Jungle Warfare - FM 72-20 War Department Field Manual

In jungle warfare, the soldier often fights two enemies: man and nature. The elimination of nature as an enemy and the use of the jungle itself as an ally are training objectives fully as important as the elimination of the human enemy. The soldier must be trained not to fight the jungle; he must be capable of living successfully in it and making it work for him against the human enemy. The jungle is a strict taskmaster; unless an individual adjusts himself to the conditions imposed by jungle environment, he will be unable to exist long, even if there is no human enemy. It must be remembered that the difficulties imposed by jungle environment are impartially imposed upon enemy as well as friendly troops, and that the unit which better overcomes the difficulties imposed by the environment has a distinct advantage over the opposing force. Section II. NATURE OF JUNGLE 2. Terrain and vegetation The term "jungle" is frequently applied to the entire area where jungles predominate, although in many cases they may cover only a portion of the terrain. The jungle itself is that dense tropical growth including underbrush, trees, vines, and giant ferns, found at elevations between the lower foothills or beaches and the high areas above the timber line. In the areas in which jungle operations are likely to take place, the sequence of growth may be as follows: a. Shore lines, fringed with almost impenetrable mangrove trees, or open beaches lined with bamboo or coconut groves are typical of the coastal regions of jungle areas. Mangrove trees are characteristic of lowlands, and high tides frequently cover the areas where they are found. The result is what is commonly known as "mangrove swamp," where tidal waters cover mud which is one to four feet deep. The twisting roots, the mud, the sharp coral outcroppings, and the maze of low hanging branches make such areas difficult and dangerous to traverse. b. Beyond the shore line there may be pineapple, coconut, sugarcane, or rubber plantations, or rice paddies. Some of these extend a considerable distance inland. The low lying foothills between these plantations and the jungle itself are frequently open to the sunlight, and may contain large areas of brush or long grasses 3 to 10 feet high. c. Next comes the jungle. In some areas, dense jungle extends to the shore line. The undergrowth varies in density according to the amount of sunlight which penetrates the branches of the tree; where it can penetrate, the underbrush is thicker than in jungles where it is excluded. Where the undergrowth is thick, progress (except along the few existing trails) is exceedingly slow and laborious; in many cases a path can be hacked out only with the greatest difficulty, and columns of troops will be in great danger of being attacked in the flanks, or isolated and surrounded. The jungle proper is frequently interrupted by broad grassy savannas or other open spaces; usually these areas are covered with the long grass mentioned above. Water courses, either relatively flush with the adjacent terrain, or following deep, precipitous gorges and gulches, add to the interruptions to progress which the jungle itself presents. In mountainous terrain, streams that are normally shallow may become raging torrents within an hour after a heavy rain. d. In some tropical areas, the jungle is broken by higher elevations where growth is sparse and stunted. Above the timber line, wind and unfertile soil limit vegetation to small, hardy, scrub growth. In general, jungle weather is hot, humid, and characterized by sudden changes.

Republished by Liber Copia LLC for convenient study and reference on any device.