It is hardly possible for a boy to select and purchase wood for his various purposes without some knowledge of the different woods and their peculiar characteristics. No two are exactly alike, and in fact two trees of the same kind growing in different parts of the country under different conditions will produce timber of very different qualities. This is specially noticeable in the tulip or white wood, for example. A tree of this species, growing in a swamp in the South, will yield a very different wood from one grown on high ground in the North.

Again, the same wood is known in different localities by different names, so in order to have a sound knowledge of lumber, it is really necessary to know something about the trees. White wood, just mentioned, is called, in many localities, yellow poplar. As a matter of fact, it is not a poplar, nor is it related to the poplars, being a member of the magnolia family.The following pages, devoted to this subject, are the cream of many talks between our boys, boiled down to the important facts and arranged in some order. It was a hobby of Ralph's, and Harry became so enthusiastic over it that they frequently laid aside their work and took long walks through the country studying trees.

Harry started a small nursery in the garden and is raising young trees from seeds and cuttings. As he remarked to Ralph one day: "It's astonishing how little people know about trees! Why they are the most interesting things that grow. Just think how many things we get from them besides wood; maple sugar, rubber, turpentine, wood alcohol, tannin for making leather, shellac, Canada balsam, spruce gum, and nuts! All of our nuts except peanuts come from trees—hickory, walnuts, butternuts, beechnuts, chestnuts, pecans, almonds, etc."

Ralph noticed that as Harry's interest in the trees grew he became less wasteful of his wood in the shop. The fact that a tree had to be cut, and in most cases killed, in order to furnish him with lumber, seemed to worry him. One day when he was thoughtfully at work in the shop, he blurted out, "It's a shame that so many trees have to be cut down for lumber!""Yes," said Ralph, "it seems so; yet if no lumber was wasted, it would not be so bad. It is estimated that 75 per cent. of the wood cut down is wasted."

"How?" asked the boy.

"Well, in the first place, many lumbermen after cutting the tree down, take just the log or lower part and leave the top to decay. It often happens that they leave the tops and branches as a great mass of litter, which soon becomes as dry as tinder, an invitation to the smallest spark to start a fire, and more woodland is destroyed by fire each year than I care to tell you."

"How much?" asked Harry.

"Every year, between twelve and fifteen million acres, and some years three times as much."

"How much is a million acres?"

"You can get some idea from this: Long Island, N. Y., is a hundred miles long and about twenty across in the widest part. It contains about a million acres. Imagine this covered by solid woods, multiply by fifteen and you would have a good idea of the amount of woodland burned over every year."

"Gracious!" exclaimed the boy. "I should think every tree would have been burned years ago.""Well, this is a big country," said Ralph. "I figured it out once. The United States is large enough to make six hundred states the size of Connecticut, and have room for twenty-five or thirty more. The state of Texas alone could be cut up into a hundred pieces as large as Connecticut.

"The forest fire is one of our worst enemies. It is far worse than the lumberman, because when he cuts down trees it gives hundreds of young seedlings which are struggling to live in the shade a chance to grow and cover the ground with a new forest; but the fire kills these young seedlings and even burns the seeds that are lying in the leaves waiting to grow. That is one of the worst things to be said against the forest fire."

"Does it kill every tree?"

"Oh, no! Trees like the oak sprout from the old roots, but most evergreen trees are killed outright."

"What happens then?"

"Why, it depends. If the forest is mixed, hard woods and conifers, the hard woods, or some of them, will in time send up sprouts, and where you formerly had a mixed stand, you will in a few years have only hard woods, unless some of the evergreens were not touched. In that case, their seeds will in time replace the old evergreens.""How long does it take?"

"From forty to a hundred years to have a large forest. Some evergreens, like the spruce, increase in diameter very slowly."

"What happens when the forest that is burned is all evergreens, and they are all killed?" asked the irrepressible boy.

"The process of reforesting in that case is very slow. Trees of little value, like the poplar or birch, appear first, because their seeds are light and are carried a considerable distance by the wind. If fires pass over the same area every few years, the forest will never come back unless seeds are planted. There are large areas in this country thus denuded, and instead of a forest we have a scrubby growth of bushes that are of little value to anybody.

"Huckleberries grow in burned-over land luxuriantly, and in some sections it is suspected that the people who make money by gathering the berries burn the brush purposely.

"The forest cover is valuable for other things besides timber. The snow melts slowly in an evergreen forest, because the rays of the sun cannot penetrate with full strength. This allows the water to sink into the ground slowly, and to come out lower down in the form of springs."Where there is no forest the snow melts much more quickly, the water rushes down the hills in streams, carrying with it the top soil, which is of so much value to the farmer, cutting the hillsides into gullies, causing floods in the valleys, and filling up the rivers with silt or mud.

"This spoils the streams, ruins the land, and causes millions of dollars' worth of damage to property. If you doubt it, read the newspaper accounts of floods in the valleys of the Ohio, Missouri, and Mississippi every spring."

"But I should think by this time all the soil would be washed away."

"It will be in time. There are large areas in China where the soil is washed away to the bare rock. The population has been obliged to emigrate because when the soil goes, the population can no longer live."

"Well, what are we going to do about it?" asked Harry in amazement.

"Wait a minute," said Ralph, warming up to his subject. "The Mississippi carries into the Gulf of Mexico every year seven and a half billion cubic feet of soil; enough to cover Long Island two inches deep every year."

"What are we going to do?" repeated the boy."We can do one of two things," said Ralph sagely, "We can follow in the footsteps of China and let the land go to ruin; or we can follow the example of Germany, take care of our forests—or what is left of them—and plant new ones. It is one of the greatest questions in this country to-day, and you are going to hear a lot about it before you are twenty-one."