Highlighting Four Publications on Forest-Fire Fuel Properties
The
ignition, buildup, and behavior of fire depends on fuels more than any other
single factor. It is the fuel that
burns, that generates the energy with which the firefighter must cope, and that
largely determines the rate and level of intensity of that energy. Other factors that are important to fire
behavior (that is, moisture, wind, etc.) must always be considered in relation
to fuels. In short, no fuel, no fire!
A.A.
Brown and K.P. Davis (1973)
Forest Fire:
Control and Use. Second Edition. McGraw-Hill, New York
Senior Researcher Dr.
Marty Alexander with FERIC’s Wildland Fire Research Operations Group has been
involved in sampling wildland fuel complexes for a number of years now[1]
and has produced several publications on the subject. His most recent publication, in which he served as the senior
author, deals with a detailed description of the jack pine-black spruce fuel
type associated with the experimental burning carried out during the
International Crown Fire Modelling Experiment in the Northwest Territories
(Alexander et al. 2004). This
publication will undoubtedly serve as a new standard for similar studies. Three other publication previously authored
by Dr. Alexander are worth noting here. Marty has previously collaborated with
fire researchers at the University of Montana in developing models for
predicting canopy fuel properties commonly employed in crown fire behavior
models (Cruz et al. 2003). He has also
been involved in the determination of the physical properties needed in
calculating dead-downed woody surface fuels with the use of the line intersect
fuel sampling method in the Canada’s three prairie provinces and Northwest
Territories. (Nalder et al. 1997, 1999).
The
abstracts associated each of these
publications follows.
Profile
of a forest showing location and classification of fuels (from Brown &
Davis 1973).
CITATIONS and
ABSTRACTS
Alexander, M.E.; Stefner, C.N.; Mason, J.A.; Stocks, B.J.; Hartley, G.R.; Maffey, M.E.; Wotton, B.M.; Taylor, S.W.; Lavoie, N.; Dalrymple, G.N. 2004. Chartacterizing the jack pine-black spruce fuel complex of the International Crown Fire Modelling Experiment (ICFME). Canadian Forest Service, Northern Forestry Centre, Edmonton, Alberta. Information Report NOR-X-393. 49 pp.
Abstract: This report describes in detail the various sampling methods and techniques used in quantifying the ground, surface, ladder, and crown or canopy fuel characteristics of the jack pine (Pinus banksiana Lamb.) – black spruce (Picea mariana (Mill.) BSP) forest in the primary plots of the International Crown Fire Modelling Experiment (ICFME), located about 50 km northeast of Fort Providence, Northwest Territories. The approach involved both general sampling in the study area as a whole and the use of a systematic grid structure for the experimental plots that were to be burned. New data and information on the fuel properties of northern forests were acquired as part of this process (e.g., organic layer bulk density and allometric equations for estimating the dry weight of jack pine and black spruce crowns from stem diameter). Detailed descriptions and summaries of the characteristics of the forest floor, dead-down woody surface fuels by roundwood diameter size class, understory canopy ladder fuel, and overstory crown fuel for each of the primary plots within the ICFME are presented in tabular and graphic form. Representative values for the fuel complex represented by ICFME forest cover type are also given. Vertical fuel profiles were developed, which allowed for the visualization of the distribution and nature of the fine fuels according to height above the ground. The ICFME forest fuel complex exhibited a number of unique characteristics that distinguish it from other stand types dominated by jack pine that have been the subject of empirical, outdoor experimental fire behavior studies.
Cruz, M.G.; Alexander, M.E.; Wakimoto, R.H. 2003. Assessing canopy fuel structure stratum characteristics in crown fire prone fuel types of western North America. International Journal of Wildland Fire 12: 39-50.
Abstract: Application of crown fire behavior models in
fire management decision-making have been limited by the difficulty of
quantitatively describing fuel complexes, specifically characteristics of the
canopy fuel stratum. To estimate canopy fuel stratum characteristics of four
broad fuel types found in the western United States and adjacent areas of
Canada, namely Douglas-fir, ponderosa pine, mixed conifer, and lodgepole pine
forest stands, data from the USDA Forest Service's Forest Inventory and
Analysis (FIA) database were analysed and linked with tree-level foliage dry
weight equations. Models to predict canopy base height (CBH), canopy fuel load
(CFL) and canopy bulk density (CBD) were developed through linear regression
analysis and using common stand descriptors (e.g. stand density, basal area,
stand height) as explanatory variables. The models developed were fuel type
specific and coefficients of determination ranged from 0.90 to 0.95 for CFL,
between 0.84 and 0.92 for CBD and from 0.64 to 0.88 for CBH. Although not
formally evaluated, the models seem to give a reasonable characterization of
the canopy fuel stratum for use in fire management applications.
Diagram illustrating data linkages used to estimate detailed canopy fuel
characteristics from Forest Inventory Analysis (FIA) plot data and published
foliage biomass equations (from Cruz et al. 2003).
Nalder, I.A.; Wein, R.W.; Alexander, M.E.; de Groot, W.J. 1997. Physical properties of dead and downed round-wood fuels in the boreal forests of Alberta and Northwest Territories. Canadian Journal of Forest Research 27: 1513-1517.
Abstract: Dead and downed woody fuels in forests are
commonly estimated using the line intersect method, which requires appropriate
values for specific gravity, piece tilt angle, and piece diameter. We present data for these variables for six
commercially important tree species based on extensive surveys of slash and
naturally fallen dead wood in four regions of the western Canadian boreal
forest. The considerable variation by
diameter size class, species, cover type, and, to a lesser, region suggests
that specific values improve fuel load estimates. We combine the three variables into a single factor so that fuel
load (megagrams per hectare) can be simply calculated by multiplying this
factor by the number of intersects per metre of sample transect.
A “go/no-go” gauge is commonly used in determining the roundwood
diameter size classes of when inventorying dead-downed woody surface fuels
using the line intersect method.
Nalder, I.A.; Wein, R.W.; Alexander, M.E.; de Groot, W.J. 1999. Physical properties of dead and downed round-wood fuels in the boreal forests of western and northern Canada. International Journal of Wildland Fire 9: 85-99.
Abstract: The quantity of dead and downed woody fuels in forests is commonly estimated using the line intersect method of sampling. Determination of the mass of wood per unit area for each size class requires values for the mean specific gravity, piece tilt angle and piece diameter. We present these values for dead and downed round-wood materials less than 7 cm in diameter based on surveys of slash and naturally fallen materials in six boreal forest regions of western and northern Canada and for eight common species in these regions. There was considerable variation in the three variables: mean specific gravity ranged from 0.34 to 0.65 Mg m–3, tilt ranged from 5˚ to 33˚, and mean squared diameter ranged from 31% below to 71% above the value at class mid-point. Values of each were strongly related to size class, species, fuel type and to region. We conclude that values derived from other study areas or species can give substantial inaccuracies in estimating dead and downed round-wood fuel loads if applied to sites within the study region, although ultimate accuracy obtainable will be more influenced by the length of sampling line. The three variables are combined into a single factor so that fuel loads can be simply calculated by multiplying this factor by the number of intersects per metre of transect.
To Order These Publications
Hard copies of all four publications mentioned here are available for free by ordering through the Canadian Forest Service On-line Bookstore at:
http://bookstore.cfs.nrcan.gc.ca/default.htm
PDF copies of the three journal articles can also be purchased. To order the Nalder et al. (1997) article from the Canadian Journal of Forest Research go to:
http://pubs.nrc-cnrc.gc.ca/cgi-bin/rp/rp2_desc_e?cjfr
To order the two International Journal of Wildland Fire articles (Nalder et al. 1999; Cruz et al. 2003) go to: