The chief difficulty in forest travel, especially in flat lands that are heavily timbered, is the lack of natural outlooks from which one could get a view of distant landmarks. Although there are plenty of marks in the woods themselves by which a trained woodsman can follow a route that he traversed not long before, yet these signs are forever changing, vanishing, being superseded by others. Not only do new growths spring up, but old ones are swept away, sometimes suddenly, as by flood or fire. Hence, when men have once picked out a course through the wroods that they intend to follow again, they leave permanent marks along the way for future guidance. The most conspicuous and durable waymarks that can easily be made are blazes on the trees. It is of no little consequence to a traveler in the wilds that he should know something about blazes and the special uses made of them in the backwoods.
On a thin-barked tree, a blaze is made by a single downward stroke, the axe being held almost parallel with the trunk; but if the bark is thick, an upward and a downward clip must be made, perhaps several of them, because, in any case, the object usually is to expose a good-sized spot of the whitish sapwood of the tree, which, set in the dark framework of the outer bark, is a staring mark in the woods, sure to attract attention, at least while fresh. Outside of white birch forests, white is the most conspicuous color in the woods, until snow falls.
If a blaze is made merely on the outer bark, it will not show so plainly by contrast. This kind of blaze, however, may be preferred for some purposes; for example, by a trapper who does not want to call everybody's attention to where his traps are set. A bark-blaze has the peculiarity that it lasts unaltered, to long as the bark itself endures, preserving its original outlines and distinctness, no matter how Lnuch the tree may grow. But if a wound, however slight, be made through the bark into the sapwood of the tree, so that the sap, which is the tree's blood, exudes, a healing process will at once set in, and the injury, in time, will be covered over. So, as soon as a blaze is made that exposes the wood, the tree begins at once to cover up its scar. This is a slow process. First the edges of the cut will widen, then a sort of lip of smooth new inner bark will form, and this will gradually spread inward over the gash. Once this new skin has formed, the wound will be covered by new annual layers of wood, as well as by new outer bark. Years after the blaze was made, nothing will show on the surface but a slight scar, a sign that takes practised eyes to detect and read.
A blaze always remains at its original height above the ground, and, where two or more spots have been cut in the same tree, they will always stand at the same distance apart. This is because a tree increases its height and girth only by building on top of the previous growth, not by stretching it.
The age of a hack or blaze in a marked tree is determined by chopping out a billet of the wood containing the mark and counting the annular rings of growth from bottom of scar outward, allowing one year for each ring. In counting annular growth, some begin with the first soft lamina (porous part of year's growth), jumping the first hard layer, to the second lamina, and so on. It is more accurate to count the hard strata, for the following reasons: Soft laminae are formed in the spring, when the sap is rising. If a hack is made at that time it may not show until a hard ring forms, over it the next fall or winter, when the sap is down. If the season has been very dry, there may be two runs of sap, hence a double soft ring that year. A mark made in wood when the sap is down (after the fall of leaves) can have its age determined very positively, but if made when the fresh sap is up it may be hard to say whether the mark goes through that year's growth or only to it.
On some kinds of trees, if a blaze goes through to the sap wood, the scar on the bark is hard to identify as an ax mark, because the wood, in growing, spreads it.
The age of an axe mark is hard to determine in birch, and impossible in tupelo or winged elm, owing to irregularity of fiber.
A blaze on a frozen tree makes a bad wound.
A mark on the sheltered side of a tree does not look nearly so old as one opposite, because moisture accumulated makes the bark rot off from the weather side.
Blazes on the bark of chestnut, tulip poplar, young white oak, many locusts, and some other trees, are not apt to be permanent because these trees shed their bark more or less and do not retain marks so well as beech, black birch, Spanish oak, mountain oak, and other close-barked trees. Bark that scales does not hold moss.
Most old woods trails are blazed on only one side of the tree, the side facing the trail, so as to be seen from either direction. Spotted trails (opposite sides blazed as previously described) are seldom made by professional woodsmen except where there is unusual danger of losing the way.
An old line of blazes on spruce or pine trees is much easier to follow than if made on non-resinous trees, because the resin deposited by the oozing sap leaves a very noticeable and durable mark. Similarly, when an inscription has been penciled or painted on a fresh blaze on a pine tree, the sap glazes over the mark and makes it almost imperishable.
In searching out a line of blazes, one should keep his eyes glancing horizontally along a plane about breast-high, because that is the height at which surveyors leave their marks, and others usually follow the custom, unless the line has been spotted by a man on horseback, or from a boat during time of overflow.
When a blazed line turns abruptly, so that a person following might otherwise overrun it, a long slash is made on that side of the tree which faces the new direction.