Abstract 



Predicted rates of fire spread using a mathematical model 

 were consistently greater but in reasonably close agreement with 

 rates observed on test fires in ponderosa pine and Douglas-fir 

 slash. Fuel loading, bulk density, particle density, particle 

 surface-to-volume ratio, heat content, total plant salt content, 

 siUca-free salt, fuel moisture, and wind velocity were deter- 

 mined as input variables for the test on plots containir^ slash 

 with and without needles, and at two loadings and three depths. 

 Fuel discontinuities and inadequate knowledge of fuel moisture 

 contents that limit ignition are discussed as the primary reasons 

 for the deviations. One-haLf of the total fuel weight loss in the 

 flame front was accounted for by particles less than 1 cm. in 

 diameter. A multiple regression for predictir^ flame length is 

 provided. 



