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Full-Text Articles in Physical Sciences and Mathematics
Old Growth Ponderosa Pine And Western Larch Stand Structures: Influences Of Pre-1900 Fires And Fire Exclusion, United States Department Of Agriculture, Forest Service
Old Growth Ponderosa Pine And Western Larch Stand Structures: Influences Of Pre-1900 Fires And Fire Exclusion, United States Department Of Agriculture, Forest Service
Forestry
Presents detailed age structure for two western larch stands that historically experienced frequent fires. Compares age structures of eleven ponderosa pine and western larch stands representing a broad range of sites that had frequent fires. Interprets causal factors possibly linked to variations in stand age structures.
Fire-Bgc -- A Mechanistic Ecological Process Model For Simulating Fire Succession On Coniferous Forest Landscapes Of The Northern Rocky Mountains, United States Department Of Agriculture, Forest Service
Fire-Bgc -- A Mechanistic Ecological Process Model For Simulating Fire Succession On Coniferous Forest Landscapes Of The Northern Rocky Mountains, United States Department Of Agriculture, Forest Service
Forestry
An ecological process model of vegetation dynamics mechanistically simulates long-term stand dynamics on coniferous landscapes of the Northern Rocky Mountains. This model is used to investigate and evaluate cumulative effects of various fire regimes, including prescribed burning and fire exclusion, on the vegetation and fuel complex of a simulation landscape composed of many stands. Detailed documentation of the model FIRE-BGC (a FIRE BioGeoChemical succession model) with complete discussion of all model parameters is followed with results of an application of the FIRE-BGC to a whitebark pine landscape in the Bob Marshall Wilderness complex. Simulation results of several management scenarios are …
Relative Corrosivity Of Currently Approved Wildland Fire Chemicals, United States Department Of Agriculture, Forest Service
Relative Corrosivity Of Currently Approved Wildland Fire Chemicals, United States Department Of Agriculture, Forest Service
Wildfires
From the early stages of the development of chemicals for wildland fire control, damage from fire retardant corrosion was recognized as a serious problem. Extensive damage was done to equipment used in the handling, mixing, storing, and delivery of retardants (Davis and Phillips 1965; USDA FS 1964a). Corrosion-related damage, especially to aircraft, creates unsafe conditions. Preventing this damage reduces the potential risk of injury and death; moreover, everyone benefits from reduced expenditures for equipment repair and replacement.
Effects Of Prescribed Fire On Biomass And Plant Succession In Western Aspen, United States Department Of Agriculture, Forest Service
Effects Of Prescribed Fire On Biomass And Plant Succession In Western Aspen, United States Department Of Agriculture, Forest Service
Forestry
Biomass of grasses, forbs, shrubs, and aspen suckers was determined annually for three prescribed fires in aspen and aspen-conifer forests in southeastern Idaho and western Wyoming. Fires ranged from low to high severity and overstory mortality from 20 to 100 percent. Over 4 postburn years, production of grasses and forbs averaged 1.5 to 3.3 times that of controls. After 5 years, shrub biomass was 21 to 100 percent of preburn biomass. The varied patterns of seral vegetation and their management implications are discussed.
Modeling Moisture Content Of Fine Dead Wildland Fuels: Input To The Behave Fire Prediction System, United States Department Of Agriculture, Forest Service
Modeling Moisture Content Of Fine Dead Wildland Fuels: Input To The Behave Fire Prediction System, United States Department Of Agriculture, Forest Service
Wildfires
A method for predicting the time-dependent nature of fine fuel moisture is badly needed to support fire behavior prediction systems used in fire management. Of the models available, none met all the requirements of the BEHAVE fire behavior prediction system. The Canadian Fire Fuel Moisture Code (FFMC) came closest to meeting our needs and was selected as a base model. Improvements to the FFMC were concentrated on providing a means of accounting for annual and diurnal variation due to solar heating of woody fuels. This was necessary because the FFMC was developed for fuels located within forest stands, a generally …
Visitor Attitudes Toward Wilderness Fire Management Policy -- 1971-84, United States Department Of Agriculture, Forest Service
Visitor Attitudes Toward Wilderness Fire Management Policy -- 1971-84, United States Department Of Agriculture, Forest Service
Wildfires
The historical role of naturally occurring fire in shaping the character of many American landscapes has become an accepted ecological principle. Prior to the coming of the Europeans, natural fires had a major influence in producing a variety of vegetational mosaics. Fire suppression policies of the 20th century, however, significantly changed the evolution of many landscapes compared to what would have occurred had natural fires been allowed to continue. Although natural fires can no longer be allowed to burn in many places because of resource values or danger to the public, such fires may be permitted in many wildernesses and …
Predicting Duff And Woody Fuel Consumed By Prescribed Fire In The Northern Rocky Mountains, United States Department Of Agriculture, Forest Service
Predicting Duff And Woody Fuel Consumed By Prescribed Fire In The Northern Rocky Mountains, United States Department Of Agriculture, Forest Service
Forestry
This paper presents numerical relationships of known precision for predicting duff consumption. They were established by assembling and analyzing data from three previous prescribed fire investigations and then testing them against other published data. Fuel loadings by diameter classes that differed among the studies were converted to a common set of diameter classes. The purpose of assimilating data from several studies was to develop predictive models that could be easily used by practitioners and that would apply over a wide range of conditions.
Llaffs - A Lightning-Locating And Fire-Forecasting System, United States Department Of Agriculture, Forest Service
Llaffs - A Lightning-Locating And Fire-Forecasting System, United States Department Of Agriculture, Forest Service
Forestry
This publication contains programs and documentation to implement an algorithm for calculating lightning fire probability. This calculation is based on a model originally developed for the National Fire-Danger Rating System. The model algorithm estimates the probability that a lightning discharge from cloud to ground will ignite a fire in fuels at the ground terminus of the lightning. Probability is estimated using variables that are measures of the fuel state and type, rain, and lightning. Details of the model can be found in Fuquay and others (1979), Latham (1979), and Fuquay (1980).
Fire Behavior In Nonuniform Fuels, United States Department Of Agriculture, Forest Service
Fire Behavior In Nonuniform Fuels, United States Department Of Agriculture, Forest Service
Wildfires
For the purposes of this study, nonuniform fire behavior is predicted by modeling fire spread through a hexagonal network of fuel cells. Fire spread is assumed to be a process of contagious growth between cells. Fuel properties are allowed to vary from cell to cell in a prescribed manner but have uniform properties within the cell. Consequently, the nonuniformity of the actual fuel array is simulated through cell to cell variations and has a resolution limited by the cell size. Because of the nature of the modeling process, it is necessary to devise a scheme for collecting data describing nonuniformity …
Fire - Decay: Interactive Roles Regulating Wood Accumulation And Soil Development In The Northern Rocky Mountains, United States Department Of Agriculture, Forest Service
Fire - Decay: Interactive Roles Regulating Wood Accumulation And Soil Development In The Northern Rocky Mountains, United States Department Of Agriculture, Forest Service
Wildfires
Decay and fire play interactive roles in recycling wood and other organic materials in forest ecosystems, and contribute to the development of high quality soils in the Northern Rocky Mountains. Decayed wood, charcoal, and other decomposed organic matter are the principal media for ectomycorrhizal and nonsymbiotic nitrogen fixing microbes. The activities of these microbes are critical to the growth of forest trees. The balance between decay and fire, as it affects the amount, distribution, and type of organic matter, controls the ability of forest soils to support the growth of trees.
A Model For Predicting Lightning-Fire Ignition In Wildland Fuels, United States Department Of Agriculture, Forest Service
A Model For Predicting Lightning-Fire Ignition In Wildland Fuels, United States Department Of Agriculture, Forest Service
Wildfires
A model has been developed for predicting the number of lightning-fire ignitions in wildland fuels. The model is based on both stochastic and physical processes. Stochastic methods are used to generalize the lightning storm characteristics and site conditions that affect the potential for ignition. Physical processes are involved in determining the ignition probability of woody fuels by individual lightning events. Input required to operate the model includes lightning activity, upper air windspeed (storm movement), fuel moisture, and fuel bulk density. The model can be used either to predict ignitions at some future time by using forecast data or to estimate …
Predicting Slash Depth For Fire Modeling, United States Department Of Agriculture, Forest Service
Predicting Slash Depth For Fire Modeling, United States Department Of Agriculture, Forest Service
Forestry
Slash or debris created by harvesting and thinning are a major fire management problem because these residues can create unacceptable fire behavior hazards. Treating slash to maintain an acceptable fire hazard is expensive and requires skillful decisionmaking. An inexpensive, simple-to-use, yet objective means of appraising the potential fire behavior of slash is added to aid decisions in managing slash. Knowledge of potential fire behavior can help determine treatment alternatives, the financing of slash treatment activities, and even determine whether the slash should be created. This report describes a method for predicting depth of slash fuels for analytical modeling of fire …