DISCUSSION AND CONCLUSIONS 



Two flame retarding chemicals, DAP and 

 AS, reduced the intensity of large wood crib 

 fires. The DAP treatments were somewhat 

 more effective. However, DAP greatly in- 

 creased particulate production. The AS treat- 

 ments had much less effect on particulate for- 

 mation. Total organic residue was increased 

 by DAP treatment; it amounted to as much as 

 14 percent original organic weight. 



As conditions for slash burning are present- 

 ly dictated from a control standpoint, it is 

 being done at low intensities and at times 

 when weather conditions are not conducive to 

 minimum air pollution. This burning results in 

 large amounts of smoke, poor fuel consump- 

 tion, and public displeasure. It might be pos- 

 sible to control intensity during the drier 

 months, keep smoke production down, and 

 insure more complete combustion by chemi- 

 cally treating the slash. Obviously, DAP 

 would not do the job. 



This study supports the possibility that 



DAP does polymerize the tars and make them 

 more thermally stable. If these tars become 

 less available to combustion, they will add to 

 the particulate in the effluent. Apparently, a 

 large amount of the phosphate ends up as 

 some form of phosphorus in the particulate. 

 The question of why AS and DAP act differ- 

 ently in particulate formation might parti- 

 ally be answered by continued study of the 

 effects of phosphate on the tars. 



Future research starting with determina- 

 tion of the difference in retarding mechanisms 

 (and therefore in particulate and residue pro 

 duction) between AS and DAP could lead to 

 the development of chemicals that catalyze 

 glowing to the point of practically no flaming 

 or effluent. 



The importance of fire in the forest is be- 

 coming more evident every day. Perhaps fu- 

 ture research and land management personnel 

 should be directed more toward fire controls 

 rather than to "alternatives to fire." 



14 



<r U.S. GOVERNMENT PRINTING OFFICE: 1972-780-623/80 REGION NO 



