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Study I What Forestry Is And What It Does

Although Forestry is not a new idea but, as a science and an art, has

been applied for nearly two thousand years, there are many persons who

still need an explanation of its aims and principles.

Forestry deals with the establishment, protection and utilization of


By establishment, is meant the planting of new forests and the cutting

of mature forests, in such a way as to encourage a natural growth of new

trees without artificial planting or seeding. The planting may consist

of sowing seed, or of setting out young trees. The establishment of a

forest by cutting may consist of the removal of all mature trees and

dependence upon the remaining stumps to reproduce the forest from

sprouts, or it may consist of the removal of only a portion of the

mature trees, thus giving the young seedlings on the ground room in

which to grow.

By protection, is meant the safeguarding of the forest from fire, wind,

insects, disease and injury for which man is directly responsible. Here,

the forester also prevents injury to the trees from the grazing and

browsing of sheep and goats, and keeps his forest so well stocked that

no wind can uproot the trees nor can the sun dry up the moist forest


By utilization, is meant the conservative and intelligent harvesting of

the forest, with the aim of obtaining the greatest amount of product

from a given area, with the least waste, in the quickest time, and

without the slightest deterioration of the forest as a whole. The

forester cuts his mature trees, only, and generally leaves a sufficient

number on the ground to preserve the forest soil and to cast seed for

the production of a new crop. In this way, he secures an annual output

without hurting the forest itself. He studies the properties and values

of the different woods and places them where they will be most useful.

He lays down principles for so harvesting the timber and the

by-products of the forest that there will be the least waste and injury

to the trees which remain standing. He utilizes the forest, but does not

cut enough to interfere with the neighboring water-sheds, which the

forests protect.

Forestry, therefore, deals with a vast and varied mass of information,

comprising all the known facts relating to the life of a forest. It does

not deal with the individual tree and its planting and care,--that would

be arboriculture. Nor does it consider the grouping of trees for

aesthetic effect,--that would be landscape gardening. It concerns itself

with the forest as a community of trees and with the utilization of the

forest on an economic basis.

Each one of these activities in Forestry is a study in itself and

involves considerable detail, of which the reader may obtain a general

knowledge in the following pages. For a more complete discussion, the

reader is referred to any of the standard books on Forestry.

The life and nature of a forest: When we think of a forest we are apt to

think of a large number of individual trees having no special

relationship to each other. Closer observation, however, will reveal

that the forest consists of a distinct group of trees, sufficiently

dense to form an unbroken canopy of tops, and that, where trees grow

so closely together, they become very interdependent. It is this

interdependence that makes the forest different from a mere group of

trees in a park or on a lawn. In this composite character, the

forest enriches its own soil from year to year, changes the climate

within its own bounds, controls the streams along its borders and

supports a multitude of animals and plants peculiar to itself. This

communal relationship in the life history of the forest furnishes a

most interesting story of struggle and mutual aid. Different trees

have different requirements with regard to water, food and light.

Some need more water and food than others, some will not endure much

shade, and others will grow in the deepest shade. In the open, a

tree, if once established, can meet its needs quite readily and,

though it has to ward off a number of enemies, insects, disease and

windstorm--its struggle for existence is comparatively easy. In the

forest, the conditions are different. Here, the tree-enemies have to

be battled with, just as in the open, and in addition, instead of

there being only a few trees on a plot of ground, there are

thousands growing on the same area, all demanding the same things

out of a limited supply. The struggle for existence, therefore,

becomes keen, many falling behind and but few surviving.

This struggle begins with the seed. At first there are thousands of

seeds cast upon a given area by the neighboring trees or by the

birds and the winds. Of these, only a few germinate; animals feed on

some of them, frost nips some and excessive moisture and unfavorable

soil conditions prevent others from starting. The few successful

ones soon sprout into a number of young trees that grow thriftily

until their crowns begin to meet. When the trees have thus met, the

struggle is at its height. The side branches encroach upon each

other (Fig. 123), shut out the light without which the branches

cannot live, and finally kill each other off. The upper branches vie

with one another for light, grow unusually fast, and the trees

increase in height with special rapidity. This is nature's method of

producing clear, straight trunks which are so desirable for poles

and large timber. In this struggle for dominance, some survive and

tower above the others, but many become stunted and fail to grow,

while the majority become entirely overtopped and succumb in the

struggle; see Fig. 139.

But in this strife there is also mutual aid. Each tree helps to

protect its neighbors against the danger of being uprooted by the

wind, and against the sun, which is liable to dry up the rich soil

around the roots. This soil is different from the soil on the open

lawn. It consists of an accumulation of decayed leaves mixed with

inorganic matter, forming, together, a rich composition known as

_humus_. The trees also aid each other in forming a close canopy

that prevents the rapid evaporation of water from the ground.

The intensity of these conditions will vary a great deal with the

composition of the forest and the nature and habits of the

individual trees. By composition, or type of forest, is meant the

proportion in which the various species of trees are grouped; i.e.,

whether a certain section of woodland is composed of one species or

of a mixture of species. By habit is meant the requirements of the

trees for light, water and food.

Some trees will grow in deep shade while others will demand the

open. In the matter of water and food, the individual requirements

of different trees are equally marked.

The natural rapidity of growth of different species is also

important, and one caring for a forest must know this rate of

growth, not only as to the individual species, but also with respect

to the forest as a whole. If he knows how fast the trees in a

forest grow, both in height and diameter, he will know how much

wood, in cubic feet, the forest produces in a year, and he can then

determine how much he may cut without decreasing the capital stock.

The rate of growth is determined in this way: A tree is cut and the

rings on the cross-section surface are counted and measured; see

Fig. 124. Each ring represents one year's growth. The total number

of rings will show the age of the tree. By a study of the rings of

the various species of trees on a given plot, the rate of growth of

each species in that location can be ascertained and, by knowing the

approximate number of trees of each species on the forest area, the

rate of growth of the whole forest for any given year can be


Forests prevent soil erosion and floods: Forests help to regulate the

flow of streams and prevent floods. Most streams are bordered by

vast tracts of forest growths. The rain that falls on these forest

areas is absorbed and held by the forest soil, which is permeated

with decayed leaves, decayed wood and root fibers. The forest floor

is, moreover, covered with a heavy undergrowth and thus behaves like

a sponge, absorbing the water that falls upon it and then permitting

it to ooze out gradually to the valleys and rivers below. A forest

soil will retain one-half of its own quantity of water; i.e., for

every foot in depth of soil there can be six inches of water and,

when thus saturated, the soil will act as a vast, underground

reservoir from which the springs and streams are supplied (Fig.

125). Cut the forest down and the land becomes such a desert as is

shown in Fig. 126. The soil, leaves, branches and fallen trees dry

to dust, are carried off by the wind and, with the fall of rain, the

soil begins to wash away and gullies, such as are shown in Fig. 127,

are formed. Streams generally have their origins in mountain slopes

and there, too, the forests, impeding the sudden run off of the

water which is not immediately absorbed, prevent soil erosion.

Where the soil is allowed to wash off, frequent floods are

inevitable. Rain which falls on bare slopes is not caught by the

crowns of trees nor held by the forest floor. It does not sink into

the ground as readily as in the forest. The result is that a great

deal of water reaches the streams in a short time and thus hastens

floods. At other periods the streams are low because the water which

would have fed them for months has run off in a few days. The farms

are the first to suffer from the drouths that follow and, during the

period of floods, whole cities are often inundated. Fig. 128 shows

such a scene. The history of Forestry is full of horrible incidents

of the loss of life and property from floods which are directly

traceable to the destruction of the local forests and, on the other

hand, there are many cases on record where flood conditions have

been entirely obviated by the planting of forests. France and

Germany have suffered from inundations resulting from forest

devastation and, more than a hundred years ago, both of these

countries took steps to reforest their mountain slopes, and thereby

to prevent many horrible disasters.

How forests are established: New forests may be started from seed or

from shoots, or suckers. If from seed, the process may be carried on

in one of three ways:

First, by sowing the seed directly on the land.

Second, by first raising young trees in nurseries and later setting

them out in their permanent locations in the forest. This method is

applicable where quick results are desired, where the area is not

too large, or in treeless regions and large open gaps where there

is little chance for new trees to spring up from seed furnished by

the neighboring trees. It is a method extensively practiced abroad

where some of the finest forests are the result. The U.S.

government, as well as many of the States, maintain forest-tree

nurseries where millions of little trees are grown from seed and

planted out on the National and State forests. Fig. 129 shows men

engaged in this work. The fundamental principles of starting and

maintaining a nursery have already been referred to in the chapter

on "What Trees to Plant and How."

The third method of establishing a forest from seed is by cutting

the trees in the existing forest so that the seed falling from the

remaining trees will, with the addition of light and space, readily

take root and fill in the gaps with a vigorous growth of trees,

without artificial seeding or planting. This gives rise to several

methods of cutting or harvesting forests for the purpose of

encouraging natural reproduction. The cutting may extend to single

trees over the whole area or over only a part of the whole area.

Where the cutting is confined to single trees, the system is known

as the "Selection System," because the trees are selected

individually, with a view to retaining the best and most vigorous

stock and removing the overcrowding specimens and those that are

fully mature or infested with disease or insects.

Fig. 130 is a diagrammatic illustration of the operation of this

system. In another system the cutting is done in groups, or in

strips, and the number of areas of the groups or strips is extended

from time to time until the whole forest is cleared. This system is

illustrated in Fig. 131. Still another method consists in

encouraging trees which will thrive in the shade, such as the beech,

spruce and hemlock, to grow under light-demanding trees like the

pine. This system presents a "two-storied" forest and is known by

that name. The under story often has to be established by planting.

In the system of reproducing forests from shoots or suckers, all

trees of a certain species on a given area are cut off and the old

stumps and roots are depended upon to produce a new set of sprouts,

the strongest of which will later develop into trees. The coniferous

trees do not lend themselves at all to this system of treatment,

and, among the broadleaf trees, the species vary in their ability to

sprout. Some, like the chestnut and poplar, sprout profusely; others

sprout very little.

How forests are protected: Forestry also tries to protect the forests

from many destructive agencies. Wasteful lumbering and fire are the

worst enemies of the forest. Fungi, insects, grazing, wind, snow and

floods are the other enemies.

By wasteful lumbering is meant that the forest is cut with no regard

for the future and with considerable waste in the utilization of the

product. Conservative lumbering, which is the term used by foresters

to designate the opposite of wasteful lumbering, will be described

more fully later in this study.

Protection from fire is no less important than protection from

wasteful lumbering. Forest fires are very common in this country and

cause incalculable destruction to life and property; see Fig. 132.

From ten to twelve million acres of forest-land are burnt over

annually and the timber destroyed is estimated at fifty millions of

dollars. The history of Forestry abounds in tales of destructive

fires, where thousands of persons have been killed or left

destitute, whole towns wiped out, and millions of dollars in

property destroyed. In most cases, these uncontrollable fires

started from small conflagrations that could readily, with proper

fire-patrol, have been put out.

There are various ways of fighting fires, depending on the character

of the fire,--whether it is a surface fire, burning along the

surface layer of dry leaves and small ground vegetation, a ground

fire, burning below the surface, through the layer of soil and

vegetable matter that generally lines the forest floor, or a top

fire, burning high up in the trees.

When the fire runs along the surface only, the injury extends to the

butts of the trees and to the young seedlings. Such fires can be put

out by throwing dirt or sand over the fire, by beating it, and,

sometimes, by merely raking the leaves away.

Ground fires destroy the vegetable mold which the trees need for

their sustenance. They progress slowly and kill or weaken the roots

of the trees.

Top fires, Fig. 133, are the most dangerous, destroying everything

in their way. They generally develop from surface fires, though

sometimes they are started by lightning. They are more common in

coniferous forests, because the leaves of hardwoods do not burn so

readily. Checking the progress of a top fire is a difficult matter.

Some fires will travel as rapidly as five miles an hour, and the

heat is terrific. The only salvation for the forest lies, in many

cases, in a sudden downpour of rain, a change of wind, or some

barrier which the fire cannot pass. A barrier of this kind is often

made by starting another fire some distance ahead of the principal

one, so that when the two fires meet, they will die out for want of

fuel. In well-kept forests, strips or lanes, free from inflammable

material, are often purposely made through the forest area to

furnish protection against top fires. Carefully managed forests are

also patrolled during the dry season so that fires may be detected

and attacked in their first stages. Look-out stations, watch-towers,

telephone-connections and signal stations are other means frequently

resorted to for fire protection and control. Notices warning campers

and trespassers against starting fires are commonly posted in such

forests. (Fig. 143.)

The grazing of sheep, goats and cattle in the forest is another

important source of injury to which foresters must give attention.

In the West this is quite a problem, for, when many thousands of

these animals pass through a forest (Fig. 134), there is often very

little young growth left and the future reproduction of the forest

is severely retarded. Grazing on our National Forests is regulated

by the Government.

As a means of protection against insects and fungi, all trees

infested are removed as soon as observed and in advance of all

others, whenever a lumbering operation is undertaken.

How forests are harvested: Forestry and forest preservation require that

a forest should be cut and not merely held untouched. But it also

demands that the cutting shall be done on scientific principles, and

that only as much timber shall be removed in a given time as the

forest can produce in a corresponding period. After the cutting, the

forest must be left in a condition to produce another crop of

timber within a reasonable time: see Fig. 122. These fundamental

requirements represent the difference between conservative lumbering

and ordinary lumbering. Besides insuring a future supply of timber,

conservative lumbering, or lumbering on forestry principles, also

tends to preserve the forest floor and the young trees growing on

it, and to prevent injury to the remaining trees through fire,

insects and disease. It provides for a working plan by which the

kind, number and location of the trees to be cut are specified, the

height of the stumps is stipulated and the utilization of the wood

and by-products is regulated.

Conservative lumbering provides that the trees shall be cut as near

to the ground as possible and that they shall be felled with the

least damage to the young trees growing near by. The branches of the

trees, after they have been felled, must be cut and piled in heaps,

as shown in Fig. 122, to prevent fire. When the trunks, sawed into

logs, are dragged through the woods, care is taken not to break down

the young trees or to injure the bark of standing trees. Waste in

the process of manufacture is provided against, uses are found for

the material ordinarily rejected, and the best methods of handling

and drying lumber are employed. Fig. 135 shows a typical sawmill

capable of providing lumber in large quantities.

In the utilization of the by-products of the forest, such as

turpentine and resin, Forestry has devised numerous methods for

harvesting the crops with greater economy and with least waste and

injury to the trees from which the by-products are obtained. Fig.

136 illustrates an improved method by which crude turpentine is


Forestry here and abroad: Forestry is practiced in every civilized

country except China and Turkey. In Germany, Forestry has attained,

through a long series of years, a remarkable state of scientific

thoroughness and has greatly increased the annual output of the

forests of that country.

In France, Switzerland, Austria, Hungary, Norway, Sweden, Russia

and Denmark, Forestry is also practiced on scientific principles and

the government in each of these countries holds large tracts of

forests in reserve. In British India one finds a highly efficient

Forest Service and in Japan Forestry is receiving considerable


In the United States, the forest areas are controlled by private

interests, by the Government and by the States. On privately owned

forests, Forestry is practiced only in isolated cases. The States

are taking hold of the problem very actively and in many of them we

now find special Forestry Commissions authorized to care for vast

areas of forest land reserved for State control. These Commissions

employ technically trained foresters who not only protect the State

forests, but also plant new areas, encourage forest planting on

private lands and disseminate forestry information among the

citizens. New York State has such a Commission that cares for more

than a million acres of forest land located in the northern part of

the State. Many other States are equally progressive.

The United States Government is the most active factor in the

preservation of our forests. The Government to-day owns over two

hundred million acres of forest land, set aside as National Forests.

There are one hundred and fifty individual reserves, distributed as

shown in Fig. 137 and cared for by the Forest Service, a bureau in

the Department of Agriculture. Each of the forests is in charge of a

supervisor. He has with him a professional forester and a body of

men who patrol the tract against fire and the illegal cutting of

timber. Some of the men are engaged in planting trees on the open

areas and others in studying the important forest problems of the

region. Fig. 138.

Where cutting is to be done on a National Forest, the conditions are

investigated by a technically trained forester and the cutting is

regulated according to his findings. Special attention is given to

discovering new uses for species of trees which have hitherto been

considered valueless, and the demand upon certain rare species is

lessened by introducing more common woods which are suitable for use

in their place.

Aside from the perpetuation of the national forests, the U.S.

Forest Service also undertakes such tree studies as lie beyond the

power or means of private individuals. It thus stands ready to

cooperate with all who need assistance.

Tree Studies

How To Identify Trees
Group I The Pines
The White Pine (pinus Strobus)
The Pitch Pine (pinus Rigida)
The Scotch Pine (pinus Sylvestris)
Group Ii The Spruce And Hemlock
The Norway Spruce (picea Excelsa)
Hemlock (tsuga Canadensis)
Group Iii The Red Cedar And Arbor-vitae
Red Cedar (juniperus Virginiana)
Arbor-vitae; Northern White Cedar (thuja Occidentalis)
Group Iv The Larch And Cypress
The European Larch (larix Europaea)
Bald Cypress (taxodium Distichum)
Group V The Horsechestnut, Ash And Maple
The Horsechestnut
The White Ash (fraxinus Americana)
Sugar Maple (acer Saccharum)
Silver Maple (acer Saccharinum)
Red Maple (acer Rubrum)
Norway Maple (acer Platanoides)
Box Elder (acer Negundo)
Group Vi Trees Told By Their Form: Elm, Poplar, Gingko And Willow
American Elm (ulmus Americana)
Lombardy Or Italian Poplar (populus Nigra, Var Italica)
Gingko Or Maidenhair Tree (gingko Biloba)
Weeping Willow (salix Babylonica)
Group Vii Trees Told By Their Bark Or Trunk: Sycamore, Birch, Beech,
Blue Beech, Ironwood, And Hackberry
The Sycamore Or Plane Tree (platanus Occidentalis)
Gray Or White Birch (betula Populifolia)
American Beech (fagus Americana)
Blue Beech Or Hornbeam (carpinus Caroliniana)
Hackberry (celtis Occidentalis)
Group Viii The Oaks And Chestnut
White Oak (quercus Alba)
Black Oak (quercus Velutina)
Red Oak (quercus Rubra)
Pin Oak (quercus Palustris)
Chestnut (castanea Dentata)
Group Ix The Hickories, Walnut And Butternut
Shagbark Hickory (hicoria Ovata)
Mockernut Hickory (hicoria Alba)
Black Walnut (juglans Nigra)
Group X Tulip Tree, Sweet Gum, Linden, Magnolia, Locust, Catalpa,
Dogwood, Mulberry And Osage Orange
Tulip Tree (liriodendron Tulipifera)
Sweet Gum (liquidambar Styraciflua)
American Linden (tilia Americana)
The Magnolias