area.

Representatives of industry, Government organizations have joined hands in the Tr to develop a program for the improved ma private nonindustrial forests. The taks for jectives:

1. To help meet the Nation's needs other forest values.

2. To maintain and enhance the tota vate, nonindustrial forest resources th

measures.

3. To maximize benefits to private w with the principles of our free enterpr 4. To enhance wildlife, water, recrea environmental values.

Senator CHURCH. Anyone else who wishe to do so.

Now, the witnesses with special problems all, Mr. Donald H. Gray.

Mr. Gray, you are a member of the fac Michigan, is that correct?

STATEMENT OF DR. DONALD H. GRA INSTITUTE FOR ENVIRONMENTAL QU PROFESSOR OF CIVIL ENGINEERING, MICHIGAN

Mr. GRAY. That is correct, sir.

I am Donald H. Gray, associate profess the University of Michigan and also acting for Environmental Quality at the Universi testifying on my own behalf. My main objec mittee about field research work we have c on impact of forest research work we have

urient loss unere. It is simply not true. I ne п. J. Anar areas that we are studying, and not only has the turbi here increased after clear-cutting, but so too has the

has taken several directions to date. We have condu rch of the technical literature, done some theoretical a out hydrolic model experiments in a tilting soil at Michigan Botanical Gardens, and instrumented some he field. The field instrumentation is designed to moni rates of downslope movement and soil moisture reg ntle before and after clear-cutting.

ies show that clear-cutting promotes not only accelera but also increased susceptibiilty to mass-soil moveme e is reviewed, in detail, in a progress report submitted Science Foundation titled "Effects of Forest Clear-C Stability of Natural Slopes," October 1969. If possib to have this report become part of the hearing record. HURCH. This is the report here?

That is correct.

HURCH. That will be a part of the file on the hearing. V have it.

t referred to will be found in the files of the committed A forest cover on a slope enhances the deep-seated st principal ways: by beneficially modifying the hydrolog soil mantle and by mechanical reinforcement from Large-scale removal of the forest cover results in wett the soil mantle (inimical to stability) and gradual d f the anchoring root system (thus they become zones

acv to believe that removal of the forest cover enhanc y by removing the weight of the forest from the slop true that the weight of the forest has a downslop ) component, this is more than offset by an increase i he soil produced by the weight component acting per o the slope. This is a nicety of soil mechanics which ked in more intuitive approaches.

ras

stability of the soil, and can cause serious ticed on steep slopes, and that the present and it should be significantly curtailed. I testimony, Mr. Gray?

Mr. GRAY. That is right. There is very goo based on our studies as to the cause-and-e clear-cutting on a massively large scale and

Senator CHURCH. Tell me, what is the ef soil itself-which, as we know, once gone tween clear-cutting, let us say, and selecti Mr. GRAY. I think that in selective cutt the conditions which lead to landsliding. mantle is not as wet. We retain a root syste soil mantle.

Senator CHURCH. So that the erosion is
Mr. GRAY. That is correct.

Senator CHURCH. Do you think that cle ped entirely on mountainsides where we h Mr. GRAY. Well, it is possible to identify graphic solid and hydrologic variables, variables that would lead to landsliding the forest cover. The state of the art is s identify

Senator CHURCH. In other words, you would indicate where considerations of preclude or should preclude clear-cutting?

Mr. GRAY. I am suggesting that it is pos lines. I do not know if they, in fact, exist, Ser Senator CHURCH. But scientifically it i of the art and the state of the knowledge Forest Service, let us say, to establish ac ing the problem of soil shrinkage and clear-cuts ought not to be undertaken; is tha

H. Gray, Associate Professor of Civil Engineering at the gan and also Acting Director of the Institute for Environme University of Michigan. I am here testifying on my own bel tive is to inform this committee about field research work the past three years on impact of forest clear-cutting on ural slopes. This work has been supported by a grant from ce Foundation.

of this research study has been to determine to what ex practices accelerate soil erosion and mass-soil movement landsliding) in steep mountain watersheds. Forest practices ern to us are road construction and forest clear-cutting. So focused primarily on the latter; although evidence reported urveys suggests that road construction may ultimately have pact.

is a timber harvesting procedure, widely employed in the Pac which all timber over a certain minimum diameter is felled . In even-age, mature stands of timber, this means that cle mount to deforestation-particularly when the clear-cut ar illsides and watersheds. The evidence for this is plain to see r tracts of Douglas fir in Oregon and Washington.

n clear-cut areas is often made even more awesome and compl slash remaining on the ground after a logging or cutover ope slash burning, of course, is justified by various arguments, t that it eliminates a potentially serious fire hazard later on. actice does for soil erosion and mass-soil movement is anoth is taken several directions to date. We have conducted a caref echnical literature, done some theoretical analyses, carried o el experiments in a tilting soil at the University of Michig ens, and instrumented some actual sites in the field. The fie is designed to monitor the change in rates of downslope mov moisture regime in the soil mantle before and after clear-cuttin o early to conclude much from the results of the instrument [owever, based on results of our literature survey, theoretic ydrologic model studies, there is overwhelming evidence to su scale clear-cutting promotes not only accelerated soil erosion, bu usceptibility to mass-soil movement. This evidence is reviewed gress report submitted to the National Science Foundation title est Clear-Cutting on the Stability of Natural Slones." Octobe e, I would like to have this report become part of the hearin

er on a slope enhances the deep-seated stability in two principa cially modifying the hydrologic regime in the soil mantle and b nforcement from its root system. Large scale removal of th ults in wetter conditions in the soil mantle (inimical to stability

Mr. KEGENSTEIN. My name is Lewis F honor of reading a statement by Dr. Rob board of directors for the Defenders of Wil

Because time is so short I have summari request that the original statement be ind Senator CHURCH. That will be done.

Mr. REGENSTEIN. Thank you, Mr. Chairm

STATEMENT OF DR. ROBERT RIENOW, M DIRECTORS, THE DEFENDERS OF WASHINGTON, D.C. (READ IN THE A BY LEWIS REGENSTEIN)

Mr. REGENSTEIN. The Defenders of W appear, are indeed grateful for this oppor of its members on the critical matter of forests. Largely because we have pressed: shocking 104 species of American birds, a on the endangered species list.

This is a consequence of man's greed ar is ecological suicide. It foretells the co foundering ecosystem. When the ecosysten but one end for man who is part of it.

We are facing today a most horrifying tion is actually witnessing the waning and of wildlife which only 8 or 10 years ago

The American eaagle is taking a long ing us. We have known for some time grizzly, the alligator, the polar bear a steadily year by year. But who would ha flocks of common sea birds and sea ani doomed?

When 350,000 of the common brown pe Mexico within 3 years, only an amazin ignore it. When, in addition, the flocks o