diately placed in a styrofoam box with dry ice 

 and airshipped frozen to the Northern Forest 

 Fire Laboratory. There the material was 

 freeze-dried to prevent volatile loss and was 

 ground to 40 mesh in a Wiley mill. For the 

 1963 sampling, the complete plants were har- 

 vested on each sample date and all of the 

 leaves removed. A subsample of all dates was 

 then taken for analysis. The mineral and ether 

 extractive contents were determined by stand- 

 ard methods (ASTM 1956a, 1956b). I ex- 

 tracted the samples with diethyl ether at a 

 rate of 10 siphonings per hour for 8 hours. 

 The weight change of the thimble was found 

 to be more reliable than the weight of the 



flask because some extractives were apparent- 

 ly lost while the ether was being evaporated. 



The heat content of the leaves and stems 

 was determined for all of the 1963 samples 

 and 14 of the 1966-67 samples. Heat contents 

 for extracted leaves and stems were deter- 

 mined for only 14 of the 1966-67 samples 

 picked at random. Heat content of extractives 

 was determined directly (ASTM 1966) for 

 some 1963 samples, but was calculated for 

 the fourteen 1966-67 samples. All heat con- 

 tents are expressed on aii ash-free basis. Karl 

 Fischer titrations were used for the moisture 

 determinations necessary to convert data to a 

 dry weight basis (ASTM 1962). 



RESULTS 



The extractive content of chamise leaves 

 and small stems varied seasonally (figs. 4 and 

 5). The highest content for leaves (12 per- 

 cent) was recorded for the fall and the lowest 

 (8.5 percent) for the spring. A similar trend 

 occurred in the stems, with a range of 4.3 per- 

 cent to 8.9 percent. Duncan's New Multiple 

 Range Test was used to test for significant dif- 



ferences between means on different dates 

 (Steele and Torrie 1960). The results of this 

 test (table 2) show the seasonal trend to be 

 significant at the 5 percent level. The 1963 

 data were tested separately and the October 

 value was found to be different from that for 

 May. Apparently the 1963 data show a rela- 

 tionship similar to the 1966-67 data. 



Figure 4. — Seasonal trend in etiier extractives of 



cliamise leaves. 



Figure 5. — Seasonal trend in ether extractives of 



chamise stems. 



