30 r 



L DESOHf 

 /C^L ADSOHP 



10 20 30 40 50 60 70 80 90 100 

 RELATIVE HUMIDITY, % 



Figure 2 — EMC curves of recently cast Douglas-fir 

 needles and larch needles, plotted from Gibbs free 

 energy equations at 300 °K for relative fiumidity, 

 are compared to EMC values observed for adsorp- 

 tion, desorption, and NFDRS estimates. 



30 - 

 25 - 



20 - 



O 15 



Ui 



10 



— QA DESORP 

 QA ADSOHP 



OF DE30RP 



HFDHS 



DF ADSOHP 



J- 



10 20 30 40 50 60 70 80 90 100 

 RELATIVE HUMIDITY, % 



Figure 3 — EMC curves of weathered Douglas-fir 

 needles and weathered quaking aspen leaves, 

 plotted from Gibbs free energy equations at 300 °K 

 for relative humidity, are compared to EMC values 

 observed for adsorption, desorption, and NFDRS 

 estimates. 



25 

 20 

 15 

 10 



322 °K 



NFDRS 



J l_L 



J L 



J [ l_| 



10 20 30 40 50 60 70 80 90 100 

 RELATIVE HUMIDITY, % 



Figure 4 — Changes in EMC desorption with tem- 

 perature and humidity for aspen, cheatgrass, 

 ponderosa pine, and Douglas-fir litter, compared 

 to NFDRS estimates. 



6 



