Document JZezoQML4BwwpGNOkzDk8qme

CERTIFICATE OF SERVICE I , W. S t u a r t C a lw e ll, J r . , one o f th e atto rn e y s f o r the p l a i n t i f f , do hereby cfeftify th at I have served a copy of " P l a in t if f ' s Response to D efen d an t's R equest For P ro d u ctio n o f M ilit a r y P ersonnel And M edical R ecords" upon co u n se l o f reco rd f o r the d e fe n d an t, by hand d e liv e r in g a tru e and e xact copy th e re o f on the 13th day o f Ju n e , 1983, to C h arles M. Love, I I I , 1500 Commerce S q u a re , C h a rle sto n , West V ir g in ia . \. r*l <rs C 'i GO ; deposition , . EXHIBIT ASSESSMENT OF ECOLOGICAL EFFECTS OF EXTENSIVE OR repeated u se o f herbicides FINAL REPORT IS August - December 1967 Confrac: No. DAHCl 5-68-C-Oll0 MR! Project No. 3103-2 /*' Sponsored by Advanced Research Projects Agency ARPA Order No. 1C36 MR) * '*'Ci.- Ml`- Tl.is research supported by t.'ie Advoi ced Research Projects Agency of the Deparrmjnt of Defense and was monitored by Department of Apmy under Contract No. DAHC1S-62-C- 0119. R elease: 'The information contained in thi.: report ca/ not i reproduced fo r non-rf'-nm aent :r.e without the w ritten pernios Ion o r the ice o f the D irecto r o f Defense ?.esear'h and H ^incer!njs. Tin* Fcat*.ror.. E is.-la ir.e r? Tha fin din gs in th is report are not to ve co n strue*.1. a s an o ff i l i a l p o sitio n o f the Bepartsant o f Arcy. -unless so ;:es;;T.&t ed ry other authorised documents. r7 s i AssEsa-err of ecological effects of extensive OR REPEATED USE O? EZHSICIDES by V. 3. House * L- H. Goodscn H. H. Gadberry K* V. Ooefcter FTAL REPORT IS August - 1 Cecenter 1267 Contract Ko. DAEC15-9-C-0119 MR! P ro je ct Ho. 3103-3 Sponsored by t' Advanced Research P ro je cts Agency ARPA Order to. ICG6 This research vas supported by the Advanced Research P ro jects Agency o f the Cepartr.ent o f Defense and v*is aonitored by Departcer.t o f Amy under Contract (o. DA3C13-Ga-C-0U9. PREFACE t3U s report v as prepared -by the Midwest pgfireh Tnatitutef under Contract Ho. ESAHC-IS-58-C-0119 fo r the Advancer Research p ro je c ts Agency o f the Department o f Defease. The authors include William 3 . House, D irector o f S lo lc g ic a l Scien ces; Louis H, Gcodsen, Senior Advisor f e r Biology; feevarrt M. Gaberry, Senior Advisor fo r Technology; Rennets W, Dockter, Senior Biochem ist; David A. Ringie, P rin cip al P h y sio lo g ist; John C. KacFerlane, Head o f the L ife Sciences Section and 0. B. G errlsh, Head o f Foci Science S e ctio n . The foHew ing consultan ts a ssiste d In the w ritin g , correction o f prelim inary d r a f t s , and provided eco logical perspective in the areas of th eir sp e c ia l knowledge; Dr. Boyaie S. Day, P rofessor o f Plant Physiology, and Chairman c f the Departsent of H orticulture, University o f C aliforn ia,.R iversid e, C aliforn ia; Dr. Korlan C. Henderson, A ssociate P rofessor o f Botany and Ecology? U n iversity o f M issouri a t KSnsas C ity , M issouri; and Dr. Janes H. Jen k in s, P ro fessor c f W ild life Management, School o f F o re stry , U niversity o f G eorgia, Athens, Georgia. We a lso wish to thank those n e stle nd th e ir o rg an isatio n whose, names are shown belcw fo r th e ir a ssista n c e in providing I n f a r c t i o n fo r use in th is rep o rt. Mfny o f the following people contributed r e p r in ts , m anuscripts, and unpublished inform ation which were invaluable to us in assem bling these data. Although we have u t il i s e d inform ation and the su g gestio n s from many sources the statem ents, opinions and recommendations o ffe re d by the authors t o f t h is report are e n tire ly th e ir own and do not n e c e ssa rily r e f l e c t the opinion o f the Department o f Defense o r other govem&wat a g e n c ie s. Mention o f prop rietary or trademark products dees not c o n stitu te in dorsement by the Government. A llen, Durvard L ., Department o f F orestry Conservation, Purdue U n iv ersity , Lafayette, fcidiana A lley, Harold P ., U niversity o f Wyoming, Laramie, Wyoming Andersen, Kenneth, B a tto lie Memorial I n s t it u t e , Columbus, Ohio Anderson, A. S .C o lo r a d o Dept, o f Game, F ish , and ie r k s , Fort C o llin s , Colorado A verett, William, U hivsrsity of Southwestern Louisiana, L afay ette, Louisiana B alcea, Robert B ., Bureau o f Reclamation, Irrig a tio n and Land Use, Dept, o f In te rio r, Washington, D. C. Ill rritreuaeaEE i Barick, Frank B . , ' i ` vrth Carolina, Research Conservation Gr.Mp, R aleigh , North Carolina Beatty, Robert K ., Aacheu, I n c ., Ambler, Pennsylvania Eer.tley, J . R ., P a c ific Southwest F o re stry O ffic e , US.DA F o rest S e rv ic e , Berkeley, C alifornia Blackburn, R. D .f Crops Researon D iv isio n , ARS, USQA, Fort Lauderdale, F lo rid a Blaksy, Harold L . , Department o f Army Corps o f Engineers ( C iv ilia n Vork&), Washington, D. C. Boyce, A lfred, School o f A gricu ltu ral Scien ces, U niversity o f C alifo rn ia, Riverside, California Bramble, Wr.. C ., Department o f F o re stry end Conservation, Puriue U n iv ersity , Lafayette, Indiana B ridge, Kenneth,. Acchem, I r e . , Ambler, Pennsylvania Droa, J . lu ck , m C , B a s te n e MemoriaL I n s t it u t e , Columbus, Ohio *^ B row , Tames W., Crops D iv isio n , Ur S . Army B io lo g ic a l Center, F t. D etrick , F rederick, Maryland Buechner, Helmut K. , O ffice o f Scology, Smithsonian I n s t it u t io n , Washington, D. C. B u ell, Murry, Rutgers U n iv ersity , Rev Brunswick, Kaw Je r s e y B u tler, P h ilip A ., Bureau o f Commercial F ish e rie s B io lo g ic a l Laboratory, Gulf Breeze, Florida Byeth, Werner, MUCCH, Pleatinny A rsen al, Dover, Hew Je r se y Byrd, Barry C ., Plant Science Research and Development., Dot* Chemical Company, Midland, Michigan Carlson, C, Edward, Central O ffic e , D ivision o f W ildlife R esearch, Bureau o f S ro rt F ish e rie e and W ild life , Dept, o f I n t e r io r , Washington, D. C. Carlson, W. T . , Science Inform ation Exchange, Smithsonian I n s t it u t io n , Washington, . C. Carpenter, Richard A ., Science Policy Research D iv ijio n , L e g isla tiv e Reference S erv ic e, Library o f Congress, Washington, 3 . C. iv L t i f l = ? W. 1B.*L4.' m eaga -\fis s q k a g iiw."a gs^ygwg-tg g y g ^ !^ ? ^ ^ ' Carpenter, ter, Ic y , U n iv ersity o f C a lifo r n ia , D avis, C a lifo rn ia Chappell, We. E . , V irgin ia Polytechnic I n s t it u t e , Blacksburg, V irginia Coech, Graham, Canadian W ild life S o c ie ty , Vancouver, Canada Cooke, Anson, B io lo g ic a l Bestarch D iv isio n , Amcnem, I n c ., A shler, Pennsylvania Cope, O liver 3 . , U. S . F ish -F tsstlcid e Research Laboratory.. Bureau o f Sport F ish e rie s and W ild life , U3DI, Columbia, M issouri C utter, W. Bowran, Science and Technology Bureau, U. S . Arms Control and Disarmament Agency, Washington, D. C. Darrov, R. A .f Crops D iv isio n , U. S Army B io lo g ic a l Center, F t. D etrick, Frederick, Maryland Davidson, J . K ., Plant S cien ces Research and Development, Dev Chemical Company, Midland, Michigan Davidson. R. S . , Eat t e l l e Memorial I n s t it u t e , Columbus, Ohio Davidson, Verne, USDA, S ta te Conservation S e r 'i e e , P ortland, Oregon D avies, John, Miami Health S e r v le t, Dade County Health Department, Miami, Florida DeAilcy. L. S . , Thompson Eayvard Chemical Company, Turner, Kansas DeVaney, Thomas E . , Bureau o f Sport F ish e rie s and W ild life , Fish and W ildlife S e rv ic e , Department o f I n t e r io r . Washington, D, C. t* ' Dickens. Ray, Department o f Agronomy and S o i l s , Auburn U n iv e rsity , A griculture Experimental S ta tio n , Auburn, Alabama D orvars, C o u ld L ., PACIC, c a t t e l l e Memorial I n s t it u t e , Columbus, Chid Dues, Sam, U. 1 . Army Corps of En gin eers, Washington, L . C. Duggan, R. B ., HEW, Food and Drug A dm inistration , Washington, D. C. D ustsan, Eugene K ., fcituxent W ild life Research Center, Div. o f W ild life Re search , Bureau o f S p o rt F ish e rie s and W ild life , Fish and w ild life S e rv ic e , Department o f I n t e r io r , la u r e l, Maryland Dykatra, V alter W., Pesticides-A nim al Control, Central O ffic e , D iv isio n of W ild life Research, Bureau o f Sp ort F ish e rie s and W ild life , Department of I n te r io r , Wasningtc.-j, D. C. v 2333$E 5?P*9 [/ ;\ asto n , S . H ., AgriucJ tu r a l S ta b iliz a t io n Conservation S e rv ic e , Commodities D iv isio n , U3LA, Washington, D. C. Eckert, R. C ., U n iv ersity o r Nevada, Reno, Nevada E lk in a, 2 . A ., The Nature Conservancy, Washington, D. -C. Ekman, P h ilip J . , Chemical D iv isio n , Ansul Chemical Company, M arinette, Wisconsin Ennis, V. 3 . , J r # , Crops P rotection Branch, Crops D iv isio n , APS, USDA, B e lta v ille , Koryland Erickson, Lambert, U n iv ersity o f Idaho, Moscow, Idaho F e r t ig , S tan , Amchea, In c , Ambler, Pennsylvania F in ley , Robert 3 . , Upland W ild life Ecology S e ctio n , Denver W ild life Research Center, Fish end W ild life S e rv ic e , USDI, Denver, Colorado '.herlor 2 , South r id id s Rciccu .a unu w n :s\rn Center, Texas AIM, Lubbcet, Texas Fosbe*g, F. R ., Smithsonian. I n s t it u t io n , Washington, D. C. F a ste r, W. R ., L ife Sciences Branch, Science Information Exchange, Washington, D. C. Fox, A ustin, Firm Production Economics D iv isio n , Economic Research S e rv ic e s, USDA, Waahiigton, 0 C* Fowler, D*. Lee. A g ric u ltu ra l S t a b ilis a t io n and Conservfat*io*n S erv ic e, CJSDA, Washington, 2. C. FTear, Donald E. K ., Pennsylvania S ta te u n iv e rsity , U niversity Park, Pennsyl vania Freeman, Monroe, Science Information acehanr, Washington, D. C. Freiburg, S . P ., R ock efeller Foundation, IRI Research I n s t it u t e , !7ew York, New fo rk Fulcher, Glen D ., Bureau o f Lend Management, Department o f In te rio r , Washington, D. C. *r F I I ri r \ rr l Z *? F u lle r, Grafcas, Section of Weed Control, D ivision o f Agronomy S e rv ic e s, Department o f A g ricu ltu re, S t . F au l, Minnesota C a lle r, Sidney, Saithsonian I n s titu tio n , Washington, D. C. Gangstad, S. 0 ., Department o f Army, O ffice o f Chief o f Engineers, M ilitary - Construction D ivision , Washington, fj. C. Gecrge, John L . . Department o f F orestry and W ild life , School o f Forest Re sources, Pennsylvania S tate U niversity, U niversity Park, Pennsylvania Gibbons, Harry, .rcoedical Branch, Federal A viation Agency, Qklahtsa C ity, Oklahoma Kayes, Wayland J . , HEW, rKS, C g si.aiiccb le D isease Center, A tlan ta, Georgia Heath, Robert G ., Patuxent W ildlife Research Center, Bureau o f Sport f i s h e r i e s ' Aii-.i t fji/ii * Fish and W ild life S e rv ic e , Dopircscut c f I n te r io r , la u r e l, Maryland K eickes, Eugene, Colorado S ta te U n iv e rsity , F t. C o llin s, Colorado Kerbel, C arlton, Jornada E xp ericen tsl S ta tio n , Range Research, USCA, Los Cruces, New Mexico H iltetran , Robert C ., Aquatic Biology Section , State R aturai History Survey, Urbana, I llin o is Hodg-son, J . M., Montana S ta te U n iv ersity , Bozesan, Montana Hoffman, Garlyn, Texas A n ricu ltu ral Extension Service-, Texas A&M College Statio n , Texas V Hais, leRoy, G ., H orticulture Dep&rtaer.t, U hiversity o f Wisconsin, Madiscn, Wisconsin % lstu n , John T . . A griculture Research C enter, Agrcncaic Crops D iv isio n , USEA, c i *.* .Linti j o l l i f f e , 7 - r g i l, U niversity c f C a lifo rn ia , Department o f H o rticu ltu re , Riverside, California Johnson, Roy, Anehem, L ie-, A sh ler, Pennsylvanie Jordan, L. S ., U niversity s f C alifo rn ia, D e p a r t s of H orticulture, R iverside, C a lifo rn ia Keniga, i>n e, Biuuroducts R e g istratio n S ectio n , Dev Chemical Cuspany, Midland, Michigan K issin g e r,' Floyd , Bureau c f Land Management, Department o f in t e r io r , Washington, 2. C. Kirch, John H ., Amchea, I n c ., Ambler, Pennsylvania & iagm aa, D. L . , Gracing Land Crop fro te c tio n , Research Branch, Crops D iv isio n , B e l t s v l l l a , Maryland Kooerek, Roy, Greenwood Farms, T h a sa sv ille , Georgia X re ftin g , L au rita W., Bureau o f Sport F ish e rie s and W ild life , F ish end w ild l i f e S e rv ic e , U. S . Department of I n te r io r , Minnesota F ie ld S t a t io n , U niversity of Minnesota, S t . Paul, Minnesota Lavrence, John M., Auburn U n iv ersity , Auburn, Alibana Lieurance, Max,* Bureau o f Land Management, V ale. Cregon Lindsey, James, Pennsylvania State U niversity, U niversity Park, Pennsylvania L is d n s k y , Stepftin A ., Pennsylvania Game Ccmmisslcn, H arrisbu rg, Pennsylvania Lynn, George . , Dov Chemical Company, Midland, Miruigan M acSougall, D aniel, Cheoagro Corporation, Kansas t i^ty, M issouri McCabe, Robert A ., R ational R eferral Center f o r Soignee and Technology, L ib rary o f Congress, Washington, D. C. K c C o lliste r, Don D ., Dov Chemical Company, Midland, Michigan KbGreggor, S . E . , USDA, AR3, B e lt s v llle , Maryland McSasara, D. P-, Pharmacology L ab o rato ries, U. S . Army Edge'-nod`A rse n al, Sdgevcod A rsen al, Maryland I Mann, Robert A R ig h t- o f- w a y , Maintenance S e ctio n , Tennessee V alley A uthority* Chattanooga, Tennessee {K555351 M artin, James ? . , Department o f `S o il and Plant N utrition , U niversity of C alifornia, Riverside, California M artin, W illiam, E a t t e lle Memorial I n s t it u t e , ColumbutyCkio Mothews, tfa. L ., S o il and Watershed ranch, Bureau o f Land Manogesent, De**rt-. cent o f In te rio r , Washington, D. C. M inarlk, Charles E ., Crops D ivision , l'. S. Army B io lo g ic a l Center, F t. D etrick, F rederick ; Maryland M itch ell, J . W., Plant In d u stries S tatio n ,. USDA, ARS, B e lts v i l l e , Maryland Morton, Howard L ., CFDA, ARS, Texas ASH U n iversity, C ollege S ta tio n , Texas M ussetl, Tea, Research S ectio n , Montana Fish and Game, Boceman, Montana * % tfe lstn , Harvey K ., Northern P r a ir ie W ild life Research Center, D ivision o f W ild life Research, Bureau o f Sport F ish e rie s and W ild life , F ish and W ild life S e rv ic e . USDI, facertow n, fo rth Dakota' flelscn, Thccns, Southern F o re st experimental 5catio n , URDA F orest S e rv ic e , Hew O rleans, Louisiana H ierlcg , V i l l i * , K itic n a l Science Foundation. Washington, D. C. nicholacn, K. P ., Water C atm ainates Characterization & Rural Run-Off Control R esearch, Southeast Wate * Laboratory, Fed. Water PcH ution Control Adminis tr a tio n , Department o f I r t e r lo r , Athens, Georgia Kooa, Jo e , R ation al A g ric u ltu ra l Chemical Association','W ashington, D. C. foren , C arl, M issouri Department o f Conservation, Je ffe rso n C ity , M issouri Gdua, Eugene P ., I n s t it u t e o f Ecology, U niversity o f G eorgia, Athens, Georgia P arker, Kenneth W,, U. S . F o rest S e rv ic e , USDA, R ossily n , V irgin ia f a r i s o t , T. J . , F ish -P e stic id e Research Laboratory, Bureau o f Sport F ish e rie s and W ild life , USDI, Columbia, M issouri F e t r i t e s , George, Michigan S ta te U n iversity , U a s in g , Michigan P r e n tiss, Louis, fo rth American Road Builders A sso ciatio n , Washington, D. C. lx Price, J . R e fe rra l S e rv ic e s,. Library z Congress, Washington, 3 . C .. Quimfcy, Son C ., Montana S ta te U n iv ersity , Eozecan, Montana Rawls, C harles, K ., U niversity o f Maryland, natural Resources I n s titu te , Chesapeake B io lo g ic a l lab o rato ry , Svilsonr, Maryland R e is le r , Irv in g , Plaaiving D iv isio n , U. S . Ansy Dorps o f Engineers, Washington 3 . C. R ltty , Paul M,, Bioproducts, Dow Chemical Company, Midland, Michigan R ob erts, Harvey, Pennsylvania Game C o saissio n , H arrisburg, Pennsylvania Siatelm&nm, 3. V ., Agronomy Department, Oklahoma S ta te U n iv ersity , S tillw a te r Oklahoma Seaman, D. . , Syracuse U niversity Research Corp., Syracu se, ffev fo rk Shade, it * nooerc a * , uawjuu^u i , **h* , Washington, D. C. *~ * t * s * 0. Amy., Pentagon, Sh adbolt, C- A ., Thompson Hayward Chemical Conpany, Turner, Kansas S h e e ts, T. J . , U n iv ersity o f fo rth C arolin a, R aleigh, fo rth Carolina Shepard, Harold H ., A g ric u ltu ra l S ta b iliz a t io n and Conservation S e rv ic e , US2A Washington, 3 . C. Shipman, R ., School o f Forest Resources, U niversity o f Pennsylvania, Universi Park, Pennsylvania /' Smith, Gordon 2 * , TVA, Wiscle Sh o als, Alabama Smith, Paul, Aercmedical lab oratory, Federal Aviation Agency, Gklahaca C ity, Oklahoma S ta e n ia , John H ., Patuxent W ildlife Research Center, Bureau o f Sport F lsh e ris and W ild life , USUI, Fish and W ildlife S e rv ice , L au rel, Maryland S to k es, W illiam, P e stic id e R egistration S ectio n , Food and Drug Adm inistration Washington, C. S tric fc le r, ? . 2 . , 7 a m Production Division., Economic Research S e rv ic e s, USDA, Washington, D, C. S u r r e tt, Lonnie, Bureau of Indian A f f a ir s , Department o f I n te r io r , Washington, D. C. Swope, Harold M., Gome Research Center, Department o f Case, F ish and Parks, S ta te of Colorado, Fort C o llin s, Colorado Tinmans, F . L . , U n iv ersity of Wyoming, Laramie, Wyoming T seh irley , Fred H ., Crops Research D iv isio n , U3IA. ARS, Santa R ita Research Center, Tucson, Arizona Uph o lt, W illiam, P e stic id e Control C o m issio n , Bethesda, Maryland Upton, Ed 7 . , Thompson Itayvard Chemical Company, Turner, Kansas Wasseman, Samuel, P u blication Brandi, Bureau o f Reclamation, Department of I n t e r io r , Washington, D. C. , Watson, Andrew J . , Plant S e rv ic e Research and Development, Dev Chemical Company, MldlaM, Michigan Weldon, W., Crops Research D iv isio n , USDA, ARS, F o rt Lauderdale, F lorid a W illiam s, C ecil S . , Denver W ildlife Research Center, D ivision of W ildlife Research USD!, Bureau o f Sport F ish e rie s and W ild life , F isa and W ildlife Serv ice. Denver, Colorado W illiam s, Llewelyn, Slew Crops Research Branch, Crops Research D iv isio n , ARS, U3DA, B e l t s v i l l c , Maryland W ilts, Mark G ., Dow Chemical Company, Midland,' Michigan Winn, Roberta, Conservation Library Center, Denver, Colorado Wolf, Mark, Dow Chemical Company, Midland, Michigan l i c k , Warren, Ansul Chemical Company, M arinette, Wisconsin Z i l l g i t t , W alter, Southeastern F o re st Range Experimental S ta tio n , A sh v iiie , w.?rth C arolina xl 3 g 3 9 j 3 :31 1 i;*l 1i I /i i i I I ! * \ zur Burg, Fred W., Southwestern Louisiana U n iv ersity , Departaent o f Cheaistry, Lafayette, Louisiana Approved fo r : MXEWE5T RESEARCH DiSTITUTS V. 3. House, D irector Biological Sciences D i/isio a 30 Hovcaber 1SS7 / lid Xii table o? cxrzz:rs Par o. I. II. j III. Introduction .......................................................................................* Herbicide Production Usage And T r e n d s ...................................... H erbiciie A pplication on Various Land A r e a s .......................... 1 5 16 A. Herbicides fo r Croplands .................................................. 3 . H erbicides fo r N o n c r o p la n d s.............................................. C. H erbicides in F o restry ' ...................................................... D. Herbicide A pplication on Rangeland ..................... 17 13 52 72 IV. Herbicide A pplication on Waterways, Feuds, Lakes and R e s e r v o ir s ...................................................... ..................................... 66 V. A pplication s o f H erbicides . .............................. ICQ 71. Toxicalogical Effects of Herbicides . . . . 151 A . 'In tr o d u c tio n ................... B. T on icity o f Honcropland H e r b ic id e s .................................. C. E ffe c ts o f Herbicides an Micro rg an isas ...................... D. Toxic E ffe c ts o f H erbicides and C o n c lu sio n s............... 151 153 133 201 V II. Herbicide Residues and Their P e rsiste n ce .............................. 208 V III. ' Scae Factors Determining the F ate o f Herbicides: r ................. 232 IX. E colo gical Consequences o f Herbicide Use .............................. 251 A. Concept o f the Ecosystem . ............................. 3 . Food Chains ................................................................................ C. D efin ition o f S p e c ific E c o s y s t e m s .................................. D. E ffe c ts o f H erbicides on an E c r s y s t e a .......................... E. E co lo g ical E ffe c ts on the A b io tic F actors ................. 251 255 256 265 276 X. An Evaluation of Sees o f the Major E colo gical F acto rs Invo)ved in the Use o f Herbicide:. . ...................................... 233 xi 11 TA5L2 OF CChTgiTS (Concluded) Pa^e Ho. A p p en d ix ............................................................................................................. . . . 293 Bibliography - Chapters I - E C ............................................................... 313 G l o s s a r y .................................................. ......................................... .... 357 /"' xiv AgSIHAC? An in fo rx a ticn survey including published lit e r a t u r e ana p e rso n a l' interview s with in d iv id u als Jaiovlecgeacle in -.-.he f ie ld s o f h erbicide t:sage, animal ecolcgy an d plan t ecology has been conducted fo r the purpose o f a s s e s s ing the eco logical consequences of, tensive or repeated use o f h erbicides for vegetatio n co n tro l. The general su b je cts discu ssed in t h is review include ( i ) herbicide prsductIon, usage and tren d s; (2) herbicide a p p lic a tio n to crop and noncroplands, e sp e cially fo r e sts, ranges, rlgh ts-of-vay , v.-terveya, pends, lak es and r e se r v o ir s; (3) n ili t a r y usage, o f herbicides in Vietnam; ( 4) acu te, subacute and chronic '-c x icitie s o f 21 h erbicides used p rim arily f s r coneropland a p p lic a tio n ; (5) p ersisten ce and, elim ination o f herbicides f r m the s o i l (G) known e c o lo g ic a l effect-, o f vegetation removal by ch tn ical methods ( e . g . , h erb icid es) and p h y sica l methods ( e . g . , b u lld osin gj f i r e , flo od in g, e t c . ) , including both the e ffe c t s on the b io tic and a b io tic components. s p e c i f ic a l l y , co n sid eratio n i s given to the e ff e c t s o f h erbicides cn w ild lif e , w ild lif e h a b ita t, endangered sp e c ie s, food ch ain s, b io tic p o te n tia l, p lan t su cce ssio n , animal succession, revegetation, clim ate, s o il eroalcn, la te r isa tio n and r e la te d t o p ic s ; (7) seme conclusion regarding the e co lo g ical changes are p re sen ted; and (8) some rectaaendations fo r fu rth er e c o lo g ical in v e stig a tio n s are given. xv V. MUIZUff APPLICATZSH3 07 KSS3KTSS? Unlike c iv ilia n ap p licatio n s o f h erbicides in fo re stry , range management, and aq u atic weed co n tro l, the development and use of h erbicides fo r m ilita ry purposes have n et been adequately documented in the s c ie n t if ic lit e r a t u r e . Although aany post-w ar m ilita r y herbicide in v e stig a tio n s have been u n c la s s ifie d , the a l l i t a r y technology r e la tin g to d e fo lia n ts , d e s ic cants and chemical agents fo r drop d estru ctio n has received l i t t l e atten tion in the*chem ical, b o ta n ie s!, and e c o lo g ic a l jo u rn als. Within th e p ast few y * a r s , a general concern has been expressed by the s c i e n t i f ic e o s s m ity regardin g the u se o f vegetatio n -co n trol chem icals by the o ilita r y . Therefore, in order to provide a better b a sis fo r considering the ecological consequences c f various m ilitary uses o f h erbicides, these a p p licatio n s must be described in somewhat g r e a t e r ,d e t a il than are the c iv ilia n uses. m i ornt ion haa uecu Jxwii e ti r e ly f;*s s p u b licly -**~ *s; the u n c la ssifie d tech n ical li t e r a t u r e and rev s accounts. The follow ing s e c .V tio n s represent a fa c tu a l account o f the background and development o f m ilita ry h erb icid es, che p o lic ie s c o n tro llin g the use o f h erb icid es, and the m a t e r ia ls _ and ap p licatio n procedures cu rre n tly used in Vietnam. A o r ie f a sc rip tio n o f the vegetation in Southeast A sia i s presented along with i t s response to h erb icld al treatm ent. The p o s sib le e c o lo g ic a l consequences o f Cu-e cp n rst?**** w ill be discussed separately. Background and H isto ric a l Sfrvelcm enl o f M ilitary Jterbicldes t ' Throughout World War I I , c l a s s i f i e d m ilita ry research cr c h e rlc a l h erbicides played an important ru le in the development o f the potent s e le c tiv e h erbicides nsv in world-wide use. In the seareU fo r chemical agents to destroy enemy cro p s, many o f the hey concepts o f h e rb icld a l mechanism and sp e cie s t e lc n tlv ity were elu cid ated , and the e ffe c tiv e n e ss o f the phenexy h erbicid es as weed co n tro l agents was f i r s t demonstrated. 7n la t e 1341, a gioup o f prominent s c ie n t is t s convinced the S ecretary o f War, Henry S tia so n , wf the p o te n tia l dangers from b io lo g ic a l war fa r e . Stinson requested the n atio n al Academy c f Sciences and the N ational Research Council vo provide the b e st p o ssib le s c ie n t if ic jd v ic e . In response, tne National Acrdemy o f Sciences e stab lish e d the " AEC" Committee, and, 1 February 1942, the c o 's i t t e e 'a Report re su lte d in the establishm ent o f che War Fesearch Serv ice, a c iv ilia n sgency with George Merck as the d ire c to r . nClT.' V ill 1C5 \ Although a number o f p lan t p h y sio lo g ists ar.3 oth er s c i e n t i s t s had carried on a decade o f research with p lan t hormones and s y n th e tic 'growthre*5u ljtin g agen ts, and many vorkcfs had noted th at overdoses o f p lan t hormones or growth reg u lato rs In ju re p lan t t is s u e o r even k i l l the p la n ts , no o s * had yet suggested that horacne-lixe agents sigh t be useful as herbicides. Several c f these research workers were destin ed to p lay p iv o ta l r o le s in tha dcveitipnent o f both m ilita ry h erb icid es and eodem weed k il l e r s .'* These s c i e n t i s t s included Dr. E. J.-K r a u s, Head o f the Botany Department o f the U n iversity o f Chicago, who had worked e x te n siv e ly with growth reg u lato rs and p lan t hormones, and two o f h is d c c tc ra l stu d e n ts, John M itchell and Charles Manner, who sin c e 1940 hsd both been working a s p lan t p h y sio lo g ists a t the USDA Plant Industry S ta tio n , B e lt s v lU e , Mavyland. Apparently, Kraus was the f i r s t to suggest th at growth re g u lato rs , might wsrk as h erb icid es i f p u rp o sefu lly ap p lied to weeds *n to x ic doses (P eters 5n, 1957a). E arly in 1941 he d iscu ssed t h is with M itch ell ar.d Kamr.er, la t e r elab o ratin g h is id e as in l e t t e r s to them (Mirth and M itch ell, 1944; M i t ^ e l l , ^ecn). i.ith in a f o r so o th s, Emus osd i l i t b e g ? * * vgjw e --<**> v ario u s synth etic growth re g u la to rs f o r th e ir h e r tic id a l a c t iv it y . In A p ril 1342, Kraus and M itch ell learned about the work seen to be published by Zirrem an and Hitchcock (1942) o f the 5cyce-Thccrs^n I n s t it u t e . Zirmermax* hed found.that the pncr.ouyacetic a c id s are exceedingly powerful growth re g u la to rs, and that cue o f the s c s t potent fu r Inducing se e d le ss t s s a t o e s was 2 , 4 - i i ehlorcphencxyacetlc a c id , which was 300 times more powerful than tne widely used lnd'jLelutyric a c id . Without in d ic a tin g the intended u se, M itch ell ob tained sc se c f these chem icals, including 2,4-D , fren Z i s e r s a n and began te stin g a v arie ty o f compounds as' h erb icid e s in the greenhouses a t the U niversity c f Chicago and 3 e lt s v ille . Kraus was s u f f ic ie n t ly encouraged by the e a rly r e s u lt s th a t, in l a t e 1942, he surgested to the ro e a itte e s o f/th e n atio n al Acadeay o f Sdim ice* that the t e t ic p ro p erties o f grow th-regulating substances i> r thr* d estru ction o f crops or the lim itatio n e f exop production" srgiit be o f m ilita ry In te re st, and proposed that the h e rb ie id a l p ro p e rtie s o f these grow th-regulating chemic a ls should be te ste d oh f ie ld crops (Kraus and M itchell, 1947). Eeccuse o f ^ the war, Kraus and M itch ell a id net p u b lic is e the r e t u l t s o f th e ir 1941-1943 experiments. * A thorough h is t o r ic a l review o f wartime research on h erb icid es, recen tly prepared by the SeiThsonian I n s titu tio n , hus been published in A g ricu ltu ral H isto r/. Ju ly 1937 ( e te r r c n ,. WS7b). M ltrh e ll's o r ig in a l 1 -lb . b o t tle o f ? , 4-D Is now a p e rt o f the c o lle c tio n In the ftstth n o n lsirs D iv isic r o f A griculture end Korent. Products. '] The United S ta te s Arty in it ia te d a co n tract v ith the U n iversity o f Chicago in March 1343 to support th e 're se arch o f Kraus and M itch ell, and to pay fo r such o f the work vnich had alre ad y been dune. Since the ver ag a in st the Japanese in the P a c ific was o f in creasin g importance, i t i s not su rp risin g th at the effe ctiv e n e sa o f 2 ,4 -0 and 2 ,4 ,5 - ? in k i l l i n g r ic e was included in these in v e stig a tio n s (Kraus and M itchell, 1347). Although the e arly r e s u lt s were prom ising, i t -was la t e r learned th a t r ic e i s gen erally q u ite r e s is t a n t to 2,4-0. Largely on the b a s is o f the r e s u lt s Kraus had reported to the R atio n al Acadeny o f Scien ces, the Army in te n sifie d I t s h e rb iclce re se a rc h , a s a i d i n g t h is m ission to the recen tly e sta b lish e d C a = S e tr ic js (P eterson , 19*S7c). The Arny research te c a ca rrie d cut th e sy n th esis and t e s t in g o f n early 1,10 0 substances in laboratory screen in g, greenhouse t e s t s , and l a t e r under the direction o f M itchell, as applied to fie ld crops. U n til the end o f the war, the U .S. research pro gran was an o f f i c i a l s e c r e t .' However, on January 3 , 1943, Secretary o f War, Hebert P atte rso n , node p u b lic s l e t t e r fr e e C-tsrca Mere!? v"h *** sons' other s ig n ific a n t accora- p lish cen ts o f the wartime pro gran, the te stin g o f "the e ffe c ts c ? core than 1,000 d iffe r e n t chemical agents os liv in g p la n t s ." Although v ic to ry was achieved before the h erbicides could be used, in wartime o p e ratio n s, Merck declared that "only the rcpid ending o f the war prevented f i e l d t r i a l s in an a c tiv e th eatre o f synth etic agents tn at vuuid, without in ju ry to human o r animal l i f e , a ffe c t the growing crops end cahe them u seless."(M erck , 1340. and Shalett 1345) ^ Even though the v a r - t is e research e f f o r t was d ire c te d p rim a rily toward an tie rc ? gents, the in v e stig ato rs could foresee the eecsldera le p o s s i b i l i t i e s th at 2,4-D had in a g ric u ltu re . The p lan t; in d u s tr y .r ts e a r c a pro" ? a t l e l t s v i l l e procured 1 lb . o f pure 2 ,4 *0 from the American Chemical P aint Company, und texaa te stin g 2,4-D fe r the con trol e f v ario u s cs emen weeds. These t r i a l ' a lso included t o x ic it y stu d ie s and cnimal feed in g t e s t s which ^ e stab lish ed the sa fe ty o f 2, 4- 0. To clin ch t h is p o in t, Xrau? p e rso n a lly ecn-j ^ sumrd 1 /2 g/'day fe r three weeks with ab so lu tely no e ffe c t (Cohen, 1946) and j (Pro*?., MCVCC, 134S). / During the rrmrer o f 1944, r e s u lt s came ra rid iy from a number o f research gioupa: the se le c tiv e action o f 2,4-0 was reverted (M itch ell and Kenner, 1944); the report by Keener and Tuiey (1944) o f su c c e ssfu l c o n tro l o f bindweed a ttra c te d considerable public atte n tio n ; end th is p u blic in t e r e s t in weed k i l l e r s persuaded sev ere! chemienl companies to preduce and market 2 , 4-0 c o s s e r c ia lly . The follow ing year, 1945, saw the introduction o f " * e e d c r e ;M th e "fir st systemic herbicide. 110 esjHUM) > 1 D efoliants fo r Ju rr lc Warfare Tearly 20 y ears o f research and testin g v ered ev c.ted to the a tta in neat o f d e fo lia tio n syotcoc capable o f strip p in g evay Jungle fo lia g e . The record o f tech n ical development d ates bach to the e s ta b lis r s te r t o f F ort O strich to the winter o f 1942- 1543. The var in the South F u c lflc vas ash in g new demands on s o lit a r y technology: "There vas a great deal of in terest at that tls e in destroyin g vegetation in the South P a c ific th e a tre , and the p rin c lp a l means a v a ila tle 'w a s high e x p lo siv e s. I have forgotten hew many a i l l i o n s o f tone o f high ex p lo siv es were required to destro y the v egetatio n on sane o f these P a c ific isla n d s. We were ashed to in v e stig a te chemicals th at were a v a ila b le in larg e q u a n titie s in the United S ta te s th at could be employed fe r 'd e f o lia t in g ' th is vegetation*" (Minarilc, 1263a). -X The t a c t i c a l u ses o f chemical d e fo lia n ts in court te r-in su rg e n t opera tions nave been su ssariz e d : y "The c a p a b ility o f destroyin g cover and concealment to defend a p iin s t and fig h t o f f g u e r r illa and ether types o f . t a c t ic s i s ab so lu te ly e s s e n t i a l . When we clear, vegetation fr e a ro a d sid e s, railw ay s, and c a n als, ve su b sta n tia lly reduce the opportunity fo r aebush, and thus allow our own operations to proceed in a more tim ely canner. . D efo lian ts vcnld a l s o be used to demarcate bound a r ie s D e fo liatio n could be used to c le a r gun ecp lacecen cs, open up f i e l d s o f f i r e , marie are as o f bcmbiiig, or t e s t whether or r o t a p a rtic u la r ' area vas camouflage or a c tu a l vegetacion'"(D elso re, 1563) Hear the clo se of the war, a e M sl spraying o f sev eral inorganic d e fo lia n ts was te ste d a g a in st su b -tro p ic a l vegetation in the F lo rid a Everglades. These t e s ts demonstrated that spray droplets applied to the fo re st canopy penetrated, not only the top leav es, but a ls o the middle s t r a t u s , and some even reached the fo r e s t flo o r (K inarlh, 1963b). T herefore, m u ltip le treatment i s not e s s e n t ia l in strip p in g away tro p ic a l cover. By June 154S, the Aray vae prepared to it-ccroer,.* the use o f araonium thiocyanate as a d e fo lia n t in tb P a c ific theatre. K<vever, higa Gcve..".cent lev els decided th at: 111 y u tittu . Figure V -l - C7. S . A ir Forc C-123 Spray Planea C e ro lla tin s Eerje F creat Cover In South V letras 112 "Aomcnim rhiccyanf.te sounded very ouch lik e cyanide, 'which ev*r;bcdy cnovs i s poisonous. I f ve used t h is chemical, we would be atcu scc c * ccnductir.3 p o iscn -;:ae w arfare; th erefo re, the plan tc- use c h c ria a ls fc r dcctr eying vegacation in the P a c ific theatre -as drt?pped. The war ended b -fe re another 'd e fc ljsn t' c c iid be developed." (M inarik, l?3a) The chemicals used a t t h is time are core a c c u rate ly termed d e siccan ts--agn ts which in ju re fo lia g e by d ir e c t chemical ac tio n -*n c c rx a c t, r a i s ing the leaves to turn broi.m, c u rl, dry up, and wither- tw af drop by abs c is s ic n cay cr cay not 0ccur. S in re th ere i s l i t t l e absorption c r tran slo ca tio n , cnly tee fo lia g e and green te c s are destroyed and the r e s t o f the p lan t cay recover. ,,The e ffe c t i s lik e a heavy f r o s t . Such agen ts are often temnd In a post-war prograa, F o rt D etrick examined approxim ately 22,CCO chemicals fo r d e fo lia n t and d e siccan t a c t iv it y . The c o s t p re c isin g 7CO chemi c a ls were screened in greenhouse and f i e l d t e s t s fo r th e ir d e fo lia n t a c tiv it y (Minarih 193b and Preston e t & 1., 1359). Scr.e o f these dei'oixants were subseeuently tested a g a in st tro p ic a l v?-taf.ino fn Puerto Rico (Bran e t a l . , 1951), ' ~ A highly s ig n ific a n t dem onstration o f v egetatio n c o n t:o l was c-onducted a t Tam? Brum, Kev v :rK , 1359. Using a mixture o f undiluted b u ty l e ste rs o f 3,4-2 and 2 ,4 ,5 -T applied a t 0 .7 5 g a l/^ c r e , the tre e s were denuded over an area o f .4 square m iles (Brown, 1939'. S h o rtly ,a fte r th is su c c e ssfu l d e fo lia tio n t e s t , the government o f South Vietnam requested the U. S. Arr.y to undertake t r i a l s o f d e fo lia n ts fo r use ag a in st g u e r r illa fo r c e s. This req u est coincided with the f i r s t announcement in^the U.S. th at*- '/ * ' "The army i s experimenting with chemical techniques fo r strip p in g jungle- areas o f fo lia g e to expose g u e r r illa fig h u -rs or other h o stile fo rces and i n s t a l l a t i o n s . . .th a t chemical agentji had a lr sa d / been p erfected th at would s t r i p wooded are as o f th*ir fo lia g e ih about two or three d ay s." (Raymond, 1561). A variety o f chemical agents ver ' shipped to the Vietnamese m ilitary a u th o r itie s, and i r e s Ju ly 12S1 to A p ril 1962, a prelim inary s e r ie s o f d e f o li ation t r i a l s were conducted under the guidance o f J . W. Brown. Even though wartime conditions. in terfe re d with the c o lle c tio n o f d e ta ile d d a ta , there te s ts establish ed that tne e ste r s o f ?,4-D and C ,4,5-T were a c tiv e in k i l l i n g s m ajority o f the sp ecies encountered in Vietnam, providing the h erbicide rpray was properly applied to .the vegetation during a period o f a c tiv e growth. In ft d iit i.o , tlie f i r s t a e r i a l nppl imM nu ut` cat-uly' ic arid showed premise as a fast-au tin g desicennr. (Brown, 1962). 113 I t was reccsnendsd that fu rth e r screening o f chemicals lnd develop ment o f ap p licatio n systems be conducted In Thailand or other tro p ic a l area*, having vegetation sim ila r to that in Vietnam. The de.'o lin tic n r e s u lt s vcre s u f f ic ie n t ly encouraging that P resident D ie t 's government in Saigon announced on January 1 , 12e2, plana to use new techniques in a i t i r j g coun ter-o ffen siv e a g a in st gcaicnn.jgt g u e r r illa fo rc e s, sta tin g ; "Numerous tertn iq u es h ith e rto unseen in South Vietnam's jungle? warfare are being inaugurated or are about to be uesd to help turn the tid e o f b a t t l e a g a in st the V iet Ceng. Cr.e c f these techniques I s 'd e fo lia t io n ' from the s i r ; a chemical neons o f s t r i p ping leaves fran the fo lia g e th at h ajes V iet Jo:.g luoveeents in th ick ly wooded arean . Known V iet Cong b a se s w ill jc surrounded by bare stretch es where the g u e r r illa s w ill find i t 1 ' f f i c u l t to nerve undetected fr-n th e ir h id eo u ts, which are often underground." (Turnbull, V*2) ru rtn er s e r e n in g o f h eroicid es and aevrlapmeat jC p p llu alic r: sy s temsLhave been conducted in a re as o f Thailand bavin# v e g e ta tio n 's im ila r to that in Vietram. f o r t D ctricl. d ire cte d the OT;CEUS d e fo lia tio n t e s t program in Thailand, u t iliz in g t e s t s i t e s approved by the Thai government and m ilita r y au th o rities (Darrow, 1366a). Concurrently, the Department o f A griculture conducted re la te d de fo lia n t s tu d ies fo r the U. S , Army a t t e s t s i t e s in Texas and Puerto Rico ' ^T ich irle^ , 1267a). . Vietrartese m ilita ry forces conducted several la r g e - sc a le t s s t s in the spring o f 1362. United S ta te s plan es sprayed ju n gle growth along Highway 15, connecting the U. S . A ir Force Sase a t 2ien Koa j u s t ou tside Saigon to the seaco ast c it y o f Cap S a in t Jacq u es. T h is 70-mile route had been con sidered unsafe fo r months, and government o f f i c i a l s had to tr a v e l by a i r . Following th is t e s t , a high Vietnamese o f f i c i a l sa id : "D efo lian t chemicals would a ls o be sprayed or V iet Cong p lan tatio n s o f manioc and sweet potatoes in the h igh lan ds. The exact locations c f there plan tations have already been p lo tted by a e r ia l surveys. T ests hav* shown th -im an io c and tweet potatoes die four days a f t e r having been sprayed. These are the two most Important food sta p le s fo r the communist bands in the mountains.'1 ( S i g a r t , 1362) f I fia u io V-2 - ftordslde near Chon Thank, 7S to 00 K llo a c tc ra North o r Saigon . Sproycd 24 AuguoL J ib ;!. Photo taken 16 November 1361 shoua p a r t ia l d e fo lia tio n 300 f t back Into nu upxa,? fo r c a t varyli.g f 'o o r e la t iv e ly dense to open. (Courtesy U .S. A,xay B io lo g ic a l L a b o ra to rie s, F t, Dciviek) .. ^ ! A dditional d e fo lia tio n t e s t s ag a in st mangrove and nipa j a l a vegeta i tion alo n g the car.ajs an.* roads o f the Ca. iiau Peninsula were conducted in I1 August 1962. In these t r i a l s the heavy d e lta vegetation was sprayed 400 meters i tacit f r c a the sdg! o f the r iv e r s *nd the roads over a t o t a l length o f 7? fern. The h erb icid e fors.-uation known au "Purple1* (a brush control fe m u la tio n coa- . p r is in g b u tyl t t t e r s o f 2 ,4 -0 and 2,4^5-T) was applied a t r a te s o f i .2 and 3 :0 gad./acre. The mangrove v egetatio n responded rapid ly , and was cctpie-iely d e fo lia te d in about one week. Nip p e ls responded slc v iy , turning yellow and lo s in g i t s le a v e s; i t tootc fiv e weeks fo r'th e se pains to f a l l to the ground. i D e fo lia tio n a f t e r fiv e weeks was ratod, 95$ l e a f drop; while the 1 v i s i b i l i t y of the ground f r e a d ir e c tly overhead van increased by 90$ (Armed . Force Chemical Jo u rn a l, 1964a, and M inarit and Bertram, 1962a). A second important asp e ct o f the consequences o f d e fo lia tio n was shown in the Ca Mau t e s t s . Following d e fo lia tio n , the mangrove stan ds along scd * c f the reads became a c c e s sib le to the n ative woodcutters, who cut the t r e e s , converted i t to ch arcoal and s a id i t fo r fu el (Minarik and Bertram, 1552b). Where the la r d was s u ito o ls a f t e r removal c f the tr e e s , v ario u s crcps have been planted and c u ltiv a te d (Aimed fo rc e s Chemical Jo u rn a l, 1964b) . Twenty y ears a f t e r Kraus had f i r s t suggested them to the N ational y / Academy o f S cie n ce s, the phenoxy h erb icid es became a tsol o f war. Cn tfov*mber 21 and 23, 1962, the Vietnamese A ir Force carried (.at the f i r s t t o p eratio n al sprayin g o f h erb icid es fo r crop destruction in known V iet Cong iI strongholds (P eterso n , 1967C) iti iii Current H erbicide Use in Vietnam Since 1961, when h erb icid e s were f i r s t used in Vietnam (flaymend, 1965, and Mohr, 1965) . m ilita r y d e fo lia tio n has beccce the la r g e s t known use o f h e rb ic id e s. The g rad u ally changing ro le o f the IT. S . in the Vietnam c o n flic t h a s, in turn, a lte re d both the extent and the nature o f h erbicide ap p lic a tio n s. Operation Kanch Wand D e fo lia tio n m issions o f the U .S. A ir Force were assign ed to the -newly created S p e c ia l Spray F lig h t o f the 509th A erial Commando Squadron. Vhen the f i r s t group o f huge C-123 cargo p lan es, sp e c ially equipped fo r spray a p p lic a tio n , came to Tan Son Nhut A irp o rt cn November 29, 1961, th e'o p eratio n , destin ed to he known as "Ranch Hand," began to practice a new m ilitary technology (Pruden, 1966). *. 116 -- HJ------ J-- _m ___ H . M I . HI JL.I.-I. Courtesy Levellyn './ill lacs Figure \f-3 - Hargrove Swamp Woodland, Shoving Uniformity o f Canopy and Density o f Stand 117 A erial spraying of herbicides for cefo licticr. w crop destruction ^ cannot be d ir e c t ly ccnpared with any o f the c iv ilia n uses o f h erb icid es. Sven -forestry spraying to suppress detidusra tr e e s / thereby releasin g conifers, represents a poor analogy. M ilitary uce o f herbicides "d iffe rs frea other / ap p lication s in several important resp ects--in o b jectiv es, herbicide formula tio n s , dosare r a t e s , and a p p lic a tio n methods; and the e f f e c t s are influenced by the clim ate, v egetatio n and s o il s found throughout Southeast A sia. There fo r e , seme o f the tech n ical d e t a ils o f m ilita r y use w ill be presented. These fa c to r s need to be considered b efo re a s s e s s in g the p o s s ib ilit y o f le n g -te m ecological consequences. Herbicide Formulatjons Three b a s ic types o f h erb icid es are employed. The most widely used i s the fa m ilia r brush k i l l e r m ixture o f 2 ,I-D and 2 , 4 , 5-T. The chemical norm ally used fo r ju n gle d e fo lia tio n i s agent gc,"* / a SO-SO m ixture o f normal b u ty l e s te r s o f 2,4-D and 2 ,4 ,5 -T . Orange i s the '/ general, purpose herbicide designed to k i l l fo lia g e , v ita le a f f a l l in three to s i x weeks, and co n tro l p e r s is t in g to r seven i.u 12 uwwths. P rior to the adoption of "Orange," a closely sim ilar interim agent known a s "P urple" was employed. This form ulation was a p ro p rie tary , ccerrerc i a l brush k i l l e r which d iffe r e d from "Orange" in containing o percent i s o b u ty l e s t e r o f 2 , 4 , 5-T. experience has shewn that "Purple" and "Orar.ge" are equivalen t in d e fo lia tio n e ffe c tiv e n e s s , and can be used interchangeably. Agent "Whlte"^ em b in as p i d o r a a with 2,4-D in a lew v o l a t i l i t y amine s a lt formulation. This ccabinatlcn provides relativ ely longer duration con t r o l o f a wide spectrum o f woody p la n ts , plus the advantages o f accu rate spray placement where v o l a t i l i t y c re a te s problems. This agent i s c lo se ly sim ila r to e x p o s it io n s used f o r a e r ia l sprayin g o f power lin e 'igh ts-of-vay throughout the IX. S . D esiccant agen t, " E lu c ." caco d y lis acid i s a contact h erbicide em ployed fo r rapid d e fo lia tio n . This fo r m la lio n does not k i l l many voedy sp e c ie s, but i t i s an e ffe c t iv e g ra ss co n tro l agen t, p a r tic u la r ly u se fu l in keeping down heavy g ra ssy vegetation along roadsides and surrounding m ilitary c n c ssp ie r.ts. For ease o f casp o rlso n , d e t a ils o f each composition a ie summarized in Table V-l. * The h erbicides d eriv e th e ir c o lo r fu l names irem the crlor-coded p ain t s tr ip e which g ir d le s each shipping .drum. 119 TABLE V-l COMPOSIT1QH AND CPAP.ACTFRr3TtCS OF MILITARY HKB9ICIPKS Agent Composition Lb/Onl AE Purpose Orange n-Butyl ester 2,4-D n-Butyl ester 2,4,5-T EO? (v t) 51/J (wt) Total 4.2 5.7 G.C Gcncrr.l d e fo lia tio n Forest Bruslr Broad-leafed crops lurple White ( Terdon 10 1) n-Butyl e ste r 2,4-D n-Butyl ester 2,4,5-T laobutyl cater 2,4,5-T 50? (vt) a t * W-\ 20* (wt) i Total Trl-isopropanolamlne s a lt 2,4-D . TrS-lisopi'opar.ol&mlnc s a l t piclnram * Total Blue (ttiytar 560-3) Sodium cacodylate Free cacodyllc acid Ifater; nediura. ch lorid e 2 7 .7% 4 .ax bal. 0 4.2 2 .2 1.5 ' 8.9 2.0 0.54 2.54 3.1 General d efoliation Interim agent used Intcrchangubly v lth Orange Forest defoliation Long-tern, jungle control Brush suppression Rapid d e fo lia tio n (snort duration) Grassy plant control Rico destruction 119 H erbicida! action o f the "Orange" and 'w h.te" f-'rm uiaticns depends upon absorption by the ria n t t is s u e and tran slo cate or. throughout the p la n ts. Properly ap p lied , in su ffic ie n t d oses, th is system ic e f f e c t v?cn h i l l p la n ts , and prevent root sprouting in a l l but the la r g e s t and most r e s is t a n t t r e e s . i Casc/Lie ac id or "3lue'" does not depend upon tra n slo c a tio n or . system ic a c tio n .. This organic a r se n ic a l compound (d is e th y ia r s e s ic c o ld ; a c ts such lik e the c lo se ly re la te d m s e n ic a l crab g ra ss k il l e r MSrfA (sor.osodiua methane orsonate) used en Vives. Both compounds are h igh ly e ffe c tiv e k i l l ers o f certain g r a ss p la n ts. Cacodylic ac id was o r ig in a lly intended fo r the co n tro l o f Z sperata, elephant g r a s s , bamboo and other p la n ts c f the g r a s s f i a i l y in d e fo lia tio n operations (Beecher, 1356). However, the e a r ly de fo lia tio n t r i a l s in Vietnam shoved tu a t cacodylic ac id vas a f a s t * a c t in g con t a c t desiccan t capable o f withering vegetation within a few .17s (Brown, 1362b). When ap p lied to fo lia g e in high con cen tration s, cacodylic a c id destroys the l e a f before appreciable tra n slo c a tio n cos tak e p la c e . When ap p lie d a t lover r a t e s , absorption and tran slocation, throughout the p la n t are c e s i b l e I t i s used cm rie** f i e l d s in ------ .* 11 . h t--*f .>. f ^^ destroys existin g crops but does so t a ffe c t subsequent growths (Lucos, 1387). *\ In most c iv ilia n a p p licatio n s o f h e rb ic id e s, the weed k i l l e r s are dilu ted in o il or vat;* as a c a rrie r, or are em ulsified a s normal or as in vert s em ulsions. For m ilitary a p p lic a tio n s, however, the " Orange'* end "P urple" agents are sprayed undiluted. Many .w ars o f experience in a e r ia l ap p licatio n -" o f h erbicides in the CJ. S . have shown th at the e s t e r form ulations g e n e ra lly achieve better control o f the treated vegetation than can be obtained with amine s a l t s and other form ulations. Am lication Factor? ,? - The 3pray equipment used in Vietnam, a s v e il a s the a p p lic a tio n parameters, are sign ifican tly differen t free vhat is used in ether herbicide spraying operations. Both fixed-wing and h e lico p te r a p p licatio n s have been cade. The HC-13 h elico p ter has beer, made a v a ila b le to the U .S. Army and to the Vietnamese Air Force (H.V;2f.A.?.)' fer sp e cial types o f herbicide ap p licatio n s. The b a sic spray p lm e , however, i s the twin engine C-123 a i r c r a f t , equipped with a chemical tank o f 1,000-gal cap acity and A/A+Sy-l in te rn a l de fo lia tio n dispensers (Form Chemicals, 196Sa). Each plane i s f it t e d with two wing b a css and a t a i l becm, using 14 n ozzles a . each wing buco and ed(p*t cn the t a i l b e . A ll spray operations are controlled fron a console located in the back o f the plane, designer *0 insure uniform flew and accurate r a te s o f spray ap p licatio n . The normal crew complement c c n s is ts of p i l o t , c o - p ilo t , 120 K Figure V-4 - Fanch ll-'ind Planes a t Tree-Top llcigh t C lear Strip through V iet Cong tronghoMa to Ula"10110 Ground A c tiv ity . Low le v e l a p p lic a tio n In u t j l l morning o il*.h elp s mini relic d r i f t and provides maximum edwetior In o bscu ratio n . (Courtesy U .S. Army B io lo g ic a l Lubujv*'0..'lea, F t. Petricfc) ! und a tech n ical s p e c i a l i s t who operates the spray console. The spray equipse n t I s c a lib ra te d to discharge the L, COO-gal tank in a 5-min period ; however the tank can be e p t i e d in 30 sec i s case o f aergen cy . Like a e r ia l spraying fo r c iv ilia n ap p lication s the spray run Is made as c lo se to the fo lia g e a s p r a c tic a l and a t a r e la tiv e ly low roeed. The fo r e s ts o f Vietnam have a canopy which generally reaches up to SO f t , with o ccasio n al tr e e s towering to about 125 f t . Th? normal a ltitu d e fo r spray a p p li catio n i s 150 f t . Speed i s maintained a t 150 knots, only 7 knots above s t a l l speed (L u cas' 1957). Under these ccn d iticn s, the spray emerging fr e e the open nozzles, i s atomized by a i r turbulence to produce h erbicide drop lets ranging from 100 to 400 in diameter with an average drop s iz e o f about SCO p, . The spray m ist s e t t l e s onto the fo r e s t canopy in a swath approximately 250 f t vide. Veather, vied and thermal currents greatly influence the e ffe c t iv e n ess o f th * h erb ic ld a l spray. The most e ffe c tiv e spray r e s u lts are obtained in the early morning when the vine i s calm ouJ the spray cum s e t t le rfire ctlv `onto the turget (Lucas, 1967). T ests have teen made to determine the degree o f spray-droplet in te r ception by the canopy, end by the interm ediate and lev er s to r ie s in the fo re st .(T schirley, IW7^ ) . ' In i m oist tr o p ic a l fo r e s t, approximately 80$ o f the spray d ro p lets are intercepted by the fo lia g e o f he topmost canopy; 14$ caught by the interm ediate le v e ls o f v egetatio n ; and caiy 6$ o f the t o t a l spray ap p lic a tio n reaches the ground level p la n ts . Data on penetration achieved with se v e ral d iffe re n t types ca spray bwcms i s contained in the Appendix, Figure A-2 (p.3Q 0). Spray d r i f t i s cm Important fa c t r which influen ces the e ffe c tiv e n e ss o f. h erbicide a p p lic a tio n s. Many fin e drop lets (2CO p, or l e s s ) are formed when liq u id i s re le a sed from a i r c r a f t . These mall drops are markedly a ffe c te d by a i r cu rren ts. For example, a 2C0 y, droplet w ill d r i f t 3 f t while f a l l i n g 20 f t in a l a t e r a l airflo w o f 1 sp a. (T schirley et a l . , 1937). The farth e r above the jun gle canopy the spray i s re le a se d , the so re d r i f t w ill occur. Seme d r iftin g o f sm all drop lets 'occurs under almost a l l ccn d iticn s. C alibration t e s ts conducted in Thinland establish ed that i t i s necessary to re le a se about 20$ sore herbicide than wall be deposited onto the jungle vegeta tio n . Fcr example, a sp e c ifie d treatment with 100$ "Purple ** a t 2 .0 g a l/a c re d ep o sit volume required release c f 2.5 g a l/a c re iron the a i r c r a f t , giving a I cover? o f SOi (larrow et a l . , I9 6 0 ). The 2C$ not deposited cn the t e s t cards used in c a lib ra tio n can be ascrib ed to a combination o f d r if t and evaporation. A ir turbulence re su ltin g from low fly in g a ir eras't Is an important facto r in providing d istrib u tion of.spray throughout the vegetative p r o file . ;fI . . . ti i *T When, a l l d r a p le t s a r e f a l l i n g in a str a ig h t lin e , most o f them w ill be in t..r-^ ^ ceptcd by the upper portion s o f the fo re st canopy. Turbulence fr c a the a ir c r a f t h.elps to d istr ib u te the d ro p lets throughout the f o lia g e . The am ber o f drops dep osited per square inch o f l e a f su rfa c e has a strid in g e ff e c t on the response o f h erb icid es. Behrens (1957) found that the e ffectiv en ess of 2 ,4 ,5 -T in creased g r e a tly as the number o f d ro p lets per square Inch in creased from nine 'f to 72, while the t o t a l amount of 2 ,4 ,5 - ? resain ed co n stan t. The p ic lo r a a end cacodylic acid form ulations are considered non v o l a t i l e , and thus are su b je c t only to wind d r i f t o f fin e d ro p le ts. The nb u ty l e s t e r s o f 2,4-D ana 2 , 4 , 5 - ? , on the other hand, e x h ib it appreciable v o la t i l i t y under both la b o ra to ry and f i e l d conditions (King, I H S , Adacs et 4 1 -, 1564,. V e m e tti and Freed, 1964, and M ille r, a t a l . f 1354). S p e c ia lis ts poin t out th a t even s o - c a lle :i low v o la t ile e s te r s o f the chlcrcphenoxy acids w ill exh ibit measurable v o la t ilit y then sprayed at the temperatures p re v a ilin g , in Vietnam. Thus i t seems c le a r th at h erbicid e Vapors are formed when "Orange^, or 'Purple" are sprayed. In fact sene of the effectiven ess of ^nese lormuia- 1 tlo n s in pen etratin g and d e fo lia tin g heavy Jungle vegetation has been ascribed/ in part to the vapors (Fam Chemicals, 1556). D r ift damage, i s u su a lly minimized by allowing a su ita b le b u ffe r tone. However, accid en ts have occurred. There ar-.i reports o f se n s itiv e vegetation , such a s rubber t r e e s or cotton , being damaged nearly 15 m iles f r c a the point o f spray release (Pace, 1563). g e fo lla tic n T a rre ts and O b jectiv es M ilita ry co n sid eratio n s d ic ta te how and where h erb icid es w ill be ap p lie d ---fa c to rs g r e a tly in flu en cin g the se v e rity end permanence o f e co lo g ic a l disturban ce, the p a rtic u la r t a c t ic a l o b jectiv es la rg e ly determine the typ.: o f v egetatio n tr e a te d , as w ell as whether temporary l e a f drop or p lan t h i l l i s ob tained. F olioles regarding targ et selection influence the geographic d is t r i bution o f where the sprayin g i s done, and the ex;en t o f the are a covered by herbicide application*. The r a te and nature o f rev g etaticn and su ccession la r g e ly depend ca whether Iso la te d s t r ip s and patches o f jungle vegetation are destroyed, or whether large contiguous areas are co n tro lled . Spraying cropland gives d if feren t e c o lo g ic a l e f f e c t s frem tnosc created by the d e fo lia tio n c f r e la tiv e ly undisturbed fo re st. A e ria l d e fo lia tio n .is ca rrie d on ag a in st vegetation which includes w ater weed- in the Mekong D elta, the m ilti-sz o rie d tr o p ic a l ra in f o r e s t s , second-growth brush and g ra sse s along coceanic a tie n ro u te s, and mixed .123 1 / deciduous or sesi-ev ergreen f o r e s t s in sevn tain regions. vSeponding on the a ilit a r y objectives sought, h erbicides are selected to produce shorc-cera d efo liatio n or long-tern p lan t k i l l . ^Jhe following l i s t enumerates scde of the najor d efo liatio n ta rg e ts. ^ * Hipa p a ls and cangrove woodlands grow in c o a s ta l are as in d e lta s and within reach o f t i d a l vat era along the banks and out Into the riv e r s and. can als o f South Vi etnas* The edges o f these waterways are sprayed fo r a d istan ce o f 2CO to SCO a e te rs back from the water (Mlcarlk and Bertram, 1562c). Since these are pcmanent t r a f f i c re u te a , the o b je ctlv e a Include t o t a l p lan t k i l l and longt e n vegetation con trol* Respreying at yearly in terv als la gener a lly required. / * Rain or .Me1 s t Evergreen f o r e s ts u su a lly have three s t o r ie s o f fo lia g e with a ground cover o f shrubs, v'.n rs, and herbs o f variable den sity . These ta rg e ts are s prsjed tc create bare stre tch e s surrounding V iet Cong strongholds so th at sovesent o f cec or su p p lie s in ax.d out o f the area can be observed rrc a the a ir (Trucbull, 1362). This type of target requires rapid d efo lia tio n ; however, lo n g-tern co n tro l or permanent k i l l i s not e s s e n t ia l. * The dense shrubbery and second-growth brush along high ways and supply * ouds c re a te cover fo r aaburi.. These are as are de fo lia te d back in to th e edge o f the fo r e s t to deprive the Viet Ceng o f concealment (Nuv fo rk Tine3 , March 10, 1235, Raymond, 1555, and Prudes l 5 ) . At p o in ts where V iet Cong are known to have s e t up road blocus fo r the co n fiscatio n o f "ta x e s ,* as area 400 e ste r s in extent is cleared to expose such operations for. a e r ia l reconnaissance and a tta c k . * In the Mekong D elta are a , the Viet Ceng often se cre te caches o f a sa n n itio a , food and su p p lie s, so v e i l concealed th at they are d i f f i c u l t to fin d cn the ground and Isp c ssib le to detect fr e a the e i r . T rees, weeds and underbrush are d efo liated to d isc lo se the lo catio n o f these supply du&ps. In areas that have been cleared fo r v illa g e s, buildings and a i l i t a r y p o s ts , heavy g ra s s e s and fo lia g e s a y hide the i n f i l t r a tion o f unseen a tta c k e r s . This fo lia g e i s treated to hold down the g ra sse s and fo lia g e out to a s a fe d istan ce , le n g - te rs control i s desirable in th is application . 124 * Upland f o r e s ts csn prise d x e i deciduous and s e d evergreen stands representing s e e c f the heaviest fo re st canopies in Vletnaa. Pathways and t r a i l s are d e fo lia te d between v illa g e s o f the p r i a i tiv e ceuntain people and nearby C l-.11 Guard defense u n its (S ig a r t , 1952). The sane type c f fo re st i s ty p ic a lly found along the i n f i lt r a t io n ro u tes and supply t r a i l s J u s t south o f the D e d lit a r ic e d Zone (New York lin e s , September 24 and 27, 1S6S). These area* arc strapped to d isc lo se tre e ? and supply covenants to a e ria l reconnaissance.* * A continuing struggle has bees cade to keep the National B a il Lines operating in sp ite of the fa c t that g u e rrilla bands have cut the lin e a t numerous p e in ts by the d e n o liticn o f b rid ges (Pruden, 1356). To d n i a i * e the opportunity f o r sabotage, the edges o f the fo re st are tre ate d a t su ffic ie n tly f remuent in te rv als to con trol fo lia g e th at would ebseure g u e r r illa a c t iv it y fre e the air. * The mountain f o r e s t s o f the A nnadte Chain hide the paths o f supply t r a i l s fr e e North Vietnan. through Casbcdia and Laos into South Vi e tn a s. S tr a te g ic p o in ts along both the Sihanouk and the Ko Chi Minh t r i l l s 'i n Lacs have been l i b e r a l l y sprayed ^ ( r o i s i e , ~TScT; and New York Tines* Kay 13, 1365), presumably with the knowledge and cooperation o f the Laotian Governcent (New York T in es, Kay 13, 1965). * The c o a t recen t and c a s s lv e la f o lia t io n e f f o r t i s new under way in the southern portion o f the T ^ i l i t a r i s e d Zone (Bloomington, D aily H erald, October 2 , 1355, end New York T in as, September 27, 1365) which contains sc c e c f th e 'c o st dense fo r e s t vegetation In a l l V ietn ss (Lucas, 1967). 7*ie IK2, a 6 - d I e vide sene extending 55 d i e s fron the J u l f o f Tonkin to the mountainous inland border has been sp xay ei fo r the l a s t few months with hundreds e f ten s n f h erbl zf.de (Washington Daily News-, February 6, 1967). The lower 4 d i e s o f the CHZ i s scheduled .fo r h e rb ic id z l tre a tse n t a s well a s mechanical removal where necessary (New York T in es, September 23 and October 2 , 1 H 5 ) . * South Vietnamese crops have been destroyed with h e rb i c id e s to deny food to the g u e r r illa s (New York T in es, March 10, 1356). R elativ ely few d e t a i l s about crop destruction m issions are a v a ila b le . Crops s a id to have been caged sin ce spraying f i r s t began in 1362 (Pace, 1966, and New York Tines, January 12, ISoC ), Include: Manioc and sweet* potatoes (B ig a rt, 1252), r ic e , sugar cane and vegetables ^Pruden, l ? ) . - The se le ctio n and scheduling o f te rc e ts fo** jur.gie d e fo lia tio n or for crop-destruction missions involve a ccrplex chain of m ilitary decisions and p o l i t i c a l review designed to achieve maximum e ffe c tiv e n e s s , as v e il as minimise the rich of unfortunate errors in herbicide spraying. These pro cedures have been described by Wesley ?rudenf J r . (1 9 6 6 ). t ''Settin g up targ ets i s a tic k lish diplom atic b u sin ess, liaainationo are made by e ith e r U .S . or Vietnamese army cccw aadtrs, but i f an American o f f ic e r vents a ta rg e t sprayed, he has to p ass the recommendation on to a Vietnamese o f f ic e r , who goes over the ta r g e t with the province c h ie f. Then the reccsaendation goes to the Vietnamese army' s general s t a f f in Saigon and, i f approved, the request i s sen t on to the in te llig e n c e se ctio n o f the U .S . M ilita ry A ssistan ce Ccmorind - Vietnam, In S aig o n ." F in ally , i f i t clears a l l these desks, the request goes to the U.S. Ambassador in Saigon . O ccasionally, an e s p e c ia lly t ic k lis h req u est goes a l l the way to Washington. Cne recen t example involved General Westmoreland's request to begin d e fo lia tio n o f the C>E, which vas subm itted to Washington fo r approval (ftev fork T ir e , October 2 , 1SSS). Xu a p ite o f a l l precau tion s, o c casio n a lly scae spray may d r i f t from a ta rg e t are a , causing damage to ric e crops cr rubber tr e e s . When claim s ir e made, prompt action i s taken to pay damages. The current p rice f o r a mature rubber tre e i s $67 (Beecher, 1266). Even so re strin g e n t procedures are used to lim it cro p -destru ction m issions to those s p e c if ic are as where m ilita ry e f f e c t w ill be g r e a t e s t . Charles Kchr (December 1965) reported: "There i s a complex system o f p o l i t i c a l and m ilita r y con- V t r o ls on the crop-destruetien program. The program which began l a s t sprisig has touched only a sm all fr a c tio n --50,000 to 73,000 a c r e s -- ox* the more than 6 m illion acres o f c u ltiv a te d land in South Vietnam. This l a the intention c f policy-cohere. "Although ihe V iet Cong control or a t l e a s t co n test 70 o f the land area o f the nation, crop-destruction m ission j are aimed only a t r e la tiv e ly sm all areas o f major m ilita ry importance, where the g u e r r illa s grew th e ir own feed o r where the population i s willing.!y cecaitted to their cause. " O ffic ia ls say that no h erbicide m ission s have been flown, or w ill be flown in h eavily populated are a s. There has been no crop d estru ctio n , fo r example, in the Mekong D elta. i 123 \ "There i s concern th a t any attempt to d e stro y crops In h eav ily populated a re as dominated by the V iet Cong could only send a new flo od o f d isp lace d Vietnamese to jo in South-Vietnam's 733,000 refugees. " I t 13 a ls o suggested th at u n less the h erb icid es v'.re applied on a v a st s c a le , a move th a t would probably be p o l i t i c a l l y im perm issible, i t could have l i t t l e e ffe c t in h eav ily populated a r e a s . 'There i s j u s t so siueh food in th-a D elta th at crop-destru c- - tio n m issions here would have no r e a l m ilita ry v a lu e ,' one o f f i c i a l sa id . 1 "D estruction operations are intended prim arily fo r food f i e ld s in such V iet Cung base a re a s as War Zone D, north o f Saigon , and in areas where growers are considered w illin g V iet Cong supporters. "Scae V iet Cong u n its are devoting as much a s 50$ o f th e ir manpower to growing food. . . .food sh ortages have dccces so acute in c e n tra l Vietnam th a t some an aly sts expect the enemy to s h if t 'a o r e o f i t s m ilita r y a c t i v i t y toward the fo rth Vietnamese border, to ease the supply' of p ro visio n s."(P ace, 1966) Major Vegetation 'Trees o f Southeast A sia ** The o v e r a ll p lan t form ations o f Southeast As. *, and in p a r tic u la r the fo r e s ts in Thailand and Vietnam, have been exten sively stu d ied and v e il docu mented in the b o ta n ic a l end fo re str y lit e r a t u r e (Leccmpt*, 1907-1933, and R ich ards, 1959). Extensive in v e stig a tio n s were f i r s t conducted by the french b o ta n ists *n c fo r e s te r s (C h ev alier, 1913 and 1999, Maurand. 1943}. Mere r e cent r t u d iis o f the v egetatio n in the are a o f the Mekong D elta (Duke, 1963, Van Cuon*;, IC30, and Duke, 1961, and the f o r e s ts o f Vietnam in general have been undertaken by s p e c i a l i s t s o f the United S ta te s (K en an , 196-v), The most cosprehenuive of these recent in vestigation s are "Vegetation of southeast A sia: S tu d ies o f fo re st-T y p e s, 1953-1965" by Llewelyn Williams (196S), and "fo r e s t? o f Southeast A sia, Puerto Rico and Tedaa" (W illiam s, 1967). The map (Figure V-5) frsm W illiam s1 rep o rt ::Lows the extent and d istrib u tio n o f variou s fo r e s t types in Vietnam and ad join in g re g io n s. / According to p u b lica tio n s issu ed by french b o ta n is ts , there are --re / than 1,500 sp -c ie s o f woody p la n ts in Vietnam, varying in s iz e fTca sm all shiubs to la rg e t r e e s ; h e r d - ste = e d reeds to bamboos; and a vide v a rie ty o f sp e cie s o f U>7 128 p alas,. woody vines u. li?.n es, and h srba;ecu s p la n ts . The m ajor fo r e s t forma tio n s occurring in Vietnam include the follow ing: 1. - Evergreen, Broad-leaved Rain or Moist f o r e s t s . Rain fo r e s t oc curs in areas where the annual r a i n f a l l exceeds ICO i n ., i s v e il d istrib u te d throughout most o f the y ear, and with only a short' cry p e rio d . True Rain fo r e s t i s rath er lim ited in d is tr ib u tio n , being confined m ainly to le v e r and middle elev atio n s on mountain slo p e s. Evergreen Moist f o r e s t i s found in areas where there are v e il defined v et and dry re?so n s o f about e q u al len gth , and in fluenced by the monsoon clim ate. 2. Diptercearp fo re st, probably the most extensive type, covering up to about S0 o f the t o t a l fo re ste d a re a o f Vietnam and neighboring co u n trie s. 3. Mixed Deciduous f o r e s t , u su a lly h eav ily cut ever and ra th e r open. 4. Dry Evergreen f o r e s t , concentrated e sp e c ia lly along r iv e r or stream banks. 5. Mcatane f o r e s t , containing oak frequen tly mixed with c o n ife rs, a t middle and upper e le v a tio n s. 6 . Coniferous f o r e s t , in which sp e c ie s of pine ( F ir u s ) form rath er extensive' stands in the uplands. 7. Swep fo rests: a . Mangrove woodland, in e o a s t a l are as, e s p e c ia lly in d e lta s and around r iv e r e s t u a r ie s . t* ' b. Stands o f n lpa palm, a lso In d eltas a n d 'tid a l reaches, u su ally where mangrove occurs* c . Stands o f cajepu t (M elaleuca) , in brack ish water along the inner border o r in the v ic in ity o f mangrove. d. Fresh water swamps, g e n e rally in the i n t e r io r . 8 . Savannas, e ith e r open or sp a rse ly wooded, and dominated by a ground cover of coarse g ra sse s. 9. Thorn woodland, c o n sistin g o f shrubs ecd sm all te medium^-sined tr e e s , cany o f which are armed with sharp sp in e s, and often mixed with bamboo to fora a tangle d iffic u lt to penetrate. 129 | 10. Bamboo brakes, frequen tly fo re le g dense frin g e s along banks *, o f streams and r iv e r s , and develop ra p id ly in abandoned t i l l e d land or when ji c le arin g s are made In most types o f f o r e s t s . Sm e o f tbe fo r e s t a sso c ia tio n s In Vietnam, a s in adjacent co u n tries, are extremely ccap lex in t h e ir f l o r i s t l c composition. Tbe t a l l e s t (up to ICO f t or nore) , sc o t dense a n i com plicated type i s an undisturbed Haln fo r e s t which, in seme In stan ces, nay contain In an a re s o f one acre up to ISO or core sp ecies o f shrubs and s n a il to la rg e t r e e s . Stands sep arate; by cr.ly a sh ort distan ce aay show str ik in g ly d iffe r e n t fe a tu re s, p a r t ic u la r ly In th e ir stru ctu re and the sp ecies p re se n t, so th a t th e ir c l a s s i f i c a t i o n i s oftentim es d iffe r e n t. Tala d iv e rsity o f fo r e s t composition I s Vietnam, a s lr. other t r o p ic a l reg io n s, may be ascrib ed to the v a r ia b ilit y o f environmental condi t io n s , Influenced by clim ate, s o i l , drain age, and by human in te rfe re n c e . The' l a s t named fa c to r i s in the form o f f e llin g f e r timber, ro u tin e burning, and the long e stab lish e d system o f s la s h and burn or s h iftin g a g r ic u ltu r e , widely p ra c tic e d e sp e c ia lly by people in h ab itin g remote or mountainous a re a s in the in te rio r. ! V a ria b ility i s f i e r i - t i c c c s p o s it ic s in shorn i s T?M e w-s*. J inventories the p rin cip al species appearing in three s t r a t a or sto r ie s forming I a Dry Svergreen f o r e s t , lo cated en two t e s t s i t e s tre a te d with h e rb icid e s in Thailand (farrow e t a l . , 1956). The two s i t e s are situ a te d in c lo se proxini t y , one on itu e a s t sid e o f the Pranburi Stiver in the upper P eninsula, the ' other on the v e st rid e . I t w ill be noted th a t S ite I i s n early devoid o f a : ground layer o f shrub growth. S ite I I , however, has a dense undergrowth, repre: venting approximately o f the p la n ts t a l l i e d . The follow ing re co rd s, exI t r a d e d from W illiam s1 recen t study, are e sp e c ia lly p e rtin e n t to any e c o lo g ic a l stu d ie s o f the e ffe c t s o f h erb icid es and desiccan ts en the v e g e taticn o f t h is * type of fo rest. I *' * " F crocts o f South Vietnam: The fo r e sts o f South Vietnam - / have been d evastated fo r many c e n tu rie s. F ir s t cocadic or * e a i - '/ savage people occupied the land and destroyed the f o r e s ts vitr.out discrim in ation . A fter th at came the A ncasites who, in. s p ite o f a more advanced c i v ili s a t i o n , regarded the f r r e s t a s capable o f re generating i t s e l f in d e fin ite ly , and gave no thought t o I t s p ro te c tio n . Despite ample r a i n f a l l and ether favorable con dition s fo r growth, the fo r e sts were unable to re - e sta b lish them selves a f t e r prelonged periods o f d e stru ctio n . As a r e s u lt , much o f the vegetacicn th at formerly covered Cochin-China, new forming southern South Vietnam, c o n sists in the main c f secondary growth, in te r spersed with sc atte re d stands o f primary fo r e s ts . 130 IJHHfiH Courtesy L v e r a W ill^sa F in ire V-S - ?.ai* Forest in the Mountains o f Southeast A sia . "Xhnnun-nok" (Faio-viiR cbovatur*./ Is ch n rau tcrL stia ot* oeolst tr o p ic a l upland f o r e s t a . 131 f 'PHqr? 7 .2 FSFCZ^T CCMFCSTOCiT M X FK53UTHCT C? PRINCIPAL wccsy sfecus gs sparasi, ruzagpiAg, AI35 s s r a IAXSSS C? TEST SITES I ATS I I Specie* CfcS`z S i t e I C n sp o siticn ( f i rTenuency Test Site n Composition (*1 Freoueney Dcninant Layer Lasers troer.ia flerifcunda Mansonia gag el Diospyros ccaetanae MlH e t t l a lencencfca D ialiun Indira Anthercroorua P ie r r e ! Diaapyros c o llis Loaeirti cesia leudenii Spondiss. ra.-urifera MenilMars hcxrndra DIosvvtos c u rra n ii Garuaa ninnata Baabusa arundinacea Grevia elatestenoides 0.2 4.5 - 7/ t 1.9 + 0.3 + 0.5 +' -5/ * 64 95 81 75 23 .72 67 66 35 61 49 37 *- 4 .3 96 0.4 37 i.r* 68 4 27 0 .9 74 +6 + 46 34 + 66 39 + 39 0 .5 47 9.0 37 1.5 29 Subtotal: ecswoaiticn 8.3 18.4 Intermediate Layer - Streblus seylanica Cle is tanthus dasyehyilus Celtas colllnsae Hydncenruus i l i c i C allus Vitey eulnata A talantla acinosa Diospyrcs c a u lif 1cm, Euphorbia trgona Fh^llanthus ap. tiiefeuhria sls s e n s is Mersecylcn evatus Grevia tesentesa Kltrerhora fceithii Sindora c a ritic a Olea r a r itiu a Fhyilnnthus er.blica Sub t o t a l : ccupo si t l on 45.0 28.0 0.7 C.4 0.3 0.5 1.2 3 2 + 6.9 r 0 .9 + 0 .5 + 87.7 132 ICO 95 32 31 SO 77 ?S 75 71 48 66 15 64 * 5 18 3 , . *9.5 0.4 0.2 4.3 2.8 0.4 + * 0.6 P.2 4 32.1 3.4 0.6 3.6 0,5 40.7 22 21 40 60 60 33 4.T 2 59 72 48 66 2 62 37 27 ' m m 41 ] a ** - -- ... -- -- ZD X) ro 5= \ TAELS V-2 (Concluded) Speclea - Test S ite X` Ce sp o si ti on V I*rwuincv T e st Si ".e rz C capesitiss ( Frequer.r/ Shrub Layer Cleistanthus sp. Acacia ccsosa Meroneuna enneabhvllun Carsaris thorelii Vcntila^o calvcul&ta KvsenocvTanis br&chiata Zicvohus cenoclia Srfcsncdeszsa pentandra Jasninua sp. Suonvsius eochinchinensis *44yvand yv* Acteohila collinsae Tarenna le n s ifo lia A talantia scandens Cecbretun precursua Subtotal: ccapcsitidn + + + 0.3 ++ 0.4 + + f 0 .7 ` 13 46 33 38 97 27 20 28 14 . wmmu 22 5 28 12 * 16.2 14.5 + 0.7 + 3.2 + 0.5 r +> ++ 1.4 ' 36.5 95 .. 91 . 31 90 55 83 64 63 51 37 33 32 31 30 - T o ta l . Composition 95.7 95.1 a/ Trace b / lone Source; C arrvs (1966) th' I 1 i* f. > \ [ l * \ I I i I 1f [ "Moat o f the burning o f the fT reat in A n u s, or Central Vietnam, i s done, a s e lssv h e re , fo r sh iftin g c u ltiv a tio n , the 'r a i * system widely adopted throughout Southeast A sia. In th is process / thousands o f scre e o f f o r e s t s are burned each y e a r, follow ed by the plan tin g o f crops mainly f^ r food. A fter tvo cr three h arvests, the patch es ere abandoned. Soon a a e r ie s o f g r a s s e s , p a r tic u la r ly the '.iniquitous Sro erata cylln d r ic a , sedges, and such weeds as Ehoatoriiaa occratua develop. v*n in normal tin e s th is p ra c tic e o f slash and burr, i s d i f f i c u l t to suppress among the t r ib e s in the mountain a r e a s, although i t can be con trolled to seme degree in the p la in s , where people are iu c lo se r crn tact with a u th o r itie s . In some instanced during a sin g le y ear the in h ab itan ts o f a large v illa g e say destroy a considerable area o f fo r e st within a radius o f 10 to IS c i l r s . Bamboo brakes are also uetroyed by f i r e . The e f f e c t o f t h is d e fo re sta tio n ever a long period i s evident a lso in C en tral and North Vietnam, as shorn by a gradual increase of uncultivated land along the base of mountains, caused by erosion or s o i l from the bar upper slo p e s, f i l l i n g up stream beds and with consequent flo o d s." X Resnor.se o f Vegetation to H erbiclip s The response o f fo lia g e to chemical treatm ent v a rie s markedly-- from l i t t l e e f f e c t to p lan t k i l l . Reports Aram observers in Vietnam lik ew ise vary. Seme say that de fo lia tio n i s temporary or re la tiv e ly in e ffe ctiv e ; ethers state that the trees are dead and b are. The follow ing verbatim re p o rts, while somewhat c o n flic tin g , are probably accurate: /* "The chemical m ixture i s supposed to k i l l a l l tre e s and brush, but the w ithering and dropping c f le a v e s may take fiv e days to three weeks." (B igart, 1962) " . . . begiz. turning fo lia g e brown in a m atter o r hours, but f u l l r e s u lt s are mot v is ib le fo r s ix m onths." (M ille r, 1667) " . . . Ccuble or t r ip le carroty Ju n gle gen erally req u ires tvo a p p lic a tio n s, with the econo, ap p licatio n feur to s ix weeks a f ter the f i r s t . . .jiv e s e ffe c tiv e vegetation control fo r nine to 12 m onths." (Farsi Chemicals,. IC-Soc) 134 I\ "P ra c tic a lly a l l the vegetation in the sprayed areas was dead and almost complete (estim ated SS$) d e fo lia tio n had resu lted .** (Aimed Forces Chen. Jo u rn a l, 1954c) "Within se v e ral weeks they cause le av e s cn tre e s and other vegetation to wither away." (Washington D aily News, February 6 , 1967) " . . . a powerful chemical k i l l e r which d estro y s a l l but the b iggest tre e s. . * " (Lucas, 1337) * . . within 24 hours the fo lia g e begins to wither and turn brown; within fiv e or s i x weeks, the le av e s c u r l and f a l l . " (Fruden, 1966) "Within three days a f t e r a sin g le sprayin g . . .the e f f e c t s are n o tic e a b le . Within a week there i s on 'autumn1 e f f e c t . 2ut three months must p a ss before the 'w inter in Vermont1 e f f e c t i s achieved. Four months a f t e r th a t, however, the fo lia g e begins to grow back ." (Mchr, 196S) Such d iv e rsity o f re p o rts i s net su rp risin g when co n sid eratio n i s given to: * The remarkable number o f woody p lan ts found (l,5 C C ); * The great d iv e r s ity o f p lan t c c ssu n itic s found; * E ffects of seasonal changes; ecnsccns; .. * 1 * D ifferences among h e ro icid e s used; and * A pplication conditions which range from optimum t r unfavorable. Few i f any s c i e n t i f ic re p o rts are a v a ila b le fr^ h the are as o f opera t ic n a l .use in Vietnam. The t a r g e t s sprayed are freq u en tly in enemy stro n g h olds. The most u se fu l data cn response to h erbicide treatm ent ccne fre a carefcillv ccnduoted te s ts carried out in Thailand, Puerto Rico, and Texas w^tc h i r l e ^ 1957c, and Earrcw, 1956c). . From th ese stu d ie s c e rtain gen eral observations have been drawn concerning thr fcehavicr c f t r c p ic a l vegetatio n and fo r e st when a e r ia lly sprayed with m i l i t a r y _f o l i a r .t s . / 1 Degree o f D e fo liatio n : Maximum d e fo lia tio n responses c f 3b to 95$ have been'recorded, but complete d e fo lia tio n c f a l l sp e cie s has not been obtained in any te s t p lc t o f nixed fo r e s t. 135 i\,\ \\ KWbtJU 2 . Rate o f D efoliation Rc-rpcnse; The phenaxy h erb icid es and ether system ic d e fo lia n ts which are absorbed and tran slocated throughout vcody p lan ts produce a b sc issio n and le a f drop over a period o f s e v e r a l months. G eneralizations .are d i f f i c u l t when dealin g with so many f a c t o r s , but perhaps two t o three months are required as an average to reach maximum l e a f r e moval. Figure V-7 shows the d e fo lia tio n response from ' Orange1' with maxi mum l e a f drop between two and four months. At the end o f seven months, the lia n a s have grown new le a v e s, and some o f the fo lia g e i s return in g to the trees. D esiccants and contact h erbicides produce l e a f n ..tr e s is , la s s o f m oisture ami w ithering so re la p id ly ; about two to three weeks on the average. S im ila r phot03, Figure V-8, shew the d e sic c a tio n achieved from cacodylic acid ("3 1 u e "). In three weeks the leav es have c i r l e d , and most have f a lle n . Regrowth i s under way three msnths a f t e r treatm ent. TabI t V-3 compares the percentage c f d efolian t obtained with various h erbicid es fo r a period o f one year. More d e ta ile d data are presented fo r v ario u s r a te s o f a p p licatio n and other agents in the Appendix, Tables. A-1 t'p.297), A-2 (p .3 0 l) and A-3 (p .3 0 5 ). 3 . Duration o f D efo liatio n ; Seme tre e s end ether woody p lan ts are k ille d ; oth ers show v o p k ill only. Many trees reco v er, growing new leaves w ithin a y ear. Root sprouting ctcu rs with seme sp e c ie s. C ertain sp e cie s of t r e e s , including Stratalus z ey lan ica, Kydnccarsus i l i c i f c l l u s , and se v e ra l Dlosoyros aro. are relativ ely rerist*.n t to d efo liatio n . D etailed an alysis o f sp e cie s response i s being compiled ( Darrcw, 1956d). Figure V-9 shews the influence of ap p lic atio n ra te on the duration o f e ffe c tiv e d e fo lia tio n , and length o f time to SC$ recovery. I t i s problem atical whether trees exh ibitin g complete d e fo lia tio n lik e th at of Figure V-iO w ill recover. The percentage o f tr e e s in mixed fo r e st stands which show t o t a l k i l l a f t e r 12 months or longer has clasped i s cot known.* * Seasonal S ffs*rt< : Woody plants in * r e a s having seaso n al rsin re seasonably su scep tib le to h erb icid es. The moat su sc e p tib le p trie d occurs when s o i l moisture has oeen adequate fo r rapid grewth. The d e fo lia tio n response to a l l systemic herbicides such as 'Orange" "White" and "Purple" was more rapid ?rd more complete during the rsii^r season , with i t s g en erally fav o r ab le s o il moisture and growing con dition s, than during the dry season. Lower ra te s of chemical treatments are necessary during periods o f activ e growth. 135 iI puu^ fc *-ih ll m Dofore Treatment, February 19o5 IVo Months A fter Treatment Figure V-7 - D efo liatio n ftcaponuc from Orane Applied at- 2.4 Gal/Acre (21 Lb/Acre AE) (Courtesy U .S. Aruy B io lo g ic a l L a b o ra to rie s, F t. D ctrlck) HiHMUJ a FKHBliU Seven Months a f t e r Treatment (Note the regrouth o f vin es) on luile.'l) t : I '1I Figure V-8 - D efo liatio n Response f r e s Plue (esce-iylic: acid ) Applied a t 1.5 Gol/Acre (4 .5 Lb/Acre A) ( Courtes y U.S. Amy B io lo g ic a l Laterat o r i e s, F t. etric k ) 139 \ i i 1t i 1 Three Months - Shewing Recrovtii Figure Y-8 (Concluded) ! TAEIS V-3 THE FS3CS:rTAGE OF S23ICCATICCT AgP "CLIA TICH aSSUITISO FBqi 553SICIESS APPUS3 AS ICU-'/OLLT-S AERIAL SPRAYS OS RAIS FCRZST VZGETATICTI Treatment H erbicidei/ Gal/Acre Lb/Acre Orange 1.5 12 1 Vk. 9/7 Time A fter Treatment 2 1ft. 1 " 0. 3 Mo. 5 nCu iiL _ J L J i L J 1 L 53/28 6S/31 65 52 1 *r. JiL 38 . * -> 3 .0 24 I S / 8 73/32 8 /?3 79 66 54 6 .0 48- 28/10 79/37 .9/73 91 71 61 P icloran l . S 3 8/0 24/14 34/32 29 27 30 * 3.0 6 8/0 51/21 70/52 30 SO 54 6 .0 12 19/9 51/22 78/56 S3 75 74 2,4,5-T Pins l .S Pic lo r an * -" * ( v . l ) -- --k 3 .0 \ 6.0 7*5 15 30 7/3 25/14 42/39 52 3 /0 25/S 39/32 42 7 /0 35/13 K>/*5 77 40 45 46 51 73 69 paraquat l.S 3 I S / ? 25/15 27/25 IS 9 10 -* 3.0 6 29/13 51/29 68/3 '51 41 30 > s . o 12 33/23 53/35 50/35 43 15 17 a / Arrows denote ty p ic a l r a .e s . i b / The figu re to the l e f t o f the s la s h nark rep resen ts the percentage o f leav es d esiccated and d e fo lia te d ; th at to the rig h t rep resen ts the percentage o f defoliation. Single figures represent d efo liatio n only. Source: (TecM riey, 1967). 141 .; p it Alt* \ Pm m Ji p i t Acre Source: Tschlrley (136?) Figure 7-9 - Duration o f Defoliat'.on Response fren Application o f Purple os Related to Dos*?* Rate. S- Miration o f maximal percent decrease in obscu ration . Data represent rean treatment values. 3. Uunber o f sor.ths u n til 04 recovery iron cuuclr^z. response. Data represent in dividual p lo t v alu es, 1 f t iof** m / m > K ia ;u before Treatment, December 1964 Three Months A fter Treatment fig u re V-10 - D efo liatio n Bcoponoe from Piirplr Applied nt 3 .0 Gal/Acre (2 6 .7 Lb/Acre AE) (Courteny U .S. Army B io lo g ic jl L a b o ra to rie s, F t. D ctrick) 1. f UHliiilJ S ix Months A lter Treoticcnt Hire Months A fter Treatment fUcurb V-10 (Concluded) In a re as such as evergreen and bread-leaved R ain fo r e s t where ra in f a l l i s high but uniformly d is tr ib u te d throughout the.yen r^ woody p la n ts are le ss subject to seasonal su scep tib ility . `Season al e f fe c t s are r e fle c te d in the le v e l o f t r **taent needed fo r e ffe c tiv e d e fo lia tio n o f mixed fo r e s t stan ds o f d iffe re n t canopy d e n sity . These h erbicide le v e ls are su oe a rise d in Table V-4. More d e ta ile d conclusions regarding herbicide e ffe c ts observed in tro p ical fo rest teats are presented in the Appendix, pp. 234-236, Figure A -l (p .2 9 9 ), and Figure A-2 (p .3 3 0 ). Revegetation and Succession T ropicel fo re st stands sprayed with q u an tities of systemic herbicides f su ffic ie n t to k i l l or produce more than 85$ d e fo lia tio n show a gen eral pattern of re v e g e ta tio a sim ila r in sorse re sp e c ts to that found in abandoned fo r e s t c le a r in g s. The s e r a i su cce ssio n s obsggggd in these devegetated a re as have been described by T.lpweiyn V 1115** t0* 7? ] . The f o r e s t s of Southeast A sia , and Puerto Rice have su ffe re d severely over the cen tu ries frem .human disturbance through f a l l i n g o f tre e s for construction tim bers, fuelwood, and ch arcoal, or to c'.ear land fo r a g r ic u ltu r a l u/.e. Considerable changes in tne v e g e tatic.i have been caused by firw s, e ith e r spontaneously or d e lib e r a te ly s e t , gracing by-dom esticated animals iLd w ild li f e , and damage by in s e c t p e s ts . .Tn Puttrto Rico much of the fo r e s t land area has been cleared fo r a g r ic u ltu r a l u se, and the remainder i s almost e n tir e ly seccndary f o r e s t . Only about 1 or 2$ o f tr.e t o t a l eras of the Island c o n sists o f stands o f primary fo re st, In Southeast A sia, a lso , the fo r e s t s have been d ev astated f e r c e n tu rie s. Only in the mountainous, Isu s a c c e ssib le regions are there ex ten siv e, undisturbed stands o f pines and herdwoods o f commercial v alu e. The t r o p ic a l Rain fo r e s t i s a p r ie s example o f a plan t community i r which r a i n f a l l , s o i l , and v ege tatio n are the p rin c ip a l fa c to r s th a t contribute to the maintenance o f a croplex equilibrium . When one o f the components of the primary fo re st i s p artly or completely destroyed, the ether fa c to rs are a lte re d and a new type c f `p lan t cover appears th at i s adapted to the m odified environment. The gen eral p attern o f regrewth i s e s s e n t ia lly the same in t r u r `.'.ral America a s in Southeast A sia . Revegetation of distu rbed areas follow s a sim ilar sequence in development of secondary grewth, ard the su ccessio n s! plant communities arc sim ila r in stru ctu re and phytosoclolcgy, but the sp e c ie s, o f co u rse, may be e n tir e ly d i s t i n c t . li.VUHHi US  nriMpkT >' T* >>i.. - . TABLE V-4 JWFLUFRCE PT BEA30H Aim FOLIAGE DENSITY OH HERBICIDE TREATMENTS REQUIRED FOR EFFECTIVE DEFOLIATION D efo liatio n Requirement Chemical Rainy Season M g!it to Moderate Cover Dense Cover (S in g le Canopy) (M ultiple Conopy) Dry Season Light to Moderate Cover Dense Cover (S in g l e Canopy) (M ultiple Canopy) fast, Short-Term D efo liatio n or D esiccatio n Ciiocxlylic Ac .4 5 to G Jb /ic r a In 2.5 to 3.0 a l. spray Equal to Blue (5 . cacodyl! t: r.cld) a t .7,7 to .l lb / acre m 5 to 6 lb /a c re In ' 2.5 to 3.0 gal. spray 5 to 6 lfa/nurc in 2.5 to 3.0 g al. spray Repeat application Equal to Blue (65 D*ay l ? needed In 2 cacodylic a c id ) to 3 wcKi foi a t 7.7 to 9.2 effective Acfolla- lb/acre tlon at ground level Effective Purple Defoliation or (60 to 7 Orange for Moderate Duration, 3 to 1 Months Max iir.um Turpi e Defoliation or and Duration,Orange 6 months *>r more 1.5 to 2.0 gal/acre undiluted or In 111 mixture with diesel fuel 2.5 to 5.0 gal/acre undiluted 2.0 to 2.5 g al/ acre undiluted 2.5 to 3.0 gal/acre undiluted Repeat application r.ay be needed a f t e r 2 months 2.5 to 3.0 g al/ acre undiluted 2 .5 to 3.0 gal/acre undiluted Repeat application may be needed a f t e r 2 months Source: {`burrow, 19C6d). 5 to 6 Xb/acxe in 2.5 to 3.0 gal. pray Repeat ap p lica tion may be needed In 3 to 4 . weeks fo r e f f e c tive d efo lia tion a t ground level 2 .5 to 3.Q g a l/ acre undiluted 3 .0 or more g a l/ acre undiluted RepeatsJ applloa* tlon may be needed In f o l lowing rainy season Gtfbt I Forest Underbrush before Treatsent, Kecruary mi'**** * Ten Months Following Treatsent, Tecesber 1255 Figure V-il - Herbiulde Treatrent Improves Horizontal V isib ility Reducing *bo Oppc.rv-ity fo r slush (Courtesy F. Tschirley) 147 The f i r s t , stave o f su c c e ssio n s! growth th at develops follow ing disturbance c f u se , humid fo r e s t i s u su ally dominated by g ra sse s and weeds. These are generally sh o rt-liv e d , o f Lias than one y ear. v'Aa a r u le , in cleared areas such as these abandoned'in sh iftin g ag ricu ltu re the plan ts th at develop in the i n i t i a l stag e o f secondary growth arc. e n tire ly d iffe r e n t from those th at grew in the primary f o r e s t ; lik e w ise, seldom-do any sp e cie s in th e secondary growth appear in the primary f o r e s t F o re st stands disturbed by the ap p licatio n of h erbicides cay show appreciable regrowth of see d lin g s rep resen tativ e o f the o rig in a l woody p lan ts due to root sp rou tin g, f r a a seeds present in the s o i l , cr seedlings that say have survived the treatment. The next phase say be d eal ra te d by shrubs, follow ed by tr e e s of quick growth. Or -.he su ccession sa y lead almost d ir e c t ly fr e e the herbaceous sta g e to tr e e dominance. The secondary fo re st i s u su a lly cosposed o f f a s t a r r i n g tr e e s with s o ft wood, and t h e ir seeds are wind c r animal d isp e rse u . - In Thailand two weeds th at develop c o st abundantly in abandoned land and in fo r e st cle a rin g s are Sunato riu n ardor a t u a , and the ubiquitous g raa s ( Icp crate c y lin d ric a ) . Toth p lan ts are lig h t lovin g and cannot th riv e !** 4 .J a . eabenW Q4wwfc--J 4 w*e1ewM4aa#w<1 aWJ* wMwA^W*WUw*< 1UC QIUUli stag e i s followed by the developsent o f a secondary f o r e s t in which tr e e s of the genera ocmhax, . O ille n ia , T ite x , and Grew!a appear, and in humid s i t e s sp e cie s of wild bananas (Muse)- appear. In nary a re as in T h rlian a, a s in the other Mekong S atin c o u n trie s, the weeds, g r a s s e s , und shrubs are grad u ally dominated by bamboos. p a rtic u la r ly sp e cie s o f Barbusa and T hyrsostach ys, which may even suppress the development o f t r e e s . This i s p a r tic u la r ly n oticeab le in eutev-r stands of te ak , a s w ell as in the humid Svergreen forest. S u ccessio n s! growth In the Rain fo r e s t o f t r o p ic a l America i s sim ila r in structure to that of secondary Rain fo r e s t 'in Southeast A sia, although i t i s q u ite d iffe r e n t, o f co u rse, in f l o r i s t i c com position. The ubiquitous g rass ( lace ra ta c y lin d ric a l' i s widely d istr ib u te d in the Old World tro p ic s and re a d ily develops in fo r e s t c le a r in g s. This weed does not occur in tr o p ic a l America except in C h ile, but I . b r > jj l i e n s ! s and other g ra sse s are analogous; Inccrowining sedges of the genus S c ie r ia , with sherp-edged leav es, often form an alm ost impenetrable tan gle in secondary fo r e s ts o f tro p ica l America. In Puerto Rico, as elsewhere in tro p ic a l America, among the n ost frequent tr e e s in secondary f o r e s t s are "Tagrumo hembra" ( Cecrouia) and "Tagrumo macho" ( 21 ^ymecenex) . Both propagate n atu rally and th e ir growth i s rapid . * r - t * i/o- Figure V-1I?- Hevegctntlon after One Year In Foreut Opening Crcoted by Heavy Application of Herbicide. Lartoo foreut la the doralnnn; nucceouor, with various grasses und voo-Jy piaiitu covering the ground layer. (Courtcny F. Tochirley) Zxtent of Herbielie Application There haa been a ste a d ily increasing pace in d e fo lia tio n f l i g h t 3 since r.ne f i r s t 'Operational employment of h erb icid es. In tne l a s t two sooth s o f 1952, when spray f lig h t s f i r s t s ta r te d , only SO a l sio n s v ere f lo r a . Only 137 a l sio n s vere' legged in a l l o f 1262* (pruden, 13S5); however, by 1366 over 3,000 so r tie s v * ;5 f l o r a (Blconlnzton Dally Herald, 1266) Chemical consumption shews th a t over 30^ o f the h erbicides sprayed are s y s te a ie s (Orange, White or P u rp le), while considerably l e s s than 1D> haa been cacodylie a c id fo r d e sic c a tio n and destroying r ic e . The follow ing t a b le shows the approximate extent and d is tr ib u tio n . 1 of h erbicide p p li^ iM n fro n 222 t o d ate. ESTIVATED* AREA KSffliriDAILY TREATED-* IK s e r a VIETKAK Year D efoliation 1362 1363 1964 1365 (Jan .-Ju n e 1366) 1966 (Ja n .-S e p t. 1367 ) 17,113 *4,517 53,373 94,726 775,394 343,636 Acres Soraved/Yeer Crop Destruction 717 237 10,223 49,637 112,678 , , 121,400 * T otal o f Beth 17,636 34,814 54,005 144,353 195,637) See,572 965,006 Sources: d a ta , contained in 'various r e le a s e s . * Hot a c tu a l lan d area measurement. Areas were estim ated from the num ber of so rtie s flown, calib rated spray rates.and average width o f spray swath covered. * Treated area includes a l l reapreying. Scee areas are retreated annually (o r more often i f needed); no estim ate 1c a v a ila b le on the extent o f re a p p lic a tio n . The ac tu a l area i s Relieved to be su b sta n tia lly lo ver than the fig u re s here shew. ISO