Modifying the Canadian Fine Fuel Moisture Code for masticated surface fuels

2015 ◽  
Vol 24 (1) ◽  
pp. 79 ◽  
Author(s):  
T. J. Schiks ◽  
B. M. Wotton
Keyword(s):  
Moisture Content ◽  
Prescribed Burning ◽  
Small Diameter ◽  
Management Technique ◽  
Fuel Moisture ◽  
Fuel Temperature ◽  
Weather Index ◽  
Fire Weather Index ◽  
Forest Fuels ◽  
Mean Error

Mechanical mastication is a fuel management technique that disrupts the vertical continuity of forest fuels by shredding of trees and understory vegetation into a highly compacted surface fuel bed. Despite the increasing application of mastication to manage wildfire risk, there is little information to date on fuel moisture in masticated fuels and optimal ignition patterns for prescribed burning. We investigated the applicability of the Fine Fuel Moisture Code (FFMC), a component of the Canadian Fire Weather Index (FWI) System, in tracking the diurnal and day-to-day changes in masticated surface fuel moisture, and developed a calibration of the standard conversion between moisture content and FFMC via regression modelling. We also proposed several modifications to the FFMC model (including a solar radiation driven fuel temperature) to better estimate the fuel-specific parameters of small diameter (<1 cm) masticated surface fuels. Model validation was performed using destructive moisture content observations from a mastication treatment in west-central Alberta, Canada. A calibrated form of the moisture content to FFMC conversion produced mean error of –2.3% moisture content, and closely resembled previous FWI System calibrations for fast drying surface fuels. Our modified FFMC-based model fit well with field observations, and was capable of producing mean error of 1.0% moisture content. The fast drying that we observed highlights the need to better understand moisture dynamics of masticated fuel beds.

Relationships between the moisture content of fine woody fuels in lodgepole pine slash and the Fine Fuel Moisture Code of the Canadian Forest Fire Weather Index System

1988 ◽  
Vol 18 (1) ◽  
pp. 128-131 ◽  
Author(s):  
R. Trowbridge ◽  
M. C. Feller
Keyword(s):  
Moisture Content ◽  
Forest Fire ◽  
Index System ◽  
Lodgepole Pine ◽  
Fire Season ◽  
Fire Weather ◽  
Fuel Moisture ◽  
Weather Index ◽  
Fire Weather Index ◽  
Moisture Contents

Unsuccessful attempts to ignite slash resulting from the mechanical knocking down of lodgepole pine in west central British Columbia led to a short-term investigation of the relationship between the Fine Fuel Moisture Code of the Canadian Forest Fire Weather Index System and the moisture content of various fine fuel components <1 cm in diameter. Of the types of fuel sampled, the moisture contents of B.C. Forest Service fuel moisture sticks and aged slash were similar to, and well correlated (r = 0.79 and 0.81, respectively) with, the equivalent moisture content calculated from the Fine Fuel Moisture Code. The Fine Fuel Moisture Code was not designed to relate to the moisture content of uncured fuels. Thus, the moisture contents of fresh living slash (material from knocked down trees still attached to living roots) and of fresh dead slash (material unattached to living trees that had not yet experienced a complete fire season in which to fully cure) were poorly correlated with moisture content (r = 0.16 and 0.42, respectively). The moisture content of the progressively curing, needle-bearing fresh dead slash was relatively high at the beginning of the fire season, but became similar to the moisture content during the first half of July. This suggests that the Fine Fuel Moisture Code can also be used to predict the moisture content of such fine slash after these fuels have cured for approximately 3 months during the snow-free period.

scholarly journals Stand-specific litter moisture content calibrations for the Canadian Fine Fuel Moisture Code

2007 ◽  
Vol 16 (4) ◽  
pp. 463 ◽  
Author(s):  
B. Mike Wotton ◽  
Jennifer L. Beverly
Keyword(s):  
Moisture Content ◽  
Significant Influence ◽  
Forest Type ◽  
Stand Density ◽  
Fuel Moisture ◽  
Large Dataset ◽  
Weather Index ◽  
Fire Weather Index ◽  
Surface Conditions ◽  
The Relationship

A large dataset of litter moisture measurements collected at several sites across Canada by the Canadian Forest Service over the period from 1939 to 1961 is analysed. The stands in which sampling was carried out were described by three main variables: forest type (pine, spruce, Douglas fir, mixedwood and deciduous), season (spring, summer and fall), and stand density (light, moderate and dense). All three variables were found to have a significant influence on the relationship between the Canadian Forest Fire Weather Index System’s Fine Fuel Moisture Code (FFMC) and surface litter moisture. Moisture in the upper duff layer was also found to have a significant influence on the relationship between FFMC and litter moisture content, with a wetter duff layer leading to moister surface conditions than would be indicated by the FFMC value. A model for litter moisture is developed, which provides a method of adjusting the standard FFMC value for the influences of forest type, stand density, season and duff moisture content.

Calibrating the Fine Fuel Moisture Code for grass ignition potential in Sumatra, Indonesia

2005 ◽  
Vol 14 (2) ◽  
pp. 161 ◽  
Author(s):  
William J. de Groot ◽  
Wardati ◽  
Yonghe Wang
Keyword(s):  
Moisture Content ◽  
Hot Spots ◽  
Influential Factor ◽  
Fuel Moisture ◽  
Weather Index ◽  
Fire Weather Index ◽  
Ignition Threshold ◽  
The Dead ◽  
Study Sites ◽  
Central Sumatra

Grass moisture and ignition studies were conducted in central Sumatra, Indonesia, to develop an indicator of grass ignition potential using the Fine Fuel Moisture Code (FFMC) of the Canadian Forest Fire Weather Index System. Moisture content of live and dead grass was measured at three sites every 6 days over an 8-month period. Grass curing was highly variable but averaged 37–39% and often exceeded 50% from April to mid-August. Grass fuel loads averaged 420–722 g/m2. There was a highly significant decrease in dead grass moisture content with increasing FFMC, decreasing grass height, and decreasing total grass biomass. The FFMC was the most influential factor, explaining 54–61% of the dead grass moisture content variation. Ignition tests were applied to live and dead grass samples with specific moisture contents. The ignition threshold of dead and live grass occurred at 35.4% and 27.8% moisture content, respectively. The dead grass ignition threshold corresponded to FFMC values of 81.0–83.3 at the three study sites. Of historical hot spots in South-east Asia, 86% occurred when the FFMC was ≥78, representing the lower 95% confidence interval of the dead grass ignition threshold. The FFMC was calibrated using experimental results for fire management applications.

A Review of Fine Fuel Moisture Modelling

1991 ◽  
Vol 1 (4) ◽  
pp. 215 ◽  
Author(s):  
NR Viney
Keyword(s):  
Moisture Content ◽  
Liquid Water ◽  
Future Research ◽  
Fuel Moisture ◽  
Fire Behaviour ◽  
Fuel Temperature ◽  
Moisture Change ◽  
Forest Fuels ◽  
Water Models ◽  
Prediction Systems

Models describing the moisture content of forest fuels are an integral component of most fire behaviour prediction systems. In this paper, models of all aspects of moisture change in fine, dead, surface litter are examined and reviewed. Included are models describing the changes in moisture content associated with isother mal vapour exchange by sorption processes, and the effects of precipitation and condensation of liquid water. Models for predicting fuel temperature and humidity, and equilibrium moisture content are also assessed. Critical reviews of the assumptions underlying each model are made, and points of comparison and contrast explored. Some recommendations for future research are suggested.

Prediction of forest-floor moisture content under diverse jack pine canopy conditions

1989 ◽  
Vol 19 (11) ◽  
pp. 1483-1487 ◽  
Author(s):  
Z. Chrosciewicz
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Jack Pine ◽  
Fuel Moisture ◽  
Weather Index ◽  
Fire Weather Index ◽  
Moisture Contents ◽  
Straight Line ◽  
Best Fitting ◽  
Pure Surface

Moisture contents of organic forest-floor materials were studied by strata in a semimature jack pine (Pinusbanksiana Lamb.) stand in relation to their within-stand locations and changes in both duff moisture code and fine fuel moisture code, the two weather-based components of the Canadian Forest Fire Weather Index System. The resulting best-fitting curvilinear regressions (Y = aebX) of the duff moisture code showed distinctive patterns of variation so that both the surface and subsurface forest-floor strata were consistently more moist in stand openings than under stand canopy. An initial moisture inversion between the surface and subsurface forest-floor materials manifested itself near the start of the regressions wherever live Schreber's moss (Pleuroziumschreberi (Brit.) Mitt.) and litter were the combined surface materials; otherwise, pure surface litter was consistently drier than the subsurface materials. Combinations of all these materials down to mineral soil showed intermediate moisture contents both in stand openings and under stand canopy. In contrast, the best-fitting regressions of the fine fuel moisture code just for surface forest-floor strata were of the straight line (Y = a + bX) category and had generally lower r2 values than those for the corresponding curvilinear regressions (Y = aebX) of the duff moisture code.

The Canadian Forest Fire Weather Index System as a predictor of total soil moisture content as estimated by the Thornthwaite water balance

1985 ◽  
Vol 15 (6) ◽  
pp. 1194-1195
Author(s):  
Robert S. McAlpine ◽  
Thomas G. Eiber
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Balance ◽  
Forest Fire ◽  
Index System ◽  
Soil Moisture Content ◽  
Fire Weather ◽  
Weather Index ◽  
Fire Weather Index ◽  
Total Soil

Weather data from Upsala and Atikokan, Ontario, were used to determine the Canadian Forest Fire Weather Index System values and to calculate the soil moisture for two soil types using the Thornthwaite water balance. The Duff Moisture Code and the Drought Code were found to give excellent correlations with the total soil moisture content under most weather patterns.

Fire weather index system components for large fires in the Canadian boreal forest

2004 ◽  
Vol 13 (4) ◽  
pp. 391 ◽  
Author(s):  
B. D. Amiro ◽  
K. A. Logan ◽  
B. M. Wotton ◽  
M. D. Flannigan ◽  
J. B. Todd ◽  
...  
Keyword(s):  
Weather Conditions ◽  
Fire Season ◽  
Fire Weather ◽  
Fuel Moisture ◽  
Weather Index ◽  
Fire Weather Index ◽  
System Parameters ◽  
System Components ◽  
Large Fires ◽  
Canadian Boreal Forest

Canadian Fire Weather Index (FWI) System components and head fire intensities were calculated for fires greater than 2 km2 in size for the boreal and taiga ecozones of Canada from 1959 to 1999. The highest noon-hour values were analysed that occurred during the first 21 days of each of 9333 fires. Depending on ecozone, the means of the FWI System parameters ranged from: fine fuel moisture code (FFMC), 90 to 92 (82 to 96 for individual fires); duff moisture code (DMC), 38 to 78 (10 to 140 for individual fires); drought code (DC), 210 to 372 (50 to 600 for individual fires); and fire weather index, 20 to 33 (5 to 60 for individual fires). Fine fuel moisture code decreased, DMC had a mid-season peak, and DC increased through the fire season. Mean head fire intensities ranged from 10 to 28 MW m−1 in the boreal spruce fuel type, showing that most large fires exhibit crown fire behaviour. Intensities of individual fires can exceed 60 MW m−1. Most FWI System parameters did not show trends over the 41-year period because of large inter-annual variability. A changing climate is expected to create future weather conditions more conducive to fire throughout much of Canada but clear changes have not yet occurred.

Fuel management effectiveness in a mixed heathland: a comparison of the effect of different treatment types on fire initiation risk

2012 ◽  
Vol 21 (8) ◽  
pp. 969 ◽  
Author(s):  
Eva Marino ◽  
Carmen Hernando ◽  
Javier Madrigal ◽  
Carmen Díez ◽  
Mercedes Guijarro
Keyword(s):  
Moisture Content ◽  
Prescribed Burning ◽  
Structural Characteristics ◽  
Logistic Models ◽  
Minor Effect ◽  
Fuel Moisture ◽  
Fuel Management ◽  
Treatment Type ◽  
Fire Initiation ◽  
Fuel Moisture Content

Fuel management is commonly used to reduce fire risk in fire-prone shrubland, but information about the real efficacy of the different techniques is scarce. In this study, we assessed in the laboratory the effects of different treatment types on fire initiation risk in a mixed heathland. The effects of two mechanical treatments and of prescribed burning were compared with untreated vegetation. Flammability tests were performed in samples of the regenerated shrubs and fine ground fuels present 2 years after treatments. Results indicate that all treatments were effective in reducing fire initiation risk in regenerated shrubs, but not in fine ground fuels. Recovery of vegetation differed between treatments, and treatment type had a significant effect on flammability, mainly affecting fire sustainability. Wind speed had a minor effect on shrub fuel flammability, whereas fuel moisture had a significant effect. The flammability of fine ground fuels differed significantly depending on fuel moisture content, even at the low levels tested. Logistic models were fitted to predict successful fire sustainability, and the probability of initial propagation was obtained as a function of treatment type, fuel moisture content and fuel structural characteristics. This study provides new insights into wildfire prevention in shrubland, and compares the effectiveness of different fuel treatment techniques.

An index for tracking sheltered forest floor moisture within the Canadian Forest Fire Weather Index System

2005 ◽  
Vol 14 (2) ◽  
pp. 169 ◽  
Author(s):  
B. M. Wotton ◽  
B. J. Stocks ◽  
D. L. Martell
Keyword(s):  
Moisture Content ◽  
Forest Fire ◽  
Forest Floor ◽  
Jack Pine ◽  
Fire Weather ◽  
Moisture Index ◽  
Northern Ontario ◽  
Weather Index ◽  
Fire Weather Index ◽  
Overstory Trees

The Duff Moisture Code (DMC) component of the Canadian Forest Fire Weather Index (FWI) System is used by fire management agencies across Canada as an indicator of the susceptibility of the forest floor to lightning fire ignition. However, this model was developed for the moisture content of the forest floor away from the sheltering influences of overstory trees, an area where lightning strikes usually ignite the forest floor. Through destructive sampling of the forest floor in a mature jack pine stand in northern Ontario over several summers, the moisture content of the forest floor in sheltered areas close to the boles of dominant overstory trees was found to be significantly lower than in other less heavily sheltered areas of the stand. Observations from a network of in-stand rain gauges revealed that rainfall penetration through the canopy (throughfall) was correlated with both open rainfall amount and the duration of a storm. Observed throughfall amounts were used to develop a throughfall relationship for extremely sheltered locations (within ~0.5 m of the boles) in a mature jack pine stand. This throughfall model was used, along with differences in forest floor drying rate, to develop a new duff moisture index for strongly sheltered areas of the forest floor. Calculated values of this new moisture model, which has the same daily weather observation requirements as the FWI System’s DMC model, were found to match observed moisture contents quite well.

Estimating fuel response time and predicting fuel moisture content from field data

2001 ◽  
Vol 10 (2) ◽  
pp. 215 ◽  
Author(s):  
E. A. Catchpole ◽  
W. R. Catchpole ◽  
N.R.Viney ◽  
W. L. McCaw ◽  
J. B. Marsden-Smedley
Keyword(s):  
Moisture Content ◽  
Response Time ◽  
Data Sets ◽  
Fuel Moisture ◽  
Fuel Temperature ◽  
Broad Agreement ◽  
Governing Differential Equation ◽  
Using Data ◽  
Fuel Moisture Content ◽  
Western Australian

We develop a method for estimating equilibrium moisture content (EMC) and fuel moisture response time, using data collected for Eucalyptus twig litter. The method is based on the governing differential equation for the diffusion of water vapour from the fuel, and on a semi-physical formulation for EMC (Nelson 1984), based on the change in Gibbs free energy, which estimates the EMC as a function of fuel temperature and humidity. We then test the model on data collected in Western Australian mallee shrubland and in Tasmanian buttongrass moorland. This method is more generally applicable than those described by Viney and Catchpole (1991) and Viney (1992). The estimates of EMC and response time are in broad agreement with laboratory-based estimates for similar fuels (Anderson 1990a ; Nelson 1984). The model can be used to predict fuel moisture content by a book-keeping method. The predictions agree wellwith the observations for all three of our data sets.

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