Posteado por: BPP | julio 26, 2008

Ecological survey of Panamá (1956)

Report of an Ecological Survey of the Republic of Panama (1956)

L. R. HOLDRIGE, Forester and Ecologist
GERARDO BUDOWSKI, Forester Interamerican Institute of Agricultural Sciences, Costa Rica

Resumen

En respuesta a una solicitud del Gobierno de la República de Panamá dirigidas a los Programa de Cooperación Técnica de la Organización de Estados Americanos, un reconocimiento ecológico de todo Panamá se hizo en la primavera de 1955. Teniendo en cuenta el tamaño de Panamá y el hecho de que los dos técnicos tenían sólo un mes disponible para el trabajo, la cartografía se limitaba a la delimitación de zonas de vida de formaciones forestales del país. Sin embargo, este es el objetivo del proyecto y las siguientes notas describen estas zonas y su relación con la agricultura y los usos silviculturales.

Este estudio ecológico es considerado como uno de los pasos básicos en la planificación nacional de usos de una nación de recursos. Al mismo tiempo se trató de esbozar las esferas más prometedoras para la concentración del trabajo de extensión, los futuros estudios y el desarrollo de la silvicultura. Las experiencias, tanto favorables y desfavorables, de otros países de la región en la utilización de los recursos renovables en las distintas zonas de vida se han utilizado como guía para Panamá, donde la población sigue siendo la densidad de la luz.

Con el fin de desarrollar y mantener un nivel satisfactorio de vida, el hombre debe mantener un equilibrio ecológico con su medio ambiente. Si trabaja en armonía con las condiciones naturales, puede desarrollar una eficiente y permanente uso de los recursos renovables que le proporcionará todos los medios necesarios beneficios de una vida abundante. Si el trabajo contra la naturaleza, los resultados serán un despilfarro de recursos, dando lugar a la pobreza y muchos problemas económicos y sociales. Afortunadamente, Panamá se encuentra todavía en una posición favorable para guiar su propio desarrollo y, en caso de que, así lo desea, pueden desarrollar una fuerte y sólida economía y una nación fuerte.

Antes de pasar a nuevas discusiones, queremos expresar nuestro sincero agradecimiento a las muchas organizaciones y personas que colaboraron de manera voluntaria en muchas maneras de facilitar nuestro trabajo. La organización de SICAP, dirigido por Benjamin Birdsall, hizo los arreglos para todos los viajes dentro del país y siempre para el transporte y otros gastos del estudio. El Dr Solís y el Sr Lawrence Cummings del SICAP tuvo el cuidado de los arreglos de viaje específico y este último nos acompañó en la mayoría de los viajes. Señor Guzmán y otros en la oficina principal nos ayudaron en la recogida de datos y agentes del SICAP en el terreno nos ha ayudado mucho en los arreglos locales.

La Chiriquí Land Co. proporcionó amablemente un automóvil de transporte en la provincia de Chiriquí. También Max Arosemena y su organización, el Instituto de Fomento Económico fueron de gran ayuda en la organización de viajes justo al este de Ciudad de Panamá. El Diputado Pablo Oten de Darién nos ayudó mucho en la región de El Real. Para todos estos y muchos otros además de los mencionados queremos expresar nuestro agradecimiento por su ayuda en la toma de nuestras datos más eficiente y agradable.

INTRODUCTION

In response to a request from the Government of the Republic of Panama directed to the Technical Cooperation Program of the Organization of American States, an ecological reconnaissance of all Panama was made in the Spring of 1955. Considering the size of Panama and the fact that the two technicians had only one month available for the work, mapping was restricted to delineation of the life zones of forest formations of the country. However, this was the goal of the project and the following notes describe these areas and their relation to agricultural and forestry uses.

Such an ecological survey is considered to be one of the basic steps in planning national uses of a nation’s1 resources. At the same time an attempt was made to sketch out the most promising areas for concentration of extension work, future surveys and forestry development. The experiences, both favorable and unfavorable, of other countries of the region in utilization of the renewable resources in the various life zones have been drawn upon as a guide for Panama, where the population is still of light density.

In order to develop and maintain a satisfactory level of living, man must maintain an ecological balance with his environment. If he works in harmony with natural conditions, he can develop an efficient and permanent use of renewable resources which will provide him with al! the necessary benefits of an abundant life. If he work against nature, the results will be a waste of resources, giving rise to poverty and many economic and social problems. Fortunately, Panama is still in a favorable position to guide its own development and, if it, so wishes, may develop a strong, sound economy and a strong nation.

Before going on to further discussions, we wish to express our sincere appreciation to the many organizations and individuals who so willingly cooperated in many ways to facilitate our work. The organization of SICAP, directed by Mr. Benjamin Birdsall, made the arrangements for all trips within the country and provided for transportation and other expenses of the survey. Dr. Solis and Mr. Lawrence Cummings of SICAP took care of specific trip arrangements and the latter accompanied us on most of the trips. Mr. Guzman and other in the main office assisted us in collection of data and SICAP agents in the field helped us a great deal on local arrangements.

The Chiriqui Land Co. kindly furnished motor car transport in Chiriqui Province. Also Mr. Max Arosemena and his organization, Instituto de Fomento Economico were extremely helpful in arranging trips just to the east of Panama City. Diputado Pablo Oten of Darien helped us very much in the region of El Real. To all these and the many other individuals two numerous to mention, we wish to express our appreciation for their assistance in making our surveys more efficient and pleasant.

General Geographical Facts of Panama

The Republic of Panama comprises the southeastern extension of what is generally considered as Central America, bounding with Colombia on the East, Costa Rica on the West and with the Atlantic and Pacific Oceans respectively on its northern and southern coasts. The area of the territory is 29,128 square miles excluding the 553 squares miles of the Canal Zone. The population of the country was used as 851,900 in 1952, constituting a density of only 29 percent inhabitants per square mile.

In shape, Panama essentially resembles an irregular and narrow arch, running in a general east-west direction, and varying in ; width from 30 to about 120 miles. The same orientation applies to the main mountain range which form the backbone of the country with only one appreciable gap in the center in the vicinity of the Panama Canal. This range reaches a height of a little over 11,000 feet in Volcan Chiriqui or Barú at the western end, but elevations are much less to the east of the Canal. Other minor mountain ranges occur in the Peninsula de Azuero to the South, along the Colombian frontier and bordering the Pacific coast in eastern Darien Province.

Due to the many mountains on such a narrow trip of territory, there is little left for the plains. The largest of these are found on the Pacific side, both in Darien Province, where the biggest rivers occur and in the provinces of Chiriqui, Veraguas, Cocle and Los Santos on the western sides of the country.

Climatic Factors

Temperature

The Republic of Panama lies wholly within the tropical belt so that all of the lowlands have a mean annual temperature of over 24 centigrade. The highest temperatures occur in the drier areas on the Pacific side of the country.

With increasing altitude, lower temperatures are encountered, which give rise to four significant elevational belts of vegetation. The lowest of these is the tropical belt, ranging from sea level up to about 600 meters on the Caribbean slopes and up to approximately 700 meters on the Pacific slopes.

The subtropical belt extends from these elevations on up to approximately 1,500 meters above sea level. The lower montane belt extends from the upper limit of the subtropical belt up to approximately 2,600 meters above sea level. The major part of this belt is restricted to western Panama in the Cordillera de Talamanca and the Serrania de Tabasara but small areas do occur in eastern Panama along the frontier with Colombia. The montane belt is restricted to a few isolated areas on the higher peaks in the Talamanca Range. Although a few sub alpine plants may be found on the peak of Volcan Chiriqui, Panama does not reach the sub alpine belt.

The approximate total acreages and percentages of the area of the country by elevational belts is shown in the following table:

Area in K2 Total Porcentaje del área
Tropical Basal Belt 56,430 76.3
Subtropical Belt 13,800 18.6
Lower Montane Belt 3,530 4.8
Montane Belt 250 0.3

Precipitation

Within the elevational belts, differences in annual rainfall give rise to significant changes in natural vegetation and correspondingly in agriculture. These natural divisions which are termed life zones or plant formations are plotted on the following map of Panama:

Ordinarily, the transition zones where two formations join are not extensive and one line delineates the change from one life zone to another. However, in the Darien region, we found that the total precipitation over considerable areas is very close to 2,000 mm. or 80 inches and the change in precipitation is so gradual that the zones of transition are extensive enough to warrant separate delineation.

The rainfall on the Caribbean coast and slopes follows the general pattern of the Caribbean area. The trade winds from the northeast and east bring air which is heavily laden with moisture to the land and precipitation is essentially orographic. Heaviest annual precipitation probably occurs in the lower part of the lower montane belt or the upper part of the subtropical belt, at around 1,500 m. elevation. At present, however, there are no meteorological stations at these elevations on the Caribbean slopes to verify this statement.

The air movement from the Caribbean passes to a limited extent over the divide during the rainy season so that the upper parts of the southern and southwestern slopes are definitely influenced by the Caribbean climatic regime. Only in the vicinity of the Canal Zone, where the country is generally low does this Caribbean influence during the wet season extend across the isthmus to the Pacific. This is evident just to the west of the canal and may be observed in the vegetation along the highway from before Chorrera to beyond Capira.

On the Pacific side, the precipitation is predominantly conventional, occurring during the rainy season when the belt of doldrums has moved north from South America to over Panama. However, there appears to be a strong influence there of winds from the southwest so that wherever parts of the isthmus face the southwest, there is an indication of higher rainfall giving rise to a vegetation similar to that of the Caribbean side.

In general then, the whole Caribbean side is moist to wet whereas the Pacific side is broken into moist or dry subregions1. The dry season is long and strong in the dry forest formation on the Pacific. Also, the dry season is more marked in the moist forest formation there than in the corresponding life zone on the Caribbean side.

The driest area observed in Panama was found on the western side of the Azuero Peninsula.

Close to the Colombian border, there is indication of entrance into a different climatic region which is generally more rainy, and thus, wind directions and mountain barriers do not seem to be as important in influencing rainfall as they are to the west. Winds

Winds are significant to the Panamanian climate mainly in producing orographic rainfall and accentuating dryness en parts of the Pacific slope, when the stronger trade winds cross the isthmus during the dry season. Fortunately, Panama lies out of the sweep of the hurricanes which cross the Caribbean sea to the north. However, in connection with storms, local wind currents may cause “blowdowns” which can affect seriously such crops as bananas.

Edaphic Factors

Although the climatic factors of temperature and precipitation determine the pattern of life zones or formations, within each formation, the plant associations, the physiognomy or appearance of the vegetation and the best use which man can make of the areas depend upon the edaphic or soil factors. These factors comprise topography, water table levels, physical condition and chemical composition of the soil.

Topography

Panama is predominantly a country of low and medium elevation. Only in the western part of the country are to be found appreciable areas in the lower montane and montane belts. As a continuation of the high mountain range of Costa Rica, the Cordillera de Talamanca and the Serrania de Tabasara occur as a high broken mountain range, which attains its highest elevation at 3,470 m. in Volcan Chiriqui.

Most of the subtropical belt comprises rough topography with only very limited areas of fiat or gently sloping lands located in the valleys or on the tops of wider ridges.

Also, the lower tropical belt which covers the major part of Panama is predominantly hilly and broken. Within the area of moist forest on the Caribbean side there are numerous narrow alluvial strips along the rivers, but only in the Bocas del Toro Province and in the area just to the west of the Canal, as between Chorrera and Gatun Lake, are there extensive areas of fiat or gently sloping lands.

On the Pacific side four significantly important areas of level and gently sloping lands are to be found in the David – Armuelles section, the Cocle, Veraguas, Herrera dry forest areas, a strip running east from Panama City with a narrower extension up the Rio Bayano Valley and lastly, the river valley areas of Darien Province.

High Water Tables and Excessive Drainage

Wherever water tables are high during part or all of the year, the vegetation of such areas is quite distint from the adyacent  normally drained forest lands. The most extensive of such areas are to the found in the lower river valleys in Darien Province and adyacents to the lagunas in Bocas del toro Province. Similar associations of limited areas are to be found also along the rivera and coasts in many parts of the country.

Of much less total acreage are the areas of sandy soils and limestone hills where drainage is excessive as reflected in a less luxuriant and more xerophytic vegetation. Examples of such areas may be observed around Patiño in the Darien, on the hills south of Conchita on the Bayano River, and on some of the volcanic cutwash areas in Chiriqui Province.

There is still another combination where a hardpan results in waterlogging during the wet season and excessive drying out during the dry season, as may be seen in the fiat savannas of the Cocle region. However, the savanna areas are also complicated with chemical poverty of the soil which may be due in part to their original composition and part to long continued, annual burning.

Physical and Chemical Conditions

Although it is general knowledge, that the physical and chemical conditions of the soil under virgin forest cover may be quite satisfactory or excellent, of special importance to man in relation to his agriculture are those areas which can maintain such conditions for long periods of time following removal of the forest. The areas which come closest to fulfilling these requirements in Panama are the fiat alluvial lands and the areas of recent volcanic soils. Such recent volcanic soils in Panama are to be found only in extreme western Panama. There, where fiat alluvial lands have been enriched with recent volcanic soil, are located the best agricultural soils of the country. Still there are extensive areas of alluvial soil in other portions of Panama which can adequately supply the agricultural needs of the country for some time to come.

Stony soils are common in the dry area of normally drained forest lands. The most ex- Chiriqui Province and extensive areas of low fertility in the dry forest formation are be found in the vicinity of David, in Cocle and Veraguas and to the east of the Canal. In the moist forest formation, a smaller area of very poor soils giving rise to savanna vegetation may be observed between Chorrera and the coast.

Biotic Factors

Although, ecologists consider under this title the effect of all forms of life on the vegetation, in the present discussion, we will restrict consideration essentially to the major influence of man, together with that of his domestic animals, and of fire which is almost exclusively spread by man.

With a quick glance at the map one can observe the apparent concentration of place names in the tropical dry forest life zone. These were the major areas of settlement in the centuries following the first European colonization of Panama and very likely had constituted previously the main centers of aboriginal settlement based on maize culture. This was primarily due to the lesser effort needed to control woody vegetation which competed with cultivated crops or, subsequent to Spanish colonization also with the grasslands established for pasturing livestock. Long continued burning in these dry regions has greatly altered the original forest vegetation and has been conducive to much impoverishment of the soils, especially on the hilly lands.

Within the past century, three other concentrations of population have been developed, one within and adjacent to the Canal Zone traversing the isthmus and the other two connected with banana culture in Bocas del Toro Province and in the Comarca del Baru.

From these various centers of population concentration in both life zones, the expanding population is now moving out into adjacent areas. Man’s influence in the rest of the Republic is much lighter and tends to date to be confined to narrow strips along the coast, along the rivers and along the highways which have been developed in recent years. In general, the overall influence of man on the vegetation of Panama is still quite limited and restricted to certain areas of concentration. Within these, the areas affected by crop cultivation are much less than those where the vegetation has been cleared by man or fire for grazing.

However, the population has now reached numbers where subsequent geometric increase are bound to result in profound changes of the vegetation and natural landscapes of Panama within the next few generations. The need for planning and the possible results of man’s future impact on the natural resources of Panama are discussed subsequently in the report.

Natural Vegetation of Panama The natural vegetation of any area is a response to the climatic and edaphic factors prevailing on the site. Within a biogeographical province, many species of plants may be used as indicators of variations in climate and soils. This is especially important in Panama where meteorological data is scant and the s’oils have been little studied. In the present study, observations were confined largely to tree species, which because of their size and major exposure to the climatic elements are considered the best indicators. Where man has made extensive clearings, however, it was found necessary to use smaller elements of the vegetation also, in addition to any scattered trees.

Since this survey was an ecological reconnaissance and time was extremely limited, few collections were made and there was no attempt made to identify all of the tree elements of any given association. Tree lists in many areas were compiled with the main purpose of locating the indicator trees which are of special importance in classifying an area and which permit interpretation not only of climatic and edaphic factors but also of present and potent’ al agricultural use.

The tropical dry forest of Panama is characterized by the following trees:

Acrocomia sclerocarpa Mart., Palma pacora o Corozo

Albizzia caribaea Apeiba tibourbou Aubl. Cortezo

Bombacopsis quinatum (Jacq.) Dugand, Cedro espino

Bumelia sp. Pino alegre (?)

Calycophyllum candidissimum (Vahl) DC. Madroño

Chlorophora tinctoria (L) Gaud. Mora

Cochlospermum vitifolium (Willd.) Spreng. Poroporo

Diphysa robinioides Benth. Macano Enterolobium cyclocarpum (Jacq.) Gris. Corotú.

Luehea candida (?) (DC.) Mart.

Pithecolobium saman (Jacq.) Benth

Platimiscium pinnatum (Jacq.) Dugand. Quira.

Prosopis juliflora (Sw.) DC. Aromo

Pseudosamanea guachapele (H.B.K.) Harms

Sciadodendron excelsum Gris. Lagarto

Simarouba glauca DC.

Sterculia apetala (Jacq.) Karst. Panama

Sweetia panamensis Beth

Tabebuia chrysantha Guayacan

Xylopia frutescens Aubl. Malagueto macho

There are nearly 100 species of trees of all sizes in the association on good soils. Also, we are not listing here many striking trees such as

Ceiba pentandra Gaertn., ceiba;

Bursera simarouba (L.) Sarg., carate; and

Didymopanax morototoni (Aubl.) D. & P. because such species are found also in the Tropical Moist Forest.

On the poorer soils, such as the savanna lands of the Pacific side, the number of species are less, the original forests were composed of trees of lower stature, there are more spiny legumes such as Prosopis juliflora (Sw.) DC and Acacia farnesiana Willd., and we find, in places, high percentages of fire resistant species which tolerate poor soils such as Curatella americana L. and Xylopia frutescens Aubl.

The two associations of poor soils in this life zone are to be found in extensive areas as exemplified in the savannas and the low foothills of Cocle province and around Day/ vid in the province of Chiriqui.

Along streams or on alluvial fiats next to rivers where the water table is high, may be found tree species from the tropical moist forest such as Anacardium excelsum (Bert. & Balb.) Skeels, espave, but these are not able to resist the long drought on the sloping lands.

The above four mentioned dry land associations are the main grouping of plants covering appreciable areas. There are small area plant associations of scientific interest, but these were not considered of importance in this study. The swamp forests are to be treated in a subsequent part of the report.

We were not able to separate out the West Forest although there are indications along the San Blas coast and farther west that possibly considerable areas may have a rainfall of over 160 inches and belong properly to another formation. However, travel within the Caribbean coastal forest strip is difficult and time did not permit our making extensive trips into the foothills.

The characteristic tree species of the Tropical Moist Forest are listed here as follows:

Anacardium excelsum (Bert. & Balb. Skeels Espave

Brosimum spp.

Carapa guianensis Aubl.

Cecropia obtusifolia

Centrolobium patinense (?) Pittier

Coccoloba (?) tuerckheimii D. Sm.

Couroupita panamensis

Dipteryx panamensis

Gustavia sp., Membrillo

Iriartea exorrhiza Mart.

Jacaranda copaia (Aubl.) D. Don, Palo de buba

Lecythis sp. Coco

Luehea seemannii Tr. & Pl., Guacimo

Pentaclstlira macroloba (Willd.) Kuntze

Theobroma purpureum Pittier, cacao cimarron

Virola spp.

Warscewiczia coccinea (Vahl) K.

Transition Forests

The Tropical Moist Forest

The Tropical Moist Forest including the transition zone to the dry forest covers approximately one half of the area of Panama.

Ordinarily transition areas between two life zones are narrow and are not mapped separately, but in Darien Province we found such extensive zones of transition that we mapped these out separately. In such transition areas, there is a mixture of the tree species from each formation plus certain species which are typically transition species.

The interesting tree, cuipo, Cavanillesia platanifolia H.B.K. is one of the latter. When one crosses the isthmus of Panama near the Zone, this huge tree is found fairly well restricted to the edges of the moist and dry forest in a narrow strip. However, in the Darien, this species occurs over a very wide section indicating clearly that this whole area is a transition belt.

The portion of the moist forest which is typed as transition forest contains a much higher percentage of valuable timber species than is ordinarily found in the moist forest, climatic conditions are also excellent for agricultural use.

Swamp Forests

The swamp forests of Panama are extensive and especially interesting for potential forest industries because of their composition of one or few species. Such pure stands are rare in the tropics except under special edaphic conditions. Of the various associations the four which are most extensive are the manglares, the alcornoque forests, the cativo forests and the orey forests.

Although there are swamp forests of various sizes scattered all along the coasts of the republic, we carried out the major part of our observations in the Darien and in Bocas del Toro Province, where these associations comprise thousands of nectares. Although the rainfall is considerably higher at Bocas del Toro, the major difference between these areas is the fluctuation in tide levels. On the Caribbean side there is a difference of a little over 20 inches between mean high and mean low tide levels whereas in Darien this difference is close to 20 feet.

With this differential in tide levels in the Darien, the effect of the tide are felt far up the rivers, although there the rise of water is due to the damming of the waters by the tide. The approximate point on a river to which the brackish waters reach appears to be marked by the disappearance of red mangrove (Rhizophora mangle L.) and the appearance of Montrichardia arborescens (L.) Scholt, a tall aroid, which grows on the soft mud of the river banks. The most extensive flooding occurs when the highest tides coincide with periods of heavy rainfall and full rivers.

Mangrove Swamps

In Darien Province, there are severa! thousand hectares of periodically inundated tidal swamps occupied by pure stands of red mangrove. With the high tides, the salt water moves back readily through the forest which probably accounts for the extensiveness of the red mangrove. At Bocas del Toro, the red mangrove is found on the fringe of the swamp only with black and white mangrove occupying the area towards dry land. In the Darien, these species show up first on the river banks where fresh water from the rivers reduce the salinity.

The stands of red mangrove appear to average around 80 to 90 feet in height with good straight boles and heavy volumes per acre. At the present, they are exploited only for the bark of the tree and this cutting has not been very extensive. Alcornoque Swamp Forests

Again in the Darien Province, this association covers extensive areas, apparently taking over the area of manglares which have been built up to a higher level. Here there is more firm ground which appears to be above normal tide levels, but which when flooded is covered with brackish water.

The trees run to larger diameters than the red mangrove and are not as tall or as straight. They do in total, however, contain a large quantity of timber in pure one species stands. Pterocarpus officinalis Jacq. ! Stands

This leguminous tree with ribbon buttresses occasionally form pure stands just next to the mangroves in perhaps softer lands and those more inundated with brackish water than the alcornoque forests. At any rate, they are nowhere extensive in Panama and are not important as commercial forests.

Orey Swamp Forests

In Bocas del Toro Province, nearly pure stands of Orey, Campnosperma panamensis Stand!, occur extensively on the low lands, .just above sea level, of the islands, peninsulas and mainland shores. It appears, that these areas are not actually flooded by the tides but that there is a high water table of brackish water.

The asociation contains a few other small trees in the understory and an occasional large tree of Symphonia globulifera L. in or above the canopy. The stand is not too heavy in volume as the trees are mostly in the 10 to 18 inch diameter range and the trees do not appear to go much beyond 60 feet in height.

Cativo Forests

On the fiat lands of the Darien extensive areas are found of nearly pure stands of cativo (Prioria copaifera Gris.). This tres seems to occur on fiats above normal tide leveis similar to those of alcornoque, but when inundated are covered with fresh water only. A few other species such as tangare. (Carapa guianensis Aubl.) and Quararibaea are mixed with the cativo even where the floods are highest and as the land beccmes progressively higher more and more of the species of the normal tropical moist forest appear in the mixture.

These stands, as described by Lamb, contain heavy volumes per unit area as the cativo is a tall, straight tree of large diameters and occurs in dense stands.

Pachira aquatica Auhl. Swamp Forest Above the alcornoque forests on the Sambú River, we observed small areas of pure stands of this trep. The association seems to be restricted to soft, unstaWe soils which are flooded by fresh water only. This association probably filis the role of stabilizing such soils, and then, is replaced by cativo. The trees in the stand are less than 30 feet tall with diameters below 8 inches. The association is of no importance for timber.

Manicaria Swamps

In Bocas del Toro Province, we observed fresh water palm swamps which are found also farther west along the Caribbean coast. The Manicaria is a large leaved and short-boled palm. No observations were made within these swamps but in some places it was noted that cedro macho reproduction was beginning to grow up above the pakas.

Subtropical Forests

Little time was spent in observations of the vegetation of this belt above the lowland tropics, primarily because they are of much less economic importance than the lowland forests. Where rainfall is high they are, how-ever, extremely important for the regulation of stream flow. Where near to center of population, they attain special importance for park, recreational, or vacation home and hotel areas.

The subtropical moist forest is typified primarily by several species of the Myrtaceae of both the genera Eugenia and Myrcia. In general, the association is composed of small-leaved species and the natural forests is of little importance for timber. Within this life zone, most of the original forest has been removed for the planting of coffee or other crops.

The subtropical wet forest is a higher denser forest with many Rubiaceae, Melastomaceae, and Lauraceae, Laplacea, Brunellia, Inga spp., Calopi¿yllum, Taonabo, Ouratea, etc. In the Cerro Azul district, we travelled beyond Loma Pelado where the vegetation approaches that of Subtropical Rain Forest. Here was found Podocarpus, Alfaroa and Quercus. As indicated by the tops of the huis, where the vegetation is low and sparse, leaching of the soils due to the high rainfall is very pronounced. Once the higher natural forest .is removed on the slopes, the same process of deterioration of the soils will take place. Thus the natural vegetation indicates very clearly that this area is not suited for agriculture.

The lower montane forest of the Chiriqui mountains is characterized by Persea schiedeana Nees, Quercus copeyensis, Weinmannia pinnata L. and Cedrela tonduzii. There are several timber species, the trees of large dimensions and the stands heavy. The area makes excellent pasture with kikuyu grass (Pennisetum clandestinum Choiv.) but most of the area in this formation is really too steep for agriculture. Both this and the montane forest above, which we did not visit, are important for the regulation of mountain streams.

REFERENCES

Holdridge, L. R.  & G. Bodowski. 1956. Report of an ecological survey of the Republic of Panama. Caribbean Forester. Julio-Diciembre: 92-110.


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