44 



MISCELLANEOUS PUBLICATION NO. 1065, U.S. DEPARTMENT OF AGRICULTURE 



forest fires in North American history started in 

 slash left from logging and land clearing. The 

 average size of fires originating in logging waste 

 is more than seven times that of fires originating 

 in uncut areas or areas where slash has been 

 disposed of. 



Forest fires are a major concern in the United 

 States. During a typical year, there are about 

 150,000 forest fires in this country, which ravage 

 5 to 7 million acres. Of these fires, between 7,000 

 and 8,000 occur in the National forests, between 

 3,000 and 4,000 on other Federal lands, and the 

 rest on State and privately owned lands. 



Prescribed burning in forests each year pro- 

 duces about 32 cubic miles of smoke in the con- 

 vection column, while generating 6,500,000 tons of 

 particulate matter and 68,000 tons of hydro- 

 carbons. 



Wild forest fires in the average year produce an 

 estimated 160 cubic miles of smoke in the convec- 

 tion column. Such fires generate about 34 million 

 tons of particulate matter each year, largely as car- 

 bon and ash; and about 338,000 tons of hydro- 

 carbons are vaporized and condensed. 



Wild fire yields more smoke and hydrocarbon 

 per ton of fuel than prescribed burning because the 

 oxygen deficiency is usually greater during wild 

 fire burns. 



The conclusion is obvious that a way should be 

 found to dispose of logging debris so that it does 

 not become a fire hazard. The cost per ton of elimi- 

 nating this material by burning is about $1 per ton, 

 whereas disposal by chipping costs about $12 per 

 ton. 



Even prescribed burning causes problems. Ore- 

 gon-Washington applegrowers have filed suit 

 against the U.S. Forest Service because they claim 

 smoke from prescribed fires prevents proper ap- 

 ple coloration. Police in several Southern States 

 have complained that smoke from prescribed fires 

 has been a significant cause of automobile acci- 

 dents. Smoke from forest fires closes a number of 

 airports each year. Recreation activities are dis- 

 couraged. 



If trash from trees is not burned, it may become 

 a serious source of disease organisms. Elm logs 

 killed by Dutch elm disease and oak logs killed by 

 oak wilt must be destroyed or treated to prevent 

 vector transmission of the disease to healthy trees. 

 The log disposal problem from trees killed by 

 Dutch elm disease is monumental. In Nassau 



County, N.Y., 3,000 trees die per year and must 

 be burned, buried, or treated with insecticides. 

 Similar conditions exist in all Eastern and Mid- 

 western States. 



Roots of conifers killed by Fomes annosus and 

 Porta weirii root rots are sources of new infections 

 for many years. 



Felled oaks with Strumella cankers must be de- 

 stroyed to prevent f ruiting and spread of the path- 

 ogen. 



The need to dispose of logging debris and dead 

 trees is urgent. It would be desirable to have meth- 

 ods for disposal alternative to burning, but the 

 probability of discovering such alternatives that 

 have economic feasibility appears to be low. 



Processing Wastes 



Wastes from food- and fiber-processing plants 

 can vary tremendously in potential for pollution. 

 Research at Louisiana State University (22) 

 showed that liquid Avastes from asparagus canning 

 have a BOD of not more than 100 p.p.m. whereas 

 the BOD for waste from squash canning would 

 run as high as 4,000 to 11,000 p.p.m. A sample from 

 concentrated pea vine ensilage juice was reported 

 to have a BOD of 75,000. These figures must be 

 evaluated in terms of water quality standards to 

 the effect that stream water with a BOD of 5 

 p.p.m. is looked upon as being of doubtful purity. 



Oxygen-demanding wastes from processing of 

 agricultural and forestry products include runoff 

 or effluent from sawmilling; pulp, paper, and 

 fiberboard manufacturing; fruit and vegetable 

 canning; cleaning of dairies; slaughtering and 

 processing of meat animals; tanning; manufactur- 

 ing of cornstarch and soy protein ; sugar refining ; 

 malting, fermenting, and distilling; scouring of 

 wool; and wet processing in textile mills. These 

 wastes on entering a stream may be of such con- 

 centration in terms of BOD as to make the water 

 unattractive, unpleasant, unesthetic, anaerobic, 

 and reeking with the redolence of fetid putrescence. 



There are difficulties in appraising the signifi- 

 cance of processing wastes in terms of p.p.m. BOD 

 in the effluent since degree of dilution by water 

 used during processing will be a primary deter- 

 minant. It is preferable to evaluate water pollution 

 potential of these wastes in terms of pounds of 

 BOD required for wastes produced from a given 

 amount of product processed. 



