MILITARY GEOGRAPHY
    FOR PROFESSIONALS AND THE PUBLIC

3. LAY OF THE LAND

In peace, soldiers must learn the nature of the land, how steep the mountains are, how the valleys debouch, where the plains lie, and understand the nature of rivers and swamps--then by means of the knowledge and experience gained in one locality, one can easily understand any other.

Niccolo Machiavelli
Discorsi

A U.S. ARMY MAJOR GENERAL WHO ADDRESSED THE NAVAL WAR COLLEGE DURING THE COLD WAR DECLARED without cracking a smile, "Young men of all services must learn terrain or learn Russian." No one will ever know for sure whether he overstated his case, because the United States and the Soviet Union never went to war with each other, but the lay of the land was militarily important long before Rennaissance Man Machiavelli made his pronouncement more than 500 years ago and likely will remain so.

LAND FORMS

Land forms comprise the foundation upon which all other terrestrial features are superimposed (figure 1 is illustrative).¹ They occupy three militarily significant categories, which table 2 lists with the highest, largest, or deepest first. High ground, level land, and depressions each uniquely influence the abilities of air and ground forces to maneuver freely, locate targets, deliver firepower effectively, conduct non-combat operations, coordinate actions, and furnish essential support at strategic, operational, and tactical levels.

HIGH GROUND

"Mountains" and "hills" are imprecise terms, the definitions of which depend on circumstantial interpretations. High spots in southern India's Palmi Hills are equal in elevation to those of the U.S. Appalachian Mountains which, in turn, are small compared with the Alps or Andes. Some summits are saw-toothed, others are smooth. Little correlation may be evident between total elevation, measured from mean sea level to any point on land, and local relief, which measures topographic features from base to top (figure 2). Pike's Peak in Colorado, for example, is 4,000 feet (1,220 meters) higher than the loftiest pinnacle along Lebanon's coastal range, yet local relief is less because its climb begins more than a mile above sea level. Airmen, who set their altimeters according to elevation, view local relief

Figure 1. Land Forms Displayed Schematically

Table 2. Land Forms Listed

from different perspectives than land forces, whose front-line troops may consider hummocks to be high ground. Gradients, which measure how rapidly the ground rises or falls vertically over given horizontal distances, generally are expressed as plus or minus percentage figures, depending on direction of movement (figure 3 shows a +23 percent ascending grade from A to B and -23 percent descending from B to A).

Very steep slopes severely limit military flexibility. Helicopter pilots, for example, must take care that rotor blades don't hit the ground on the uphill side while they hover or decapitate troops when they debark and ensure that the skids will hold instead of sliding

Figure 2. Elevation and Local Relief

downhill if they have to land. The proficiency with which ground forces negotiate steep terrain depends on professional skills, types of transportation, and loads. Mountaineers can

scale walls that would stop standard infantry; tracked vehicles can negotiate steeper ground than trucks; railway locomotives can tow longer trains up sharper grades if flatcars are laden with tents instead of tanks. Aerial observers and high-flying bombers are hard pressed to identify and hit targets concealed by rugged terrain where closely-spaced ridges make close air support a perilous proposition even in perfect weather.

Points and areas on bare slopes are visible from the top to the bottom of any hill only if the topographical crest (the highest elevation) and the military crest (the highest point from which terrain all the way to the base is visible) happen to coincide. Convex slopes and other surface irregularities commonly create "blind spots"--masks or defilades in military parlance--that protect enemy positions from flat-trajectory weapons, such as rifles and machine guns (see figure 4). Terrain masks also degrade the performance of Very High Frequency (VHF) radios, which likewise depend on line-of-sight. Surface-to-surface missile and field artillery batteries emplaced along steep, narrow valleys cannot elevate launchers or tubes high enough to clear nearby crests.

RELATIVELY LEVEL LAND

Flat to rolling surfaces include relatively small mesas and buttes as well as the gargantuan U.S. Great Plains, Russian steppes, and high plateaus such as the Tibetan Tableland, which, at 16,000 feet (4,875 meters), is higher than most mountains. Slopes nowhere exceed 5-15 degrees on large plains and plateaus, except for isolated protuberances that rise abruptly above otherwise horizontal terrain.

Figure 3. Slopes and Gradients

Relatively level lands throughout history have witnessed major military operations. One of the first confrontations between pastoral and agricultural societies occurred in the 18th century B.C, when Hyksos horsemen overran Lower Egypt, which, then as now, mainly occupied the Nile Delta. Roman luminaries Actius and Theodoric stopped Attila the Hun on the Mauriac Plain near what now is Chalôns-sur-Marne, France, in 451 A.D. Charles Martel, a Frank, defeated Moorish invaders in the Loire Valley close by Tours (732 A.D.) to stem the Islamic tidal wave that was sweeping northward from Africa. Washington defeated Cornwallis on rolling lands around Yorktown, Virginia, in l781 and thereby assured eventual victory for the infant United States, while Napoleon met Wellington and his Waterloo on Belgian lowlands in 1815.² It should come as no surprise that the most expansive military campaigns in modern times took place on vast Soviet flatlands that allow gigantic armed forces to maneuver fluidly and conduct air-land combat on a grand scale. Operation Zitadelle, the epic clash at Kursk, reportedly culminated in 70,000 Germans killed or wounded (not counting captured or missing in action) and the destruction of 3,000 tanks, 1,400 aircraft, 1,000 artillery pieces, and 5,000 trucks. Soviet loses in that largest of all armored battles were only slightly less.³

TOPOGRAPHICAL DEPRESSIONS

Canyons and gorges make awesome obstacles, but are fewer than caverns and caves, which come in many sizes and serve many military purposes. Mao's strategic concepts, for example, took shape in a Shaanxi cave where he had ample time for reflection after the Long March. Natural shelters, perhaps further hollowed out and refined, need not be nearly as large as the cliff side cavity that hid the fictional Guns of Navaronne. Tenacious Japanese troops on Peleliu, Saipan, Iwo Jima, Okinawa, and other contested Pacific islands that were

Figure 4. Line-of-Sight and High-Angle Trajectories

honeycombed with comparatively small caves made U.S. forces root them out at the expense of frightful casualties on both sides, because air strikes and heavy naval artillery left those sanctuaries virtually intact.⁴ Yugloslav guerrillas who took refuge in caverns and caves from 1941 through 1944 gave fits to a sizable number of German divisions that might have been profitably employed on other fronts.⁵ Weapons, equipment, and supplies stockpiled deeply beneath bedrock generally are safe from direct hits by conventional bombardment. Subterranean facilities used by enemies to store nuclear, biological, or chemical munitions cause concern for identical reasons, because actions to neutralize them by frontal assaults would be costly and outcomes uncertain. An 11-man sabotage team, following surreptitiously acquired floor plans, hit Hitler's heavy water plant at Vermork, Norway, and with one small explosion crippled Nazi Germany's nuclear weapons program,⁶ but that spectacular achievement has proved to be an exception instead of a rule.

Basins surrounded by steep terrain expose forces on the bottom to murderous fire if opponents occupy commanding heights, as French paratroopers in Vietnam found at Dien Bien Phu (1954) and U.S. Marines discovered at Khe Sanh during the next decade (1967-1968). Alfred, Lord Tennyson immortalized the Charge of the Light Brigade during the battle of Balaclava in 1853 with these heart-wrenching words:

Cannon to the right of them,
Cannon to the left of them,
Cannon in front of them
Volley'd and thunder'd . . .
Into the jaws of death,
Into the mouth of hell
Rode the six hundred.

Shocked onlookers became so hushed when the Light Brigade entered the "Valley of Death" that the jingle of bits and accouterments could clearly be heard. Twenty minutes later almost 250 men and twice that many horses were dead.⁷

RIVERS AND RESERVOIRS

Fast-moving offensive ground forces that lack sufficient air assault capabilities must swim, ford, ferry across, or build bridges over large streams without breaking stride or forfeit forward momentum while defenders on the far bank hold in place.⁸ All military services routinely require adequate water for drinking, cooking, and sanitation, plus special purposes such as decontamination during chemical combat. Drainage systems, river crossing sites, and militarily useful reservoirs thus are relevant topics. (Chapter 11 covers inland waterways.)

DRAINAGE SYSTEMS

Drainage systems generally are shaped like asymmetrical trees, each branch of which empties its contents into a larger stream until the biggest tributaries connect with the trunk. Immense systems such as the Amazon and Mississippi funnel runoff from several million square miles, while minor systems service much smaller areas. Great rivers that arise and remain in well-watered regions have many tributaries. Streams 30 to 60 feet wide (9 to 18 meters), for example, lace Western Europe every 6 miles (9+ kilometers) or so, while rivers up to 300 feet across occur on the average at 30-mile intervals. Relatively few branches in contrast feed the Tigris, Euphrates, and Nile, which arise where water is plentiful but traverse dry lands thereafter.⁹

Militarily important riverine characteristics begin with widths, measured in feet, yards, or meters from bank to bank, and with depths which indicate the distance from surface to bottom (figure 5). Current velocities, usually stated in feet or meters per second, depend primarily on the steepness of the stream bed. Twenty-five to 30 feet (7-9 meters) per second or 17 to 20 miles an hour is considered quite fast, whereas 1 or 2 feet per second or less is sluggish. The deepest, fastest flow normally follows the main channel well above the bottom, because stream banks and beds function as friction brakes. Currents accelerate along outside curves, where they figuratively play "crack the whip."

Widths, depths, velocities, and volumes measured in cubic feet, yards, or meters past particular points are by no means constant. Military planners and operators anticipate seasonal fluctuations, typified by annual inundations along the Nile Valley, and are fully aware that tidal rivers rise and fall twice daily in response to lunar cycles. Not all destructive floods, however, are predictable nor are they all from natural causes: Germans defenders in November1944 blew dams on the Roer River at Schmidt to delay advancing Allied armies; Chinese "volunteers" at Hwachon Reservoir in Korea (1951) threatened to release a wall of water that could have washed away command posts, supply dumps, and bridges and split U.S. IX Corps.¹⁰

Sand bars, mud banks, and rock outcroppings impose natural obstacles close to shore, especially along outside curves. Floating debris and ice floes in stream can be destructive

Figure 5. Selected Stream Characteristics

to river craft and bridges, but solid ice is beneficial when thick enough to bear the weight of troops, trucks, and tanks.

CROSSING SITES

River crossings at many places on broad fronts minimize enemy abilities to concentrate decisive defensive power against vulnerable targets, perhaps employing weapons of mass destruction. Ideal locations exhibit the following attributes:¹¹

• Good roads closely parallel the river so that offensive forces can easily reach the best crossing sites.
• Well-protected areas are ample to hold follow-on forces waiting to reinforce assault waves.
• Easily negotiable slopes lead to water on the near shore and to land on the far side.
• Narrows facilitate fast assault crossings, round trips by rafts and ferries that support subsequent buildups, and combat bridge construction.
• Current velocities less than 5 feet per second (3.5 miles per hour) limit down-stream drift.
• Fording sites are consistently shallow, their bottoms are firm enough to bear heavy traffic, and selected routes are free from militarily significant obstacles.
• Unfordable streams are consistently deep enough to float swimming vehicles, inflatable boats, rafts, and ferries.
• Rapids, shoals, sandbars, snags, debris, and icy obstructions are conspicuously absent.
• Conveniently located islands that act as stepping stones reduce combat bridging requirements.

The best crossing sites unfortunately are apt to be staunchly defended and actual conditions seldom are ideal. German panzer divisions in Russia during World War II, for example, frequently found that marshy lowlands abutted both banks of large streams, floods loaded with sediment clogged inboard engines, ice floes each spring bombarded expedient bridges, and vehicles became toboggans on moderate slopes after torrential summer rains.¹² Skilled tacticians nevertheless overcame such adversities and learned that landings at unexpected spots improve prospects for low-cost success.

WATER SUPPLIES

Large armed forces demand enormous quantities of water in peacetime as well as war, whether active or passive, at fixed installations or in the field. Requirements are most difficult to satisfy in arid regions, especially when division-sized ground elements and air wings move frequently. Drinking water must be palatable (color, odor, and taste all count) and be unpolluted by pathogenic bacteria that spread contagious diseases such as typhoid fever, cholera, and amoebic dysentery. Time-consuming and expensive purification processes become obligatory when water for use as coolants is corrosive. Surface and subsurface sources are complementary, because neither suffices under all conditions. Both contribute supplies that differ quantitatively as well as qualitatively from time-to-time and place-to-place with varying degrees of convenience.¹³

Surface Water. Rivers, lakes, and some inland seas are large sources of fresh water on Earth's surface. Lesser repositories include ponds, small streams, and springs. Some sources are consistently reliable, whereas floods and droughts elsewhere seasonably reduce usable water supplies below required amounts. Unpredictable depletions caused by nature or enemy actions may do likewise with little or no notice. Prudent commanders consequently try to identify alternative sources before water crises occur.

Perennial flows of sweet, cool spring water usually are low in organic impurities but tend to be widely scattered, high in mineral content, and output seldom is enough to satisfy large military formations which most often must establish, operate, and maintain water supply points at locations that are easily accessible and facilitate distribution by road. Large quantities of good quality surface water are commonly available on plains and plateaus where rainfall annually exceeds 25 inches (60 centimeters), but ample sources are hard to find in mountains where runoff starts, in frigid climes where sources are ice-bound many months each year, in the tropics where pollution frequently is rampant, and near small towns and urban centers where raw or incompletely treated sewage and toxic chemicals sometimes contaminate running water and reservoirs.

Naval vessels and some coastal countries distill brine to produce fresh water. The world's largest desalinization plant, located in Saudi Arabia, siphons more than 5 million gallons per day from the Persian Gulf (nearly 19 million liters) and, after purification, pipes fresh water as far inland as Riyadh. Allied missile defense batteries took special precautions to protect that facility against Iraqi Scud attacks during Operations Desert Shield and Desert Storm in 1990-1991.¹⁴ The U.S. Marine garrison at Guantanamo Bay, Cuba, which is isolated from the rest of Oriente Province by minefields and other man-made obstacles, routinely requires about 1.2 million gallons (4.5 million liters) of desalinated sea water per month. Surplus capacity and barges, plus 15 million gallons in storage, made it possible to accommodate 55,000 Cuban and Haitian refugees who inflated peak consumption to more than 73 million gallons in October 1995 (27.6 million liters).¹⁵

Subsurface Water. Not all precipitation and melt water empties directly into surface drainage systems. A good deal seeps into subterranean reservoirs instead. How much depends on total accumulations, slopes, soil compositions, and the permeability of underlying rocks. Moisture first percolates through an aerated zone that alternately dampens and dries, then reaches the water table, a saturated layer of variable thickness and depths that may be shallow or deep (figure 6). Some water continues to trickle down through cracks and crannies until contained by aquifers encased in nearly impervious rock formations. Artesian springs that rise to the surface under hydrostatic pressures along fissures and fault lines are little affected by seasonal fluctuations or by pollution, but often are too mineralized for human consumption or cooling systems. Relatively shallow wells sunk into the water table generally are preferable with two prominent exceptions: well water along littorals tends to be brackish; supplies drawn from arctic sources above permafrost are only briefly productive each year.¹⁶

Mobile ground forces seldom sit still long enough to tap subsurface reservoirs, but ports, airfields, supply depots, major maintenance shops, and other static installations frequently benefit. So do Civil Affairs well-digging teams whose humanitarian mission is to improve the quality of life for impoverished people. Subterranean repositories furnish the only reliable source of water inland wherever lands are parched, a fact of particular importance when

Figure 6. Water Tables, Acquifers, and Wells

summer heat heightens routine requirements and demands soar under stressful conditions. Conservative estimates, for example, indicate that it would take approximately 200,000 gallons of wash water to decontaminate the personnel, weapons, equipment, and facilities (such as aid stations and field hospitals) of just one U.S. Army or Marine division hard hit by persistent chemical warfare (CW) agents.¹⁷ That would be a tall order even if fire hydrants were handy, and perhaps impossible in the desert, where the employment of CW munitions could entail unconscionable risks for both sides if reprisals in kind drenched aggressors.

GEOLOGY AND SOILS

Commanders, staffs, and subordinates from the highest to the lowest echelons of every armed service need to know how geology and soils affect combat and support operations, but most are bored to tears by those technical subjects. This brief section, which seeks to stimulate interest, first characterizes Earth's mantle, then explains important military implications in simple terms.

SURFACE CHARACTERISTICS

Soil covers Earth's land surface in layers that vary from several hundred feet thick on some alluvial plains to an inch or so on steep mountain slopes. Various grades of gravel, sand, silt, and clay, classified in descending order of particle size, occasionally appear in pure form but more often in a mix (silty gravel, sandy clay, and so on), each with distinctive properties such as texture, compactness, porosity, and consistency that affect military utility (table 3).¹⁸

Table 3. Selected Soil Characteristics

Gravel consists of coarse and smooth rocks, rounded or angular, that range from about 1/4 inch to 3 inches (2.5 to 7.6 centimeters) in diameter and are unaffected by weather conditions. Smaller grains constitute sand, which is unconsolidated when dry yet compact when wet. Dry silt is finer still, but solid except for the surface, which raises dust clouds under windy conditions, whereas wet silt constitutes soft, slippery mud until sunshine, warmth, or wind re-solidify it. Plasticity and adhesiveness are salient characteristics of microscopic (almost poreless) clay particles, which are hard and often brittle when dry. Clay sheds water well but, once saturated, combines the worst attributes of slime and glue. Clay also takes a long time to dry and, like silt, heaves in response to alternating freezes and thaws. Combinations modify each basic soil type, depending on the mix.

Top soils heavy in humus (decomposed vegetation ) are several feet thick in peat bogs, somewhat less in marshes and meadows. Humus invariably is thin in deserts where scanty precipitation supports little plant life, in the arctic where cold retards decay, and wherever tropical heat and humidity disintegrate organic waste.

Bedrock beneath all soil sometimes lies at or near the surface, but often is deeply buried. Structures (laminated or solid), textures (coarse or smooth), and fracture patterns (clean or jagged breaks) are notable attributes. "Rock of Ages" like granites and quartzites are exceedingly hard, but all conglomerates, sandstones, siltstones, even splintery shales are more durable than their basic constituents, which were gravel, sand, silt, and clay before being cemented together under great pressures. Calcium-rich limestones range from very hard construction material to very soft chalk, the latter typified by the white cliffs of Dover.¹⁹

CROSS-COUNTRY TRAFFICABILITY

Load-bearing capacities, traction, and stability despite sustained use characterize the abilities of particular soils to tolerate traffic by wheeled and tracked vehicles as light as snowmobiles and as heavy as tractor-trailers or tanks. Cross-country mobility over gravelly ground is consistently feasible, whereas bogs and swamps are impassable to all but small amphibians. Off-the-road movement, however, most often depends on weather conditions. Frozen fields generally are conducive. So are dry soils other than sand, which in its loose state immobilizes trucks that lack low-pressure tires. Saturated silt, in contrast, churns into soft mud after the first few vehicles pass, faster than usual when loosened by cultivation. Wet clay is worse: deep ruts rapidly appear; stickiness gums drive trains, degrades speed, and complicates steering; modest inclines become too slippery to climb; and after soaking rains tanks and armored fighting vehicles slide down slopes like Olympic-class luges.²⁰

Terrain strewn with boulders also inhibits free movement, as British Brigadier John Bagot Glubb discovered in 1931, when he took an Arab Legion patrol into Trans-Jordan's panhandle to suppress rambunctious Bedouins. Blocks of black lava so littered the landscape that progress on horseback was painfully slow and dismounted legionnaires took 10 days to clear a path that was barely wide enough for a column of trucks to proceed 6 miles (9.6 kilometers), then turn around.²¹

WEAPON PERFORMANCE

Soil conditions and rock affect the performance of many conventional weapons and delivery vehicles. Rocky outcroppings and gravel magnify the lethal radius of conventional munitions, which ricochet on impact and scatter stone splinters like shrapnel, whereas mushy soil smothers high explosives that burrow before they detonate. Even light artillery pieces leave fairly heavy "footprints" in saturated earth, a peculiarity that limits (sometimes eliminates) desirable firing positions. Gunners struggled to keep towed artillery pieces on targets when they worked at or near maximum tube elevations on wet ground in Vietnam where it didn't take many rounds to drive 155-mm howitzer trails so deeply into the mire that recoil mechanisms malfunctioned. Each piece consequently had to be shifted several times each night, a grueling proposition that caused trucks to snap winch cables when soil suction exceeded their capacities. Howitzer trails proved impossible to seat permanently at lower angles of fire, which caused whole batteries to slide after one or two volleys. No amount of shoring solved those problems, but resourceful artillerymen in the Mekong Delta improvised long-legged heliborne platforms that rested on solid foundations that gave their guns acceptable stability.

Surface conditions likewise amplify or mute nuclear weapon effects. The diameters and depths of craters are less when soil is dry than when soaked, nuclear shock waves transmitted through wet clay are perhaps 50 times more powerful than those through loose sand, and the intensities as well as decay rates of nuclear radiation reflect soil compositions and densities. Research and development specialists at underground test sites use related data to determine how deeply they must bury nuclear devices of specified yields to prevent radiation from venting in open air. Massive beds of volcanic ash called "tuff" seem best.²²

MILITARY CONSTRUCTION MATERIALS

Engineers whose mission is to build, repair, and maintain military roads, airstrips, vehicle parks, bridge foundations, and field fortifications routinely use bulldozers, front loaders, dump trucks, and shovels to scoop, prepare, and redeposit surface soils. Some materials, however, are much better suited than others for such purposes..

Excavations in granite and other hard rock require demolitions and power tools, whereas most sandstones, limestones, and shales are easier to extract, provided the earthen overburden allows easy access. Amalgams of gravel with silt or sand make good material for fill, stable embankments, and foundations, but no mix of silt or clay is suitable for aircraft runways, taxi strips, or road surfaces, even with palliatives to keep dust down during dry seasons. Weathered basalt, which forms a hard crust when dry but develops deep ruts after rains, also is undesirable.²³ Laterite, a common deposit in tropical alluviums, was the construction material of choice for main supply routes and C-130-capable airfields in Vietnam, because its iron and aluminum oxide concretions harden irreversibly and withstand tremendous abuse. Peneprime, oil, or some other asphaltic compound waterproofed and controlled dust.²⁴

VEGETATION

Paleolithic foot soldiers armed with stone axes and wooden clubs discovered that dense vegetation limits land mobility and observation to front, flanks, and rear. Problems multiplied when warriors began to employ "standoff" weapons that required clear fields of fire (spears, javelins, slingshots, bows and arrows), formed cavalry squadrons, and devised "mechanized" modes of transportation (mainly horse-drawn chariots). Technological innovations that include armor, aircraft, and thermonuclear weapons have profoundly altered the significance of vegetative cover since then, but none has neutralized its effects. Bare ground still favors offensive forces; forests still favor defense.

GLOBAL DISTRIBUTION

Arctic and Antarctic barrens girdle the globe around the North and South Poles, but the Earth is covered thickly or sparsely with some sort of vegetation in most other places (map 7).²⁵ Several distinctive belts, one below the other from high to low latitudes, are observable in the Northern Hemisphere where huge land masses predominate.

Tundra, a bleak zone that begins where perpetual ice caps terminate, supports a mat of mosses, lichens, summer flowers, and a few grotesquely twisted dwarf trees that hug the ground. A great band of evergreens, commonly called the "taiga," replaces tundra somewhat farther south in response to a longer growing season. Spruce, pine, hemlock, and fir forests intermingled with deciduous birch, alders, larch, and willow trees sweep across subarctic Alaska, Canada, European Russia, and Siberia. Moss-covered swamps cover level, poorly drained lands.

Broadleaf woodlands, once typified by Sherwood Forest in England, Germany's Schwartzwald (Black Forest), and the northern United States east of the Mississippi River, replace the taiga in middle latitudes (some say a squirrel could cross the State of Pennsylvania in colonial times without touching ground). Cultivated fields and pastures, however, have long since supplanted primeval stands of oak, ash, maple, hickory, elm, walnut, and beech trees. Natural grasslands originally covered much of mid-western Canada and the United States as well as Eurasian steppes from Ukraine to the Orient, where the climate is too dry for trees. A good deal of that land also is agricultural today.

Mediterranean borders, southern California, central Chile, and South Africa's Cape Province furnish conditions conducive to squat cork oaks, olive trees, vineyards, and scrubs that prefer cool, wet winters and long summer droughts. Prickly, leathery-leaved plants such as cacti, mesquite, creosote bushes, and chaparral favor deserts and their fringes that are more or less centered along the Tropics of Cancer and Capricorn. Neither of those discontinuous strips dips closer to the Equator than 15 degrees or much farther away than 40, but individual deserts very considerably. The 3.5-million-square-mile Sahara (6.3 million square kilometers) occupies almost as much space as all 50 United States, and the Great Australian Desert constitutes almost half of its parent continent, whereas the Lut Desert in

Map 7. Regional Vegetation

Iran, at 155,000 square miles (401,000 square kilometers), is relatively small. Some stretches of sand and bare stone are devoid of vegetation, although even the driest soils by and large support some struggling plant life.

Tropical forests ring the world at its midriff, most notably in the Amazon Basin, West-Central Africa, parts of India, Southeast Asia, Indonesia, and nearby Pacific Islands where abundant rainfall and an endless growing season encourage exuberant vegetation. Jungle giants that include teak, mahogany, and ebony trees commonly form double, triple, even quadruple canopies that exclude sunshine from forest floors. Undergrowth, contrary to popular misconception, is dense only where light filters through. Mangrove thickets that straddle the Equator flourish best along salt water coasts, but those botanical flying buttresses take root as far upstream as tidal influences are felt.

Vegetation varies with altitude as well as latitude. Each 1,000-foot ascent (305 meters) is roughly equivalent to a trip 300 miles (480 kilometers) north or south of the Equator. Sage brush and short grass, for example, greet back-packers at the eastern base of the Colorado Rockies a mile above sea level. Routes to the top enter woods with widely-spaced ponderosa pines, then thick stands of Douglas fir before they reach the timber line at about 11,500 feet (3,500 meters). Landscapes thereafter consist of alpine pastures, then a crust of lichens well below wind-swept peaks where the environment is too hostile for the hardiest plants.

OPERATIONAL IMPORTANCE

Each type of vegetation significantly influences military operations in unique ways. Varieties that are offensively advantageous almost always frustrate defense and vice versa, as the following vignettes indicate.

Forests. Fairy tales fantasize about ogres who wait for unwary travelers in gloomy forests. Legitimate terrors confront warriors in dark woods, where armed forces battle like blindfolded boxers who cannot see their opponents, small-unit actions by foot troops predominate, control is uncertain, and fluid maneuvers are infeasible. State-of-the-art technologies confer few advantages regardless of the day and age:

• Vehicles of any kind are virtually useless, except on beaten paths.
• Tree trunks deflect flat-trajectory projectiles.
• Nuclear blasts that topple timber could create impassable abatis that benefit nobody.
• Tanks can bulldoze small trees, but the vegetative pileups impede or stop progress.
• The lethal radius of conventional bombs and artillery shells is much less than in open terrain, although the "bonus" effect of flying wood splinters can be considerable.
• Hand grenades bounce aimlessly unless rolled at short ranges that sometimes endanger the senders.
• Napalm burns out rapidly in moist greenery; flares illuminate very little; and dense foliage deadens radio communications.

Winners and losers are hard to predict when combat takes place in forests. Publius Quintilius Varus lost three well-armed, well-trained Roman legions when beset by teutonic barbarians near what now is Münster during the battle of Teutoburgerwald in 9 A.D. He and his senior henchmen committed suicide to avoid capture after that defeat, while survivors were crucified, buried alive, or sacrificed to pagan gods. Caesar Augustus shaped the political outline of Europe in many respects when, as a result, he abandoned plans to colonize lands that have become Germany.²⁶ Forest campaigns ever since have often been costly to belligerents on both sides. Wilderness (U.S. Civil War, May 1864), Belleau Wood and Argonne Forest (World War I), Guadalcanal, Burma, and New Guinea (World War II), Vietnam, and Laos typify a few among many unhappy experiences that involved the United States.

Scantily Clad Landscapes. Brush, high grass, tall crops typified by sorghum and corn (maize), orchards, and widely spaced plantation trees do little to limit aerial or spaceborne sensors and weapon systems. Such vegetation hinders vehicular movement very little, but it slows foot soldiers, reduces their visibility, and restricts fields of fire for land-based line-of-sight weapons. Wire-guided missiles that require clear ground between gunners and targets are useless in thickets and other entanglements. Dense herbage deflects thermal radiation caused by nuclear blasts, yet amplifies the persistence of chemical warfare agents. Immense steppes sparingly carpeted with short grass and deserts devoid of vegetation afford little cover or concealment for armed forces or military installations, but favor long-range observation and clear fields of fire. Air superiority and technological prowess count a lot under those conditions, as Iraq's President Saddam Hussein discovered during Operation Desert Storm (1991), which took place on the geographic equivalent of a sand-colored pool table. His army, which was tactically and technologically deficient, lacked an air umbrella. Allied forces, aided by satellite intelligence, thus were able to bombard and maneuver at will while Iraqi formations risked destruction whether they moved or stayed still. One U.S. Marine Corps pilot quipped, "It was like being in the Super Bowl, but the other team didn't show up."²⁷

MILITARY MODIFICATIONS

Military men have long sought to modify vegetative cover whenever it interferes with observation, fire lanes, cross-country trafficability, or affords adversaries convenient ambush sites. Roman legionaires in hostile territory often stripped brush and trees a bow-shot distance on both sides of dangerous roads. Clearing processes eliminate offensive verdure, while grubbing removes roots and stumps. Techniques employed depend on the type and thickness of vegetation, the acreage involved, perceived urgency, troops on hand, and available implements that range from heavy engineer equipment to hand tools.

Land Clearing. Bulldozers, which are used for most large-scale land clearing operations, can upend small trees and stumps up to 6 inches in diameter (15 centimeters), tree dozers (commonly called "Rome plows") shear off somewhat larger trunks at ground level, leaving chain saws to fell timber of almost unlimited diameters and cut forest giants into manageable segments. Tractor-mounted units pull stumps; rippers reduce root systems; and graders windrow debris for disposal. Carefully controlled brush fires sometimes assist. Explosives occasionally may prove indispensable, but it takes additional time and energy to fill resultant craters.²⁸

U.S. Army engineers in Vietnam used 30 bulldozers and Rome plows per team to remove dense vegetation around base camp perimeters, enemy infiltration routes, and potential ambush sites. Each team could create a helicopter landing zone in a matter of minutes or clear 150 to 250 forested acres a day on reasonably level terrain, although rough ground and thick secondary growth reduced output by half. Amphibious tree crushers, which weighed in at 97 tons, could churn through bogs and hack out wide swaths on dry land at a steady 3 miles (4 kilometers) an hour, but welders and radiator repairmen had to work round-the-clock on all vehicles to patch up punctured cooling systems and replace hydraulic lines that heavy brush ripped off.²⁹

Defoliation. The U.S. Air Force, with permission from the Republic of Vietnam, began to spray chemical defoliants over the Cau Mau Peninsula in the Mekong Delta during 1962. That practice spread to the Rung Sat Special Zone, a mangrove swamp along shipping channels into Saigon, then countrywide, including the southern half of the demilitarized zone. Herbicides thus deposited produced desired results, but accompanying ecological and health problems sparked controversies that remained unresolved decades after the last load was released.³⁰

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