Transfer of Fuel Between Live and Bead Categories - All the herbaceous fuel load 

 is included in the 1-h TL fuel load before greenup. During greenup, the live herbaceous 

 fuel load is transferred from the 1-h TL to the live fuel category as the herbaceous 

 moisture increases from 30 percent to 120 percent. The herbaceous fuel load is at its 

 maximum and the 1-h TL fuel load at its minimum when the herbaceous moisture is greater 

 than 120 percent. 



As herbaceous plant moisture decreases later in the growing season, the load of 

 perennial herbaceous fuels is shifted between the live and dead fuel categories as its 

 moisture varies between 120 percent and 30 percent. This is the transition stage; 120 

 percent is an approximate value, serving as the upper limit for transition because it 

 roughly defines the moisture content at which new growth is complete and the foliage 

 is mature. Thirty percent was defined as the minimum moisture for transition because 

 that is the approximate fiber saturation point, below which herbaceous plants are 

 assumed to be dead. 



For annual herbaceous plants, the process differs slightly. After greenup, the 

 moisture content of annuals is not allowed to increase, so the fuel load for annuals 

 then transfers from the live category to the dead category; never in the reverse direc- 

 tion as allowed with perennials. At 30 percent moisture content, all the herbaceous 

 fuels have been added back into the 1-h TL class, i.e., after phonological curing or 

 after a freeze in the fall. 



The fuel load transfer equations are: 

 WIDP = WID + WHERE * FCC 

 WHERBC = WHERE * (1.0 - FCC) 

 where: FCC = -0.111 * HFM + 1.33 and £ FCC £l.O 



and WIDP = total load of 1-h TL fuel, including dead herbaceous fuel transferred 



to the 1-h TL category 



WID = load of the 1-h TL fuel before inclusion of any cured herbaceous 

 material 



WHERE = total load of herbaceous fuel 



FCC = fraction of the herbaceous fuel that is to be transferred to the 1-h 

 TL class 



WHERBC = load of herbaceous fuel that is still green 



HFM = herbaceous fuel moisture 



Figure 5 shows herbaceous fuel load changes in relation to moisture content 

 changes . 



10 



