Rangelands 9(6), December1987 251

Brush Problems in 's : I. Chañar [ decorticans] in Northwestern Santa Fe Israel Feldman and Susana R. Feldman

Resumen ciallythe beef fattening, is concentrated in the region named El chañar es una ieñosa "Humid Pampa" on cultivated pastures. Surrounding the (G.offro.a d.cortlc.ns) especie Humid originaria de Argentina. Aparece en pasturas y campos Pampa there is an extensivearea with very different soils and from humid to arid conditions. abandonadosen distintas regionesdel pals. En este trabajo, climates, ranging cc presenta una descrlpclon del problema en ci noroeste de Calf production is the main activityin this area and most of the are Brush invasion is a Ia provincia de Santa Fe. Las aradas discontinuas y ci mal pastures rangelands. common manejo de las pasturas parecieran ser los factores antro- problem of these rangelands. pogenos mM importantes que determinan Ia Invasion del Brush, whichin Argentina is generally named "monte", is chañar. Se sugieren algunos métodos de control. an ancient problem. Argentine shrubland ecosystems are much the same as those in other countries, (Scifres et al. The Argentina Republic is located in South America, 1985; Walker et al. 1981). The shrublands originate from between thesouth parallels 210 46'and 55° 3'and the meridi- different situations: (1) grasslandswhere the flux of naturally ans 53° 38' and 790 55'W of Greenwich. occurringfires and floodingshas been altered; (2) forests Beef cattleraising is one ofthe most important economic which were selectively exploited and abandoned—in these activities in most of the country.Much of this activity, espe- casesthe cattle's selective grazing had an important role in theestablishment of shrublands; (3) fieldsfirst dedicated to agriculture or cultivated pasturesthat were later not plowed anymore, letting the spontaneousvegetation reappear under cattlegrazing. This is the case of the shrub chanar (Goof- froea decorticans), that will be considered here. Chañar Chanar (Geoffroea decorticans) (Gill ex H. et A. Bur), a Dalbergia leguminosae is a woody species (Burkhart 1949, 1952). It grows as a shrub type or a tree, which can reach up to 10 meters height. It is more common as a shrub, not very spiny, ranging between 4 to 5 meters height. it has compound deciduous leaves and on the stem and principal

Ubication of the Argentina Republic. The Humid Pampa Region (I/I//I) and the area under study (\\\\). Generalview of a . New chañar sproutings in the back- A dense Authors are professors of plant ecolo9y, Facultad de Ciencias Agrarlas ground. 30-year-old chanar islete at the left. Northwestern (Universidad Naclonal de Rosarlo). Fellowship of the Argentine National Santa Feprovince, Argentina. Research Council (CONICET),Santa Fe 2051, Rosario,Argentina. 252 Rangelands 9(6), December1987 z 20

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0 0 0,5 I 1,5 2 2,5 3 3,5 4 4,5 S Chaflar sproutings in a field where plowing was quit 4 years ago. Northwestern Santa Fe, province, Argentina. meters height ods. Meantemperature is 18.8° C, meanmaximum and min- Height distribution (inmeters) ofchañar ofa field that hasn't imum are 26° C and 13° C and maximum and from five 10 X 10-rn respectively been cultivated for 20 years. Data plots minimum values are 42.6° C and -4.7° C respectively.There expressedas percentagevalues. is a frost-free periodof 286 days(Burgos 1970). branches it has stripsof dead bark, which fall down leaving The landscape is generally plain, with a slight slope behind the new green bark. The fruit is a drupe eatenby local towards northand east. The soils are typical natracuols and Inhabitants and cattle. natralbols, and in less proportion in swampy areas, typical Burkart (1949) pointed out thatthere could be 2 varieties: natracualts (Mosconi et al. 1981). (1) subtropicalis is atall tree that may reach 10 metersheight, There is no reference on the original vegetation of this not very spiny, which is only reproduced by seeds and is a area. Oral tradition, and some written information (Fren- from the woodlands in the common component subtropical guelli 1941) coincide in mentioning that the general vegeta- northern part of the country;(2) typica is more a shrub-like tion was a savannawith scattered ssp. in the grass- plant which appeared originally in almost purestands in a land, and some chañar isletes. The brushland where chañar patch distribution surrounded by grasslands and may be is dominant is locallycalled "chañaral". It appears in isletes propagated by seeds but mostly by sprouting roots. Some scattered in the grasslandsand very seldom associatedwith features of the root buds sprouting were analyzed under very few Prosopis spp. Low shrubs like Grabowskia dupli- laboratory conditions (Feldmanand Feldman 1985). cata, Celtis spp., Schinus molle, and Acacia aroma appear Chanar can be found growing in different soils and cli- in the upper layer. There could be lianas like Muelenbeckia matic conditions. It is axerophytic speciesand when itgrows sagitifolia, Mikania spp., Arauja spp., Clematis monteviden- in humid climates it appears mostly in typical natracualf sis, etc. In the herbaceous layer, below the brush and in the soils. It grows on sandy soils in the southern part of the surrounding grasslands, there is dense turf with abundant country and on typical natracuals and natralbols in the grasses like Trichioris crinita, Chioris polidactyla, Setaria northcentral part. Due to these different ecological situa- spp., Bothriochloa laguroides, Panicum bergil, Eragrostis tions in which chañar appears, there is a firm assumption spp., Cynodon pleistotachyum etc. In some cases lresine that there must be many ecotypes. difusa, Hoimbergia tweedie, Pterocau!on subvirgatum, and Thefirst botanistwho visited thecountry, Grisebach,1879, Bacharis pingraea appear. In extreme overgrazing Bacharis mentioned chaflar as a natural component of different vege- choridifolia appears,which is a toxic species. del tation types. Frenguelli (1941) named a region "Parque Following Jenny's (1941) concept of soil formation the the area Chaflar", considering it corresponded to part of authors (1985) suggestedthat the vegetation at a given place which Grisebach had previously designated "Chaflar- and time is a functionof multivariate factors: Stepe". The vegetation of these area was recently surveyed by D'Angelo etal. (1985).This region is placed between 29° V=f (cl, a, p, f, Il, m, t, a, 30' and 31° 30' south latitude and 60° 32' and 62° west of Greenwich. where: V: vegetation fI: flora cI: climate m: microorganisms Chañar in Northwestern Santa Fe Province s: soil t: time p: propagules a: anthropogeneous In this region thereis a warm temperature, humidor sub- f: fauna humid climate, with rainfalls mostly in summer and a dry at the end of winter. It rains from 800 to 950 mm In chañar the main factordetermining the new vegetation period per At the end of the last year, with a greatvariability with droughts or flooding pen- type was anthropogeneous (man). century, there began an intensive occupation of thisarea by Range/ends 9(6), December 1987 253

Generalview of chañar brushland 40years old. On the right side the fieldwas under cultivation until4 years ago. NorthwesternSanta Fe province, Argentina.

Chañer sproutings 4years old. Northwestern Santa Fe province, Argentina. farmers who cultivated , flax, and corn. Most of the area was plowed drastically, destroying the native grasses. Most of the woods disappearedbecause the plants were dug out. The normal extraction of chañar plants eliminated the principal roots, butpart ofthe secondary roots remained in thesoil. Theseroots havesprouting budsthat were cut and dispersed by agricultural labors. As a result, new plants of chañar increased. While there was frequent agricultural work,chañar was not aproblem becausethe new plants were eliminated by mechanical labor. Nowadaysagriculture is not a frequent alternative. Fields are generally plowed for sowing pastures, but only a small proportionof farms and ranches is dedicated to cultivated Me/i/ofus a/ba, sorghums, oats, rye, and barley for direct grazing. Most cattlegraze on spontaneouspastures. These grasslands, as it was pointed out, are composed mainly of Ch/oris spp., Eragrostis spp., Setaria spp., Trichloris spp., and Sfipa spp. Cynodon dacfy/on is also a very common some cases dominant. species, being in Detail of chañar, 40 years oia. NorfnwesternSanta ie province, Since plowing is no more an annual occurence, native Argentina. grassesreappear. Atthe same time, the chañar roots sprout. return unless man takes direct action. Under a After 2 without the a count of grassland years cultivating soil, continuous grazing system, the brush community will e- resprouted chañar ranged from 8,500 to 30,000 plants per more stable conditions. In afield that hasn't hectare. These counts were done on 60 to volve, reaching pastures. Only been cultivated for20 years, 5,400 chañar plants hectare 70%of the total field was covered with islets of chañar. per were counted, ranging from 0.5 to 23 cm in diameter and Without soil alteration, this vegetation type does not let 254 Rangelands 9(6), December1987 from 2 to 5 meters high. Literature Cited con- Due to the high plant density most of the plants are Anderson, DL. 1976. InvasiOn del chañar (Geoffroeadecorticans) centrated in the lowest stem diameter classes. The height (Gill ex H.et A.Burk) en los pastizalesde a Provinciade San Luis. data show wide variability—40% of the plants are located 1110 CongresoALAM y Vlll° ReuniOn Argentina de Malezas. Ia between 1 and 2.5 meters. In these conditions, it is Burgos. J.J. 1970. El Clima de Region Noroeste de Ia Republica very Bot II 37-102. difficult to walk the brush. In some cases it forms a Argentina. Bol. Soc. Arg. (SupI.) through Burkhart, A. 1949.La posicion sistemáticadel "Chañar" y las espe- purestand of chañar in the upper layer and in othercases a ciesdel género(Leguminosae-Dalbergieae). Darwiniana9(1 ):9-23. few low shrubs appear associated to chañar: Grabowskia Burkart, A.1952. Las leguminosasargentinas silvestres y cultivadas. Celtis spp., Schinus sp., Acacia aroma. These 20 Ed. Ed. Acme, , Argentina. duplicata, The of the of San shrubs are branchyand spiny and their presence restricts D'Angelo, C. et al. 1985. vegetation surrounding Cristobal,province ofSanta Fe (Argentina).Vegetatio. (in press). even more the traffic of man and cattle. F.ldman, I. 1966. Control del Chanar (Geoffroeadecorticans Bur) RIA 3:109-22. ManagementSuggestions Feldman, I. y Feldman, S.R.,1985. Algunos factores antropOgenos difusiOn del Chanar. Univ. Nacional Once the chaflar is established, it enters a que dinamizaron Ia agamica ecosystem de Rosario(in press). dynamic-steady-state. Changes are almost imperceptible. Fr.nguelll,J. 1941. Rasgos principalesde Ia fitogeografiaargentina. Only direct and dramatic human intervention may reverse Rev. Museode La Plata 3(12):65-181. thesituation; for instance,manual extraction, root plowing at Grisebach,A. 1879. Symbolaead FloramArgentinam. Abh. Kgl. Ges. Wiss. 24:1-346. the first stages,bulldozing, etc. Goetting Jenny, H. 1941. Factorsof soil formation. Ed. McGraw Hill Co., N. Reinfestation is almost sure, even under more rational York. grazing. Plowing and seeding Grama rhodes is a good Mosconl,F.P. etal. 1981. Mapade suelos do Ia provincia de Santa Fe. method to avoid reinfestation, but at least every 3 years the Tomo I. INTA & MAG Santa Fe. Argentina. grama shouldn't be grazed to allow the accumulation of Sclfres,C.J. et al 1985. Developmentof integratedbrush manage- sufficientmaterial to start and fire. Thedense sod of ment systems (IBMS): Decision-marketingprocesses. (in press). develop Walker, B.H. .t al. 1981. Stability ofsemi-arid savanna grazing sys- G. rhodes, combined with fire action will avoid chañar tems. J. Ecol. 69:473-98. reinfestation. Chemical individual treatment isaveryeffective methodof eliminating chañar invasion at the first stages. The recom- mended base treatment, is spraying with a 2% solution of "Togar" in gasoil. 'Togar is the commercial trade mark for a mixture of picolinic acid and trichiofyr acid.

The Grasses in Literature—Addendum II Alan A. Beetle

In 1963 Morgan W. Evans cited in his "The Grasses of Now I would like to propose a second addendum and to Literature" (see Vol. 16: pages 98 and 99 of the Journal of start with Walt Whitman, specifically his "Leaves of Grass" Range Management) first published in 1885and in particularhis poem"A song for (1) the Bible occupations" which says in part: Flour-works, grindingof (2) Ralph Waldo Emerson wheat, rye, , rice, the barrels and the half and quarter (3) John Greenleaf Whittier barrels -— (5) Rudolph Ruse (2) Kirschner's "Nature's Healing Grasses" wherein he (6) John James Ingals. says in part in recommendinggrasses and herbs as a thera- Thatsame article initiated a responsefrom E.J. Dykster- peutic agency, the emphasis should be placed upon their huls. With the sametitle he made an "Addendum" (see Vol. intelligentuse but what are the grasses mentioned?Alfalfa! 16: pages 225 and 226, Journalof Range Management)and Comfrey! Kelp! Watercress!Parsley! Celery! Licorice! suggestedthe following: (3) Killeffer's "Two Ears of Corn, Two Blades of Grass" (1) Jullan Stearns Cutler The wonders of modern chemistry that can now produce (2) Robinson Jeffers all the necessitiesof life. (3) Carl Sandberg (4) Buell and Brigman in 1968 "The Grass Roots" (4) W.A. Silveus "In Kansas,a farmer complained that Johnson grass was (5) Donald Culross Peattie spreading to his field from the neighboring county road (6) L.H. Pammel right-of-way, and ultimately was successful in persuading (7) W.J. Showalter the county commissioners to declare that grass a noxious (8) William Elsey Connelly weed, thus bringingit within the scope of the public weed (9) and an anonymous poet of the 1930s. eradication program. Here, by the way, is an excellent illus- trationof the way by whicha function long considered pri- The author isProfessor Emeritus, Department of Range Management, Uni- versity of Wyoming,Laramie. vate comes to be taken over by government. Here was no