This paper presents formulae tables, and figures that can be used to estimate the ratio of mean windspeed acting on the flame from a spreading wildland fire to the mean windspeed 20 ft (6 m) above the vegetation cover. The formulae are based upon the logarithinic windspeed variation law characteristic of constant shear turbulent flow, and are restricted to flat terrain with uniform, continuous vegetation cover.By equating integrated bulk drag due to crown foliage to the shear stress at the top of the crown layer, a model for relating windspeed within and below a uniform forest canopy to windspeed 20 ft (6 m) over the canopy is developed. Important variables in this model include stand height, crown closure, foliar surface/ volume ratio, and crown bulk density. Comparison of model predictions with reported experimental measurements shows good agreement.

As part of the development of a model for predicting fuel loading reductions by and intensity histories of fires burning in large woody natural fuels, it was necessary to develop separate models for the processes of ignition and rate of burning of individual fuel elements. This paper describes the derivation of predictive equations for ignition delay time and burning rate (from diameter reduction rate) of large woody natural fuels in a fire environment. The method consists of deriving approximate functional forms using fuel component properties and a measurable ''fire environment temperature'' and then fitting these forms to data taken in laboratory fires using a large propane burner. The equations describe the calibration data with precision adequate for the purpose for which they were designed.

This paper outlines the subject matter of research on the physics and phenomenology of' wildland fire, focusing on topics that bear upon issues of fire control and fire safety. Motivations for research on fire phenomenology are identified as arising from the activities necessary to achieve fire-related objectives, including acceptable levels of fire safety. Differences in the activities, techniques, and tactical objectives for control and prevention of' fires in natural fuels and in manmade structures are noted. Sources of wildland fire research information and operational planning aids are identified, and some cautions are ventured concerning their use by nonspecialists.

This paper presents a mathematical formulation of the construction of a containment perimeter for a wildland fire. The formulation permits the calculation of total burned area, final perimeter, and containment time, if the rate of growth of the fire can be specified as a function of time and position. Using a simple but flexible fire shape function, numerical results are given, showing the influence of the rate of spread in the front, flank, and back directions expressed in ratio to the rate of control line construction. These results may be useful in presuppression planning and effectiveness analyses. This paper is the result of collaborative effort carried out as part of theU, S. /U. S. S, R. scientific-technical exchange program in forestry. of the computational methods laboratory, and members of his staff, including Ms. E. H. Gorovaya, on the analysis presented in this paper. The group formulated the scope of the analysis, methods of computation, and mathematical expressions. Numerical results were generated independently and compared later. This paper, in Russian, is included in the annals of the Leningrad Institute for 1977. The translation presented here should be useful in tactical planning for forest fire suppression, a matter of practical importance in both countries.

after 12 years of pure and applied research and systems analysis both in private industry and at the nonprofit Institute for Defense Analyses. JAMES K. BROWN received his bachelor's degree from the University of Minnesota in 1960, his master's from Yale University in 1961, and his Ph.D. from the University of Michigan in 1968, all in forestry. From 1961 to 1965 he did research on field measurement of fuel properties and fire-danger rating systems while with the Lake States Forest Experiment Station. In 1965, he transferred to the Northern Forest Fire Laboratory, Missoula, Montana, where he is responsible for research on the physical properties, inventory, and prediction of fuels.