* Contribution to the 4th symposium of Tropical Ecology, March 1977, Panama. ** Thanks are due to Dr. H. Lieth for extensive editorial work

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1 ~~~ sj (ip I. e Vegeaio vol. 37,l: 53-60, 1978 AN ARCHITECTURAL STUDY OF THE VEGETATION S REGENERATION IN FRENCH GUIANA* J.P. LESCURE** O.R.S.T.O.M., Cayenne, French Guiana Keywords: Fores archiecure, Iniial model, Inversion surface, Rain fores, Reieraion, Succession lnroducion This sudy is a mall par of a research program concerning he inerrelaionships beween an Indian ribe and is environmen. This ribe, he Wayãpi, dwells in he souhern par of French Guiana, along he Oyapock River. They belong o he linguisic family of he Tupi. They live sill in harmony wih heir radiional culure in which our own civilizaion has very lile place. The sudy is a French conribuion o M.A.B., and deals wih differen scienific fields such as anhropology, boany, pedology, medical enomology, plan chemisry and differen aspecs of zoology. The inerrelaionship beween he differn sciences has been presened during 47h Congress of he Sociéé des Americanises, Sepember 1976 in Paris. This paper deals wih some aspecs of he revegeaion occurring in differen plos previously used by Indians for shifing culivaion. Those plos had been seleced and daed by anhropologiss. I chose six of hem, covered wih secondary vegeaion, and 24, 34, 4, 11, 23, and 33 years old. Two oher plos, covered wih primary fores, siuaed in he viciniy of he secondary fores plos were chosen for reference. Only archiecural aspecs of his succession are reaed, for I believe he size of he plos sudied was oo small for florisic analyses. The sudy is widely based on he heory of fores archiec- * Conribuion o he 4h symposium of Tropical Ecology, March 1977, Panama. ** Thanks are due o Dr. H. Lieh for exensive ediorial work on his manuscrip. Thanks are also due o my Wayãpi assisans in he fields, R. Yawalu and R. Alasuka.. - ~. ure by Oldeman (1974), and I shall firs summarize he mos imporan conceps of his work. Absrac of Oldeman s work A he beginning of he ree s life, afer germinaion, i produces an iniial model, which is one of hose described by Hallé & Oldeman (1970). Laer and under propiious ecological condiions, merisems which do no iniiae any growh during he model s developmen, may copy all or par of he model. This copy should no be confused wih a ramificaion and is called a reieraion. Trees in he fores, which conform o he iniial model, or hose having few reieraions - which may occur afer raumaic inerferences - consiue he se of he fuure. Those which have developed a lo of reieraions, ofen occurring in a successional process leading o he maximal spaial expansion of he ree, consiue he se of he presen. I emphasize he fac ha a ree of he fuure is no always younger han one of he presen, bu i sill keeps is growing poenial. Of course, his poenial is no reached frequenly, because rees die oo early. Las, he hird se of rees is he se of he pas. I is consiued by he rees of which he old age or poor ecological condiions lead o he archiecure s degradaion. When he fores is well srucured, rees of he presen are organized in several srucural ensembles, each of hem appearing on differen levels. Those srucural ensembles are correlaed wih he florisic composiion of he fores, he species of which do no all have he same growh poenial. This sraificaion is differen from disinguishing differen sraa in he all arborescen populaion. The srucural ensembles consis only of rees of he presen which can be defined by archiecural consideraions, i.e., by heir morphogeneic sages. 53 7

2 4 l- U Fig. I. 2$ years old vegeaion; doed line is he level of liana ype vegeaion; dashed line, shoo. I Fig years old vegeaion. Doed line, level of he liana ype vegeaion; one line, rees of he fuure; wo lines, rees of he presen; black line, inversion surface. 54

3 In each srucural ensemble, he differen poins where bigger reieraions appear, consiue an irregular surface which is called he inversion surface. Sill following Oldeman, he levels of hose surfaces correlae wih differen sories where he endency o produce always bigger organs, such as sems, reverses and becomes a endency o produce smaller organs such as lile branches around he crown. This archiecural inversion involves he regulaion of verical gradiens of ligh and humidiy which change o a higher or lower degree han in he average gradien. Applicaion o he sudy of he plos In he firs plo he vegeaion is 2f years old. One can observe (Fig. I), a few arborescen plans which all conform o heir iniial model. Some of hem grow above he level of a liana ype vegeaion, bu hose pioneers do no have any reieraion; in his way, i is impossible o disinguish a se of he presen. On he oher hand, pioneer rees, as he ohers, are passing a phase of he fuure (expansion), a phase of he presen (sagnaion), and a phase of he pas (recession), even if hey never, or almos never, have fi reieraions. This behavior is shown for example by Cecropia. A se of such rees in heir sagnaion phase consiue a se of he presen; bu missing he reieraions, he diagnosis is more difficul. One can observe in his plo a regeneraing, old shoo.which reieraes he model, wih a more imporan biovolume han ha of he oher rees, because of he already well srucured roo sysem. In he second plo, he vegeaion is 3f years old (Fig. 2). Some of he rees show reieraions and consiue he se of he presen. Exending he survey beyond he designaed plo one sees ha he se of he presen is disconinuous and emerges as lile islands above he level of he liana ype vegeaion. The same archiecure is found in he hird plo (Fig. 3), where he vegeaion is 4 years old. The vegeaion in he fourh plo (Fig. 4) is 11 years old. The se of he presen shows now wo levels, wo srucural ensembles and wo inversion surfaces. This archiecure does no change during he following years and can be observed in he 23 years old vegeaion (Fig. 5), as well as ha of 33 years old (Fig. 6). During his ime, he se of he pas appears. The firs plo in he primary fores (Fig. 7) is quie ypical Fig years old vegeaion. Same convenion as in Fig. 2. Dashed line, shape of he se of he fuure. Fig years old vegeaion; he se of he fuure is no drawn Same convenion as in Fig

4 Fig years old vegeaion. Black line, inversion surface; rees of he presen are drawn wih unbroken lines, of he fuure wih dashed lines, of he pas wih large black line. -- Fig years old vegeaion. Same convenion as in Fig. 4. Dashed line connecs poins where lower ramificaions occur on unreieraing pioneer rees. of he fores in French Guiana, wih regard o he heigh of he emergen rees. The second one (Fig. 8) is quie excepional wih emergen heighs of 55 meers. In boh of hem, we disincly see a new srucural ensemble above he ohers, which only includes emergen rees. I is possible o analyze he variaion of a few measurable parameers which occur during he ime of fores regeneraion. Those parameers are he number of inversion surfaces (or he number of srucural ensembles), he absolue heigh of heir average levels, and he relaive heigh of he inversion surfaces calculaed in percenages of he oal heigh of vegeaion (Fig. 9). The variaion in numbers of inversion surfaces shows ha we can find four phases during he sylvigeneic process : in he firs one, beween O and 3 years old, hg arborescen vegeaion archiecure is no ye srucured. In he second, from 3 years o an age of abou 5 years, he vegeaion shows only one inversion surface, one srucural ensemble. The hird phase, including he 11,23 and 33 year old plos, display wo srucural ensembles wih wo inversion surfaces. The primary fores finally has hree srucural ensembles and hree inversion surfaces, and consiues he las phase of he succession. We canno dae exacly he primary fores plos; we assume ha he alles one is he oldes. Besides he srucural ensembles generaed by he reieraions described, here are pioneer rees which never or nearly never reierae. They consiue a se of unreieraing pioneer rees, which appear very early (abou six monhs afer burning he fields), and grow ill 23 years. During ha ime, hese rees are aller han he previously described srucural ensembles and we can hink ha hey play he par of an upper srucural ensemble, regardless of he change of ecological gradiens. In order o analyze he variaion of absolue levels of inversion surfaces, I have o anicipae he florisic changes during he succession. The firs srucural ensemble which occurs in he succession is consiued by differen species of Znga (Mimosaceae). This is also he case in he hird phase where one finds hese Znga rees again in he upper srucural ensemble. This fac suggess an uplif of he inversion surface level, which says a around five o six meers in heigh during he second phase, hen increases during he hird one o abou meers. This heigh, I 56

5 Fig. 7. Primary fores; same convenion as in Fig. 6. increase of he inversion surface is he resul of florisic changes as well as looping branches. For changes beween phase 3 and 4, I lack daa bu offer he following hypoheses : - The upper srucural ensemble during phase 3 coninues o increase in is heigh and becomes he upper one of phase 4. - The heigh of he upper srucural ensemble during phase 3 is sabilized. The srucural ensemble becomes he middle one in phase 4, afer having regulaed he ecological gradien in such a way ha a new level of reieraions appears, leading o he developmen of a new and upper srucural ensemble. The heigh of he lower inversion surface increases during phase 3 from 5 o 12 meers. In he primary fores, he level is abou 14 o 16 meers. Here also, I lack daa o deermine if his phase 3 lower' srucural ensemble says he lower one in he primary fores or if i becomes he middle one. If we assume ha he florisic composiion of he srucural ensemble does no change, he variaion of relaive levels of inversion surfaces correlaes wih loops on one hand and crown growh on he oher. The relaive Fig. 8. Primary fores; same convenion as in Fig. 6. level decreases when only he crown grows up. I will increase - unil deah - when jus loops occur. I will say equal beween a ime T 1 and a ime T 2 if he raio loops o crown growh is consan. However, we found many inermediae siuaions and can also assume ha a florisical change correlaes wih an increase of he relaive level (compare Table 1). The relaive level of he firs inversion surface appearing in he succession decreases rapidly during phase 2 (crowns of he rees grow up) hen increases unil 23 years (loops occur). Afer and beween 23 o 33 years, here is very lile increase. During phase 3, he relaive level of he lower inversion surface is increasing oo bu slower han ha of he upper inversion surface. This suggess a consequence of he climae regulaion of he upper srucural ensemble. 57,

6 ~ i e 3elaivc hclgh in oi absolue one HASE PHASE II -Variaion of he level of he inversion surfaces - - Varlaion of he absolue heigh Variaion of He relaive hegh PHASE absolue heigh m..y-- /./ *e TIME IN YEARS absolue average heigh of he inversion surface and of he average relaive one (average vegeaion x 100). The number of inversion surfaces defines 4 differen archiecural - phase 3 : wo inversion surfaces - phase 4: hree inversion surfaces In phase 4 he plos on he ime axis represen: x 1 he primary fores drawn in Fig. 7; x 2 he primary fores drawn in Fig. 8. Glancing a he size of he rees, i can be assumed ha x 2 is older han. 1. I emphasize he fac ha in he second par of phase 3 (23-33 years), he variaion in relaive levels correlaes wih florisical changes - in he srucural ensembles (see Table 1). In he primary fores, all he relaive levels decrease from he assumed younger phase o he older one. This suggess ha in a well - srucured primary fores, crown growh remains more imporan han loops. In he older plo, developmen of he srucural ensembles in a succession arises from hree facs: crown growh, loops and florisic changes in he srucural ensembles. The observaion of he firs srucural ensemble which appears and consiss during 11 years solely or nearly so of Inga species, shows ha his florisic phase of a srucural ensemble is passing hrough a sage of crown growh - he relaive level decreases fas - and hen hrough an equilibrium one in which crowns grow a lile faser han loops occur. This sugges han he dynamics of a srucural ensemble could be described as a succession of such florisic phases. 58

7 Table I (Con.) age 2% ANACARDIACEAE Anawrdium occidenale L. Tapirira guyanensis Aubl. ANNONACEAE Cymbopealum brasiliense Benh. Guaeria sp. Rollinia sp. Xylopia sp. APOCYNACEAE Ambellania acida Aubl. Anacampa macrocalyx (M. Arg.) Mgf. Geissospermum sericeum (Sago) Benh. Lacmella sp, ARALIACEAE Didimopanax moroooni (Aubl.) Den. & Planch. BIGNONIACEAE Jacaranda copaia U. Don. Tabebuia sp. BORRAGINACEAE Cordia cf. exalaa Lam. Cordia sp. UURSERACEAE Gusavia augusa Alm. I roiuin ncplecum Swar. i roiuln sp. Teragasris hosmanii (Engl.) O.K., lhchigalia paniculaa Aubl., 1 CI<LASTKACk:AE, Goupia Elabra Aubl. CLUSIACIAI: I Vismia cayenensis [Jacq.) Pers. Vismia sp. ( OMBRI<TACEAE Terminalia sp. L.LAI:OCARI ACEAI: Sloanea sp. LRYTHROXYLACEAE liryhrohylon sp. I:UI HORBIACEAiS Mabca piriri Aubl. Ilyeroninia lahilora M. Arg. IFLACOURTIACkAl< ( ssearia ssp. Lacia procera Eiclil. ICACINACI:Al< 1)iscopliurd puyaiionsis Micrn. LAURACI:Ak: Ococa cf. splendens (Mciss.) Mez. Ococa sp. c1. Ococa LI:CYTHIDACEAI: Lecyhis corrueaa Poilcilu. M1:LASTOMACI:Al: Miconia sp.. Undcermined, WayBpi iiamc: waimuu i Undecrmincd. WayBpi namo: wilakiii MI:LIACI.Ali Carapa guyanensis Aiibl. C;uarca ssp. c MIMOSACI<AI! Inka aurisellac Ilarnis. lnpa cl. b~jurpolllli (Auhl.) I1.C. (i lnga dislicha Miq. lnw CI. lalcrifdia Miq. inpa rubipinosii (A. Rich.) U(, lnpa cf. Iliibaudian;i I)(. lnaa sp. Inpa sp. 4 II x, x1 I Inaga sp. lnga sp. Inga sp. Inga sp. Inga sp. lnga sp. Parkia pendula OVilld) Bh. Pihe celldbium ssp. MORACEAE Bagassa sp. Brocimum rubescens Tauber Cecropia ssp. Helicosilis omenosa (P&E) Rusby Pourouma minor Benois Pourouma sp. Trymaococcus oligandrus (Benois) Lanjouw. MUSACEAE Heliconia sp. Ravelana guianensis Benh. MYRISTICACEAE lryanhera sagoiana (Benh) Warb. MYRTACEAE Eugenia ssp. Myrciaria floribunda (Wes & Willd.) Berg. PALMAE Asrowryum paramaca Marius Syagrus sp. PAPILIONACEAE Derris amazonica Killip. Dioclea sp. Perocarpus ofïcinalis J acq. QUIINACEAE Lacunaria crenaa Smih. Quiina sp. ROSACEAE Hírella racemosa Lam. Licania ssp. RUBIACEAE Duroia SD. lseria coccinea (Aubl.) Gmel. RUTACEAE Vagara sp. SAPINDACEAE Cupania sp. Talisia sp. SAPOTACEAE Chrysuphyllum sericeum U?. SOLANACEAE Solanum arboreum I1.B.K. Solanum sp ST RCULlACAL 3% x, x; i 4. i Serculia sp. ULMACAL Trema micrana Blunre. VOCHYSIACAF Qualea cocrulea Aubl. Vochynia dcnsillora Spruce c~ Warm. 4 i Vuohysia omcnosa (G.I.W. Mcy.) DC. a i i UNDETERMINKD: WayHpi namcn (Phoneic symbols) akusi i akusi i kusi i awi a inamusï, umi i iwaw s~wï kllh i niaau ; pa alr1wape palakua IaywilcnipiZ ulisi w:i incmi* Wlhkfd 59

8 Table 1 (Con.) age 2% 3% xi x1 wilapilelu wilai * winämc i yakami i yäsileã?y Summary This paper deals wih one aspec of an archiecural sudy of differen phases in secondary vegeaion. An invesigaion has been carried ou on he abandoned fields of one Indian ribe of French Guiana. This sudy is largely based upon he heory of fores archiecure by R.A.A. Oldeman (1974). A shor revue of he mos imporan conceps of his heory is presened, such as iniial model, reieraion, se of he presen, of he fuure and of he pas, srucural ensemble and inversion surface. Moreover, differen sages of he archiecure of vegeaion, 2$, 3$, 4, 11, 23, and 33 years old have been described wih help of diagrams, as well as wo aspecs of primary fores siuaed in he viciniy of secondary vegeaion. Finally, a variaion of a few measurable parameers hrough a period of ime has been analyzed and conclusions drawn abou he observed succession of archiecural phases. Resume secundaria. Las invesigaciones de campo han sido efecuadas en las chacras abandonadas de una ribu indígena de la Guyana francesa, la de los Wayãpi. El análisis se apoya en la eoría de la bioarquiecura del bosque, publicada por Oldeman,en 1974, y comienza defimiendo algunas de las nociones más imporanes de ese.méodo, al como el modelo inicial, la reieración, los conjunos del presene, del fuuro y del pasado. Además, han sido presenados varias fases bioarquiecurales del bosque secundario respecivamene de 2, 3$4,11, 23 y 33 años de edad, y ambién, dos aspecos de selva primaria ubicada en la vecindad del bosque secundario. El méodo de represenación gráfica se sirve de diagramas esquemáicos. Por fin, han sido analizados algunos parámeros mesurables durane un periodo de iempa. Las conclusiones incluyen los caracerísicos del proceso de succesión que se observó a ravés de sus fases bioarquiecurales. References Halle, F. & R.A.A. Oldeman Essai sur l archiecure e la dynamique de croissance des arbres ropicaux. Masson, Paris, 178 pp. Oldeman, R.A.A L archiecure de la forê guyanaise. Mémoire O.R.S.T.O.M. no. 73. ORSTOM, Paris. Acceped 24 November 1977 L aueur éudie l archiecure de differenes phases de la régénéraion foresière observée en Guyane française sur d anciens essars de l une des ribus amérindienne du pays. Cee éude qui se fonde sur la héorie de l archiecure foresière que l on doi à Oldeman (1974) en résume ou d abord les principaux conceps. Puis l archiecure es éudiée sur differenes parcelles où la végéaion es agée de 2$, 3$, 4, 11, 23 e 33 ans, ainsi que sur deux parcelles de forê primaire proches des anciens essars éudiés. L aueur décri enfin les variaions, au cours de la régénéraion, de quelques paramères mesurés e dégagés par l éude de l archiecure; il décri ainsi des phases archiecurales de la régénéraion. J I w Reshnen El sujeo de esa comunicación es un aspeco del esudio bioarquiecural de las disinas fases de la vegeación 60