preservation of forests: judicious burning. 317 
4. Preservation of the forests and encouragement to 
tree planting. — Without entering into a discussion as to the value 
of forests in ameliorating climate, and fully conscious that they must 
succeed rather than precede such amelioration^ in other words, that it 
is impossible, as a rule, to cultivate forests or extend them successfully 
in arid regions without first supplying the requisite conditions of moist- 
ure ; we nevertheless fully appreciate the great importance of preserv- 
ing as far as possible the timber already sparsely existing in the regions 
we are considering, and also the desirability of extending it, as a se- 
quence and valuable outgrowth of the increased irrigation we have just 
been advocating. There are also many sections of the West, especially 
near the limit line of the distribution of the Locust, where timber growth 
is spontaneous whenever the prairies are protected from the annual fires 
which usually sweep over them and hinder forest extension. These 
facts add weight to all efforts looking either to increased irrigation or 
judicious restriction and use of fire. 
5. Judicious burning. — In this connection we find little occasion to 
materially modify our views expressed in our first report and repeated 
on page 272, ante. In order not to overestimate the practical benefits 
that may arise from judicious burning Mr. Thomas lias brought together 
in Chapter II (pp. 1G-18) the strongest possible arguments against its 
practicability, and, after giving these due weight, it yet remains true 
that in thus burning we have one of the most, if not the most, inexpen- 
sive ways of temporarily checking locust increase in many parts of the 
country where the insect freely breeds. Xo amount of theoretical ob- 
jections or of unsatisfactory results, often due to imperfect or injudicious 
burning, can offset the beneficial results that may be obtained with care 
and under favorable circumstances. The writer himself has personally 
witnessed the slaughter of myriads of locusts in this way, and this mode 
of reducing the numbers of the destructive hordes in their natural hab- 
it at once forces itself upon the attention of all who have had experience 
in that country. The fact that locusts are not destroyed in very great 
numbers in the Temporary region is due to the fact that the eggs are 
not laid in this region in the ground covered with dense, long or prairie 
grasses. The insects would be destroyed by burning were they there. 
In the more humid prairie country, bare dry spots are preferred for 
oviposition ; but in the Permanent region the insects wdl abound most 
where the vegetation is rankest and most succulent. A study of Map 
I will give an approximate idea of the amount of land in the plaius area, 
the vegetation of which is susceptible of being burned over, and wilt 
also show that it includes all the more arable and valuable land for set- 
tlement — a fact of great importance. 
In the plains area proper there is little or nothing to prevent whole- 
sale burning of the vegetation late- in the spring, after the bulk of the 
locusts have hatched out, beyond the expense of preventing such burn- 
ing the previous fall. The only practical way in which this could be done 
