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Living Fuel Breaks Guide for Leeward Hawaii by: Neil Logan (Integrated
Living Systems Design LLC)
Draft v1.3
Acknowledgments Ben Kamm, Richard Felger, Yatra Sylviera de
Barbosa, Ernst Go‘sch, 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.
Mahalo! Preface 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 Go‘sch 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.
Table of Contents I. Inroduction II. History of Fuel breaks
III. Living Fuel break Concept
IV. Critical Factors for Successfully Establishing Fuel breaks
V. Example Images VI. Appropriate Species VII. Summary Appendices Contacts References I. Introduction 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.
Figure
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
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.
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 competitorŐs 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 LoŐi), 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 3) Water 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 © 2009
Images: Neil Logan © 2009 VI. Summary 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.
Appendices 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.
Contacts: Integrated Living Systems Design LLC
Amy
Greenwell Ethnobotanical Garden References Cuddihy, Linda W. and
Stone, Charles P., 1990. Alteration of Native Hawaiian Vegetation: Effects of
Humans, Their Activities and Introductions Cooperative National Park Resources
Studies Unit. 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. |
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