. Bulletin. Forests and forestry -- United States. GKOVND FIRES. 85 of rottiDg fallen trees. (See PI. XLIII.) lu the same way it climbs dead staudin^* trees, and breaks out in bursts of flame liigli in the air. Dead trees help pow- erfully to spread a lire, for in high winds loose pieces of their burning bark are carried to almost incredible dis- tances, and drop into the dry forest far ahead, while in calm weather they scatter burning fragments all about them when they fall. (Seelig. 80.) aROUNU FIRES. When the duft' is very deep or the soil peaty, a fire may burn beneath the surface of the g
. Bulletin. Forests and forestry -- United States. GKOVND FIRES. 85 of rottiDg fallen trees. (See PI. XLIII.) lu the same way it climbs dead staudin^* trees, and breaks out in bursts of flame liigli in the air. Dead trees help pow- erfully to spread a lire, for in high winds loose pieces of their burning bark are carried to almost incredible dis- tances, and drop into the dry forest far ahead, while in calm weather they scatter burning fragments all about them when they fall. (Seelig. 80.) aROUNU FIRES. When the duft' is very deep or the soil peaty, a fire may burn beneath the surface of the ground for weeks or even months, sometimes showing its presence by a lit tie smoke, sometimes without giving any sign of life. Even a heavy rain may fail to quench a tire of this kind, which often breaks out again long after it is be- lieved to be entirely extinct. Fires which thus burn into the ground can sometimes be checked only by digging a trench through the layer of decaying wood and other vegetable matter to the mineral soil beneath. Ground fires usually burn much more slowly than surface fires, but they are exceptionally long lived, and very hard to init out. It is of the first importance to attack such fires quickly, before they have had time to burrow far. Fig. 80.—The effect vi tires. Xot only the old trees are dead, but the seedlings which, succeeded them have perished also. Western Yellow Pine in the BlacK Hills Forest Eeserve, South Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Division of Forestry. Washington : G. P. O.
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