THE FORMATION OF FORESTS 137 
soil at one time is objectionable. It is an excellent 
system for the production of park effects where vari- 
ety is desirable. In this system the best is constantly 
favored. It isa process of weeding out the poor kinds 
and favoring the good. The French, in fact, call it 
(455 = ye?) 
jardinage, 
or gardening. It is just the opposite 
of what has been practised heretofore in this coun- 
try. In our mixed forests the owner often sells 
one species to one man and another to another man, 
and so on till everything of any value whatever has 
been removed. The tree weeds, or worthless spe- 
cies, with the increase of room and light, grow with 
great vigor until in time they may have complete pos- 
session of the soil. In the selective system, by judi- 
cious cutting here and there, wherever possible, and 
whenever financial conditions permit, the weeds are 
eut, and the forest is gradually rendered of greater 
value and of better appearance. To practise this sys- 
tem in an intensive way requires a great deal of skill 
and a great deal of supervision. One must know well 
how the different species act in varying quantities 
of light, since the amount of light determines the 
amount of seed and the kind of young growth which 
will follow. It requires, in other words, a knowledge 
of the science of ecology. This word comes from the 
Greek oikos, a house. It treats of the correlations of 
organisms inhabiting the same locality. It is, in 
