If a second greenup occurs during a growing season, the XIOOO value is again set 

 equal to the 1000-h TL fuel moisture, and the same greenup procedure is followed, ex- 

 cept the herbaceous moisture increases from its current value instead of the 1-h TL FM. 



After the greenup period is complete, (GREN = 1.0] the herbaceous fuel moisture 

 is calculated from: 



HFM = HERBGA + HERBGB * XIOOO 



until the user specifies that the herbaceous vegetation has cured phenologically , or 

 frozen.^ Then the herbaceous fuel moisture is again equal to the 1-h TL fuel moisture. 



Figure 4 illustrates the relationship between the XIOOO value and the annual and 

 perennial herbaceous moistures. 



Figure 4. — An example of the relationship between the XIOOO VALUE, and aalaulated mois- 

 ture content of annual and perennial herbaceous plants. All herbaceous moisture 

 follows the 1-h TL fuel moisture before green-up and after curing or freezing. 



^"Green, cured" and "frozen" are always specified manually by AFFIRMS users. But 

 in FIRDAT, which is used to process historical data, the user defines a date after which 

 a freeze is possible. The specific date of the freeze is defined by one of two "freezing" 

 criteria : 



1. Five days (nonconsecutive) with a minimum temperature <_ 32°F (0°C] 



2. One minimum temperature <_ 25°F (-4°C) 



9 



