Effect of certain chemical attributes of vegetation on forest inflammability

Abstract

Forest Service administrators and fire-research men have long felt the need of information concerning the effect of vegetation such as shrubs, grasses, and forbs (nongrasslike herbs) on the rate of spread of fires. To date, all knowledge of the subject has been acquired empirically in the field, or deduced from knowledge of fire behavior as influenced by the condition of deadwood, duff, etc. It is known that the luxuriant green vegetation of late spring and early summer does not lend itself to dangerous, fast-spreading fires, and that the matured and naturally cured or dried vegetation of September and October materially augments forest inflammability. Beyond this, the whole matter is one of conjecture. No information is available as to quantitative effects of forest undergrowth conditions on rate of fire spread, and no method has been evolved for determining readily and accurately whether these conditions at any particular time are such as would retard fire spread. Furthermore, little is known as to variation in volume of vegetation from season to season. Consequently, forest officers rating fire conditions and forecasting the approach of fire danger do not know what significance to assign to volume and condition of vegetation. Before fire danger can be properly rated on areas bearing large volumes of shrubs, grasses, and forbs, methods must be devised for evaluating these factors with reference to the spread of fire and for integrating data on these factors with measurements of the factors being utilized in fire-danger ratings at the present time - wind velocity and moisture content of dead fuels.

Citation

Richards, Leon W. 1940. Effect of certain chemical attributes of vegetation on forest inflammability. Journal of Agricultural Research. 60(12): 833-838.