Woody Fuel and Duff Consumption by Prescribed Fire in Northern Idaho Mixed Conifer Logging Slash


Book Description

Experimental burns were conducted on 36 plots in mixed conifer logging slash in northern Idaho to investigate consumption of duff and woody fuel. Prescribed fires were conducted in spring and fall, in YUM (yarded unmerchantable material) and non-YUM clearcuts and seedtree cuts. Preburn and postburn fuel loadings were measured, and fuel moistures were sampled shortly before burning. Preburn duff depth ranged from 1.2 to 2.6 inches. Preburn woody fuel loadings ranged from 28 to 86 tons/acre. Sixty-four percent of the duff was consumed. Most of the small woody fuel was consumed, along with an average of 15.5 tons/acre of large woody fuel. Postburn mineral soil exposure averaged 66 percent. Residual loading of large woody fuel averaged 31 tons/acre. Methods for predicting duff and woody fuel consumption are reported. For predicting percentage of duff reduced, the best independent variables were shallow duff moisture content and unit average diameter reduction of large woody material. For predicting duff depth reduction, the best independent variables were average duff moisture content and preburn duff depth. Diameter reduction of large woody fuel was best predicted using moisture content and average preburn diameter as independent variables. Guidelines are included for fire prescription development. These include recommendations for amounts of fuel to retain and to consume and discussion of tradeoffs in setting fire objectives. Equations are presented for computing moisture contents.




Woody Fuel and Duff Consumption by Prescribed Fire in Northern Idaho Mixed Conifer Logging Slash


Book Description

Experimental burns were conducted on 36 plots in mixed conifer logging slash in northern Idaho to investigate consumption of duff and woody fuel. Prescribed fires were conducted in spring and fall, in YUM (yarded unmerchantable material) and non-YUM clearcuts and seedtree cuts. Preburn and postburn fuel loadings were measured, and fuel moistures were sampled shortly before burning. Preburn duff depth ranged from 1.2 to 2.6 inches. Preburn woody fuel loadings ranged from 28 to 86 tons/acre. Sixty-four percent of the duff was consumed. Most of the small woody fuel was consumed, along with an average of 15.5 tons/acre of large woody fuel. Postburn mineral soil exposure averaged 66 percent. Residual loading of large woody fuel averaged 31 tons/acre. Methods for predicting duff and woody fuel consumption are reported. For predicting percentage of duff reduced, the best independent variables were shallow duff moisture content and unit average diameter reduction of large woody material. For predicting duff depth reduction, the best independent variables were average duff moisture content and preburn duff depth. Diameter reduction of large woody fuel was best predicted using moisture content and average preburn diameter as independent variables. Guidelines are included for fire prescription development. These include recommendations for amounts of fuel to retain and to consume and discussion of tradeoffs in setting fire objectives. Equations are presented for computing moisture contents.
















Wildland Fires and Air Pollution


Book Description

Wildland fires are one of the most devastating and terrifying forces of nature. While their effects are mostly destructive they also help with regeneration of forests and other ecosystems. Low-intensity fires clear accumulating biomass reducing risk of catastrophic crown fires and can be used as an effective management tool. This book presents current understanding of wildland fires and air quality as well as their effects on human health, forests and other ecosystems. in the first section of the book the basics of wildland fires and resulting emissions are presented from the perspective of changing global climate, air quality impairment and effects on environmental and human health and security. in the second section, effects of wildland fires on air quality, visibility and human health in various regions of the Earth are discussed. The third section of the book deals with complex issues of the ecological impacts of fires and air pollution in forests and chaparral in North America. The fourth section discusses various management issues facing land and fire managers which are related to wildfires, use of prescribed fires, and air quality. This section also presents various modeling systems used for describing fire dangers and behavior as well as smoke and air pollution predictions applied in the risk assessment analysis. The book concludes with a series of expert recommendations for wildland fire and atmospheric research.




Wildland Fire Behaviour


Book Description

Wildland fires have an irreplaceable role in sustaining many of our forests, shrublands and grasslands. They can be used as controlled burns or occur as free-burning wildfires, and can sometimes be dangerous and destructive to fauna, human communities and natural resources. Through scientific understanding of their behaviour, we can develop the tools to reliably use and manage fires across landscapes in ways that are compatible with the constraints of modern society while benefiting the ecosystems. The science of wildland fire is incomplete, however. Even the simplest fire behaviours – how fast they spread, how long they burn and how large they get – arise from a dynamical system of physical processes interacting in unexplored ways with heterogeneous biological, ecological and meteorological factors across many scales of time and space. The physics of heat transfer, combustion and ignition, for example, operate in all fires at millimetre and millisecond scales but wildfires can become conflagrations that burn for months and exceed millions of hectares. Wildland Fire Behaviour: Dynamics, Principles and Processes examines what is known and unknown about wildfire behaviours. The authors introduce fire as a dynamical system along with traditional steady-state concepts. They then break down the system into its primary physical components, describe how they depend upon environmental factors, and explore system dynamics by constructing and exercising a nonlinear model. The limits of modelling and knowledge are discussed throughout but emphasised by review of large fire behaviours. Advancing knowledge of fire behaviours will require a multidisciplinary approach and rely on quality measurements from experimental research, as covered in the final chapters.