical Factors for Successfully Establishing Fuel breaks
V. Example Images
VI. Appropriate Species
Like water, fire is an essential ingredient to life. Fire acts as an ephemeral, organotrophic, aerobic, organism of pure catabolic metabolism and fluctuating structure (depending upon substrate composition), transforming fuels through its system. Fire has both inputs (oxygen, anhydrous fuel, ignition) and outputs (mineral ash and carbon char) and excretes byproducts (gases, flames (light), heat, deoxy) and behaves according to quantifiable variables. Fire can be used as a beneficial tool and it can also be quite destructive.
Over the past 500 years the industrial driven demand for fuelwood has placed extreme pressure on our forests reducing them to 50% of their former size. The absence of forests contributes to the destabilization of earth's climate, leading to extreme erratic patterns. Droughts and floods ensue, taking with them topsoil and seed banks, further exacerbating the issue.
Before the arrival of humans, the Hawaiian Islands were completely forested from mauka to makai with a complex assemblage of mostly endemic species like Prichardia shattauerii, Abutilon menziesii, Kokia drynariodes, Pleomele hawaiiensis, and Caesalpinia kavaiensis (Cuddihy and Stone 1990). Since the arrival of humans to the islands circa 900 AD, the leeward coast of the Island of Hawaii has been gradually denuded of forest via: fires set by lava flows, newly arriving Hawaiians in an effort to clear land for dwellings and agriculture, the sandalwood trade, cattle ranching and most recently, development. As a result, some of the negative consequences include, decreased moisture retention, soil and suitable microclimates, making natural regeneration and active reforestation more difficult.
In coastal leeward Hawaii, real estate and native forests adjacent to unmanaged kiawe forests (Prosopis pallida) or fountain grass fields (Pennisetum setaceum) are in serious danger especially during seasonal drought. During the dry seasons, the grass becomes desiccated and brittle, creating a situation of highly flammable fuels. Fire hazards in Hawaii have increased most recently due to a decrease in management by animals after a long period of intensive grazing.
The concepts outlined in this manual offer solutions to some of the fundamental natural resource management challenges faced in the Hawaiian Islands and other places around the globe. Intelligent and caring forethought and implementation of living fuel breaks can help to restore ecosystems while protecting lives and property from destructive wildfires. Below we will identify the critical factors for successful establishment and appropriate species for lowland coastal Hawaii.
Fire History Map
II. History of Fuel Breaks
Throughout history humans have sought to protect homes and other valuable structures or artifacts of embodied energy from fire. An ideal preemptive strategy would prevent a fire from beginning in the first place. When a fire does break out it is important that other precautionary methods have been taken to stop or slow a fire that is burning out of control and keep it from consuming valuable property. Some of the most ancient models tend to be physical barriers to fire including: walls and motes. The first walls were likely made of stone or wood arranged into a barrier. Motes were a multifunctional approach of creating clay for building material while simultaneously protecting. Both barriers are labor intensive and quite effective. Humans probably learned early on through their relationship with grazing animals that these allies help control fire by reducing and transforming fuels. In Hawaii the first fuel breaks were rock walls used to partition farm plots and exclude cattle from dwellings. The fundamental characteristic common to all of these barriers is that they represent a break in the fuel type and quantity thereby slowing or stopping the spread of fires. Other non-physical strategies will work as well and some of these are discussed below.
Fuels Reduction – Compact fuels that lack oxygen are very difficult to ignite. A reduction of fuels is achieved by chopping up the fuels into small pieces that compact together decreasing the amount of aeration and flammability. This is accomplished via machines or animals and often requires a pre-treatment of herbicide(s).
Fuel Breaks - Conventional fuel breaks are often swaths bulldozed or weed-whipped (using a grass string-trimmer) to reduce or remove most potential fuels. Generally considered effective, mechanical methods are energy and labor intensive or expensive to maintain Additionally, they are associated with the loss of ecosystem services like erosion control and habitat while also lacking a vertical component to capture firebrands in high winds.
Controlled / Proscribed Burns - Perhaps the oldest fire management tool, used to manage vast expanses of land, is to fight fire with fire. Proscribed burns require precision execution including the use of previously cut fire lines and must be used frequently otherwise the fuels build up making this strategy far more difficult and dangerous. Regular burning of non-canopied lands can be associated with erosion of precious topsoil.
Biological Reduction and Grazing – When carefully monitored grazing animals offer a sustainable solution for large tracks of land. The grazer converts would-be fuels into energy for continued growth, while the byproduct of this process is a rich fertilizer that is deposited upon the land. Animals require monitoring so they do not over graze areas and cause erosion or escape into adjacent protected areas. Other biological solutions to fuels tend to retard or stop the continuing expansion of a particular species considered a fuel type under certain conditions. A predator organism is released on a host suspected to be a hazardous fuel type. The resulting, standing, dead trees or grass (fuels) still need to be reduced.
Chemical Reduction - Similar to biological control with predator organisms, chemical methods (i.e., herbicides), often kill target species of suspected fuel types and usually require a follow-up mechanical reduction strategy. Chemical methods may have toxic ramifications that compromise environmental health quality (i.e., toxicity in fish, aquatic invertebrates, birds, amphibians and drinking water). In some situations, chemicals are expensive, hard to obtain, or difficult to apply properly.
Living Fuel Break - Assemblages of succulent, fire resistant plants strategically arranged, spatially and temporally, for the purpose of protecting an area. They are multifunctional fuel-type disruption zones that serve to slow the spread of fire across a landscape. If properly designed and implemented they tend to be self-regenerating and expanding corridors of diverse habitat that disrupt the spread of fire.
III. Living Fuel Break Concept
The purpose of a living fuel break (LFB) is to protect valuable property inside or behind a living, regenerative barrier. The LFB converts highly combustible fuels into slow burning, fire and drought resistant plants that maintain themselves over time. The plants are arranged to eliminate ladder fuels up into the canopy of neighboring trees and slow or stop an oncoming ground fire. Embers are snagged by the fire resistant overstory trees then fall into an understory of succulents, thereby containing the fire. These multifunctional fuel breaks can also help reduce the force and damage of flood events by capturing large debris and quickly absorbing water. Living fuel breaks release captured storm water at a conservative rate, which cools the local environment by reducing local surface temperatures and re-establishing microclimates for animals and birds. In addition to the above, this integrated living system provides multiple benefits for the ecosystem including: conserving and building soil, providing windbreaks (helping to decrease transpiration in neighboring plants), and recycling greywater. An intelligently designed and implemented fuel break can pay for itself by essentially eliminating maintenance over time.
1 is a design that incorporates cactus and other
succulents, a species pallet representative of the Americas and Africa. In
this example the vegetation lowest in stature is at the outer interface in
relative proximity to where a fire event is most likely to originate (the
fire vector). Towards the back edge, nearest the area to be protected, is the
tallest vegetation. In this case a gabion basket (river stones bound in a
wire mesh basket) is incorporated to dissipate water during floods to avoid
channeling and erosion.
Figure 2 is a design that uses larger sized area-adapted trees and succulents as a fuel break. This design incorporates a similar graduated layout as figure 1. The design represents the species assemblage present during the primary phase of microclimate establishment in a living fuelbreak, which will ultimately harbor rare, endemic Hawaiian, coastal, dry forest plants. Swales are made on contour so as to capture and redistribute water. Empty spaces would be filled in later with rare endemic plants once there is a protective overstory.
Figure 3 depicts a multi-story mature endemic Hawaiian leeward dry forest assemblage that is the long-range result of figure 2. This assemblage would have the branches limbed and chipped and the border is planted with succulents to stop a ground fire from intruding into the canopy or interior understory.
Figure 4 illustrates the zones of a typical fire safe home site layout showing earthworks and general context of the landscape in relation to the structure. The home is placed inside of concentric circles representing the different themed zones each with their own unique finction. For more info on zonation, please see Mollison 1988.
The layout and sequencing of the species assemblage in living fuel breaks is crucial to its success. The unique context of each site will determine the strategic and functional layout of plants for protecting the object within. The layout is generally divided into 5 rows that total approximately 50 feet in width and can be as wide as needed (ie. Figure 2 which has 8 rows). The outer edge of the fuel break, row #1 (figs. 1 & 2), is the area that will confront the flammable fuel zone beyond the site boundaries. The edge of confrontation tends to have low growing, moisture conserving plants, such as Aloe or Portulaca, succulent vines like Beach Morning Glory and other ground covers like gourds and pumpkins (see Fig. 1 above). This front helps to push down fine fuels (grasses) and create micro fissures in the extra boundary fuel matrix. Moving away from the edge of the fuel break inward towards row #5, the plants become gradually larger in stature. Outside of the fuelbreak, beyond row #5, resides the object to be protected. Row #5 can be at the inner edge of a one-sided fuel break (community or forest boundary figure 2 Row #8) or it can be bordering zone 4 in the home site example in figure 4. Trees are incorporated in row #5. All trees are limbed so that ladder fuels are eliminated. The trees create a canopy, providing shade for a succulent understory and create a shield from radiant heat and a fire resistant net that can capture firebrands produced during high winds. Additionally, trees found in rows 1-4 can be cut and used as mulch once the understory is established, and the remaining trees produce mulch from fallen leaf litter that helps the soil retain moisture, decreasing the chance of ignition while suppressing the growth of fine fuels in the understory. Once established, a LFB can be driven towards long-term endemic flora as in Figure #3.
IV. Critical Factors for Successfully Establishing Fuel Breaks
1) Deep irrigation at infrequent intervals - Forces the root systems of trees to grow deep, eventually connecting with existing underground water stores. Initially, it may be necessary to water frequently and in some cases use a mist or shallow watering system in order to get superficial rooters like Aloe vera and beach morning glory (Ipomoea pes-capre var. brasiliensis) to creep and spread over the surface. Over time, once plants become better established, it is possible to scale the water back gradually so that the irrigation becomes infrequent and deep. High volume irrigation is essential, therefore a 2" line, throughout the entire break, to give pressure and volume to the system, is ideal.
2) Create Microclimates - An overstory casting shade that can be removed gradually as fragile plants firmly establish is vital in the harsh leeward coast environment. Non-native trees and shrubs can be used like Pigeon Peas (Cajanus cajan), Madre de Cacao (Gliricidia sepium), Monkey Pod (Albizia saman) and other fast growing, non-spiny, bi-pinnate, nitrogen fixing trees. These can be cut as needed to create mulch and adjust light levels. Eventually they are completely removed from the system and replaced by long-lived species.
3) Soil building and mulching - Mulch works well to conserve moisture, while feeding plants and suppressing grasses. When nutrient sources and microclimates are not available it is important to create them. This is accomplished by amending the soil with black cinder, coconut husk fiber (coir), finished, seedless, black, rich, compost and a top-dressing of woodchips. Ideally, all imported amendments are sterile. (*Note: Woodchips are made from tree branches and other woody refuse created on-site in order to avoid importing disease and should be of small highly compactable chips not shreds.) These are applied in succession to recreate the natural soil layering process.
4) Direct sow seeds for root development - Ultimately trees grown from seed, directly sown in situ will be more drought tolerant and disease resistant than those transplanted from containers. Obviously this is not always possible, especially in the case of rare, slow-growing, endemic, Hawaiian plants that are easily predated or lost among other plants. In these cases it is important to establish a microclimate before planting and use "root trainer" pots when affordable. Also, synergistic planting of rare natives in complimentary guilds helps to protect delicate, newly forming root systems and invites the roots to grow deeper.
5) Stratified Ecological Guilds – are complementary, non-competing, mutually compatible plants, occupying different root and aerial zones which fill any space that competitorĠs might attempt to occupy. This includes trees, mid-story, climbing or creeping vines, and groundcovers all in one pot or hole. This technique also creates an effect similar to root trainer pots. The different plants occupying different soil layers protect the long-term trees roots and force them to grow down below the roots of the neighboring plants. Synergistic guilds of plants can help conserve water, making the overall system more efficient. It is important to consider long-term spacing. Different colonies have different themes depending upon their placement in the fuel break scheme.
6) Planting edges - Typical fuelbreak schematics will show that the succulents and low growing groundcovers will form an outer edge around the object to be protected. This helps to form a disruption in fuels before reaching the drip line of trees where ladder fuels are normally found. The design typically reflects a graduated pattern from small, low-growing succulents at the outside edge to taller trees at the inner edge. Living fuel breaks tend to be built upon established edges of forests or residential landscapes.
7) Plant in a depression - In dry areas like coastal leeward Hawaii drainage is not as much of an issue as capturing and conserving water because infrequent rains drain quickly from the porous soil. One way to do this is to plant everything in shallow depressions that are irrigated (a kind of LoĠi), like gullies, swales, and water catchment basins. For more information on these concepts and more please see: Landcaster 2007.
8) Site Preparation – The use of grazing, selective herbicides, weed-whipping, cover cropping, tilling, cardboard, or black plastic weed mat to kill off competitor species is essential, in most cases, to ensure successful conversion of fuels and decrease maintenance during establishment. Of these options, recycled cardboard, placed around the guilds and covered with a dense layer of woodchips is the most ecological, inexpensive and effective strategy.
9) Density - the more dense you plant the living fuel break from the outset, the less weeding and maintenance will be needed during establishment. Spatial relationship in a 4-dimensional garden accounts for quantity vs. quality of life and space vs. time. A thoughtful design plans long-term by balancing these four attributes. The concept is to offer the greatest diversity of plants in a given area to completely express themselves naturally coming into existence, completing their life cycle and then phasing out of the system only to be replaced by something else in a harmonious fashion with a seamless transition. When implemented well, pioneers grow and establish a microclimate for newly sprouting tree seedlings and transplants. The pioneers finish their life cycle, provide products like mulch or food and are replaced by a more long-lived species assemblage that in turn is replaced by yet another wave of more long-term plants again and again repeating the cycle gradually approaching a centuries-old climax forest. This is the perspective we need to have when developing our living fuel breaks for native reforestation plots.
When implementing living fuel breaks there are a few critical factors for efficient and successful implementation.
á Be sure to have all permits and permissions.
á Identify the boundaries of the site and have an agreed upon design.
á Finish all earthworks and prep the site.
á Do you have the four essential ingredients?
1) Plant material
2) Amendments and Chips
4) Installation Labor
If you do not have all of the above in the amounts required to complete the current phase of the project then you are not ready to proceed to implementation.
IV. Example Images:
Image 2: Echinopsis spp., Furcrae foetida and Papayas at Uluwehi farm in north Kohala, Hawaii
Image 3: Roadside barrier of Agave spp. for protecting Eucalyptus plots near Huaraz, Peru.
Image 4: Opuntia sp. and Echinposis sp. cacti halt a fire near Luribay, Bolivia.
V. Potential species for Living fuel breaks:
Appropriate plant species list: Leeward, Low-elevation (0-2,000 ft), Kohala coast
Images: Neil Logan İ 2009
Images: Neil Logan İ 2009
Pruning and fuels reduction are the first steps to establishing a living fuel break. The mulch created from this process is cycled into the planting. Whenever possible build upon established microclimates even if they are non-native. It is essential to build soil and establish microclimates in situations where none exist. Direct sow when possible and utilize deep and infrequent irrigation, which encourages deeper root growth to tap underground water. Plant guilds of plants that occupy different strata, above and below ground and focus on the establishment of long term site-adapted species which require little maintenance and water compared to many non-native species. If installed properly, living fuel breaks can provide added safety from wildfire for the community while re-establishing habitat and ecosystem services. In conjunction with other appropriate treatments, living fuel breaks are a long term, sustainable solution to the challenges posed by wildfire.
Fuels reduction and limbing of trees:
Tree limbing and subsequent fuels reduction of the removed limbs and woody debris lying on the ground, is the most crucial aspect of a living fuelbreak and a fire safe landscape. Generally trees are limbed up to approximately 10 feet. Ladder fuel and fine fuels on the ground below the trees and shrubs are removed. Kiawe is the dominant tree on the leeward coast of the Island of Hawaii and is specifically addressed in other documents. Please refer to: Wildfire Threats and Mitigation in the Puako Forest: An Analysis and Report - Appendix B "How to prune a kiawe for fire safety, productivity and long term health of the tree" (Logan 2008).
Roof runoff and greywater (recycled):
Grazing in conjunction with LFB:
It is common to graze an area on either side of the LF once it is established to enhance the effectiveness by reducing grasses around the break. Depending upon the species a mature LFB may also function as an animal barrier without the need for fencing.
LFB development utilizing species of economic importance:
A Living fuel break may be populated with species that produce alternative products such as fruit, medicine or fiber. The harvesting is the maintenance and the products pay for the LFB. Some examples are: 1) the use of Agave spp. for making syrup and fiber 2) fruit bearing succulents for additional crops like dragon fruit trellised on the fence line for fruit production and fire barrier, 3) Plumeria and other succulent lei flowers, 4) Chaya for edible greensand living fence, and Aloe leaf products.
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Juvik, James, John Delay, Mark Merlin Michael Castillo, Lyman Perry, Kealohanuiopuna Kinney, 2008. Endangered Plants and Threatened Ecosystems on the Island of Hawai'i. Hilo Bay Printing Company LTD, Hilo, Hawaii.
Lancaster, Brad, 2006. Rainwater Harvesting for Drylands: Vols. 1 & 2 Guiding Principals, Rainsource Press, Tucson, AZ.
Lilleeng-Rosenberger, Kerin E., 2005. Growing Hawai'i's Native Plants, Mutual Publishing.
Logan Neil, 2008. Wildfire Threats and Mitigation in the Puako Forest: An Analysis and Report.
Mollison, Bill, 1988. Permaculture: A Designer's Manual Tagari Publications, Tyalgum.
Pope, Willis T., 1968. Manual of Wayside Plants of Hawaii, Charles E. Tuttle Co. Inc.
Wright, Clinton S. et al., 2002. Grassland, Shrubland, Woodland, and Forest Types in Hawaii, USDA.