524 DISCUSSION: FORESTS, RESERVOIRS, AND STREAM FLOW 
Mr. Chitten- mile is over 300, while in the Province of Kwang Su it exceeds 800. 
den. Doubtless there are extensive areas in the Great Plain where it ex- 
ceeds 1000. The population of Rhode Island is about 450, and of 
Belgium about 590 per sq. mile, these two areas representing, prob- 
ably, the maximum densities of population in America and Europe. 
Now look at the opposite picture. When Columbus crossed the At- 
lantic, the continent of North America from the ocean to and beyond 
the Mississippi was covered with the largest unbroken primeval forest 
then existing upon the globe. The country was inhabited, and the 
race found here had been here long enough for the forces of procre- 
ation and the restraints of environment to have found their equi- 
librium.. There is no evidence that the population was increasing. 
While the estimates are uncertain, none of them give a population for 
the country as a whole exceeding one inhabitant to 7 to 10 sq. miles. 
This is what an all-forest country can support. The first thing our 
ancestors did on coming to these shores was to destroy the forests, and, 
the greatest single work ever done on this continent has been the re- 
moval of the forest and the clearing of the land for cultivation. Its 
cost in money and labor has amounted to many billions of dollars. 
Lest this illustration be construed as an argument against the 
usefulness of forests, Germany may be cited as a high type of progres- 
sive civilization, with a population of about 300 per sq. mile, and 25% 
of its area devoted to forest. Possibly that country presents the 
equilibrium between the forest and cultivated land that comes nearest 
an ideal condition. To us it seems that China might introduce wood 
into her economic life with advantage to her people, and that the plant- 
ing of trees would be of great benefit. It would not simplify in the 
least, degree the problem of her rivers, but if a portion of her territory 
could be devoted to forests, and if transportation facilities could be so 
developed that the product could be brought to the people, it would 
seem that their condition would be improved thereby. 
The history of irrigation reveals the fact that in all the countries 
here considered irrigation was practiced in very ancient times. Re- 
mains of canals, aqueducts, etc., are indisputable proof of this fact, 
and therefore of the aridity of the climate where such measures were 
necessary. In our own country the remains of ancient ditches have 
been found in Arizona, yet no one would think of attributing their 
abandonment, nor the disappearance of the people who built and used 
them, to the destruction of forests. So likewise it is wholly unjustifi- 
able to assume that the climate of these historic countries has changed, 
if at all, through any change that Man has wrought in the forests 
which are supposed to have existed there. 
The instability of industrial and commercial conditions is a 
marked characteristic of human history, and quite as much so of the 
present as of the past. Cities grow up and play a great part in the 
