What are the legacies to Vietnam of the defoliation that went on during the war?

Well, I think the legacies of defoliation that went on during the war are really two. One of them had to do with the immediate destruction of forest in Southern Vietnam. And the second had to do with the problem of forest recovery since that time. So immediately there was tremendous devastation of productive force in the south.

For instance the mangrove forests were forty percent totally destroyed, which supplied the charcoal production that the City of Ho Chi Minh used for their total cooking needs. And approximately at least twelve percent, perhaps as high as forty percent of the inland forests, the forests away from the seashore were destroyed by defoliation.

Now following chemical spraying, what often followed was a burning, either deliberate burning by napalming or some other method of setting...

Just a second. I’m going to ask you to back up to that... Following chemical spraying...Just so that we can change the focal length on this…Okay. Go ahead.

Following chemical spraying, if an... it was often the policy to burn either deliberately by napalm bombing the litter after it dried out, or it just naturally happened that the fire, the forest later caught on fire, because of the dry season which spraying usually occurred. In this case it often destroyed a lot of the understory vegetation which was not killed directly by chemicals, and allowed the establishment in these areas of a degraded grassland type vegetation.

Now, much to our surprise when we visited some of these sites in January of '83, these areas that we had known from aerial photography to have been this type of degraded grassland immediately after the end of defoliation still remain this type of grassland. And apparently what’s happened in this relatively seasonal tropical forest environment is that this grassland became established, and subsequent to that time has remained grassland because of its periodic burning, probably on a yearly basis.

So although defoliation wasn't directly the cause of the establishment of this grassland, in fact in that ecological context, destroying the canopy of a tropical forest and allowing the establishment of large patches of this degraded grassland in fact it's directly responsible for that vegetation now.

What has been the ah, what has been the ah impact of this on the animal life in that environment?

The impact of this vegetation on animal life of course follows simply from the fact that animals are directly re... directly require particular types of vegetation for their habitat needs. And associated with each type of vegetation is a particular animal community.

And the richest kinds of animal community in Vietnam as in most tropical or sub tropical areas are the animal communities associated with the tall species-rich tropical forest. And when you degrade that forest into a different kind of vegetation, either a low woody vegetation which happened after low intensity spraying, or this degraded grassland, you find a very depauperate fauna, one that is very poor in species, and is missing the canopy animals that are the most... I better stop there.

What have the uh, what have the Vietnamese tried to do or been able to do to remedy this, this ah environmental degradation?

Well, the Vietnamese have tried within their means to get a grip with these problems. It's been very depressing probably how little they’ve managed to do even in trying to describe what is the legacy of chemical spraying. Naturally their efforts have been directed towards rehabilitating productive forests. So replanting the mangrove has occupied a great proportion of the effort of the forestry department.

The animal ecologists and zoologists have been concerned with censusing areas for endangered species including some primates like the , the which is an endangered forest cattle, and some of the Imperial Pheasants, just trying to find out where populations of these animals remain in the forests. And unfortunately almost no effort has been directed towards actually censusing in a quantitative way what the densities of the different animal species, both vertebrate or invertebrate animals are remaining in these different types of vegetation.

So ah, ah it's extremely frustrating to a scientist to even try to describe what the current situation is now lacking. Detailed on the ground studies and even an overview of vegetation that could be produced by aerial photography.

You were, however, you and a colleague were able to visit one of these grassland areas yourself and observe it at firsthand when you were there recently.

Yes, my... Peter Aston, a forest economist and myself managed to go for a day into one of these areas that we had a good record of the history of use of from earlier aerial photographs.

And when we went into this area on a day trip this is when we became convinced that this problem of burning was a...was a very strong problem, a very important problem, the lack of woody succession tending to take this grassland towards the forest once again was just not occurring. And also on the other hand we were in an area that had low vegetation, woody vegetation that was a result of low intensity spraying, that seemed to indicate that this was going towards the reestablishment of a good forest.

So that isn't much of a current concern. The more major concern has to do with what's going to happen to these grasslands areas? Are they in fact expanding in size as our observations would indicate from the fact that around the edge of the burns, the trees on the margins were being killed, or are they remaining the same size or in fact is the forest trying... slowly replacing the grassland once again. Now one of the disturbing...

Hold it. Just let him change lens. Go ahead.

Now one of the disturbing features of the pattern of defoliation which is not obvious at first from just recording the total amount of acreage defoliated, is the spatial pattern in which these areas are now distributed. They form a patchwork.

And you can clearly see on an aerial photograph the fact that these occur in long strips intermixed with strips of relatively good forest and not so much damage by spraying. What this does in effect is dissect a forest into small little islands of appropriate vegetation for animals. Forming little islands or pockets of habitat.

The problem is, each one of these little islands or pockets may be insufficient to really support a population of animals, particularly those that require large home ranges. Animals such as primates, some of the forest birds, etc. So in fact if you added up all the total area of good habitat remaining, it may not be sufficient to support the population of animals because of this dissected nature of it.

In fact, these animals, canopy animals, don't cross grassland to go to another piece of forest. They may as well be islands, and unoccupiable.

What lessons about the future decisions maybe to be made in another war in a similar kind of terrain would you think that we as a nation might derive from what happened there?

Well, I think those short term gains in terms of military objectives have to be very, weighed very strongly, of what kind of environment the people who have to live there afterwards are left with. And perhaps long into the future.

Certainly it is surprising to us to see that now really fifteen years after the cessation of chemical spraying there is still no recovery towards forest of these grassland areas.

You mentioned another consequence of the war, not directly related to chemical spraying but affecting their timber industry. Can you describe that?

Ah.What ah... yes, one effect of unrelated chemical spraying was impressed upon us when we visited a sawmill, a functioning sawmill in southern Vietnam. And apparently one of the great frustrations of the forestry department and people working in these sawmills is the fact that they constantly encounter pieces of munition, shrapnel, bullets, etc., in the logs they are trying to cut up.

And they are using saw blades that cost upwards of several hundred dollars and as soon as they hit a piece of shrapnel the teeth on the blade is shredded and the log is then thrown away because of the risk of further damage to the saws.

And this isn't just an occasional problem. If you look at the quantities of armaments dumped on those forests, it is very substantial the portion of trees that actually have pieces of metal in them that are encountered during the timbering or the sawmill operation. And...

We have to change rolls.

I'd like you to describe what the Vietnamese have been doing to try to... How they are going about trying to get the mangrove forest back to life.

To resurrect the mangrove vegetation their emphasis has been on direct replanting of mangrove stock. So seedlings, replanting seedlings, and allowing those to mature to the point where they once again...

...and become...

Let’s start all over again.

Yeah. To try and rehabilitate the mangrove areas, Vietnamese foresters have been relying mostly on direct replanting of seedlings and allowing those to grow to maturity in the mangroves. This is a very long term process necessarily taking decades, to once again produce harvestable wood timber.

And that effort because of the charcoal needs of Ho Chi Minh City has meant that relatively little effort has gone into trying to reestablish, the hardwood timber industry in the inland forests. And there have been other forestry projects as well, trying to rehabilitate land in this grassland area. Trying to establish fast growing softwood trees for a paper industry, but again much to the neglect of the hardwood forest industry in the inland forest.

There was a certain amount of ah, of spraying of croplands during the war, as well as forest lands. Were you able to observe any longterm effects of the crop destruction?

No, we weren't able to observe any long-term effects of the crop destruction program. That falls under the realm of the epidemiological studies mostly, and any place that was under cultivation, the subsequent history of land use isn't very well documented so it’s very difficult for an ecologist to try and find out what's going on here, especially as regards anything about crop yields or changes in the soil structure and chemistry, etc. Those, the sequence of use since that time has a great deal to do with what exactly those profiles look like now, and it's very difficult to sort out.

What do you say to the argument that some people make that actually lots of places in America have been defoliated and chemically treated just as heavily as Vietnam, and it didn't really do any harm?

Well, I’d say when the environmental context of an assault on a piece of land always has to be foremost in making blanket statements about the effect of spraying, per se. In the case of Vietnam one has to bear in mind that the forests most heavily sprayed are those that are most tropical in their nature.

That the canopy in those forests acts as a homeostatic mechanism that keeps the soil moisture high and humidity high. And during the dry season in a forest like that, fire does not penetrate. There’s no history of fire in such a forest.

Once you massively destroy forests over large areas, kilometers by hundreds of meters and allow the establishment of this grassland then you’ve set up a cycle whereby the grassland is continually replaced by the dry season fires.

So in that context it’s not as if a vegetation as we have the United States that is fire adapted per se will recover as it does in the kinds of controlled studies that have been done in the United States.

Cut.

The uh... the fires now that are occurring in these grassland areas seem mostly to be set by people. In fact rather than resulting from natural causes. And one thing that’s reported and one thing that we saw ourselves on our field trip into these areas is that hunters use these areas extensively.

And apparently what hunters derive from this is that after burning dry grassland there is an immediate flush of green grass which attracts deer, and... which attracts deer into these areas that they can then hunt. It's a very short lived phenomenon of course because once that new flush of grass dies then there is not anymore hunting that can be done in there.

But we actually saw Vietnamese forestry workers carrying M-16s into these areas with their night lamps on, to go and hunt in these dried areas. And from what we hear from other Vietnamese scientists is that this is a wide ranging phenomena. That there are a lot of M-16s left around out there in the countryside.

And with the great meat shortage that exists in the south it is very profitable to, for a lot of people to make a living or to supplement their income by hunting in these grassland areas.

Cut. Thank you. Are you picking up that camera sound?