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(Tropical) Andes: CPD Site SA38


Location:  Over 100 km south-east of Quito eastern flanks of Andes surrounding Pan de Azúcar and Sumaco volcanoes and adjacent Amazonian lowlands including Upper Napo River Valley, between latitudes 0°00'-1°10'S and longitudes 77°55'-77°10'W.
c. 9000 km² (proposed Biosphere Reserve and buffer zones).
300-3732 m.
Range of vegetation types along altitudinal gradient, from lowland tropical wet forest to undisturbed wet páramo.
Very high diversity - c. 6000 species; high endemism.
Useful plants: 
Many species used for medicinal and artisanal purposes by indigenous inhabitants; fruit trees; wild relatives of important crops.
Other values: 
Watershed protection for Upper Napo River Basin; habitat for many vertebrate taxa; genetic resources.
Road construction and colonization, conversion of forest to subsistence farms and cattle pastures; possible mining development.
Sumaco Napo Galeras National Park (2052 km²), Jatun Sacha Biological Station (15 km²).

Map 73: CPD Site SA38


The Gran Sumaco region, including the Upper Napo River Valley, comprises the outlying eastern slopes of the Ecuadorian Andes and adjacent piedmont at the extreme western edge of the Amazon Basin. Physiographically, the region is dominated by Sumaco Volcano (which means beautiful mountain in Quechua), an isolated cone-shaped volcano c. 50 km east of the main eastern range of the Andes. The summit of Sumaco (3732 m) is visible almost everywhere in the region; Cerro Pan de Azúcar is to its north. Both may be extinct. "Gran Sumaco" has been used in recent years by conservation planners (DESFIL 1990; AHT 1993) and refers to the entire region. The geographic concept of Gran Sumaco is here extended 20 km farther south to include the Upper Napo River Valley. This slightly expanded delimitation of the region is justified from a floristic standpoint as well as for conservation purposes.

The Gran Sumaco region of Napo Province is not easily defined, but the following boundaries may by considered (Map 73): to the north, the Coca River; to the east, a north-south line at the longitude of the lowland town of Loreto (c. 77°15'W); to the south, an east-west line c. 10 km south of the Napo River (c. 1°10'S); to the west, the Tena-Baeza- El Chaco road. These are the approximate limits of the proposed Gran Sumaco Biosphere Reserve.

The cone of Sumaco Volcano rises at the northern end of a relatively level plateau at 1000-1200 m. The top of the plateau is a thick cap of distinctive volcanic basalt. Beneath are the Napo and the Hollín formations, which are Cretaceous deposits respectively of limestone and sandstone. The Napo limestone is exposed at the bottom of deep gorges cut through the plateau by numerous rivers, including the Hollín, Huamaní, Pucuno and Suno which arise on the slopes of Sumaco - these are tributaries of the Upper Napo River. Thirty km south of Sumaco, separated by the Hollín and Pucuno river valleys, is the isolated limestone massif of the Cordillera Galeras (north-east of the town of Tena).

Average annual precipitation in the region ranges from c. 3500 mm at Loreto to over 6000 mm on the slopes of Sumaco. There is no true dry season, but rainfall generally lessens during July-August and December-January (exhibiting the bimodal rainfall distribution typical of the equatorial zone). Even during these relatively dry spells, monthly precipitation rarely falls below 120 mm. Although most plants probably do not experience significant moisture stress, the drier months are marked by distinct peaks in flowering and fruiting of the canopy tree species.

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The region is covered by tropical rain forest that varies in physiognomy and floristic composition with changes in altitude, geological substrate and precipitation. The vegetation map of the region (DESFIL 1990) distinguishes four principal Holdridge life zones; four corresponding vegetation types are recognized (Neill and Palacios 1990).

Tropical wet forest
Tropical wet forest is lowland forest, mostly below 600 m, with annual precipitation exceeding 4000 mm. In the Amazon Basin, this vegetation type is confined to the piedmont region, a narrow belt (50-100 km wide) at the base of the Andes. Farther east on the Amazonian plains, the climate is somewhat drier and tropical moist forest is dominant.

The canopy of the wet forest is composed of trees 35-40 m tall such as Cedrelinga cateniformis, Parkia multijuga, Erisma uncinatum and Phragmotheca ecuadoriensis. Myristicaceae are very abundant in the canopy, especially Otoba glycycarpa and Virola spp. On fertile alluvial soil near river margins, Ceiba pentandra is the most conspicuous emergent, and Chimarrhis glabriflora, Guarea kunthiana and Celtis schippii are common canopy trees. In the subcanopy (15-25 m high), the stilt-root palm Iriartea deltoidea is very common and a good zone indicator.

Premontane rain forest
Premontane rain forest covers a large area between 1000-1600 m elevation. The forest canopy is somewhat lower (30-40 m) than in tropical wet forest (Valencia et al., in prep.). The largest trees are strangler figs (hemi-epiphytic Ficus). Meriania hexamera, a canopy tree with spectacular lilac-coloured blooms in December-February, is a good zone indicator. Numerous species of Lauraceae are present, many of which are new, undescribed taxa. On flat areas Dacryodes cupularis is the most abundant canopy tree. Common subcanopy trees include Metteniusa tessmanniana, Ocotea javitensis and the palms Wettinia maynensis and Catoblastus praemorsus. On ridges above 1300 m, the very tall palm Dictyocaryum lamarckianum is common, occasionally in nearly pure stands. In areas of natural disturbance are pure stands of bamboo, Bambusa sp. In the forest understorey are many shrubby species of Rubiaceae, Melastomataceae and Piperaceae. Epiphytes are abundant, especially Orchidaceae, Araceae and ferns.

Lower montane rain forest
Lower montane rain forest (true cloud forest) occurs from 1600-2800 m. Epiphytes are even more abundant than in the premontane rain forest. In the lower portion of this zone, trees are large (to 35 m tall and 1 m diameter); the forest canopy is progressively lower at higher elevations. Predominant are species of Ficus, Clusia, Weinmannia and Lauraceae. Rather surprisingly, very large individuals of Cedrela odorata occur at elevations up to 1800 m. In the subcanopy, Morus insignis is very common as well as Croton and Alchornea. Shrubby Melastomataceae are dominant in the understorey. On windswept ridges and poorly drained sites, the tall forest is replaced by dwarf dense scrub dominated by Clusia, Weinmannia and Hedyosmum. On steep slopes are large pure patches of dwarf bamboo (Chusquea).

Montane rain forest, and páramo
Montane forest occurs above 2800 m on the upper slopes of Sumaco Volcano and Cerro Pan de Azúcar. Forest cover on Sumaco extends to c. 3300 m; above, treeless "páramo" vegetation extends to the summit at 3732 m. No direct information is available for the upper forest zone of Sumaco. Aerial reconnaissance and knowledge of similar areas on the eastern slopes of the Andes indicate that near the upper limits is a very dense elfin forest with trees 5-10 m tall, dominated by species of Clusia. The Sumaco páramo has never been disturbed by grazing, fire or other human activities, which is probably unique among Ecuadorian páramos. A botanical expedition reached the summit of Sumaco by helicopter in 1979 (Løjtnant and Molau 1982). The páramo is dominated by the shrubby fern Blechnum loxense and the bunchgrass Cortaderia nitida.

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The flora of the Gran Sumaco and Upper Napo River region, from the tropical zone to the páramo, probably exceeds 6000 species. The most thorough floristic inventories have been carried out in the lowland tropical wet forest, particularly since 1985 on the south bank of the Napo River at Jatun Sacha Biological Station, by botanists from Missouri Botanical Garden and the Herbario Nacional del Ecuador. More than 1800 species of vascular plants have been collected and identified from the 15 km² reserve (Neill, Cerón and Palacios, in prep.) and hundreds more species are yet to be identified. Based on these collections, since 1987 more than 25 species of trees new to science have been described. Some of them, e.g. Pleurothyrium insigne, are relatively widely distributed in western Amazonian Brazil, Peru and Ecuador. Others, such as Rollinia helosioides, are locally endemic to the Upper Napo River Valley and have not been found outside of the immediate vicinity of the Jatun Sacha reserve.

The flora of the higher elevation forests in the Gran Sumaco region has been much less well studied. Floristic inventories in the premontane rain forest, along the Hollín-Loreto road at 800-1400 m elevation, were initiated during 1988-1989 by Missouri Botanical Garden in conjunction with the Herbario Nacional of the Museo Ecuatoriano de Ciencias Naturales. Forests above 1400 m have been sampled very little. The Galeras massif has not been explored botanically at all, but is expected to contain many locally endemic species adapted to the exposed limestone substrate. Many new species of trees, aroids and orchids are being described from the recent collections in the premontane zone of Gran Sumaco. Species endemism at middle and upper elevations is undoubtedly quite high, but cannot be estimated reliably without more complete floristic data.

The forests of the region are highly diverse on a local as well as a regional scale. Several 1-ha permanent study plots have been established in lowland forest at the Jatun Sacha Biological Station (Neill et al. 1993), with all trees 10 cm or more in dbh marked, measured and identified within each plot. Up to 250 tree species occur in a single hectare. At higher elevations, tree diversity diminishes; a similar 1-ha plot at 1200 m on the slopes of Sumaco Volcano included c. 150 tree species (Valencia et al., in prep.).

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Useful plants

The Gran Sumaco and Upper Napo River region contains a wealth of plant species used traditionally by the native Quichua inhabitants for medicine, food, construction, crafts and clothing. A recent survey of Quichua ethnopharmacology (Marles, Neill and Farnsworth 1988) documented 120 plant species used medicinally in the region. Some of these are already marketed locally and internationally, such as Croton lechleri, a common second-growth tree which produces a dark red latex used traditionally to speed healing of wounds, and for other medicinal purposes. A U.S. pharmaceutical firm is carrying out clinical trials with an extract of Croton used to treat infant respiratory diseases. In anticipation of commercial demand, a Croton silvicultural programme is being initiated with indigenous communities in the region.

The Quichua also use numerous native species of food plants, particularly fruit trees. Western Amazonia in general has been cited as an important centre for the domestication of crop plants (Clements 1990). Domesticated and semi-domesticated land-races of fruit-bearing trees such as Bactris gasipaes, Rollinia mucosa and Gustavia macarenensis, and Chrysophyllum venezuelanense and Pouteria caimito, are commonly grown in Quichua house-gardens. These selected land-races are important genetic resources, and some of the edible fruit trees merit consideration for cultivation in other tropical regions.

A botanical garden and plant conservation centre is being established at Jatun Sacha Biological Station. Wild species of economically useful plants native to Amazonian Ecuador, as well as local native land-races of crop plants, are being brought into cultivation for purposes of research, agronomic improvement, education and conservation of germplasm.

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Social and environmental values

Sumaco Volcano is the source area for many tributary rivers of the Upper Napo River and the forest cover is vital to the stability of the regional hydrological cycle. The volcano figures prominently in many Amerindian legends. The Sumaco region has been a traditional hunting-and-gathering area for Quijos Quichua communities of the Upper Napo River Basin (cf. Whitten 1976).

Preservation of a swath of intact forest from the lowlands to the upper limit of arborescent vegetation may be important for the future of fruit-eating birds (such as trogons, cotingas, cracids) that migrate up and down the slopes and, in turn, play a vital role in seed dispersal for many of the tree species.

The region around Sumaco Volcano falls within the Eastern Andes of Ecuador and northern Peru Endemic Bird Area (EBA B18), which is centred between 800-2000m. Fifteen bird species of restricted range occur in this EBA, most inhabiting premontane and lower montane rain forest on the Andean slopes. Due to the widespread, increasing forest destruction throughout the Eastern Andes, three of these species are considered threatened.

Economic assessment

The mid-elevation forests of the Gran Sumaco region have been recently colonized by small farmers along the new Hollín-Loreto road, which transverses the plateau and gorges along the southern flanks of Sumaco Volcano. However, prospects for truly sustainable agriculture in the premontane and montane zones (above c. 1000 m) appear limited. Few crops perform well in the extremely wet climate and waterlogged soils. The main initial commercial crop is "naranjilla" (Solanum quitoense), which can be grown for about three years and then the site must be left fallow for a number of years before replanting. Ecotourism may have limited potential, given the difficulty of access to many areas and the rainy climate.

An alternative that is being developed on an experimental basis is sustained-yield timber production. A preliminary assessment of possibilities for sustainable timber production in the region was made by Palacios and Simione (1990). Cultural Survival and FOIN (the Federation of Indigenous Organizations of the Napo, which is for local Quichua-speaking communities) have begun a programme for forest management and sustained-yield timber harvest in three indigenous communities along the Hollín-Loreto road. Included are training in dendrology, silviculture and ecologically sound extraction methods for members of the local community and a technical team of Quichua foresters. As of October 1992, this programme is in training and inventory phases; timber extraction has not begun.

Economic assessment of non-timber forest products suggests that the establishment of "extractive reserves" within which fruits, medicinal barks, resins and the like are collected from the forest could be a viable economic alternative for inhabitants of the region. The forest would remain intact in such reserves. A recent study assessed the annual yield, local market value and extraction costs of such non-timber products in the three 1-ha permanent forest plots at Jatun Sacha Biological Station (Grimes et al. 1994). The net annual value of products that could be extracted from each hectare ranged from US$60 to US$156. These values compare very favourably on a per-hectare basis with alternative land uses such as timber extraction and cattle-ranching, particularly because extraction of non-timber products is sustainable on a long-term basis whereas the other uses are not. The most valuable product cited was neither edible fruit nor medicinal bark, but rather the resin of Protium spp., which is used by the Quichua to make a traditional ceramic varnish.

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The Sumaco region was isolated and sparsely populated until late 1987, when the Hollín-Loreto road was completed. (Construction accelerated following a March 1987 earthquake that destroyed long sections of the Baeza-Lago Agrio road, the main route from Quito to the oil fields in Napo Province.) Following completion of the Hollín-Loreto road, several thousand colonists settled along it and cut the forest to establish cattle pastures and cultivate cash crops, principally Solanum quitoense. Many settlers were Quichua Amerindians from the Archidona area who had used the Sumaco region only as hunting grounds.

Most original forest is gone in a swath up to 1 km wide on both sides of the Hollín-Loreto road. Several subsidiary roads are being built, and deforestation is proceeding along them. The land-tenure situation exacerbates deforestation. Many of the indigenous communities and mestizo colonists do not yet have legal title to the land they occupy, so there is little incentive to undertake conservation measures.

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Preservation of tropical wet forest in Upper Amazonia is a high conservation priority. The vegetation and floristic composition of this high-rainfall forest are notably different. The tropical wet-forest life zone, a rather narrow belt below 600 m at the eastern base of the Andes (the piedmont region), was the major vegetation type in Amazonian Ecuador that lacked sufficient legal protection - until 1994. The Sumaco region is the only remaining large area of undisturbed forest within this life zone in eastern Ecuador. Cayambe-Coca Ecological Reserve and Sangay National Park (CPD Site SA31), both also located on the eastern Andean slopes, do not include significant areas below 1000 m. Cuyabeno Wildlife Reserve and Yasuní National Park (CPD Site SA8), both farther east on the Amazonian plain, do not include terrain above 250 m and are covered by tropical moist forest, which has lower precipitation and somewhat lower species diversity at the community level.

An important feature in the Gran Sumaco region is the altitudinal transect of undisturbed forests and páramo from the lowlands (at 400 m) to the summit of Sumaco (3732 m). An undisturbed transect of this sort does not exist elsewhere in the eastern equatorial Andes - a comparative transect is in southern Peru at 16°S latitude, in Manu National Park (see CPD Sites SA11 and SA37).

Much of the Gran Sumaco region is classified officially as Protection Forest (which is owned by the government). Although deforestation and agricultural activity are prohibited, the regulations are not enforced. A small (15 km²) private reserve protecting tropical wet forest is the Jatun Sacha Biological Station at the southern limit of the Gran Sumaco region. Jatun Sacha is currently in process of expansion through purchase of adjacent properties, with funding by donations from Children's Rainforest organizations in Europe and North America. This reserve may be able to protect 30 km² of forest.

A major conservation project for the Gran Sumaco region has been initiated, with funding provided by the German Government through its financial assistance bureau KFW. Earlier, the U.S. Agency for International Development, in conjunction with the Dirección Nacional Forestal (DINAF) of the Ecuadorian Ministerio de Agricultura y Ganadería, had commissioned two preliminary studies of the region: an overview by Fundación Natura and DINAF (1989) and the diagnostic management plan by DESFIL (1990). The KFW, in conjunction with the Instituto Ecuatoriano Forestal y de Areas Naturales y Vida Silvestre (INEFAN), commissioned a third study which included a detailed plan for conservation and sustainable development of the Gran Sumaco region (AHT 1993). Concurrently, in a separate agreement with INEFAN, the Australian Rainforest Information Centre and Izu Mangallpa Urcu (an Ecuadorian foundation formed by local Quichua families) initiated a management plan for the conservation of the Galeras area.

The Gran Sumaco conservation project proposed establishment of two national parks as core protected areas (Map 73); in June 1994, Sumaco - Napo Galeras National Park (2052 km²) was established. The Sumaco sector of the park (1906 km²) protects a continuous altitudinal transect from lowland forest to páramo on the eastern slopes of Sumaco. The Napo Galeras sector (147 km²) protects the unique flora on the limestone Galeras massif. Furthermore, the entire Gran Sumaco region (9000 km²) is expected to be declared as a biosphere reserve by UNESCO-MAB. The inhabited areas will be managed as buffer zones where sustainable agriculture, forestry and other activities will be promoted that help to protect the core areas.

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Map 73. Gran Sumaco and Upper Napo River Region, Ecuador (CPD Site SA38)


AHT (Agrar- und Hydrotechnik Gmbh.) (1993). Proyecto protección de la selva tropical Gran Sumaco: estudio de factibilidad. Quito. 251 pp. + appendices.

Clements, C.R. (1990). A center of crop genetic diversity in western Amazonia. BioScience 39: 624-631.

DESFIL (1990). Manejo de la zona del Gran Sumaco, Provincia del Napo, Ecuador. Development Strategies for Fragile Lands (DESFIL), Washington, D.C. 104 pp.

Fundación Natura and DINAF (Dirección Nacional Forestal) (1989). Proyecto Sumaco – Informe para la definición del area a protegerse y la selección de alternativas de manejo del Sumaco. Fundación Natura, Quito.

Grimes, A., Loomis, S., Jahnige, P., Burnham, M., Onthank, K., Alarcón, R., Palacios, W.A., Cerón, C.E., Neill, D.A., Balick, M., Bennett, B. and Mendelsohn, R. (1994). Valuing the rain forest: the economic value of nontimber forest products in Ecuador. Ambio 23: 405-410.

Hurtado, F., Neill, D.A. and Alvarado, A. (in prep.). Inventario cuantitativo de una hectárea de bosque pluvial premontano en la región del Volcán Sumaco.

Løjtnant, B. and Molau, U. (1982). Analysis of a virgin páramo plant community of Volcán Sumaco, Ecuador. Nordic J. Bot. 2: 567-574.

Marles, R.J., Neill, D.A. and Farnsworth, N.R. (1988). A contribution to the ethnopharmacology of the lowland Quichua people of Amazonian Ecuador. Rev. Acad. Colombiana Cienc. Exactas Fís. Nat. 63: 111-120.

Neill, D.A. and Palacios, W.A. (1990). Características naturales. In DESFIL, Manejo de la zona del Gran Sumaco, Provincia del Napo, Ecuador. DESFIL, Washington, D.C. Pp. 11-25.

Neill, D.A., Cerón, C.E. and Palacios, W.A. (in press). Flora de la Estación Biológica Jatun Sacha: lista preliminar. Rev. Museo Ecuatoriano Cienc. Nat.

Neill, D.A., Palacios, W.A., Cerón, C.E. and Mejía, L. (in prep.). Composition and structure of tropical wet forest in Amazonian Ecuador: diversity and edaphic differentiation. [Abstracts: Association for Tropical Biology Annual Meeting, June 1-4, 1993.] San Juan, Puerto Rico. Pp. 117-118.

Palacios, W.A. and Simione, R. (1990). Técnicas adecuadas y sostenidas para el manejo natural de los bosques. In DESFIL, Manejo de la zona del Gran Sumaco, Provincia del Napo, Ecuador. DESFIL, Washington, D.C. Pp. 62-72.

Valencia, R., Balslev, H., Palacios, W.A., Neill, D.A., Josse, C.,Tirado, M. and Skov, F. (in prep.). Diversity and family composition of trees in different regions of Ecuador: a sample of 18 one-hectare plots. In Dallmeier, F. and Comiskey, J. (eds.), Measuring and Monitoring Forest Biological Diversity: The International Network of Biodiversity Plots. Proceedings of the International Symposium, May 23-25, 1995, Washington, D.C. Smithsonian Institution Press, Washington, D.C.

Whitten Jr., N.E. (1976). Sacha Runa: ethnicity and adaptation of Ecuadorian Jungle Quichua. University Illinois Press, Urbana and Chicago. 348 pp.


This Data Sheet was written by Dr David A. Neill (Herbario Nacional, Casilla 17-12-867, Quito, Ecuador and Missouri Botanical Garden, P.O. Box 299, St. Louis, MO 63166-0299, U.S.A.) and Walter Palacios (Herbario Nacional, Casilla 17-12-867, Quito, Ecuador).

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