Mangrove forests in Vietnam traditionally grow very fast. They trap silt and function to increase land area, extending the shoreline out into the water at a rapid rate. Now, due to American herbicide use, that natural role has been reversed for about half of the forests. The trees are dead and the presence of crabs which eat seedlings insures that new trees will not soon return. Moreover, the major mangrove spraying was done five and six years ago-a major typhoon is likely soon which will probably greatly increase erosion and physically change the coastline and delta regions.

There will also be some secondary effects from the mangrove destruction. Villagers in the south relied on the mangroves as a major source of wood for fuel and charcoal. Mangrove-lined waterways provide food and nursing grounds for fish and crustaceans, too. Mangroves are active photosynthesizers and fix carbon into an organic form the fish can use. The HAC was unable to estimate the magnitude of this function but suggested that its impact on the fishing industry deserved study.

Hardwood forests of some kind cover nearly 90 per cent of South Vietnam. Mature forests of economically valuable hardwood cover about 50,000 square kilometers. Through 1969, the HAC estimates 13,500 square kilometers were sprayed, with a third of that being sprayed more than once.

From the HAC preliminary report: "Approximately one-fifth of South Vietnam's merchantable hardwood forests have been sprayed, including many of the oldest and most valuable stands. Aerial inspection of forests in a wide are north of Saigon extending from the Cambodian frontier in the west to the South China Sea on the east showed more than half of the forest to be very severely damaged. Over large areas, most of the trees appeared dead and bamboo had spread over the ground. A danger in this is that the invading bamboo species may be essentially worthless and very expensive to eradicate. Bamboo will retard the reestablishment of forest trees, at least for many decades. A further hazard is that large amounts of nutrient minerals previously tied up in forest vegetation may have been released and leached out of sprayed forests by the heavy tropical rains." The danger from this "nutrient dumping" is that on a large scale soil fertility would be reduced drastically.

Hardwood forest spraying, then, has seriously reduced South Vietnam's economic forestry resources, with effects to be felt for many more years. The forests are relatively unpopulated, so there should be little direct effect on human life from the hardwood destruction.

Strip spraying is the name given to herbicide use in a variety of situations. Narrow strips along roadsides, along the perimeters of military installations, along canals and along rivers have been sprayed to reduce cover which might hide troop movements. In the Delta region of the south, most of the population lives in homes along the canal banks, with their rice fields extending away from the canals, behind their homes. American strip spraying dumped herbicides directly on these huts (and their inhabitants) while killing vegetation along the banks of the canals.

Herbicide use for crop destruction has continued this year in contrast tomangrove and hardwood forest destruction, which have been ordered stopped. The HAC estimated 2,000 square kilometers of cropland were sprayed, which amounts to five per cent of the cropland in South Vietnam. From the HAC report again: "It has been authoritatively estimated that this entailed the destruction of enough food to feed approximately 600,000 persons for a year. Our observations in Vietnam lead us to believe that precautions to avoid destroying the crops of indigenous civilian populations have been a failure and that nearly all of the food destroyed would actually have been consumed by such populations. Even so, if the affected civilians were distributed throughout the country or if they lived in food surplus areas, the impact would be small compared to other hardships, since the food destroyed amounts to less than two per cent of the national crop in any one year. However, anti-crop spraying has been largely confined to the food-scarce Central Highlands, the entire population of which is only about one million. Most of these are Montagnards. . . . We believe the anti-crop program may have had a profound impact on a large fraction of the total Montagnard population of South Vietnam and we believe this to be a point for urgent consideration."