A PINE SHAVING AND AN OAK SPLINTER.
For kindling wood that will split commend me the " soft " pine. Set the hatchet into the top of a stick with no matter how light a stroke, :Ind the spread of the blade sends a cleft on before it. Down the length of the blade the hatchet follows, but never overtakes the cleft unless there is a knot. Then one of two things will happen: either the grain will lead the hatchet by a gentle curve around the knot and on, or it will lead it right into the knot, and the choppt r will have to chop his way out. But that is another story. Let us sit down on the chopping block, and look at our straight-grained kindling stick.
Plainly, pine wood is fibrous stuff, like the lean of meat. Cut it any way you like—across the grain, with the grain, or at any slant. The evidence on this point is always clear. Cut off a shaving that dwindles out into nothing. The wood becomes almost transparent, and frays out into shreds. The finest thread may be torn into still finer ones. The fibers of pine must be very small.
My shaving is Hui inch wide, and shows eighteen binds, each pale shaded to deeper yellow. This means that it took a certain tree eighteen years to produce that inch of wood. It must have been grown by an old tree, and in its old age. A thrifty young t.roe would have dune as much in half the time. Twelve years to the inch is the average, taking all kinds of trees as they come in the woods. Su says ;In eminent authority.
In each yearly band of our pine shaving the dark yellow part is the summer wood. It gradually succeeds the pale spring 'wood. The cells funned in the early part of the growing season are larger and more loosely packed than those formed later. Ibolding our shaving up so that the light will strike its roughest surface, we may readily see bands fibers that cross the grain at right angles, and look like thin blades set vertically and cutting through the ammal layers. These are the pith otys. 'Hwy exteial frown the center of the tree to its circumference. In pine they are numerous tInaigh small, and almost cover ttly radial sec tion. Under the microscope the wood of pine is seen to be made up of straight, hollow cylinders, packed together and closed at both ends.
These are fibers called totrheids. Each lets along its sides little curtained doorways or pores, called bniderrd pits. Through these openings the sap is able to course in and out of the fibers. 'Ihe pith rays are Intndles of fibers, just like the rest, except that they are shorter and smaller.
Amonu. the fibers of pine wood are pockets which are full of resin.
These are nut tubes, but simply intercellular spac( s without walls Ivhich enlarge as the resin. accumulates. Resin is not the sap of pine trees, as
many suppose. It is a substance made by the breaking down of cells. Its origin and use to the tree are not well understood. When a pine tree is wounded resin flows out and covers up the wound, thus preventing the intrusion of disease germs. The gum of cherry trees serves a similar purpose. Whether protoction is the purpose for these substances exist is petite another question, and is at present unanswered.
Our pine kindling stick is a type of the so-called non porous 'woods, which simply means that the fibers are so small that their hollows are invisible to the eve except under a magnifier of high power. _.\11 cone bearing trees have wood of this kind.
No such regularity of shape and arrangement of fibers is to be seen among the woods of the broad-leaved trees. They are all classed as pooms woods. The oak is a type of this class. We may take a stick of oak from the woodpile, or better, examine the surface of any piece of oak furniture. The varnish brims out more clearly the details of structure of the wood.
Oak is coarse-grained wood, full of "holes," but its fibers are tough as sinews and hard as bone. They are spindle-shaped and extremely various in size. They are crowded together, big and little, breaking joints by the overlapping of ends. here is one secret of the toughness of oak wood. Many fibers end near together in pine, and they du not overlap, hence the brittleness of the wood. Oak fibers have many open doors in their sides and ends that permit the fire circulation of the sap. These doors are as yari(clti in shape and size as are the fibers they belong to. They are not curtained as the bordered pits of tracheids are.
The annual rings of oak wood are shaded light to dark. But unlike the pine, the dark edge is the .sprinq wood coarsely porous, and quite narrow in good lumber compared with the band of yellow close knit mmmer wood. Oak lumber has broad and very prominent pith rays crossing the grain. in specimens of good white oak it has been found that they form about 1(3 to 25 per cent of the wood." (F. Roth, in Bulletin No. 10, LT. S. Department of Agriculture.) They form the gleaming bands which are the " mirrors seen in "quarter-sawed" oak. In other than radial sections of the wood they appear as brown, more ur less long and narrow pencils crowded in between the bundles of wood fibers. Because these large pith_ rays interlace the other wood fibers, and because the regular longitudinal fibers are tough. mid overlap their end:, the splitting of oak is a difficult matter compared with the splitting of pine.