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WHITFORD. 
INTRODUCTION. 
An estimate of the capacity of any region to produce and maintain a 
virgin forest presupposes a standard of comparison by which to judge 
success in forest growth. 
What is meant by success depends on the investigator’s standpoint. 
Those who critically examine forest growth can, I think, be roughly 
divided into four classes. These are systematic botanists, ecological bot- 
anists, lumbermen, and foresters. The systematic botanist would usually 
consider the most successful forest to be that which contains on a unit 
of surface the greatest number of species of all kinds from the ground to 
the tops of the highest trees. On the above idea, variety in species and 
form are the main points considered. Thus the forest is composed of 
a great many species assuming in outline a great many forms, such as 
lichens, mosses, liverworts, herbs, epiphytes, parasites, climbing bamboos 
and palms and dicotyledonous trees. He usually brings his material 
together in the form of a “flora,” associating plants in groups or families. 
Thus a qualitative analysis is made of the forest. The idea of bulk is 
expressed in vague terms, associated with different species, like “common” 
or “abundant,” “a large tree,” “a liana,” etc. A brief description of 
the region usually precedes the lists of plants. This is the conventional 
idea of the tropical forests and those people, who disregard value as an 
element of success would place such a forest as the most successful in 
the world. 
The ecological botanist will consider habitat as well as vegetation. He 
will divide the forest into formations or societies, or types, corresponding 
to the different habitats, and then describe each forest type in greater or 
less detail, calling attention qualitatively, and more or less quantitatively, 
to the composition of the forest. He may or may not make an attempt 
to measure, or express in some way, the factors of the habitat. To him 
the best physical and biotic conditions produce the best or most successful 
forest which he calls a mesophytic forest. The idea of “succession” may 
or may not be considered. In the above ideas there is little or no attempt 
to measure the amount of vegetation per unit of surface, hence they may 
be designated as qualitative standards in distinction from the quantitative 
standards, viz, the standard of the lumberman and the forester. 
The lumberman takes into consideration “value” as an element of 
success in forest growth. Any given forest would be judged by the trees 
suitable for his needs and the rest would be considered as “weed trees.” 
As the cost of handling a large amount and a few kinds of lumber is 
less than in handling a small amount and many kinds on any given area, 
he desires to obtain a great bulk of one or of very few kinds of timber 
per unit of area. To him the most successful forest in the world would 
be the greatest amount of the most valuable timbers of the most con- 
