Part 1 (1/2)

The School Book of Forestry

by Charles Lathrop Pack

INTRODUCTION

Our forests, with their billions of trees, are the backbone of agriculture, the skeleton of lu, and the heart of industry Even now, in spite of their depletion, they are the cream of our natural resources They furnish wood for the nation, pasture for thousands of cattle and sheep, and water supply for countless cities and farms They are the doame animals, and fish live in the forests and the forest streareatest playgrounds of America It is necessary that we preserve, protect, and expand our ti we shall provide for the needs of future generations

The forest is one of the most faithful friends of man It provides hiriculture by preventing floods and storing the surplus rainfall in the soil for the use of farm crops It supplies the foundation for all our railroads It is the producer of fertile soils It gives employment to millions of workmen It is a resource which bountifully repays kind treatanized feature of the plant world The forest is not merely a collection of different kinds of trees It is a per periods when properly htlessly squandered by successive generations of spendthrifts Fortunately, it is not too late to rebuild it through cooperative effort

The work has been well begun, but it is a work of years, and it is to the youth of the country that we must look for its continuous expansion and perpetuation A part of our efforttheent forestry policy

CHAPTER I

HOW TREES GROW AND MULTIPLY

The trees of the forest grow by for new layers of wood directly under the bark Trees are held upright in the soil by means of roots which reach to a depth of many feet where the soil is loose and porous These roots are the supports of the tree

They hold it rigidly in position They also supply the tree with food Through delicate hairs on the roots, they absorb soilto the tree The body of the tree acts as a passage way through which the food and drink are conveyed to the top or crown The crown is the place where the food is digested and the regeneration of trees effected

The leaves contain a ht and heat, changes ives the leaves their green color The cells of the plant that are rich in chlorophyll have the power to convert carbonic-acid gas into carbon and oxygen These cells combine the carbon and the soil water into cheested when they reach the crown of the tree The water, containing salts, which is gathered by the roots is brought up to the leaves Here it coas taken froht these substances are split up, the carbon, oxygen and hydrogen being combined into plant food It is either used iency

Trees breathe soive off carbonic-acid gas The air enters the tree through the leaves and ss in the bark, which are easily seen in such trees as the cherry and birch Trees breathe constantly, but they digest and assiht In the process of digestion and assien in abundance, but they retain as, which is a plant food, and whatever part of it is not used irowth and developh the leaves and bark Otherwise they would beco rapidly frorow by increasing the thickness of the older buds Increase in height and density of crown cover is due to the developrowth on the tree is spread evenly between the wood and bark over the entire body of the plant This process of wood production resembles a factory enterprise in which three layers of ed

In the first two of these delicate tissues the wood is actually made The inner side of the rows bark The third layer is responsible for the production of the tough, outer bark Year after year new layers of wood are formed around the first layers This first layer finally develops into heartwood, which, so far as growth is concerned, is dead material Its cells are blocked up and prevent the flow of sap It aids in supporting the tree The living sapwood surrounds the heartwood Each year one ring of this sapwood develops This process of growth may continue until the annual layers a to the life of the tree

One can tell the age of a tree by counting the nus Sorowth, two false rings

However, such blenize Heartwood does not occur in all varieties of trees In some cases, where both heartwood and sapwood appear, it is difficult to distinguish between them as their colors are so nearly alike Because it takes up so much moisture and plant food, sapwood rots much more quickly than heartwood The sapwood really acts as a pipe line to carry water froest trees the h the sapwood

Strange though it ht with each other for a place in the sunlight Sprightly trees that shoot skyward at a swift pace are the ones that develop into the rowth because at all tiht The less fortunate trees, that are more stocky and sturdy, and less speedy in their clie numbers each year The weaker, spindly trees of the forest, which are sloers, often are sorous trees

Sorow in the shade They develop near or under the large trees of the forest When the giants of the woodland die, these smaller trees, which previously were shaded, develop rapidly as a result of their freedoe and high as the huge trees that they replace In our eastern forests the hemlock often follows the white pine in this way Spruce trees may live for many years in dense shade Then finally, when they have access to plenty of light they ion due to different conditions of growth and climate For example, the canoe birch at its northern liher than a few feet above the ground Under the most favorable conditions in Florida, where this species thrives, such trees often tower to a height of 125 feet

In sheltered regions the seeds of trees may fall, sprout and take root close to their parent trees As a rule, the wind plays a pro seed in every section of the country Pine and fir seeds are equipped ings like those of a bird or an airplane They enable the seeds to fly long distances on the wind before they drop to the ground and are covered with leaves Maple seeds fly by ed sails which carry them far afield before they settle Ash seeds have peculiar appendages which act like a skate-sail in transporting thes which aid their flight, while basswood seeds are distributed over the country by s

The pods of the locust tree fall on the frozen ground or snow crust and are blown long distances from their source On the other hand, oak, hickory, and chestnut trees produce heavy seeds which generally remain where they fall

Squirrels are the most industrious foresters in the anireat quantities of tree seeds in hoards or caches hidden away in hollow logs or in the moss and leaves of the forest floor Birds also scatter tree seed here, there, and everywhere over the forests and the surrounding country Running streams and rivers carry seeds uninjured for many miles and finally deposit therow into trees Many seeds are carried by the ocean currents to distant foreign shores

The decay of leaves and woodland vegetation forms rich and fertile soils in the forests, in which conditions are favorable for the develop tree seeds are exposed to proper amounts of moisture, warrow A root develops which pushes its way down into the soil, while the leaf-bud of the plant, which springs from the other end of the seed, works its way upward toward the light and air This leafy part of the seed finally forms the stem of the tree But trees may produce plenty of seed and yet fail to maintain their proper proportion in the forest This results because much of the seed is unsound Even where a satisfactory supply of sound fertile seed is produced, it does not follow that the trees of that variety will be maintained in the forest, as the seed supply errow in the forest each year, but only a se trees This is because so s are destroyed by forest fires, cattle and sheep grazing, unfavorable soil and weather conditions, and many other causes

Beech and chestnut trees and others of the broad-leaved type reproduce bystumps of broad-leaved trees produce more sprouts than the stu the cone-bearing trees reproduction by sprouts is rare The redwood of California is one of the few exceptions The pitch pine of the Eastern States produces many sprouts, fehich live and develop into rown in nurseries, the practice is to sow the seed in special beds filled with rich soil Lath screens are used as shade They protect the young seedlings from the sun just as the parent trees would do in the forest The seedbeds are kept well cultivated and free of weeds so that the seedlings rowth Generally the seeds are sown in the spring between March and May Such seeds as the elms and soft maples, which ripen in the early suathered Practical tests have shown that thick sowings of tree seeds give the best results