Studies of Trees | Page 2

not only in the trees that we pass in our daily walks, but also in
the forest considered as a community of trees, because of its aesthetic and protective
value and its usefulness as a source of important economic products.
As a nation, we are thinking more about trees and woods than we were wont to do in the
years gone by. We are growing to love the trees and forests as we turn more and more to
outdoor life for recreation and sport. In our ramblings along shady streets, through grassy
parks, over wooded valleys, and in mountain wildernesses we find that much more than
formerly we are asking ourselves what are these trees, what are the leaf, flower, twig,
wood and habit characteristics which distinguish them from other trees; how large do
they grow; under what conditions of soil and climate do they thrive best; what are their
enemies and how can they be overcome; what is their value for wood and other useful
products; what is their protective value; are they useful for planting along streets and in
parks and in regenerating forests; how can the trees of our streets and lawns be preserved
and repaired as they begin to fail from old age or other causes? All these questions and
many more relating to the important native and exotic trees commonly found in the states
east of the Great Lakes and north of Maryland Mr. Levison has briefly answered in this
book. The author's training as a forester and his experience as a professional
arboriculturist has peculiarly fitted him to speak in an authoritative and interesting way
about trees and woods.
The value of this book is not in new knowledge, but in the simple statement of the most
important facts relating to some of our common trees, individually and collectively
considered. A knowledge of trees and forests adds vastly to the pleasures of outdoor life.
The more we study trees and the more intimate our knowledge of the forest as a unit of
vegetation in which each tree, each flower, each animal and insect has its part to play in
the complete structure, the greater will be our admiration of the wonderful beauty and
variety exhibited in the trees and woods about us.
J.W. TOUMEY, Director, Yale University Forest School.
NEW HAVEN, CONN., June, 1914.

STUDIES OF TREES
CHAPTER I
HOW TO IDENTIFY TREES
There are many ways in which the problem of identifying trees may be approached. The
majority attempt to recognize trees by their leaf characters. Leaf characters, however, do
not differentiate the trees during the other half of the year when they are bare. In this
chapter the characterizations are based, as far as possible, on peculiarities that are evident
all year round. In almost every tree there is some one trait that marks its individuality and

separates it, at a glance, from all other trees. It may be the general form of the tree, its
mode of branching, bark, bud or fruit. It may be some variation in color, or, in case of the
evergreen trees, it may be the number and position of the needles or leaves. The species
included in the following pages have thus been arranged in groups based on these
permanent characters. The individual species are further described by a distinguishing
paragraph in which the main character of the tree is emphasized in heavy type.
The last paragraph under each species is also important because it classifies all related
species and distinguishes those that are liable to be confused with the particular tree
under consideration.

GROUP I. THE PINES
[Illustration: FIG. 1.--Twig of the Austrian Pine.]
How to tell them from other trees: The pines belong to the coniferous class of trees; that
is, trees which bear cones. The pines may be told from the other coniferous trees by their
leaves, which are in the form of needles two inches or more in length. These needles keep
green throughout the entire year. This is characteristic of all coniferous trees, except the
larch and cypress, which shed their leaves in winter.
[Illustration: FIG. 2.--Twig of the White Pine.]
The pines are widely distributed throughout the Northern Hemisphere, and include about
80 distinct species with over 600 varieties. The species enumerated here are especially
common in the eastern part of the United states, growing either native in the forest or
under cultivation in the parks. The pines form a very important class of timber trees, and
produce beautiful effects when planted in groups in the parks.
How to tell them from each other: The pine needles are arranged in clusters; see Fig. 1.
Each species has a certain characteristic number of needles to the cluster and this fact
generally provides the simplest and most direct way of distinguishing