INTRODUCTION 
E DO Nort have to be scientists to recognize the value of trees to life. 
From the scientist we can (and ought to) learn of this vital relationship 
between the life-giving sun and chlorophyll—the substance which gives the 
green color to vegetation. We should know that on this relationship all life 
on this planet depends. 
Most of us will store such facts away in the recesses of our minds and gratefully 
add them to our store of general knowledge and culture. We shall then go about 
our business of living, seldom thinking of trees as great engines in the tremendous 
laboratory of Nature, but rather as familiar and precious companions of our daily 
life, demanding little, giving much. 
Without benefit of clergy or scientist, we discover for ourselves that trees 
are of the utmost importance to us; that they minister to our needs in 
a thousand material ways; that they spread their arms to protect and comfort 
us; and that they fill our world with an amazing beauty, ever changing, 
forever inspiring. 
A force of such value to the race, a phase of our social economy so important, 
demands a special attention and study; calls for the creation of a group of men 
who, by their devotion to their subject, shall be able to speak with authority on 
it and bring together the great army of seekers and the things they seek. And 
so the business of studying trees, of growing and distributing them, has risen 
to the plane of a high and inspired calling. It has aroused the interest and 
furnished a career for some of our best minds. The late Charles S. Sargent, 
whose rich and cultured personality could have adorned almost any profession, 
chose this as his life work, and has left us a monument to his devotion in 
the Arnold Arboretum. 
Is it not possible that such men as he, through the harmony of their own 
personal pleasure and absorption in the pursuit of their objectives, have heard a 
dim cry from far down the line such as is related by Mr. Donald Culross Peattie 
