101 
and too high a moisture content of the atmosphere, were all 
conducive to burning, and that less burning occurred on clou 
ranging from §5° 
° 
a 
“a, 
e 
the trees in forests where they are exposed to more intense light 
than elsewhere. Moreover burning is intimately associated 
with the assimilative process taking place in the leaves which is 
at its maximum during bright sunlight. 
Susceptibility to burning is also associated with the degree of 
the development of the foliage, as is shown by injurious pane 
conditions of the stomata are involved is not at present known, 
t numerous observations have shown that most gases close 
