60 - 

 55 - 



50 - Legend: 



12 24 36 48 60 72 84 96 108 



Time in seconds 



Figure 5. --The weight-loss curve for the small-scale burning tests. 



High ash content of the treated leaves corresponded with a decrease in the 

 pyrolytic rate and an increase in residue, or a reduction in volatile production. The 

 cellulose endotherm and exotherm in the DTA analysis were smallest for the treated 

 leaves. Similar results are observed when pure cellulose is treated with inorganic 

 contaminants (2) . Apparently the cellulose in natural fuel responds to treatment in the 

 same way as pure cellulose. However, in tests of the treated leaves, the temperatures 

 at which pyrolysis occurred did not change with treatment as they did in tests of 

 cellulose . 



The results of the small-scale burning tests tended to agree with those of the TGA 

 curves in N2 and air. The maximum and average weight loss rates and energy release 

 rates were lowest for treated foliage and highest for dead foliage. The differences 

 between treatments seem to be greater in the burning tests. This could be due to the 

 effects of the nonpyrolytic volatiles on the combustion rate. Extractives would have 

 little effect on the TGA curves because they volatilize well below 200° C. 



Conclusions 



1. Herbicide-treated foliage of guava had a higher ash content and a lower ether- 

 extractive content than green leaves or naturally killed leaves. 



6 



