636 
Journal of Agricultural Research vot xxiii, no . a 
When the third chartings were made most of the vegetative growth 
for the season had taken place. Nevertheless, it will be seen that in 
each year there were more squares containing grasses on the burned than 
on the unburned areas. The variation from year to year is no more 
than would normally be expected, since it is a well known fact that the 
amount of vegetation produced in any area may vary from io to 40 
per cent. The variations shown in these tables are probably due, there¬ 
fore, to seasonal conditions rather than to treatment. 
Burning seems to have resulted in a decrease in the number of sedges, 
as they are decidedly fewer in the last two years of the experiment 
than in the first and second years. The number has increased somewhat 
on the unburned section. Since the number to begin with was less 
on the unburned areas, the effect of burning on these plants is not entirely 
clear. In this pasture, sedges are not common enough to be an important 
factor and hence no great importance can be attached to the changes 
so far recorded. 
In order to give an idea of the changes in composition that are taking 
place on the two plots, Table III, which shows the species of grasses 
and sedges and their abundance in 1918 and in 1921, has been prepared. 
TabIvE III.— Average composition of all quadrats on burned and unburned areas in igi8 
and in IQ21 (third charting) 
Species. 
Big bluestem. 
Little bluestem. 
Side oats grama... . 
Kentucky bluegrass 
Others 1 . 
Sedges 2 . 
Total grasses. 
1 Principally Sporobolus heterolepsis Gray. 
* Principally Carex pennsylvanica tam. and Carex meadii Dewey. 
Burned area. 
Unburned area. 
June 3, 
July 1, 
June 3, 
July 1, 
1918. 
1921. 
1918. 
1921. 
Squares. 
Squares. 
Squares. 
Squares. 
165 
138 
133 
232 
265 
394 
308 
122 
88 
12 
40 
II 
15 
42 
O 
135 
5 
66 
5 
24 
145 
US 
73 
145 
538 
652 
486 
5 2 4 
The most marked effect of burning has been to decrease the amount 
of big bluestem and increase the amount of little bluestem. The decrease 
in big bluestem is especially noteworthy in view of its tendency to in¬ 
crease on the unburned plot. This ohange is very noticeable when the 
plots are examined. There has been an increase of 48 per cent in little 
bluestem on the burned plot and a decrease of 60 per cent on the un¬ 
burned plot. Side oats grama decreased in both cases but the decrease 
is much greater on the unburned plots. No Kentucky bluegrass was 
recorded on the unbumed plots in 1918 but in 1921 there were 135 
squares containing this grass. On the burned plot there were 15 squares 
in 1918, but only 42 in 1921, a very small increase as compared with the 
unburned plots. Chief among the grasses listed as “others” is Sporo¬ 
bolus heterolepis . The amount of this grass present in the burned area 
is quite noticeable and it appears to be increasing. 
It is probable that those grasses which start earliest in the spring 
are injured most. The injury by burning no doubt kills some plants and 
