Vietnam: war and the environment

July 14, 1993
Spraying HC
An estimated 72.4 million litres or 100,000 tons of herbicides were sprayed on South Vietnam by the US, affecting 43% of the cultivated area and 44% of the total area.

"Not since the Romans salted the land after destroying Carthage has a nation taken such pains to visit the war on future generations", wrote Ngo Van Long of the US war against Vietnam. John Tully describes the ongoing ecological catastrophe.

The suffering of Vietnam did not end with the liberation of Saigon in 1975. Perhaps no country since Haiti has come to independence under such adverse conditions — conditions which included environmental damage on a scale hitherto unseen in warfare.

The damage was not the accidental by-product of war, but part of the attrition strategy which deliberately aimed to drive the peasants into the cities in order to deprive the National Liberation Front of a population and food base, and safe jungle havens.

Much of Vietnam's interior is composed of rugged mountains and deeply dissected plateaus and is sparsely inhabited by "Montagnard" tribespeople, including Miao, Man, Lolo, Thai, Kha and Cham. The ethnic Vietnamese, as wet-rice farmers, have preferred to cluster in the relatively small areas of lowland: the Red River delta in the north, the Mekong delta in the south, and the narrow connecting coastal plain.

Stretching from the Tropic of Cancer to latitude 8 degrees north, Vietnam has widely varying relief and a variety of micro-climates. However, the country as a whole and the lowland areas in particular are characterised by a monsoonal climate, typified by high precipitation, humidity and temperatures. There is also a marked dry season, particularly in the south, between January and March.

Much of the high rainfall comes in the form of "cloudbursts". These deluges have a great capacity to erode and/or compact bare soil. This factor is important when considering the effects of deforestation.

There is a marked difference in fertility between the geologically recent alluvium and the older soils of

Vietnam. The older soils have generally had essential humus and nutrients leached from them by millennia of tropical rains. The luxuriant tropical upland forests belie the poor nature of the soil below. The most fertile soils are to be found in the two large deltas and the connecting coastal plain.

Erosion was a problem on steep hillsides with thin jungle soils long before the wars which devastated the country. Even on flat land, denudation may result in marked deterioration of soil fertility due to the removal of the forest canopy.

Natural vegetation

In 1947 broad-leafed tropical forests covered about one-half of the surface area of Indochina. Another two-fifths of the surface was covered in scrub forest and savanna grassland. The lower slopes of the mountains of the Annamite Chain often supported extensive stands of bamboo, and coastal mangroves were common, especially on the great sandspit of the Cape of Camau, south of the Mekong delta.

These forests were not, however, "virgin". Accounts by geographers before the US war show that much of the vegetation had been disturbed by human activity. E. Willard Miller, for example, wrote in 1947:

"The Forestry Service of Indochina has indicated that 16 percent of the forests were being destroyed by ray cultivation [that is the traditional 'slash and burn' method employed by the wandering tribes], 17 percent were impoverished by deforestation, 33 percent were intact but largely in the inaccessible interior areas of Laos and Cambodia, and 34 percent were accessible and were being exploited."

Miller stated that timber operations, "largely in the hands of Annamites and Chinese", were extremely wasteful, and Shannon McCune (Far Eastern Quarterly, 1947) wrote that "Little is left of the true natural vegetation because of the practices of man ... the forests are generally second-growth stands, characterised by a multitude of species ..." McCune also warned, ominously with hindsight, of the immense destruction that would result if there was further damage to these forests.

The forest cover is crucial for both natural and human systems. The jungle acts as a protective canopy, preventing the torrential rains from eroding and compacting the thin soils. The complex cycle of death and decay maintains the scanty nutrients in the soil. The canopy also regulates the humidity and temperature of the forest, which acts as a gigantic sponge, soaking up rainfall and releasing it gradually.

The Vietnamese have always tended to shun the uplands, but they are nevertheless dependent upon the "dynamic equilibrium" of the mountain forests, which guard against floods, drought and silting. (Contrary to popular belief, silting does not lead to increased fertility, at least in the short term. It is river water itself which brings essential minerals to the lowland fields. Silt merely buries crops and fertile soils.)

The intensive cultivation of rice has sustained dense populations, but success has been dependent upon the reliability of the monsoons and other natural factors. Floods, droughts, insect plagues and even low pressure over the South China Sea or delay in rains, can, and do, lead to hunger to the point of famine.

The abundant waters which pour through the Vietnamese deltas have also been important in other ways. Firstly, the rivers, canals, mangroves and paddy fields themselves have been a rich source of fish, which has supplied important protein in an otherwise overwhelmingly carbohydrate diet.

Secondly, the traditional wet rice agriculture largely destroyed the habitat of Anopheles maculatus mosquitoes, the vector for the most virulent strain of malaria in the region. In the past the mosquito has, however, continued to flourish in sunlit streams in cleared uplands.

US strategy

Into this fragile land charged the behemoth of US military power, its battle cry the bloodcurdling words of Air Force General Curtis Le May: "Tell the Vietnamese to draw in their horns or we're going to bomb them back into the Stone Age".

The US expeditionary force and its ARVN (Army of the

Republic of Vietnam, i.e. South Vietnam) allies faced an elusive and tenacious opponent, who, by 1965, controlled much of the southern countryside and population. The NLF was popular with the peasantry, who saw the link between it and the Viet Minh, who had driven out the French.

In Mao Zedong's aphorism, the guerillas were the fish and the peasants were the water. By 1968 the US commanders had decided that their best strategy lay in depriving the fish of water by removing the peasantry from the countryside. This process was labelled "forced-draft urbanisation" by the cynical Professor Samuel Huntington, a member of the US government's "brains trust".

Such a strategy necessarily involved the massive destruction of human life. But, no matter, opined the US commander-in-chief, General William Westmoreland, because, "The Oriental doesn't put the same high price on life as does a Westerner. Life is plentiful, life is cheap in the Orient" (Far Eastern Economic Review, April 21, 1975).

Much of Vietnam was turned into "free fire zones", into which hurtled immense tonnages of explosives and herbicides. The intention was to crush a peasant army by "the profligate use of technologically advanced weapons and techniques". This involved "truly massive rural area bombing, chemical and mechanical forest destruction, large-scale crop destruction, destruction of food stores, the destruction of hospitals, and large-scale population displacements — in short the massive, intentional disruption of both the natural and human ecologies of the region" (Arthur H. Westing, Natural Resources Journal, April 1983).

The war involved the greatest expenditure of bombs and shells in history. Between early 1965 and mid-1968, over 2.5 million tons of bombs were dropped on South Vietnam alone — more than were dropped in all theatres of World War II by all sides. In total the US fired some 10.2 million tons of munitions in South Vietnam, and 11.3 million tons in all of Vietnam.

Westing estimates that around 100,000 hectares, or some 1% of the forest lands of Vietnam, were completely obliterated by bombing and that a further 5 million hectares , or over 40%, were damaged. Much of this damage was due to shrapnel, a significant cause of tree mortality because it gives access to fungus and decay. The shrapnel remains a hazard in sawlogs today.

Bombing on such an enormous scale was a significant contributor to devastation of the natural eco-system.

Forest destruction

The amount of herbicides dumped on the forests and paddy fields of South Vietnam was stupendous. One study by Australian government scientists claims, "The figures for Agent Orange alone indicate that the amount of 2,4,5-T sprayed over Vietnam during the period 1962-1971 is far in excess of the amount of 2,4,5-T which has been used in Australia since the herbicide's introduction into Australia over 30 years ago" and points out that the chemical has been used over a much wider surface area in Australia.

An estimated 72.4 million litres or 100,000 tons of herbicides were sprayed on South Vietnam, affecting 43% of the cultivated area and 44% of the total area. Seventy per cent of the south's coconut groves and 60% of its rubber plantations were destroyed, together with 110,00 hectares of forest and 150,000 hectares of mangroves, along with enough crops to feed 2 million people. It has also been claimed that 43% of the south's plantations and orchards were destroyed, and 44% of the forest wealth.

In addition to high explosives and spraying, this destruction was achieved by the use of napalm and "Rome ploughs". These latter were large bulldozers equipped with sharpened three-metre wide blades. They would smash line abreast through the forests, linked together with huge chains, uprooting everything in their paths. Elizabeth Kemf wrote that the Rome ploughs completely removed the trees and significantly disturbed the topsoil of 325,000 hectares, or 3% of southern Vietnam's forests (New Scientist, June 23, 1988).

It appears that deliberate attempts to set fire to the forests were foiled by extremely wet conditions. Significant local fires were, however, caused by napalm and phosphorous bombs.

The scale of the chemical assault was quite without precedent. Although the British had experimented on a small scale with herbicides during the so-called "Malayan emergency" in the 1950s, it was only in Vietnam (and to some degree in Cambodia in 1969) that the full military potential of "defoliants" was realised.

The program was known as "Operation Ranchhand" after the earlier, more sinister name "Operation Hades" was discounted. Of the 91 million kilograms used, 55 million kg were made up of "active ingredients", mainly phenoxy chemicals, usually mixtures of 2,4-D and 2,4,5-T, known to the pilots as Agents Orange, Blue and White. Agents Orange and White kill plants by interference with their metabolisms, Agent Blue by desiccation. The two former mixtures were used on forests, the latter on crop lands.

Westing estimates that about 10% of southern Vietnam was sprayed, mostly in Military Region III around Saigon, where about 30% of the area was sprayed. Thirty-four per cent of the total target areas were sprayed more than once.


Agent Orange contains quantities of the dioxin TCDD as an impurity from the manufacturing process, and a great controversy has raged in scientific circles over the effects of this on living organisms. It is said to be both teratogenic and carcinogenic (i.e. to induce deformities in foetuses, and to cause cancer).

Staff in Vietnamese hospitals near sprayed areas believe that the evidence is overwhelming, but lack the resources to run exhaustive scientific tests. Ever since the 1960s there have been persistent reports of grotesquely deformed infants and a high incidence of liver cancers among inhabitants of the affected areas. US and Australian Vietnam veterans, too, have fought a dogged campaign to establish compensation claims for similar conditions.

Vietnamese authorities have on many occasions offered to cooperate with the US government in assessing the medical effects of defoliants, but their offers have been spurned.

There is no doubt that the chemicals had immediate deleterious effects on living organisms, particularly on birds and other inhabitants of the over-storey in forested areas. One report tells of dead cattle and "river fish [which] floated on the surface of the water, belly up, soon after the chemicals were spread". There have been more recent reports of a lack of fish in waters in herbicide-affected areas.

Another side effect appears to have been the enhancement of the habitat for Anopheles maculatus by the flooding of the estimated 10-15 million large bomb craters in southern Vietnam. Reports of increases in the rate of malarial infection were made even during the war.


After two to three weeks, forests treated with the herbicides would lose leaves, flowers and fruits, especially in the upper canopy. Climax rainforests, with multiple layers of trees, would need a second or third dose to reveal the soil (and guerillas) below.

About 10% of trees, depending on the strength of the dose and the species involved, would be killed outright; the survivors would show various stages of damage, including dieback and sterility.

It is not possible to remove forest cover on such a scale, particularly in a tropical country, without causing massive long-term damage to both human and natural ecosystems.

Clearing exposes thin soils to the violence of the tropical elements. A consequence of defoliation and bombing has been accelerated soil erosion and nutrient leaching. This is particularly the case on steep slopes with rapid run-off, but soils on level ground are also subject to leaching and compaction, or hardening. This results in a hard crust of laterite, useless for both forests and agriculture.

Neither can it be assumed that "nature will take its course" and eventually re-establish the forest. The evidence shows that "pioneer vegetation" often consists of hardy grasses, such as Imperata cylindrica (dubbed "American grass" by the Vietnamese) and bamboo, particularly

in the areas sprayed more than once. These densely rooted plants are almost impossible to eradicate, even by fire, and prevent the spontaneous regrowth of the original broadleaf forest.

The forest also serves as a regulator for the rate of surface run-off. The dry and wet monsoons are sharply differentiated in southern Vietnam, and forest destruction has led to summer flooding and winter droughts.

Vietnam has over half a million acres of coastal swampland, much of it concentrated in the south of the Mekong delta and Cape of Camau regions. Much of this swampland was formerly thickly covered with mangroves, which formed a natural hide-out for the NLF guerillas, and which was subjected to intense chemical attack by the Americans.

The main type of mangrove, Rhizophora spiculata, was especially sensitive to defoliants, one spraying being enough to kill the plants outright. Erosion of the exposed soil has been rapid.

There was also a massive decrease in bird life, and "50% of the productive woodlands and fisheries" of the Cape of Camau mangroves were destroyed, according to Kemf. Even today much of the area resembles a moonscape, and species extinction is a real possibility.


Vietnam is one of the world's poorest countries, and since the end of the war population pressure and the effects of the US-led economic blockade have cruelly taxed the renewable resource base of the country. As Kemf puts it:

"More forests have been lost in Vietnam since the US/Vietnam war ended in 1975 than during it. Because of post-war lumbering operations (the rebuilding of 10 million homes, schools, hospitals, roads and irrigation systems), the relentless collection of firewood, forest fires and centuries-old methods of slash-and-burn agriculture, Vietnam loses around 200,000 hectares of forest each year. Some 40% of the country is now considered wasteland."

In 1988 the country's forest cover had fallen to an all-time low of 21% of the land surface. Vietnamese scientists believe that the country needs to bring the figure back to around 50% if environmental disaster is to be avoided.

The government has conducted an ambitious and partly successful program of reafforestation, despite limited foreign aid and access to scientific assistance. The plan is based on the World Conservation Strategy and involves the reafforestation of 1.5 million hectares within 10 years.

There have been some notable successes in the replanting of tropical moist forests, such as the Ma Da woods, and the resuscitation of blighted mangrove swamps such as at Rung Sat, near Ho Chi Minh City. Vietnam has also pioneered the use of exotic trees such as Australian gums and acacias to give shelter during the early stages of growth of replanted native forest trees.

Despite these successes, large sections of the country remain wastelands, known as "Agent Orange Museums" to the Vietnamese.

In 1973 the United States promised the Vietnamese an aid package to help rebuild the country they had so grievously abused. The Vietnamese are still waiting. Using the bogus issue of "MIAs" (troops "missing in action") as a pretext, the United States chose instead to impose a crippling diplomatic and economic blockade.

US and Australian involvement in the Vietnam War was a gigantic abuse of human rights. Enforced isolation of Vietnam has compounded that abuse and ensured that the country remains desperately poor. Closer ties, symbolised by the recent visit of Vietnamese Prime Minister Vo Van Kiet, are long overdue.

And who knows, a spin-off may be that we are able to learn something from the Vietnamese experience on how to rebuild shattered environments.

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