Pest Control and Wildlife Relationships (1961)

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FOREST PEST CONTROL Tom Gill Charles Lathrop Pack Forestry Foundation It may be well at the outset to mention some of the basic differences between pest control in the forest and in agriculture, especially as they affect wildlife and wildlife habitats. One essential difference has to do with the size of the average operation, which in forest control work covers much larger areas than in agriculture. There is very little analogy between the con- trol activities of the individual farmer and the small forest owner. The small forest owner does not greatly concern himself with pest control. Much forest pest control is on a cooperative basis, be- tween Federal, State and industrial agencies. Operations of this type can be carefully planned, with definitely established responsi- bilities, and made to follow definite procedures, to safeguard not only wildlife but other forest values. Another fundamental difference lies in the comparatively small amounts of pesticides used in forest pest control. Out of the several hundred million pounds of pesticides consumed annually in the United States, less than one and three-quarters million are em- ployed in Forest Service control operations. Of this, fully one and a half million pounds are used in bark beetle control, and directly applied to individual trees. So what remains as a potential hazard to wildlife is the application of about 180,000 pounds of DDT sprayed from the air—not very much, surely, compared with the over 70, 000, 000 pounds used annually in the United States. You may wonder why bark beetle work so completely over- shadows the control of defoliators. It is simply a choice as to where the dollar will accomplish the greatest protective good. With defi- nate limitations on the money that can be spent, forest managers recognize the more immediate emergency in bark beetle infesta- tions. As between bark beetle and defoliators, the beetle requires instant action. The defoliators, if necessary, can wait. But the

point, I think, to make here, is that from the wildlife standpoint the direct application of pesticides to beetle infested trees has no known effect on the environment or on wildlife mortality. Certainly no harm has come to the forester's ally, the woodpecker. As a matter of fact, the woodpecker and the control men seem to have entered into an informal compact. The control men spray the lower 20 or 30 feet of the infested tree, and above that the wood- pecker takes over, and so far as I know without any deleterious ef- fects. But I should not want to leave you with the impression that the relatively small amounts of insecticides used in forest pest control are any measure of the need for control itself, nor of the damage caused. Insect damage in the forest is staggering enough. It has been estimated at an annual loss of five and a half billion board feet of merchantable timber, plus an additional three and a half billion lost in the death of immature trees, in slowing down growth, and in other unfavorable factors. Someone more pictorially inclined has estimated this loss at about 600,000 five-room houses a year, plus about one-fourth of the amount of pulp wood which goes into the nation's newsprint. Nor does the small amount of forest spraying indicate that we need not concern ourselves about hazards to wildlife, or with detri- ment to the environment. It must be remembered that every forest acre that is sprayed is potentially wildlife habitat. Further, the small amount of spraying done this year might be vastly increased next year because of an emergency, or because of more available money. Meanwhile the use of silvicides is likely to increase with the coming years. So it is of primary importance that when chemi- cals are sprayed over forest land their use be confined to situations in which no other form of control is effective, and under conditions which safeguard the application. I would like to tell you briefly just what some of these safe- guards are. Today, most insect control in our forests is based es- sentially on the Forest Pest Control Act of 1947. Prior to that time there was no Federal authorization for cooperation with the States, or with private owners in pest control, but this Act auth- orized Federal cooperation with State and private land owners in a united attack upon insects and diseases on forest lands of all own- erships. Under it the Federal Government has set up very detailed and precise procedures. Here in a much oversimplified way is

about how it works. A request for aid to combat some insect in- festation originates with the land manager. On Federal lands this might be the local supervisor. On private or State lands requests would ordinarily come through the State Forestry Department or some similar organization. After due processing, the request ordinarily goes to the Forest Experiment Station of that area. Here a biological evaluation is made to determine the damage being done, probable trends of the outbreak, whether any feasible control exists, and the foreseeable results. The station staff checks on the abundance and probable trends of parasites and predators. These evaluations are not confined to the economic value of the timber lands. They are the result of studies made by entomologists, wildlife specialists, foresters, and others. They estimate control costs, and the multiple forest values threatened. They consider possible dangers to fish and other wildlife. For projects of any size, there are written work plans, progress reports, and inspec- tions. If control is indicated, there are further examinations into whether the measures should be cultural, biological, chemical or a combination. It would probably be hard to conceive of a more integrated operation, or a more promising instance of team work in bringing together the viewpoints not limited to timber as an industrial prod- uct, but giving due consideration to the values represented by recreation, hunting, and wildlife. The decision to use chemicals is never made lightly. Chemi- cals are called into play only when other methods cannot do the job, and the forest manager has little choice. Either he sprays, or he loses his forest. The Forest Pest Control Act has worked well. Probably no other field of control has such definite legislation. Perhaps its one weakness lies in the fact that it is predicated largely on cooperation with States, and State laws are variable. Some are good, some are weak, and some States have no laws governing pest control. Now a word about other forms of control. Dr. Decker has mentioned biological and cultural measures available in agriculture. We have them too in forestry, where they are playing an increasingly important role. Cultural controls—particularly those effected by forest management—offer an immense field of hopefulness, es- pecially in preventing epidemic infestations. Some foresters will 10

tell you that the potentialities of cultural control are far greater than those of chemicals. There is no lack of instances illustrating how dangers of in- festations can be diminished by cultural means — how, for example, a light overstory of an immune species will protect a vulnerable species beneath. Prof. Samuel Graham has instanced the protective value of mixed versus pure stands. In the North, where you have the familiar mixture of beech, birch, maple, hemlock and pine, you seldom find damage done to the hemlock. But where the species exists in pure stands it may be destroyed in a single season by the hemlock looper. Similarly, maple is attacked by a number of de- foliators when it occurs pure, but in association with other species, outbreaks are virtually unknown. This is a field in which it pays the forest manager to be ever- lastingly alert. In the past, we have actually set the stage for insect attack in some of our reforestation work. In the Lake States, the Civilian Conservation Corps planted mile after mile of pure red pine, and today we are paying a heavy price for that ecological blunder. There are many preventive steps the forester can take besides simply avoiding pure stands. There is much to be gained by fitting the right species to the right site, by taking out high-risk trees, by thinning too dense stands. And there is this to be said about cul- tural control: When it does work, it is much more satisfactory than chemical control, and more lasting. That is why the forest manager looks forward hopefully to the day when we will know enough to apply cultural control on a wider scale. That phrase, "when we know enough, " brings out a major need in forest pest control—the need for more research, especially eco- logical research. We simply don't know enough. In pest control we are today just about where we were 25 years ago in forest fire con- trol. What do we know about the bark beetle, an enemy that accounts for over 90 per cent of forest insect damage? Well, we know a great deal about some species, but in comparison to our fund of ignorance, our knowledge is a scant drop in the bucket. As Noel D. Wygant has pointed out, we have not even been able to develop a synthetic food to enable us to rear these beetles in the laboratory and learn their nutritional requirements. We know these requirements are critical, but we don't know whether they are due to toxic substances, or nutri- tional deficiencies. We don't know why certain trees are resistant, 11

and others are apparently a toothsome morsel. We don't know by what organism the beetle senses the tree chosen for attack, or how he is guided to it. The life histories and habits of their parasites and predators are largely a closed book. One could go on and on in cataloging our lack of knowledge re- garding other insect species, but it would all add up to saying that for effective pest control we need a vastly accelerated program of research. Public awareness of the extent of insect damage to forest values can do much toward hastening effective control, and the forest manager is becoming increasingly alert to the need for bring- ing the public into the pest control picture. This does not mean selling the public a bill of goods, but giving them better advance information, keeping them informed of the damage and dangers of infestations, and especially making it possible to secure the view- points of all affected groups. The public wants to know and has a right to know the need for pest control, the price that may have to be paid, the possible adverse effects on wildlife, and if mortality is likely they should know how much to expect. One forward step in securing public cooperation has been through the so-called Forest Pest Action Councils. Originally organized on the West Coast, they have spread to the East and into British Columbia. These Councils are not control agencies, but informal organizations made up of groups and individuals likely to be affected by control programs, and include Federal, State and private forest and land owners. The Councils act as coordinating bodies, consolidating the plans for control programs before they are put into actual operation. They scrutinize the needs for control and the ultimate effects on all forest values. They insure that both the problems and the plans for control are fully understood by all affected groups, with the result that a project must have undoubted merit to survive this scrutiny. Although the Councils' decisions are advisory, they have the force of public opinion. Mr. Chairman, in the one minute left, I should like to try to make a little clearer what I believe is the viewpoint of the forest manager toward the use of chemical pesticides. One can, I think, say this: The forest manager in his never-ending battle against in- sects has come to look on chemicals as an emergency weapon that is both necessary and effective. He may look on chemical control as a last resort, but at certain times and under certain conditions 12

it is the only resort. He knows that chemical pesticides often de- mand a price and he is continually working to reduce that price by smaller dosage, better materials, and safer methods of application. Meanwhile, he looks forward to the day when biological, cultural, systemic and other controls may drastically curtail the need for chemical pesticides. But as a forest manager—whether Federal, State or private—he can never forget that in his keeping lie enor- mous resource values, and that his clear responsibility is to pro- tect these values by the best techniques available. And often that means chemical pesticides. 13