CLIMATE AND rORKST FIRES 



969 



RATE OF MOISTURE LOSS FROM LITTER 



Litter loses moisture at a surprisingly rapid rate when exposed to sun 

 and wind. Chart 3 shows the result of a series of tests made in June 

 on samples of litter, first saturated with moisture, then exposed to sun 

 and wind and weighed at intervals at first of one-half hour and later of 



Table 3 



Summary 



Moisture Content 



Above 8 per cent Below 8 per cent 



Days Per cent Days Per cent 



Average, south slope 38.4 32.3 80.6 67.7 



Average, north slope 65.7 58.7 46.3 41.3 



For the period, litter vi^as above danger point one-third of the time on the 

 south slope, three-fifths of the time on the north slope. 



one hour until a constant air-dry weight was reached. The samples, 

 each 6 inches by 12 inches and from 1 to II/2 inches thick, were started 

 at intervals of one hour, beginning at 9 a. m. It is seen that in all 

 cases the moisture loss is extremely rapid at first. As a matter of fact, 

 the very top layer of each sample was dry enough to burn within one 

 hour after exposure, as was proved by test, and later losses were from 

 the lower layer, protected from excessively rapid dessication. Note 

 that the earlier samples had practically ceased to lose moisture by 6 



