Trees Worth Knowing

TREES WORTH KNOWING

A BEND IN THE TRAIL

Little Nature Library

TREES

WORTH KNOWING

By JULIA ELLEN ROGERS

(Author of The Tree Book, The Tree Guide, Trees Every Child Should Know, The Book of Useful Plants, The Shell Book, etc., etc.)

With forty-eight illustrations, sixteen being in color

PUBLISHED BY

DOUBLEDAY, PAGE & COMPANY

FOR

NELSON DOUBLEDAY, Inc.

1923

Copyright, 1917, by

Doubleday, Page & Company

All rights reserved, including that of translation into foreign languages, including the Scandinavian

PRINTED IN THE UNITED STATES
AT
THE COUNTRY LIFE PRESS. GARDEN CITY, N. Y.

CONTENTS

LIST OF COLORED ILLUSTRATIONS

LIST OF OTHER ILLUSTRATIONS

INTRODUCTION

Occasionally I meet a person who says: "I know nothing at all about trees." This modest disclaimer is generally sincere, but it has always turned out to be untrue. "Oh, well, that old sugar maple, I've always known that tree. We used to tap all the sugar maples on the place every spring." Or again: "Everybody knows a white birch by its bark." "Of course, anybody who has ever been chestnutting knows a chestnut tree." Most people know Lombardy poplars, those green exclamation points so commonly planted in long soldierly rows on roadsides and boundary lines in many parts of the country. Willows, too, everybody knows are willows. The best nut trees, the shagbark, chestnut, and butternut, need no formal introduction. The honey locust has its striking three-pronged thorns, and its purple pods dangling in winter and skating off over the snow. The beech has its smooth, close bark of Quaker gray, and nobody needs to look for further evidence to determine this tree's name.

So it is easily proved that each person has a good nucleus of tree knowledge around which to accumulate more. If people have the love of nature in their hearts—if things out of doors call irresistibly, at any season—it will not really matter if their lives are pinched and circumscribed. Ways and means of studying trees are easily found, even if the scant ends of busy days spent indoors are all the time at command. If there is energy to begin the undertaking it will soon furnish its own motive power. Tree students, like bird students, become enthusiasts. To understand their enthusiasm one must follow their examples.

The beginner doesn't know exactly how and where to begin. There are great collections of trees here and there. The Arnold Arboretum in Boston is the great dendrological Noah's Ark in this country. It contains almost all the trees, American and foreign, which will grow in that region. The Shaw Botanical Garden at St. Louis is the largest midland assemblage of trees. Parks in various cities bring together as large a variety of trees as possible, and these are often labelled with their English and botanical names for the benefit of the public.

Yet the places for the beginner are his own dooryard, the streets he travels four times a day to his work, and woods for his holiday, though they need not be forests. Arboreta are for his delight when he has gained some acquaintance with the tree families. But not at first. The trees may all be set out in tribes and families and labelled with their scientific names. They will but confuse and discourage him. There is not time to make their acquaintance. They overwhelm with the mere number of kinds. Great arboreta and parks are very scarce. Trees are everywhere. The acquaintance of trees is within the reach of all.

First make a plan of the yard, locating and naming the trees you actually know. Extend it to include the street, and the neighbors' yards, as you get ready for them. Be very careful about giving names to trees. If you think you know a tree, ask yourself how you know it. Sift out all the guesses, and the hearsays, and begin on a solid foundation, even if you are sure about only the sugar maple and the white birch.

The characters to note in studying trees are: leaves, flowers, fruits, bark, buds, bud arrangement, leaf scars, and tree form. The season of the year determines which features are most prominent. Buds and leaf scars are the most unvarying of tree characters. In winter these traits and the tree frame are most plainly revealed. Winter often exhibits tree fruits on or under the tree, and dead-leaf studies are very satisfactory. Leaf arrangement may be made out at any season, for leaf scars tell this story after the leaves fall.

Only three families of our large trees have opposite leaves. This fact helps the beginner. Look first at the twigs. If the leaves, or (in winter) the buds and leaf scars, stand opposite, the tree (if it is of large size) belongs to the maple, ash, or horse-chestnut family. Our native horse-chestnuts are buckeyes. If the leaves are simple the tree is a maple; if pinnately compound, of several leaflets, it is an ash; if palmately compound, of five to seven leaflets, it is a horse-chestnut. In winter dead leaves under the trees furnish this evidence. The winter buds of the horse-chestnut are large and waxy, and the leaf scars look like prints of a horse's hoof. Maple buds are small, and the leaf scar is a small, narrow crescent. Ash buds are dull and blunt, with rough, leathery scales. Maple twigs are slender. Ash and buckeye twigs are stout and clumsy.

Bark is a distinguishing character of many trees—of others it is confusing. The sycamore, shedding bark in sheets from its limbs, exposes pale, smooth under bark. The tree is recognizable by its mottled appearance winter or summer. The corky ridges on limbs of sweet gum and bur oak are easily remembered traits. The peculiar horizontal peeling of bark on birches designates most of the genus. The prussic-acid taste of a twig sets the cherry tribe apart. The familiar aromatic taste of the green twigs of sassafras is its best winter character; the mitten-shaped leaves distinguish it in summer.

It is necessary to get some book on the subject to discover the names of trees one studies, and to act as teacher at times. A book makes a good staff, but a poor crutch. The eyes and the judgment are the dependable things. In spring the way in which the leaves open is significant; so are the flowers. Every tree when it reaches proper age bears flowers. Not all bear fruit, but blossoms come on every tree. In summer the leaves and fruits are there to be examined. In autumn the ripening fruits are the special features.

To know a tree's name is the beginning of acquaintance—not an end in itself. There is all the rest of one's life in which to follow it up. Tree friendships are very precious things. John Muir, writing among his beloved trees of the Yosemite Valley, adjures his world-weary fellow men to seek the companionship of trees.

* * * * *

"To learn how they live and behave in pure wildness, to see them in their varying aspects through the seasons and weather, rejoicing in the great storms, putting forth their new leaves and flowers, when all the streams are in flood, and the birds singing, and sending away their seeds in the thoughtful Indian summer, when all the landscape is glowing in deep, calm enthusiasm—for this you must love them and live with them, as free from schemes and care and time as the trees themselves."

Tree Names

Two Latin words, written in italics, with a cabalistic abbreviation set after them, are a stumbling block on the page to the reader unaccustomed to scientific lore. He resents botanical names, and demands to know the tree's name in "plain English." Trees have both common and scientific names, and each has its use. Common names were applied to important trees by people, the world over, before science was born. Many trees were never noticed by anybody until botanists discovered and named them. They may never get common names at all.

A name is a description reduced to its lowest terms. It consists usually of a surname and a descriptive adjective: Mary Jones, white oak, Quercus alba. Take the oaks, for example, and let us consider how they got their names, common and scientific. All acorn-bearing trees are oaks. They are found in Europe, Asia, and America. Their usefulness and beauty have impressed people. The Britons called them by a word which in our modern speech is oak, and as they came to know the different kinds, they added a descriptive word to the name of each. But "plain English" is not useful to the Frenchman. Chêne is his name for the acorn trees. The German has his Eichenbaum, the Roman had his Quercus, and who knows what the Chinaman and the Hindoo in far Cathay or the American Indian called these trees? Common names made the trouble when the Tower of Babel was building.

Latin has always been the universal language of scholars. It is dead, so that it can be depended upon to remain unchanged in its vocabulary and in its forms and usages. Scientific names are exact, and remain unchanged, though an article or a book using them may be translated into all the modern languages. The word Quercus clears away difficulties. French, English, German hearers know what trees are meant—or they know just where in books of their own language to find them described.

The abbreviation that follows a scientific name tells who first gave the name. "Linn." is frequently noticed, for Linnaeus is authority for thousands of plant names.

Two sources of confusion make common names of trees unreliable: the application of one name to several species, and the application of several names to one species. To illustrate the first: There are a dozen ironwoods in American forests. They belong, with two exceptions, to different genera and to at least five different botanical families. To illustrate the second: The familiar American elm is known by at least seven local popular names. The bur oak has seven. Many of these are applied to other species. Three of the five native elms are called water elm; three are called red elm; three are called rock elm. There are seven scrub oaks. Only by mentioning the scientific name can a writer indicate with exactness which species he is talking about. The unscientific reader can go to the botanical manual or cyclopedia and under this name find the species described.

In California grows a tree called by three popular names: leatherwood, slippery elm, and silver oak. Its name is Fremontia. It is as far removed from elms and oaks as sheep are from cattle and horses. But the names stick. It would be as easy to eradicate the trees, root and branch, from a region as to persuade people to abandon names they are accustomed to, though they may concede that you have proved these names incorrect, or meaningless, or vulgar. Nicknames like nigger pine, he huckleberry, she balsam, and bull bay ought to be dropped by all people who lay claim to intelligence and taste.

With all their inaccuracies, common names have interesting histories, and the good ones are full of helpful suggestion to the learner. Many are literal translations of the Latin names. The first writers on botany wrote in Latin. Plants were described under the common name, if there was one; if not, the plant was named. The different species of each group were distinguished by the descriptions and the drawings that accompanied them. Linnaeus attempted to bring the work of botanical scholars together, and to publish descriptions and names of all known plants in a single volume. This he did, crediting each botanist with his work. The "Species Plantarum," Linnaeus's monumental work, became the foundation of the modern science of botany, for it included all the plants known and named up to the time of its publication. This was about the middle of the eighteenth century.

The vast body of information which the "Species Plantarum" contained was systematically arranged. All the different species in one genus were brought together. They were described, each under a number; and an adjective word, usually descriptive of some marked characteristic, was written in as a marginal index.

After Linnaeus's time botanists found that the genus name in combination with this marginal word made a convenient and exact means of designating the plant. Thus Linnaeus became the acknowledged originator of the binomial (two-name) system of nomenclature now in use in all sciences. It is a delightful coincidence that while Linnaeus was engaged on his great work, North America, that vast new field of botanical exploration, was being traversed by another Swedish scientist. Peter Kalm sent his specimens and his descriptive notes to Linnaeus, who described and named the new plants in his book. The specimens swelled the great herbarium at the University of Upsala.

Among trees unknown to science before are the Magnolia, named in honor of the great French botanist, Magnol. Robinia, the locust, honors another French botanist, Robin, and his son. Kalmia, the beautiful mountain laurel, immortalizes the name of the devoted explorer who discovered it.

Inevitably, duplication of names attended the work of the early scientists, isolated from each other, and far from libraries and herbaria. Any one discovering a plant he believed to be unknown to science published a description of it in some scientific journal. If some one else had described it at an earlier date, the fact became known in the course of time. The name earliest published is retained, and the later one is dropped to the rank of a synonym. If the name has been used before to describe some other species in the same genus, a new name must be supplied. In the "Cyclopedia of Horticulture" the sugar maple is written: "Acer saccharum, Marsh. (Acer saccharinum, Wang. Acer barbatum, Michx.)" This means that the earliest name given this tree by a botanist was that of Marshall. Wangheimer and Michaux are therefore thrown out; the names given by them are among the synonyms.

Our cork elm was until recently called "Ulmus racemosa, Thomas." The discovery that the name racemosa was given long ago to the cork elm of Europe discredited it for the American tree. Mr. Sargent substituted the name of the author, and it now stands "Ulmus Thomasi, Sarg." Occasionally a generic name is changed. The old generic name becomes the specific name. Box elder was formerly known as "Negundo aceroides, Mœnch." It is changed back to "Acer Negundo, Linn." On the other hand, the tan-bark oak, which is intermediate in character between oaks and chestnuts, has been taken by Professor Sargent in his Manual, 1905, out of the genus Quercus and set in a genus by itself. From "Quercus densiflora, Hook. and Arn." it is called "Pasania densiflora, Sarg.," the specific name being carried over to the new genus.

About one hundred thousand species of plants have been named by botanists. They believe that one half of the world's flora is covered. Trees are better known than less conspicuous plants. Fungi and bacteria are just coming into notice. Yet even among trees new species are constantly being described. Professor Sargent described 567 native species in his "Silva of North America," published 1892-1900. His Manual, 1905, contains 630. Both books exclude Mexico. The silva of the tropics contains many unknown trees, for there are still impenetrable tracts of forest.

The origin of local names of trees is interesting. History and romance, music and hard common sense are in these names—likewise much pure foolishness. The nearness to Mexico brought in the musical piñon and madroña in the southwest. Pecanier and bois d'arc came with many other French names with the Acadians to Louisiana. The Indians had many trees named, and we wisely kept hickory, wahoo, catalpa, persimmon, and a few others of them.

Woodsmen have generally chosen descriptive names which are based on fact and are helpful to learners. Botanists have done this, too. Bark gives the names to shagbark hickory, striped maple, and naked wood. The color names white birch, black locust, blue beech. Wood names red oak, yellow-wood, and white-heart hickory. The texture names rock elm, punk oak, and soft pine. The uses name post oak, canoe birch, and lodge-pole pine.

The tree habit is described by dwarf juniper and weeping spruce. The habitat by swamp maple, desert willow, and seaside alder. The range by California white oak and Georgia pine. Sap is characterized in sugar maple, sweet gum, balsam fir, and sweet birch. Twigs are indicated in clammy locust, cotton gum, winged elm. Leaf linings are referred to in silver maple, white poplar, and white basswood. Color of foliage, in gray pine, blue oak, and golden fir. Shape of leaves, in heart-leaved cucumber tree and ear-leaved umbrella. Resemblance of leaves to other species, in willow oak and parsley haw. The flowers of trees give names to tulip tree, silver-bell tree, and fringe tree. The fruit is described in big-cone pine, butternut, mossy-cup oak, and mock orange.

Many trees retain their classical names, which have become the generic botanical ones, as acacia, ailanthus, and viburnum. Others modify these slightly, as pine from Pinus, and poplar from Populus. The number of local names a species has depends upon the notice it attracts and the range it has. The loblolly pine, important as a lumber tree, extends along the coast from New Jersey to Texas. It has twenty-two nicknames.

The scientific name is for use when accurate designation of a species is required; the common name for ordinary speech. "What a beautiful Quercus alba!" sounds very silly and pedantic, even if it falls on scientific ears. Only persons of very shallow scientific learning use it on such informal occasions.

Let us keep the most beautiful and fitting among common names, and work for their general adoption. There are no hard names once they become familiar ones. Nobody hesitates or stumbles over chrysanthemum and rhododendron, though these sonorous Greek derivatives have four syllables. Nobody asks what these names are "in plain English."

TREES WORTH KNOWING

TREES

PART I

THE LIFE OF THE TREES

The swift unfolding of the leaves in spring is always a miracle. One day the budded twigs are still wrapped in the deep sleep of winter. A trace of green appears about the edges of the bud scales—they loosen and fall, and the tender green shoot looks timidly out and begins to unfold its crumpled leaves. Soon the delicate blade broadens and takes on the texture and familiar appearance of the grown-up leaf. Behold! while we watched the single shoot the bare tree has clothed itself in the green canopy of summer.

How can this miracle take place? How does the tree come into full leaf, sometimes within a fraction of a week? It could never happen except for the store of concentrated food that the sap dissolves in spring and carries to the buds, and for the remarkable activity of the cambium cells within the buds.

What is a bud? It is a shoot in miniature—its leaves or flowers, or both, formed with wondrous completeness in the previous summer. About its base are crowded leaves so hardened and overlapped as to cover and protect the tender shoot. All the tree can ever express of beauty or of energy comes out of these precious little "growing points," wrapped up all winter, but impatient, as spring approaches, to accept the invitation of the south wind and sun.

The protective scale leaves fall when they are no longer needed. This vernal leaf fall makes little show on the forest floor, but it greatly exceeds in number of leaves the autumnal defoliation.

Sometimes these bud scales lengthen before the shoot spares them. The silky, brown scales of the beech buds sometimes add twice their length, thus protecting the lengthening shoot which seems more delicate than most kinds, less ready to encounter unguarded the wind and the sun. The hickories, shagbark, and mockernut, show scales more than three inches long.

Many leaves are rosy, or lilac tinted, when they open—the waxy granules of their precious "leaf green" screened by these colored pigments from the full glare of the sun. Some leaves have wool or silk growing like the pile of velvet on their surfaces. These hairs are protective also. They shrivel or blow away when the leaf comes to its full development. Occasionally a species retains the down on the lower surface of its leaves, or, oftener, merely in the angles of its veins.

The folding and plaiting of the leaves bring the ribs and veins into prominence. The delicate green web sinks into folds between and is therefore protected from the weather. Young leaves hang limp, never presenting their perpendicular surfaces to the sun.

Another protection to the infant leaf is the pair of stipules at its base. Such stipules enclose the leaves of tulip and magnolia trees. The beech leaf has two long strap-like stipules. Linden stipules are green and red—two concave, oblong leaves, like the two valves of a pea pod. Elm stipules are conspicuous. The black willow has large, leaf-like, heart-shaped stipules, green as the leaf and saw-toothed.

Most stipules shield the tender leaf during the hours of its helplessness, and fall away as the leaf matures. Others persist, as is often seen in the black willows.

With this second vernal leaf fall (for stipules are leaves) the leaves assume independence, and take up their serious work. They are ready to make the living for the whole tree. Nothing contributed by soil or atmosphere—no matter how rich it is—can become available for the tree's use until the leaves receive and prepare it.

Every leaf that spreads its green blade to the sun is a laboratory, devoted to the manufacture of starch. It is, in fact, an outward extension of the living cambium, thrust out beyond the thick, hampering bark, and specialized to do its specific work rapidly and effectively.

The structure of the leaves must be studied with a microscope. This laboratory has a delicate, transparent, enclosing wall, with doors, called stomates, scattered over the lower surface. The "leaf pulp" is inside, so is the framework of ribs and veins, that not only supports the soft tissues but furnishes the vascular system by which an incoming and outgoing current of sap is kept in constant circulation. In the upper half of the leaf, facing the sun, the pulp is in "palisade cells," regular, oblong, crowded together, and perpendicular to the flat surface. There are sometimes more than one layer of these cells.

In the lower half of the leaf's thickness, between the palisade cells and the under surface, the tissue is spongy. There is no crowding of cells here. They are irregularly spherical, and cohere loosely, being separated by ample air spaces, which communicate with the outside world by the doorways mentioned above. An ordinary apple leaf has about one hundred thousand of these stomates to each square inch of its under surface. So the ventilation of the leaf is provided for.

The food of trees comes from two sources—the air and the soil. Dry a stick of wood, and the water leaves it. Burn it now, and ashes remain. The water and the ashes came from the soil. That which came from the air passed off in gaseous form with the burning. Some elements from the soil also were converted by the heat into gases, and escaped by the chimneys.

Take that same stick of wood, and, instead of burning it in an open fireplace or stove, smother it in a pit and burn it slowly, and it comes out a stick of charcoal, having its shape and size and grain preserved. It is carbon, its only impurity being a trace of ashes. What would have escaped up a chimney as carbonic-acid gas is confined here as a solid, and fire can yet liberate it.

The vast amount of carbon which the body of a tree contains came into its leaves as a gas, carbon dioxide. The soil furnished various minerals, which were brought up in the "crude sap." Most of these remain as ashes when the wood is burned. Water comes from the soil. So the list of raw materials of tree food is complete, and the next question is: How are they prepared for the tree's use?

The ascent of the sap from roots to leaves brings water with mineral salts dissolved in it. Thus potassium, calcium, magnesium, iron, sulphur, nitrogen, and phosphorus are brought to the leaf laboratories—some are useful, some useless. The stream of water contributes of itself to the laboratory whatever the leaf cells demand to keep their own substance sufficiently moist, and those molecules that are necessary to furnish hydrogen and oxygen for the making of starch. Water is needed also to keep full the channels of the returning streams, but the great bulk of water that the roots send up escapes by evaporation through the curtained doorways of the leaves.

See [page 37]

SHAGBARK HICKORY

See [page 40]

MOCKERNUT FRUIT AND LEAVES

Starch contains carbon, hydrogen, and oxygen, the last two in the exact proportion that they bear to each other in water, H²O. The carbon comes in as carbon dioxide, CO². There is no lack of this familiar gas in the air. It is exhaled constantly from the lungs of every animal, from chimneys, and from all decaying substances. It is diffused through the air, and, entering the leaves by the stomates, comes in contact with other food elements in the palisade cells.

The power that runs this starch factory is the sun. The chlorophyll, or leaf green, which colors the clear protoplasm of the cells, is able to absorb in daylight (and especially on warm, sunny days) some of the energy of sunlight, and to enable the protoplasm to use the energy thus captured to the chemical breaking down of water and carbon dioxide, and the reuniting of their free atoms into new and more complex molecules. These are molecules of starch, C⁶H¹⁰O⁵.

The new product in soluble form makes its way into the current of nutritious sap that sets back into the tree. This is the one product of the factory—the source of all the tree's growth—for it is the elaborated sap, the food which nourishes every living cell from leaf to root tip. It builds new wood layers, extends both twigs and roots, and perfects the buds for the coming year.

Sunset puts a stop to starch making. The power is turned off till another day. The distribution of starch goes on. The surplus is unloaded, and the way is cleared for work next day. On a sunless day less starch is made than on a bright one.

Excess of water and of free oxygen is noticeable in this making of starch. Both escape in invisible gaseous form through the stomates. No carbon escapes, for it is all used up, and a continual supply of CO² sets in from outside. We find it at last in the form of solid wood fibres. So it is the leaf's high calling to take the crude elements brought to it, and convert them into food ready for assimilation.

There are little elastic curtains on the doors of leaves, and in dry weather they are closely drawn. This is to prevent the free escape of water, which might debilitate the starch-making cells. In a moist atmosphere the doors stand wide open. Evaporation does not draw water so hard in such weather, and there is no danger of excessive loss. "The average oak tree in its five active months evaporates about 28,000 gallons of water"—an average of about 187 gallons a day.

In the making of starch there is oxygen left over—just the amount there is left of the carbon dioxide when the carbon is seized for starch making. This accumulating gas passes into the air as free oxygen, "purifying" it for the use of all animal life, even as the absorption of carbon dioxide does.

When daylight is gone, the exchange of these two gases ceases. There is no excess of oxygen nor demand for carbon dioxide until business begins in the morning. But now a process is detected that the day's activities had obscured.

The living tree breathes—inhales oxygen and exhales carbonic-acid gas. Because the leaves exercise the function of respiration, they may properly be called the lungs of trees, for the respiration of animals differs in no essential from that of plants.

The bulk of the work of the leaves is accomplished before midsummer. They are damaged by whipping in the wind, by the ravages of fungi and insects of many kinds. Soot and dust clog the stomates. Mineral deposits cumber the working cells. Finally they become sere and russet or "die like the dolphin," passing in all the splendor of sunset skies to oblivion on the leaf mould under the trees.

The Growth of a Tree

The great chestnut tree on the hillside has cast its burden of ripe nuts, flung down the empty burs, and given its yellow leaves to the autumn winds. Now the owner has cut down its twin, which was too near a neighbor for the well-being of either, and is converting it into lumber. The lopped limbs have gone to the woodpile, and the boards will be dressed and polished and used for the woodwork of the new house. Here is our opportunity to see what the bark of the living tree conceals—to study the anatomy of the tree—to learn something of grain and wood rings and knots.

The most amazing fact is that this "too, too solid flesh" of the tree body was all made of dirty water and carbonic-acid gas. Well may we feel a kind of awe and reverence for the leaves and the cambium—the builders of this wooden structure we call a tree. The bark, or outer garment, covers the tree completely, from tip of farthest root to tip of highest twig. Under the bark is the slimy, colorless living layer, the cambium, which we may define as the separation between wood and bark. It seems to have no perceptible diameter, though it impregnates with its substance the wood and bark next to it. This cambium is a continuous undergarment, lining the bark everywhere, covering the wood of every root and every twig as well as of the trunk and all its larger divisions.

Under the cambium is the wood, which forms the real body of the tree. It is a hard and fibrous substance, which in cross section of root or trunk or limb or twig is seen to be in fine, but distinctly marked, concentric rings about a central pith. This pith is most conspicuous in the twigs.

Now, what does the chestnut tree accomplish in a single growing season? We have seen its buds open in early spring and watched the leafy shoots unfold. Many of these bore clusters of blossoms in midsummer, long yellow spikes, shaking out a mist of pollen, and falling away at length, while the inconspicuous green flowers developed into spiny, velvet-lined burs that gave up in their own good time the nuts which are the seeds of the tree.

The new shoots, having formed buds in the angles of their leaves, rest from their labors. The tree had added to the height and breadth of its crown the exact measure of its new shoots. There has been no lengthening of limb or trunk. But underground the roots have made a season's growth by extending their tips. These fresh rootlets clothed with the velvety root hairs are new, just as the shoots are new that bear the leaves on the ends of the branches.

There is a general popular impression that trees grow in height by the gradual lengthening of trunk and limbs. If this were true, nails driven into the trunk in a vertical line would gradually become farther apart. They do not, as observation proves. Fence wires stapled to growing trees are not spread apart nor carried upward, though the trees may serve as posts for years, and the growth in diameter may swallow up staple and wire in a short time. Normal wood fibres are inert and do not lengthen. Only the season's rootlets and leafy shoots are soft and alive and capable of lengthening by cell division.

The work of the leaves has already been described. The return current, bearing starch in soluble form, flows freely among the cells of the cambium. Oxygen is there also. The cambium cell in the growing season fulfils its life mission by absorbing food and dividing. This is growth—and the power to grow comes only to the cell attacked by oxygen. The rebuilding of its tissues multiplies the substance of the cambium at a rapid rate. A cell divides, producing two "daughter cells." Each is soon as large as its parent, and ready to divide in the same way. A cambium cell is a microscopic object, but in a tree there are millions upon millions of them. Consider how large an area of cambium a large tree has. It is exactly equivalent to the total area of its bark. Two cells by dividing make four. The next division produces eight, then sixteen, thirty-two, sixty-four, in geometric proportion. The cell's power and disposition to divide seems limited only by the food and oxygen supply. The cambium layer itself remains a very narrow zone of the newest, most active cells. The margins of the cambium are crowded with cells whose walls are thickened and whose protoplasm is no longer active. The accumulation of these worn-out cells forms the total of the season's growth, the annual ring of wood on one side of the cambium and the annual layer of bark on the other.

What was once a delicate cell now becomes a hollow wood fibre, thin walled, but becoming thickened as it gets older. For a few years the superannuated cell is a part of the sap wood and is used as a tube in the system through which the crude sap mounts to the leaves. Later it may be stored full of starch, and the sap will flow up through newer tubes. At last the walls of the old cell harden and darken with mineral deposits. Many annual rings lie between it and the cambium. It has become a part of the heart wood of the tree.

The cells of its own generation that were crowded in the other direction made part of an annual layer of bark. As new layers formed beneath them, and the bark stretched and cracked, they lost their moisture by contact with the outer air. Finally they became thin, loose fibres, and scaled off.

The years of a tree's life are recorded with fair accuracy in the rings of its wood. The bark tells the same story, but the record is lost by its habit of sloughing off the outer layers. Occasionally a tree makes two layers of wood in a single season, but this is exceptional. Sometimes, as in a year of drought, the wood ring is so small as to be hardly distinguishable.

Each annual ring in the chestnut stump is distinct from its neighboring ring. The wood gradually merges from a dark band full of large pores to one paler in color and of denser texture. It is very distinct in oak and ash. The coarser belt was formed first. The spring wood, being so open, discolors by the accumulation of dust when exposed to the air. The closer summer wood is paler in color and harder, the pores almost invisible to the unaided eye. The best timber has the highest percentage of summer wood.

If a tree had no limbs, and merely laid on each year a layer of wood made of parallel fibres fitted on each other like pencils in a box, wood splitting would be child's play and carpenters would have less care to look after their tools. But woods differ in structure, and all fall short of the woodworker's ideal. The fibres of oak vary in shape and size. They taper and overlap their ends, making the wood less easily split than soft pine, for instance, whose fibres are regular cylinders, which lie parallel, and meet end to end without "breaking joints."

Fibres of oak are also bound together by flattened bundles of horizontal fibres that extend from pith to cambium, insinuated between the vertical fibres. These are seen on a cross-section of a log as narrow, radiating lines starting from the pith and cutting straight through heart wood and sap wood to the bark. A tangential section of a log (the surface exposed by the removal of a slab on any side) shows these "pith rays," or "medullary rays" as long, tapering streaks. A longitudinal section made from bark to centre, as when a log is "quarter-sawed," shows a full side view of the "medullary rays." They are often an inch wide or more in oak; these wavy, irregular, gleaming fibre bands are known in the furniture trade as the "mirrors" of oak. They take a beautiful polish, and are highly esteemed in cabinet work. The best white oak has 20 per cent. to 25 per cent. of its substance made up of these pith rays. The horny texture of its wood, together with its strength and durability, give white oak an enviable place among timber trees, while the beauty of its pith rays ranks it high among ornamental woods.

The grain of wood is its texture. Wide annual rings with large pores mark coarse-grained woods. They need "filling" with varnish or other substance before they can be satisfactorily polished. Fine-grained woods, if hard, polish best. Trees of slow growth usually have fine-grained wood, though the rule is not universal.

Ordinarily wood fibres are parallel with their pith. They are straight grained. Exceptions to this rule are constantly encountered. The chief cause of variation is the fact that tree trunks branch. Limbs have their origin in the pith of the stems that bear them. Any stem is normally one year older than the branch it bears. So the base of any branch is a cone quite buried in the parent stem. A cross-section of this cone in a board sawed from the trunk is a knot. Its size and number of rings indicate its age. If the knot is diseased and loose, it will fall out, leaving a knot hole. The fibres of the wood of a branch are extensions of those just below it on the main stem. They spread out so as to meet around the twig and continue in parallel lines to its extremity. The fibres contiguous to those which were diverted from the main stem to clothe the branch must spread so as to meet above the branch, else the parent stem would be bare in this quarter. The union of stem and branch is weak above, as is shown by the clean break made above a twig when it is torn off, and the stubborn tearing of the fibres below down into the older stem. A half hour spent at the woodpile or among the trees with a jack-knife will demonstrate the laws by which the straight grain of wood is diverted by the insertion of limbs. The careful picking up and tearing back of the fibres of bark and wood will answer all our questions. Basswood whose fibres are tough is excellent for illustration.

When a twig breaks off, the bark heals the wound and the grain becomes straight over the place. Trees crowded in a forest early divest themselves of their lower branches. These die for lack of sun and air, and the trunk covers their stubs with layers of straight-grained wood. Such timbers are the masts of ships, telegraph poles, and the best bridge timbers. Yet buried in their heart wood are the roots of every twig, great or small, that started out to grow when the tree was young. These knots are mostly small and sound, so they do not detract from the value of the lumber. It is a pleasure to work upon such a "stick of timber."

A tree that grows in the open is clothed to the ground with branches, and its grain is found to be warped by hundreds of knots when it reaches the sawmill. Such a tree is an ornament to the landscape, but it makes inferior, unreliable lumber. The carpenter and the wood chopper despise it, for it ruins tools and tempers.

Besides the natural diversion of straight grain by knots, there are some abnormal forms to notice. Wood sometimes shows wavy grain under its bark. Certain trees twist in growing, so as to throw the grain into spiral lines. Cypresses and gum trees often exhibit in old stumps a veering of the grain to the left for a few years, then suddenly to the right, producing a "cross grain" that defies attempts to split it.

"Bird's-eye" and "curly maple" are prizes for the furniture maker. Occasionally a tree of swamp or sugar maple keeps alive the crowded twigs of its sapling for years, and forms adventitious buds as well. These dwarfed shoots persist, never getting ahead further than a few inches outside the bark. Each is the centre of a wood swelling on the tree body. The annual layers preserve all the inequalities. Dots surrounded by wavy rings are scattered over the boards when the tree is sawed. This is bird's-eye grain, beautiful in pattern and in sheen and coloring when polished. It is cut thin for veneer work. Extreme irregularity of grain adds to the value of woods, if they are capable of a high polish. The fine texture and coloring, combined with the beautiful patterns they display, give woods a place in the decorative arts that can be taken by no other material.

The Fall of the Leaves

It is November, and the glory of the woods is departed. Dull browns and purples show where oaks still hold their leaves. Beech trees in sheltered places are still dressed in pale yellow. The elfin flowers of the witch hazel shine like threads of gold against the dull leaves that still cling. The trees lapse into their winter sleep.

Last week a strange thing happened. The wind tore the red robes from our swamp maples and sassafras and scattered them in tatters over the lawn. But the horse-chestnut, decked out in yellow and green, lost scarcely a leaf. Three days later, in the hush of early morning, when there was not a whiff of a breeze perceptible, the signal, "Let go!" came, and with one accord the leaves of the horse-chestnut fell. In an hour the tree stood knee deep in a stack of yellow leaves; the few that still clung had considerable traces of green in them. Gradually these are dropping, and the shining buds remain as a pledge that the summer story just ended will be told again next year.

Perhaps such a sight is more impressive if one realizes the vast importance of the work the leaves of a summer accomplish for the tree before their surrender.

The shedding of leaves is a habit broad-leaved trees have learned by experience in contact with cold winters. The swamp magnolia is a beautiful evergreen tree in Florida. In Virginia the leaves shrivel, but they cling throughout the season. In New Jersey and north as far as Gloucester, where the tree occurs sparingly, it is frankly deciduous. Certain oaks in the Northern states have a stubborn way of clinging to their dead leaves all winter. Farther south some of these species grow and their leaves do not die in fall, but are practically evergreen, lasting till next year's shoots push them off. The same gradual change in habit is seen as a species is followed up a mountain side.

The horse-chestnut will serve as a type of deciduous trees. Its leaves are large, and they write out, as if in capital letters, the story of the fall of the leaf. It is a serial, whose chapters run from July until November. The tree anticipates the coming of winter. Its buds are well formed by midsummer. Even then signs of preparation for the leaf fall appear. A line around the base of the leaf stem indicates where the break will be. Corky cells form on each side of this joint, replacing tissues which in the growing season can be parted only by breaking or tearing them forcibly. A clean-cut zone of separation weakens the hold of the leaf upon its twig, and when the moment arrives the lightest breath of wind—even the weight of the withered leaf itself—causes the natural separation. And the leaflets simultaneously fall away from their common petiole.

There are more important things happening in leaves in late summer than the formation of corky cells. The plump green blades are full of valuable substance that the tree can ill afford to spare. In fact, a leaf is a layer of the precious cambium spread out on a framework of veins and covered with a delicate, transparent skin—a sort of etherealized bark. What a vast quantity of leaf pulp is in the foliage of a large tree!

As summer wanes, and the upward tide of sap begins to fail, starch making in the leaf laboratories declines proportionately. Usually before midsummer the fresh green is dimmed. Dust and heat and insect injuries impair the leaf's capacity for work. The thrifty tree undertakes to withdraw the leaf pulp before winter comes.

But how?

It is not a simple process nor is it fully understood. The tubes that carried the products of the laboratory away are bound up with the fibres of the leaf's skeleton. Through the transparent leaf wall the migration of the pulp may be watched. It leaves the margins and the net veins, and settles around the ribs and mid vein, exactly as we should expect. Dried and shrivelled horse-chestnut leaves are still able to show various stages in this marvellous retreat of the cambium. If moisture fails, the leaf bears some of its green substance with it to the earth. The "breaking down of the chlorophyll" is a chemical change that attends the ripening of a leaf. (Leaf ripening is as natural as the ripening of fruit.) The waxy granules disintegrate, and a yellow liquid shows its colors through the delicate leaf walls. Now other pigments, some curtained from view by the chlorophyll, others the products of decomposition, show themselves. Iron and other minerals the sap brought from the soil contribute reds and yellows and purples to the color scheme. As drainage proceeds, with the chemical changes that accompany it, the pageant of autumn colors passes over the woodlands. No weed or grass stem but joins in the carnival of the year.

Crisp and dry the leaves fall. Among the crystals and granules that remain in their empty chambers there is little but waste that the tree can well afford to be rid of—substances that have clogged the leaf and impeded its work.

We have been mistaken in attributing the gay colors of autumnal foliage to the action of frost. The ripening of the leaves occurs in the season of warm days and frosty nights, but it does not follow that the two phenomena belong together as cause and effect. Frost no doubt hastens the process. But the chemical changes that attend the migration of the carbohydrates and albuminous materials from the leaf back into twig and trunk and root for safe keeping go on no matter what the weather.

In countries having a moist atmosphere autumn colors are less vivid. England and our own Pacific Coast have nothing to compare with the glory of the foliage in the forests of Canada and the Northeastern states, and with those on the wooded slopes of the Swiss Alps, and along the Rhine and the Danube. Long, dry autumns produce the finest succession of colors. The most brilliant reds and yellows often appear long before the first frost. Cold rains of long duration wash the colors out of the landscape, sometimes spoiling everything before October. A sharp freeze before the leaves expect it often cuts them off before they are ripe. They stiffen and fall, and are wet and limp next day, as if they had been scalded; all their rich cell substance lost to the tree, except as they form a mulch about its roots. But no tree can afford so expensive a fertilizer, and happily they are not often caught unawares.

Under the trees the dead leaves lie, forming with the snow a protective blanket for the roots. In spring the rains will leach out their mineral substance and add it to the soil. The abundant lime in dead leaves is active in the formation of humus, which is decayed vegetable matter. We call it "leaf mould." So even the waste portions have their effectual work to do for the tree's good.

The leaves of certain trees in regions of mild winters persist until they are pushed off by the swelling buds in spring. Others cling a year longer, in sorry contrast with the new foliage. We may believe that this is an indolent habit induced by climatic conditions.

Leaves of evergreens cling from three to five years. Families and individuals differ; altitude and latitude produce variations. An evergreen in winter is a dull-looking object, if we could compare it with its summer foliage. Its chlorophyll granules withdraw from the surface of the leaf.

They seek the lower ends of the palisade cells, as far as they can get from the leaf surface, assume a dull reddish brown or brownish yellow color, huddle in clumps, their water content greatly reduced, and thus hibernate, much as the cells of the cambium are doing under the bark. In this condition, alternate freezing and thawing seem to do no harm, and the leaves are ready in spring to resume the starch-making function if they are still young. Naturally, the oldest leaves are least capable of this work, and least is expected of them. Gradually they die and drop as new ones come on. As among broad-leaved trees, the zone of foliage in evergreens is an outer dome of newest shoots; the framework of large limbs is practically destitute of leaves.

How Trees Spend the Winter

Nine out of every ten intelligent people will see nothing of interest in a row of bare trees. They casually state that buds are made in the early spring. They miss seeing the strength and beauty of tree architecture which the foliage conceals in summertime. The close-knit, alive-looking bark of a living tree they do not distinguish from the dull, loose-hung garment worn by the dead tree in the row. All trees look alike to them in winter.

Yet there is so much to see if only one will take time to look. Even the most heedless are struck at times with the mystery of the winter trance of the trees. They know that each spring reënacts the vernal miracle. Thoughtful people have put questions to these sphinx-like trees. Secrets the bark and bud scales hide have been revealed to those who have patiently and importunately inquired. A keen pair of eyes used upon a single elm in the dooryard for a whole year will surprise and inform the observer. It will be indeed the year of miracle.

A tree has no centre of life, no vital organs corresponding to those of animals. It is made up, from twig to root, of annual, concentric layers of wood around a central pith.

It is completely covered with a close garment of bark, also made of annual layers. Between bark and wood is the delicate undergarment of living tissue called cambium. This is disappointing when one comes to look for it, for all there is of it is a colorless, slimy substance that moistens the youngest layers of wood and bark, and forms the layer of separation between them. This cambium is the life of the tree. A hollow trunk seems scarcely a disability. The loss of limbs a tree can survive and start afresh. But girdle its trunk, exposing a ring of the cambium to the air, and the tree dies. The vital connection of leaves and roots is destroyed by the girdling; nothing can save the tree's life. Girdle a limb or a twig and all above the injury suffers practical amputation.

The bark protects the cambium, and the cambium is the tissue which by cell multiplication in the growing season produces the yearly additions of wood and bark. Buds are growing points set along the twigs. They produce leafy shoots, as a rule. Some are specialized to produce flowers and subsequently fruits. Leaves are extensions of cambium spread in the sun and air in the season when there is no danger from frosts. The leaves have been called the stomachs of a tree. They receive crude materials from the soil and the air and transmute them into starch under the action of sunlight. This elaborated sap supplies the hungry cambium cells during the growing season, and the excess of starch made in the leaf laboratories is stored away in empty wood cells and in every available space from bud to root tip, from bark to pith.

The tree's period of greatest activity is the early summer. It is the time of growth and of preparation for the coming winter and for the spring that follows it. Winter is the time of rest—of sleep, or hibernation. A bear digs a hollow under the tree's roots and sleeps in it all winter, waking in the spring. In many ways the tree imitates the bear. Dangerous as are analogies between plants and animals, it is literally true that the sleeping bear and the dormant tree have each ceased to feed. The sole activity of each seems to be the quiet breathing.

Do trees really breathe? As truly and as incessantly as you do, but not as actively. Other processes are intermittent, but breathing must go on, day and night, winter and summer, as long as life lasts. Breathing is low in winter. The tree is not growing. There is only the necessity of keeping it alive.

See [page 42]

A GROVE OF BEECHES

See [page 44]

THE CHESTNUT

Leaves are the lungs of plants. In the growing season respiration goes on at a vigorous rate. The leaves also throw off in insensible vapor a vast quantity of water. This is called transpiration in plants; in animals the term used is perspiration. They are one and the same process. An average white oak tree throws off 150 gallons of water in a single summer day. With the cutting off of the water supply at the roots in late fall, transpiration is also cut off.

The skin is the efficient "third lung" of animals. The closing of its pores causes immediate suffocation. The bark of trees carries on the work of respiration in the absence of the leaves. Bark is porous, even where it is thickest.

Look at the twigs of half a dozen kinds of trees, and find the little raised dots on the smooth surface. They usually vary in color from the bark. These are lenticels, or breathing pores—not holes, likely to become clogged with dust, but porous, corky tissue that filters the air as it comes in. In most trees the smooth epidermis of twigs is shed as the bark thickens and breaks into furrows. This obscures, though it does not obliterate, the air passages. Cherry and birch trees retain the silky epidermal bark on limbs, and in patches, at least, on the trunks of old trees. Here the lenticels are seen as parallel, horizontal slits, open sometimes, but usually filled with the characteristic corky substance. They admit air to the cambium.

There is a popular fallacy that trees have no buds until spring. Some trees have very small buds. But there is no tree in our winter woods that will not freely show its buds to any one who wishes to see them. A very important part of the summer work of a tree is the forming of buds for next spring. Even when the leaves are just unfolding on the tender shoots a bud will be found in each angle between leaf and stem. All summer long its bud is the especial charge of each particular leaf. If accident destroy the leaf, the bud dies of neglect. When midsummer comes the bud is full grown, or nearly so, and the fall of the leaf is anticipated. The thrifty tree withdraws as much as possible of the rich green leaf pulp, and stores it in the twig to feed the opening buds in spring.

What is there inside the wrappings of a winter bud? "A leaf," is the usual reply—and it is not a true one. A bud is an embryo shoot—one would better say, a shoot in miniature. It has very little length or diameter when the scales are stripped off. But with care the leaves can be spread open, and their shape and venation seen. The exact number the shoot was to bear are there to be counted. Take a horse-chestnut bud—one of the biggest ones—and you will unpack a cluster of flowers distinct in number and in parts. The bud of the tulip tree is smaller, but it holds a single blossom, and petals, stamens, and pistil are easily recognizable. Some buds contain flowers and no leaves. Some have shoots with both upon them. If we know the tree, we may guess accurately about its buds.

There is another popular notion, very pretty and sentimental, but untrue, that study of buds is bound to overthrow. It is the belief that the woolly and silky linings of bud scales, and the scales themselves, and the wax that seals up many buds are all for the purpose of keeping the bud warm through the cold winter. The bark, according to the same notion, is to keep the tree warm. This idea is equally untenable. There is but feeble analogy between a warm-blooded animal wrapped in fur, its bodily heat kept up by fires within (the rapid oxidation of fats and carbohydrates in the tissues), and the winter condition of a tree. Hardy plants are of all things the most cold blooded. They are defended against injuries from cold in an effective but entirely different way.

Exposure to the air and consequent loss of its moisture by evaporation is the death of the cambium—that which lies under the thick bark and in the tender tissues of the bud, sealed up in its layers of protecting scales.

The cells of the cambium are plump little masses of protoplasm, semi-fluid in consistency in the growing season. They have plenty of room for expansion and division. Freezing would rupture their walls, and this would mean disintegration and death. Nature prepares the cells to be frozen without any harm. The water of the protoplasm is withdrawn by osmosis into the spaces between the cells. The mucilaginous substance left behind is loosely enclosed by the crumpled cell wall. Thus we see that a tree has about as much water in it in winter as in summer. Green wood cut in winter burns slowly and oozes water at the ends in the same discouraging way as it does in summertime.

A tree takes on in winter the temperature of the surrounding air. In cold weather the water in buds and trunk and cambium freezes solid. Ice crystals form in the intercellular spaces where they have ample room, and so they do no damage in their alternate freezing and thawing. The protoplasm stiffens in excessive cold, but when the thermometer rises, life stirs again. Motion, breathing, and feeding are essential to cell life.

It is hard to believe that buds freeze solid. But cut one open in a freezing cold room, and before you breathe upon it take a good look with a magnifier, and you should make out the ice crystals. The bark is actually frozen upon a stick of green stovewood. The sap that oozes out of the pith and heart wood was frozen, and dripped not at all until it was brought indoors.

What is meant by the freezing of fruit buds in winter, by which the peach crop is so often lost in Northern states? When spring opens, the warmth of the air wakes the sleeping buds. It thaws the ice in the intercellular spaces, and the cells are quick to absorb the water they gave up when winter approached. The thawing of the ground surrounds the roots with moisture. Sap rises and flows into the utmost twig. Warm days in January or February are able to deceive the tree to this extent. The sudden change back to winter again catches them. The plump cells are ruptured and killed by the "frost bite."

It is a bad plan to plant a tender kind of tree on the south side of a house or a wall. The direct and the reflected warmth of the sun forces its buds out too soon, and the late frosts cut them off. There is rarely a good yield on a tree so situated.

There is no miracle like "the burst of spring." Who has watched a tree by the window as its twigs began to shine in early March, and the buds to swell and show edges of green as their scales lengthened? Then the little shoot struggled out, casting off the hindering scales with the scandalous ingratitude characteristic of infancy. Feeble and very appealing are the limp baby leaves on the shoot, as tender and pale green as asparagus tips. But all that store of rich nutritive material is backing the enterprise. The palms are lifted into the air; they broaden and take on the texture of the perfect, mature leaf. Scarcely a day is required to outgrow the hesitation and inexperience of youth. The tree stands decked in its canopy of leaves, every one of which is ready and eager to assume the responsibilities it faces. The season of starch making has opened.

Cut some twigs of convenient trees in winter. Let them be good ones, with vigorous buds, and have them at least two feet long. You may test this statement I have made about the storing of food in the twigs, and the one about the unfolding of the leafy shoots. Get a number of them from the orchard—samples from cherry, plum, and apple trees; from maple and elm and any other familiar tree. Put them in jars of water and set them where they get the sun on a convenient window shelf. Give them plenty of water, and do not crowd them. It is not necessary to change the water, but cutting the ends slanting and under water every few days insures the unimpeded flow of the water up the stems and the more rapid development of the buds you are watching. When spring comes there are too many things that demand attention. The forcing of winter buds while yet it is winter is the ideal way to discover the trees' most precious secrets.

PART II

THE NUT TREES

The Walnuts—The Hickories—The Beech—The Chestnuts—The Oaks—The White Oak Group—The Black Oak Group—The Horse-Chestnuts, or Buckeyes—The Lindens, or Basswoods

THE WALNUTS

Hickories are included with their near relatives, the walnuts, in one of the most important of all our native tree groups. They are distinct, yet they have many traits in common—the flowers and the nut fruits, the hard resinous wood, with aromatic sap and leaves of many leaflets, instead of a single blade.

The walnuts are decidedly "worth knowing." All produce valuable timber and edible nuts, and all are good shade trees. Four native walnuts are well known in this country, for in October, every tree in every bit of woods is likely to be visited by school boys with bags, eager to gather the nuts before some other boy finds the tree, and thus establishes a prior claim upon it. The curiously gnawed shells outside the winter storehouse of some furry woods-dweller reveal the most successful competitor boys have, the constant watcher of the nut trees, a harvester who works at nothing else while the season is on.

The Southwestern Walnut

Juglans rupestris, Engelm.

The walnut of the Southwest grows into a spreading, luxuriant tree, where its roots find water. But on the canyon sides, and higher on mountain slopes, it becomes a stunted shrub, because of lack of moisture.

The nut is smaller than that of the eastern walnuts and has a thick shell, but the kernel is sweet and keeps its rich flavor for a long time. The Mexicans and Indians are glad to have this nut added to the stores they gather for their winter food.

One striking feature of this tree is the pale, cottony down on its twigs, which sometimes persists three or four years. The long limbs droop at the extremities, almost deserving to be called "weeping." But nothing could be more cheerful in color than the yellow-green foliage, shining in the sun, against the white bark of the tree. In autumn the foliage turns bright yellow. A specimen, much admired, grows in the Arnold Arboretum in Boston.

The California Walnut

J. californica, Wats.

The California walnut is a stocky, round-headed tree, with heavy, drooping branches, and bark that is white and smooth on limbs and on trunks of young trees. Ultimately the trunk turns nearly black, and is checked into broad, irregular ridges. In bottom lands, along the courses of rivers, back thirty miles from the coast, these trees are found, from the Sacramento Valley to the southern slopes of the San Bernardino Mountains.

The foliage is bright pale green, feathery, the leaflets often curved to sickle form, showing paler silky linings. Californians admire and plant this tree for shade and ornament. Its greatest value is as a hardy stock upon which the "English" walnut is grafted by nurserymen, for planting orchards of this commercial nut. The fruit of the native nut is excellent, but it cannot compete with the thin-shelled nut that came from Persia, via England.

The Butternut, White Walnut, or Oilnut

J. cinerea, Linn.

In eastern woods the butternut is known by its long, pointed nuts, with deeply and raggedly sculptured shells, in fuzzy, clammy, sticky husks that stain the hands of him who attempts to get at the oily meat before the husks are dry. This dark stain was an important dye in the time when homespun cotton cloth was worn by men and boys. The modern khaki resembles in color the "butternut jeans," in which backwoods regiments of the Civil War were clad. Butternut husks and bark yield also a drug of cathartic properties.

Pickling green oilnuts in their husks is a housewifely industry, on the summer programme of many housewives still, if the woods near by furnish the raw material for employing her great-grandmother's recipe, brought from England, or perhaps from France. The green nuts are tested with a knitting needle. If it goes through them with no difficulty, and yet the nuts are of good size, they are ready. Vigorous rubbing removes the fuzz after the nuts are scalded. Then they are pickled whole, in spiced vinegar, and are a rare, delectable relish with meats for the winter table.

See [page 42]

WEEPING BEECH

See [page 31]

BLACK WALNUT

A butternut tree, beside the road, or elsewhere, with room to grow, has a short trunk, and a low, broad head, with a downward droop to the horizontal limbs. The bark is light brown, the limbs grayish green, the twigs and leaves all ooze a clammy, waxy, aromatic sap, and are covered with fine hairs of velvety abundance.

Because it is low and rather wayward in growth, late to leaf out in spring, and early to shed its leaves in summer, the butternut is not a good street tree. It breaks easily in the wind, and crippled trees are more common than well-grown specimens. Insect and fungous enemies beset the species, and take advantage of breaks to invade the twigs through the chambered pith. Short-lived trees they are, whose brown, satiny wood is used in cabinet work, but is not plentiful.

The Black Walnut

J. nigra, Linn.

The black walnut (see illustrations, pages [31], [70]) is the second species east of the Rocky Mountains, and the tree chiefly depended upon, during the century just closed, by the makers of furniture of the more expensive grades. Black walnut wood is brown, with purplish tones in it, and a silvery lustre, when polished. Its hardness and strength commend it to the boat and ship builder. Gunstock factories use quantities of this wood. In furniture and interior woodwork, the curly walnut, found in the old stumps of trees cut long before, is especially sought for veneering panels. Old furniture, of designs that have passed out, are often sold to the factories, and their seasoned wood cut thin for veneering.

Walnut trees one hundred and fifty feet high were not uncommon in the forests primeval, in the basin of the Ohio and Wabash rivers. These giants held up their majestic heads far over the tops of oaks and maples in the woods. They were slaughtered, rolled together, and burned by the pioneers, clearing the land for agriculture. These men had a special grudge against walnut trees, they were so stubborn—so hard to make away with. How unfortunate it is that our ancestors had the patience to go forward and conquer the unconquerable ones. Had they weakly surrendered, and let these trees stand, we should have had them for the various uses to which we put the finest lumber trees to-day.

Unhappily, the growing of young trees has not been extensively undertaken to replace those destroyed. The newer forestry is awake to the need, and the loss may be made good, from this time forward.

The black walnut is nearly globular, deeply sculptured, with a sweet nut rich in oil, very good if one eats but a few at a time. Locally, they find their way to market, but they soon become rancid in the grocer's barrel. At home, boys spread them, in their smooth, yellow-pitted husks, on the roof of the woodshed, for instance, so the husks can dry while the nuts are seasoning. No walnut opens its husk in regular segments, as the hickories all do. But the husking is not hard. The thick shells require careful management of the hammer or nut-cracker, to avoid breaking the meats.

Dark as is its wood and bark, no walnut tree in full leaf is sombre. The foliage is bright, lustrous, yellow-green, graceful, dancing. A majestic tree, with a luxuriant crown from May till September, this walnut needs room to display its notable contour and size. It deserves more popularity than it enjoys as a tree for parks. No tree is more interesting to watch as it grows.

The bitter spongy husk deters the squirrels from gnawing into the nut until the husk is dry and brittle. Hidden in the ground, the shell absorbs moisture, and winter frost cracks it, by the gentle but irresistible force of expanding particles of water as they turn to ice. So the plantlet has no hindrance to its growth when spring opens.

Imitating nature, the nurseryman lays his walnuts and butternuts in a bed of sand or gravel, one layer above another, and lets the rain and the cold do the rest. In spring the "stratified" nuts are ready for planting. Sometimes careful cracking of the shell prepares the nut to sprout when planted.

The Japanese walnuts (J. Sieboldiana and J. cordiformis) are grown to a limited extent in states where the English walnut is not hardy. They are butternuts, and very much superior to our native species. A Manchurian walnut has been successfully introduced, but few people but the pioneers in nut culture know anything about these exotic species. South America and the West Indies have native species. So we shall not be surprised, in our travels, to find walnuts in the woods of many continents.

The English Walnut

J. regia, Linn.

Originally at home in the forests of Persia and northwestern India, the English walnut was grown for its excellent nuts in the warm countries of Europe and Asia. It was a tree of great reputation when Linnaeus gave it the specific name that means royal. Indeed, this is the tree which gave to all the family the name "Juglans," which means, "Jove's acorn," in the writings of Roman authors. Kings made each other presents of these nuts, and so the range of the species was extended, even to England, by the planting of nuts from the south.

It became the fad of gardeners, before the fifteenth century, to improve the varieties, and to compete with others in getting the thinnest shell, the largest nut, the sweetest kernel, just as horticulturists do now. In 1640 the herbalist Parkinson wrote about a variety of "French wallnuts, which are the greatest of any, within whose shell are often put a paire of fine gloves, neatly foulded up together." Another variety he mentions "whose shell is so tender that it may easily be broken between one's fingers, and the nut itsself is very sweete."

In England, the climate prevents the ripening of the fruit of walnut trees. But the nuts reach good size, and are pickled green, for use as a relish; or made into catsups—husks and all being used, when a needle will still puncture the fruit with ease.

In America, the first importations of the walnuts came from the Mediterranean countries, by way of England, "the mother country." In contradistinction to our black walnuts and butternuts, these nuts from overseas were called by the loyal colonists "English walnuts," and so they remain to this day in the markets of this country.

It was natural and easy to grow these trees in the Southern states. But little had been done to improve them, or to grow them extensively for market, until California undertook to compete with Europe for the growing American trade. Now the crop reaches thousands of tons of nuts, and millions of dollars come back each year to the owners of walnut ranches. Hardy varieties have extended the range of nut-orcharding; and so has the grafting of tender varieties on stock of the native black walnut of California.

The beauty of this Eurasian walnut tree would justify planting it merely for the adornment of parks and private grounds. Its broad dome of bright green foliage in summer, and its clean gray trunk and bare branches in winter, are attractive features in a landscape that has few deciduous trees. A fine dooryard tree that bears delicious nuts, after furnishing a grateful shade all summer, is deserving the popularity it enjoys with small farmers and owners of the simplest California homes.

As a lumber tree, the walnut of Europe has long been commercially important. It is the staple wood for gun-stocks, and during wars the price has reached absurd heights, one country bidding against its rival to get control of the visible supply. Furniture makers use quantities of the curly walnut often found in stumps of old trees. The heart wood, always a rich brown, is often watered and crimped in curious and intricate patterns, that when polished blend the loveliest dark and light shades with the characteristic walnut lustre, to reward the skilled craftsman.

In the United States this wood is rarely seen, because the trees are grown for their nuts. They require several years to come into bearing, are long-lived, have few enemies, and need little pruning as bearing age approaches.

THE HICKORIES

Americans have a right to be proud that the twelve hickory species are all natives of this country. Eleven of the twelve are found in the eastern half of the United States; one, only, strays into the forests of Mexico. No other country has a native hickory.

Indians of the Algonkin tribe named this tree family, and taught the early colonists in Virginia to use for food the ripe nuts of the shagbark and mockernut. After cracking the shells, the procedure was to boil and strain the mixture, which gave them a rich, soupy liquid. Into this they stirred a coarse meal, made by grinding between stones the Indian corn. The mush was cooked slowly, then made into cakes, which were baked on hot stones. No more delicious nor wholesome food can be imagined than this. Frequently the soup was eaten alone; its name, "Powcohicora," gave the trees their English name, part of which the botanist, Rafinesque, took, Latinized, and set up as the name of the genus.

Cut a twig of any hickory tree, and you realize that the wood is close-grained and very springy. The pith is solid, with a star form in cross-section, corresponding to the ranking of the leaves on the twigs. The wind strews no branches under a hickory tree, for the fibres of the wood are strong and flexible enough to resist a hurricane. (See illustrations, pages [6], [71].)

Hickory wood is unequalled for implements which must resist great strain and constant jarring. The running-gear of wagons and carriages, handles of pitchforks, axes, and like implements require it. Thin strips, woven into baskets for heavy market use, are almost indestructible. No fuel is better than seasoned hickory wood.

Shagbark or Shellbark

Hicoria ovata, Britt.

The shagbark has gray bark that is shed in thin, tough, vertical strips. Attached by the middle, these strips often spring outward, at top and bottom, giving the bole a most untidy look (see illustrations, pages [6], [71]), and threatening the trousers of any boy bold enough to try climbing into the smooth-barked top to beat off the nuts.

In spite of the ragged-looking trunk, a shagbark grown in the open is a noble tree. The limbs are angular, but they express strength to the utmost twig, as the bare oblong of the tree's lofty head is etched against a wintry sky.

The nuts are the chief blessing this tree confers upon the youngsters of any neighborhood. Individual trees differ in the size and quality of their fruit. The children know the best trees, and so do the squirrels, their chief competitors at harvest time.

Frost causes the eager lads to seek their favorite trees, and underneath they find the four-parted husks dropping away from the angled nuts. There is no waiting, as with walnuts, for husking time to come. The tree is prompt about dropping its fruit. Spread for a few weeks, where they can dry, and thieving squirrels will let them alone, hickory nuts reach perfect condition for eating. Fat, proteid, and carbohydrates are found in concentrated form in those delicious meats. We may not know their dietetic value, but we all remember how good and how satisfying they are. No tree brings to the human family more valuable offerings than this one, rugged and ragged though it be.

The Big Shellbark

H. lacinata, Sarg.

The big shellbark, like the little shellbark, is a common forest tree in the Middle West and Middle Atlantic states. It has a shaggy trunk, stout limbs, picturesquely angular, and it bears nuts that are sweet and of delicious flavor. In winter the orange-colored twigs, large terminal buds, and persistent stems of the dead leaves are distinguishing traits. These petioles shed the five to nine long leaflets and then stay on, their enlarged bases firmly tied by fibre bundles to the scar, though the stems writhe and curve as if eager to be free to die among the fallen blades.

"King nuts," as the fruit of this tree is labelled in the markets, do not equal the little hickory nuts in quality, and their thick shells cover meats very little larger. But the nut in its husk on the tree is often three inches long—a very impressive sight to hungry nut-gatherers.

In summer the downy leaf-linings and the uncommon size of the leaves best distinguish this tree from its near relative, whose five leaflets are smooth throughout, small, very rarely counting seven.

See [page 42]

WHITE OAK

See [page 51]

BUR, OR MOSSY-CUP, OAK—LEAVES AND FRUIT

The Pecan

H. Pecan, Britt.

The pecan tree bears the best nuts in the hickory family. This species is coming to be a profitable orchard tree in many sections of the South. Most of the pecan nuts in the market come from wild trees in the Mississippi Basin. But late years have seen great strides taken to establish pecan growing as a paying horticultural enterprise in states outside, as well as within, the tree's natural range. And these efforts are succeeding.

Experiment stations have tested seedling trees and selected varieties of known merit, until they know by actual experiment that pecans can be raised successfully in the Carolinas and in other states where the native species does not grow wild. Thin-shelled varieties, with the astringent red shell-lining almost eliminated, have been bred by selection, and propagated by building on native stock. The trees have proved to be fast-growing, early-fruiting, and easy to grow and protect from enemies.

The market pays the highest price for pecans. The popularity of this nut is deserved, because by analysis it has the highest food value combined with the most delicate and delicious flavor. No nut is so rich in nutriment. None has so low a percentage of waste. The demand for nuts is constantly increasing as the public learns that the proteid the body needs can be obtained from nuts as well as from meat.

Pecans have suffered in competition with other nuts because they are difficult to get out of the shells without breaking the meats. The old-fashioned hammer and block is not the method for them. A cracker I saw in use on the street corner in Chicago delighted me. Clamped to the nut-vendor's stall, it received the nut between two steel cups and, by the turn of a wheel, crowded it so that the shell buckled and broke where it is thinnest, around the middle, and the meat came out whole.

The Mockernut

H. alba, Britt.

The mockernut is a mockery to him who hopes for nuts like those of either shagbark. The husk is often three inches long. Inside is a good-sized nut, angled above the middle, suggesting the shagbark. But what a thick, obstinate shell, when one attempts to "break and enter!" And what a trifling, insipid meat one finds, to repay the effort! Quite often there is nothing but a spongy remnant or the shell is empty. (See illustration, [page 7].)

As a shade tree, the mockernut has real value, showing in winter a tall, slender pyramidal form, with large terminal buds tipping the velvety, resinous twigs. The bark is smooth as that of an ash, with shallow, wavy furrows, as if surfaced with a silky layer of new healing tissue, thrown up to fill up all depressions. Mockernut leaves are large, downy, yellow-green, turning to gold in autumn. Crushed they give out an aroma suggesting a delicate perfume.

The flowers are abundant, and yet the most surprising show of colors on this tree comes in late April, when the great buds swell. The outer scales fall, and the inner ones expand into ruddy silken sheathes that stand erect around the central cluster of leaves, not yet awake, and every branch seems to hold up a great red tulip! The sight is wonderful. Nothing looks more flower-like than these opening hickory buds, and to the unobserving passerby the transformation is nothing short of a miracle. In a day, the leaves rise and spread their delicate leaflets, lengthening and becoming smooth, as the now useless red scales fall in a shower to the ground.

The Pignut

H. glabra, Britt.

The pignut deserves the better name, "smooth hickory," a more ingratiating introduction to strangers. A graceful, symmetrical tree, with spreading limbs that end in delicate, pendulous branches, and gray bark checked into a maze of intersecting furrows, it is an ornament to any park, even in the dead of winter. In summer the tree laughs in the face of the sun, its smooth, glossy, yellow-green leaflets, five to seven on a stem, lined with pale green or yellow. In spring the clustered fringes among the opening leaves are the green and gold stamen flowers. The curiously angled fertile flowers, at the tips of twigs, are green, with yellow stigmas. Autumn turns the foliage to orange and brown, and lets fall the pear-shaped or rounded fruit, each nut obscurely four-angled and held fast at the base by the thin, 4-ridged husk, that splits scarcely to the middle. The kernel is insipid, sometimes bitter, occasionally rather sweet. Country boys scorn the pignut trees, leaving their fruit for eager but unsophisticated nut-gatherers from the towns.

Pigs used to be turned into the woods to fatten on beech- and oak-"mast." They eagerly devoured the thin-shelled nuts of H. glabra, and thus the tree earned the friendly regard of farmers, and a name that preserves an interesting bit of pioneer history.

The range of the pignut is from Maine to Florida on the Atlantic seaboard, west to the middle of Nebraska and Texas, and from Ontario and Michigan south to the Gulf.

THE BEECH

The American Beech

Fagus Americanus, Sweet.

One of the most widely distributed trees in our country, this is also one of the most useful and most beautiful in any forest. It is the sole representative of its genus in the Western Hemisphere. One species is a valuable timber tree in Europe. Three are natives of Asia. A genus near of kin includes the beech trees of the Southern Hemisphere, twelve species in all. There is closer resemblance, however, between our beeches and their next of kin, the chestnuts and oaks.

From the Great Lakes to the Gulf of Mexico, from Florida to Texas, from New England to Wisconsin, beech trees grow; and where they grow they are very likely to form "pure forests," on the slopes of mountains and rich river bottoms. The largest specimens grow in the basin of the lower Ohio River, and on the warm slopes of the Alleghany Mountains.

Standing alone, with room for full development, the beech is a fine, symmetrical tree, with horizontal or slightly drooping branches, numerous, thickly set with slender, flexible twigs. The stout trunk supports a round or conical head of very dense foliage. One hundred and twenty feet is the maximum height, with a trunk diameter of three to four feet. (See illustrations, pages [22], [30].)

The older the trees, the greater the amount of red heart wood in proportion to the white sap-wood, next to the bark. Red and white beech wood are distinguished by lumbermen. Red beech makes superior floors, tool-handles, chairs, and the like, and there is no more perfect fuel than seasoned beech wood.

It is unreasonable to think that any but the blind could live where beech trees grow and not know these trees at a glance. The bark is close, unfurrowed, gray, often almost white, and marked with blotches, often nearly round of paler hue.

The branches are dark and smooth and the twigs polished to the long, pointed winter buds. Throughout, the tree is a model of elegant attire, both in color and texture of the investing bark.

In the growing season the leaves are the tree's chief attraction. They are closely plaited, and covered with silvery down, when the bud scales are pushed off in the spring. In a day, the protective fuzz disappears, and the full-grown leaf is seen, thin, strongly feather-veined, uniformly green, saw-toothed. Summer shows the foliage mass almost as fresh, and autumn turns its green to pale gold. Still unblemished, it clings, often until the end of winter, lighting the woods with a ghostly glow, as the rain fades the color out. The silky texture is never quite lost.

The delicate flowers of the beech tree are rarely seen, they fade so soon; the stamen tassels drop off and the forming nuts, with their prickly burs, are more and more in evidence in the leaf angles near the ends of new shoots. With the first frost the burs open, the four walls part, releasing the two nuts, three-angled, like a grain of buckwheat.

The name of this grain was suggested by its resemblance in form to the beechnut, or "buck mast," sweet, nutritious food of so many dwellers in the forest. Buck mast was the food of man when he lived in caves and under the forest cover. We know that beechnuts have a rich, delicate flavor that offsets the disadvantages of their small size and the difficulty of opening their thin but leathery shells. All along the centuries European peoples have counted on this nut, and oil expressed from it, for their own food and the dried leaves for forage for their cattle in winter.

The American pioneer turned his hogs into the beech woods to fatten on the beech-mast, and Thanksgiving turkeys were always finer if they competed with the wild turkey on the same fare.

Birds and lesser mammals do much to plant trees when they carry away, for immediate or future use, seeds that are not winged for flight. Beechnuts are light enough to profit, to some extent, by a high wind. And beech trees in their infancy do well under the shade of other trees. So each fruiting tree is the mother of many young ones. But the seedling trees are not so numerous and important as the sapling growth that rises from the roots of parent trees. By these alone, a few isolated beeches will manage to take possession of the ground around them and to clothe it with so dense a foliage screen that all young growth, except certain ferns and grasses, dies for lack of sun. Before we can realize what is going on, the tract is a pure forest of beech, rapidly enlarging on all sides by the same campaign of extension.

THE CHESTNUTS

Chestnut and Chinquapin

Castanea dentata, Borh., and C. pumila, Mill.

Our native chestnut and its little brother, the chinquapin, are the American cousins of the sweet chestnut of southern Europe. Japan has contributed to American horticulture a native species which bears large but not very sweet nuts, that are good when cooked. Our two trees bear sweet nuts, of a flavor that no mode of cooking improves. In truth, there is no finer nut; and the time to enjoy it to the highest degree is a few weeks after the frost opens the burs and lets the nuts fall. "Along about Thanksgiving," they have lost some of their moisture and are prime.

In foreign countries the chestnut is a rich, nourishing food, comparable to the potato. Who could go into ecstasies over a vegetable that is a staple food for the peasants of Europe, Asia, and North Africa? Our chestnut is no staple. It is a delicacy. It is treasure trove from the autumn woods, and the gathering of the crop is a game in which boys and squirrels are rivals.

Ernest Thompson Seton, always a boy, knows the impatience with which the opening of the burs is watched for, as the belated frosts keep off, and the burs hang tantalizingly closed. The cruel wounds made by the spines and the raw taste of the immature nuts are poor recompense for the labor of nutting before Nature gives the sign that all's ready.

Here is Mr. Seton's estimate of the chestnut of "brown October's woods."

"Whenever you see something kept under lock and key, bars and bolts, guarded and double-guarded, you may be sure it is very precious, greatly coveted. The nut of this tree is hung high aloft, wrapped in a silk wrapper, which is enclosed in a case of sole leather, which again is packed in a mass of shock-absorbing, vermin-proof pulp, sealed up in a waterproof, ironwood case, and finally cased in a vegetable porcupine of spines, almost impregnable. There is no nut so protected; there is no nut in our woods to compare with it as food."