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A one-stop location for information on big-leaf mahogany (Swietenia macrophylla, Meliaceae)

EXPLOITATION

Big-leaf mahogany is the premier timber species of the American tropics. Two closely related timber species, West Indian mahogany (Swietenia mahagoni) and Pacific Coast mahogany (Swietenia humilis), have been logged so intensively since the European conquest in the 1500s that commercially viable populations of these two species were extirpated by the early to mid-1900s. Swietenia macrophylla is the only true or New World mahogany with substantial populations surviving in natural forests.

Mahogany logging in the western Amazon before 1950 depended on transporting logs by river.
Log Raft
Mahogany logging in the western Amazon before 1950 depended on transporting logs by river.

In South America, industrial logging in the Amazon rapidly depleted commercial stocks in previously inaccessible regions as overland transportation networks expanded during recent decades. Conventional logging practices are unsustainable because natural mahogany seedling densities are generally low before harvesting, while silvicultural practices necessary to ensure future production are rarely implemented. Shrinking supply and a steady strong demand for old-growth tropical timber, particularly from the United States, combine to drive mahogany’s value up. High value in turn drives continued exploitation, both legal and illegal.

Mahogany’s exploitation in South America during the last century can be divided into two phases: the extensive early phase when riverine populations were targeted because trees could be felled into or near rivers for easy transport by water to sawmills; and the intensive recent phase exploiting terra firme populations using industrial logging equipment, with overland transport of logs by truck. The early river phase occurred from the first decade of the 1900s through the 1960s in Venezuela and Colombia and within major watersheds of western Amazonia.

Heavy truck transporting logs–these are not mahogany–in the southwest Amazon.
Log Raft
Heavy truck transporting logs–these are not mahogany–in the southwest Amazon.

The terra firme phase began in the 1950s in Venezuela and Peru, in the late 1960s in Bolivia, and the 1970s in Brazil. The boom-and-bust exploitation model for mahogany means that local resource depletions coalesce into regional depletions, forcing the logging industry to migrate ever further into previously inaccessible regions in search of new commercial stands.

The first documented sales of mahogany from Brazil were recorded during the 1920s, with small volumes extracted from the state of Mato Grosso and exported through the Atlantic port of Santos. In the western state of Acre, the earliest exploitation occurred during the 1930s and 1940s along the margins of principal western rivers such as the Juruá, Tarauacá, Envira, and Purús. A second phase of exploitation began in the late 1970s in the eastern portion of Acre as overland access improved through completion of the Porto Velho (Rondônia)–Brasília highway (BR-364).

Limited exploitation began in the 1940s along the eastern limits of mahogany’s range in Brazil, particularly in the state of Tocantins. In Pará, difficult access impeded exploitation until the mid-1960s, when the opening of the Belém–Brasília highway (BR-010) facilitated logging along the margins of the Araguaia River and its tributaries. These stocks were quickly exhausted, forcing loggers to shift west into southeastern Pará in the early 1970s to mahogany-rich forests along the newly opened state highway PA-150. These stocks were in turn depleted by the mid 1980s and the logging frontier pushed farther west from the major processing center of Xinguara along state highway PA-279 towards São Félix do Xingu on the Xingu River. Throughout this vast region loggers invaded untitled federal land (terra devoluta) and Indigenous Lands through a variety of access arrangements, both legal and illegal, in search of mahogany. Commercial stands were often located by spotters in small planes.

Harvesting a mahogany tree using best felling practices in Acre, Brazil.
Log Raft
Harvesting a mahogany tree using best felling practices in Acre, Brazil.

A separate logging front opened in the state of Rondônia during the early 1980s as the southern Transamazon highway (BR-364) provided access to vast tracts of previously inaccessible forests. A federal export subsidy program sparked a ‘mahogany rush’ on terra devoluta and in protected areas and Indigenous Lands, essentially liquidating Rondônia’s mahogany stocks by 1985. Another logging frontier spread north across Mato Grosso and into southwestern Pará via the Cuiabá–Santarém highway (BR-163). From the early 1990s loggers entered the region between the Xingu and Iriri Rivers from São Felix do Xingu in the east, from entry points along the Transamazon highway across the northern limits of mahogany’s range in Pará, and from the new logging center of Novo Progresso in southwestern Pará.

The logging industry’s extraordinarily rapid advance across mahogany’s range in Brazil was fueled by expansion of regional transportation infrastructure, technological advances in logging equipment, an enormous expanse of unexploited timber, insufficient public funds for land management and regulation by state and federal authorities, government subsidies, and rising market prices due to declining supply from Central America. Production statistics vary widely according to source. The Brazilian NGO Imazon estimated that 4 million cubic meters of sawn mahogany were exported from Brazil from 1971–2001; the majority (75%) went to the United States and England, while ~1.7 million cubic meters were consumed domestically during this period. This corresponds to approximately 10 million cubic meters in logs or more than 2 million mahogany trees felled. By comparison, IBAMA, the Brazilian ministry responsible for regulating forest management, reported 2.1 million cubic meters of sawn mahogany produced between 1992–2000, with 1.3 million cubic meters consumed domestically. [GRAPH]

Mahogany exports and domestic Brazilian consumption of sawn wood (1992–2000, based on IBAMA reports), and total mahogany exports based on CITES export permits (1997–1999). From Martinez et al. (2008).

A large logged mahogany tree with hollow interior, rendering it unmerchantable.
Log Raft
A large logged mahogany tree with hollow interior, rendering it unmerchantable.

In spite of a series of logging moratoria for mahogany from 1996 to 2003, Brazil exported more than 100,000 cubic meters of mahogany between 1999 and 2001. Brazilian officials estimated in 1998 that 80% or more of mahogany production originated from illegal sources. Given widespread illegal logging, in 2001 Brazil suspended all forest management plans for mahogany approved by IBAMA in the states of Pará, Mato Grosso, and Acre. In 2003 the Brazilian federal government revised forest legislation targeting mahogany production from natural forests, implementing stringent harvest regulations in an effort to protect remaining populations from unsustainable logging practices. Since 2003, only two forest management areas containing mahogany have been approved for commercial harvesting in Brazil.

In Bolivia, a United Nations Food and Agriculture Organization (FAO) mission arrived in eastern Bolivia in 1966 and recommended the extraction of forest products for the international market. As a result, industrial exploitation began in 1967 when Brazilian logging equipment arrived in the Chore, Guarayos and Bajo Paragua Reserves in the Department of Santa Cruz. The first species logged was high-value mahogany. The mahogany frontier in Bolivia has been retreating ever since. As the most accessible regions were commercially exhausted, the logging industry opened new frontiers. Logging companies entered the Ixiamas zone during the mid-1970s, the Chimanes zone of the Department of Beni during the 1980s, and the Riberalta and Cobija zones of the Pando in northern Bolivia during the mid-1990s. A drastic decline in national mahogany production occurred from the late 1980s to 2000 in spite of a sharp increase in the number of sawmills. Lack of supply was the primary cause of reduced production. [GRAPH]

Mahogany sawn wood production in Bolivia from 1970 to 2000, and number of sawmills for selected years. From Martinez et al. (2008).

Recently felled mahogany crown in primary forest, Acre, Brazil.
Log Raft
Recently felled mahogany crown in primary forest, Acre, Brazil.

Forest exploitation in Bolivia followed a chaotic pattern with little government control before 1996, when Forestry Law No. 1700 was introduced. The new law mandated improved management standards and increased legal enforcement of the forestry sector. Management plans for sustainable forestry were required for new logging concessions. However, in spite of improved government regulations, illegal harvest and trade in mahogany persisted, especially clandestine cross-border trade with neighboring countries. Production statistics from the Bolivian Forest Chamber and the Forest Superintendency do not include estimates of illegally harvested timber. As one example, Bolivia exported 11,000 cubic meters of mahogany in 2000, more than twice the official export quota for this species. This was facilitated by a Presidential Decree (Decreto Supremo 25561) authorizing exports of mahogany obtained from Indigenous Territories.

In Peru, commercial exploitation of mahogany along tributaries of the Amazon River began during the first decade of the 20th Century and accelerated after construction of sawmills in Iquitos during the 1920s, following the collapse of the rubber industry. This earliest exploitation targeted trees growing along riverbanks or within manual hauling distance of flowing water for ease of transport to sawmills downriver. As annual production gradually increased, the mahogany frontier retreated from Iquitos as loggers had to travel ever further afield to obtain sawlogs. An estimated 50,000 hectares of riverine forests were logged annually from the 1920s through the 1940s from watersheds surrounding Iquitos and along principal tributaries of the region such as the Ucayali River.

The first trans-Andean road from Lima reached Pucallpa during the 1950s, allowing overland log transport and export via the Pacific coast. This spurred expansion of the logging frontier to adjacent watersheds and the upper Ucayali region, including the Tamaya River and Alexander von Humboldt Forest, with an estimated 150,000 hectares exploited annually during this period. A road reached San Martin Department in the 1970s, opening a new logging front for mahogany and again expanding exploitation to an estimated 250,000 hectares annually within the Biabo, Saposoa, Sisa, and Huallabamba River watersheds. During this period, loggers expanded their search area into terra firme forests as riverine populations were extirpated.

Mahogany tree with forked stem above logyard, Acre, Brazil.
Log Raft
Mahogany tree with forked stem above logyard, Acre, Brazil.

The export market expanded dramatically during the early 1980s as mechanized logging made it profitable to log mahogany from increasingly remote areas. This encouraged illegal activities. Loggers exploited mahogany in protected areas using banned techniques such as cuartoneo (quartering sawlogs with chainsaws to facilitate overland transport). In the mid 1990s, with mahogany supplies declining from Bolivia and Brazil, logging pressure on remaining stocks in Peru further intensified. A spike in exports during the second half of the 1990s led the Peruvian government to ban logging from some watersheds suffering severe over-exploitation, including the Tamaya River watershed. [GRAPH]

Annual production of mahogany in Peru from the 1920s to 2000, and number of sawmills in the Peruvian Amazon for selected years. Volume data before 1980 are presented as annual averages per decade. From Martinez et al. (2008).

Mahogany’s late ‘appearance’ in Ecuador may be attributable to a number of related factors. Industrial logging was slow to develop in Ecuador’s Amazon region due to the challenge of moving timber over the Andes to processing centers and ports on the Pacific coast. For this reason, forestry authorities were unfamiliar with the species, and the common Quichua name for mahogany, ahuano, apparently failed to register as high-value mahogany. In fact, the Spanish-language name for mahogany, caoba, refers in Ecuador to other commercial timber species, including Platymiscium spp. (Fabaceae), Caryodaphnopsis theobromifolium (Lauraceae), and Guarea cartaguenya (Meliaceae). However, a commercial boom occurred during the decade after mahogany was first recorded in 1985. Ecuadorean mahogany was illegally harvested and exported through the northern Sucumbíos Province into Colombia via the San Miguel River, ending up, among other uses, as ornate doors at luxury hotels. No production data are available for Ecuador.

Quartered mahogany timber stacked for eventual transport in Acre, Brazil.
Log Raft
Quartered mahogany timber stacked for eventual transport in Acre, Brazil.

Along with Peru, Venezuela, and Central American colonies, Colombia supplied Spain with mahogany during colonial times. Records of sales from Colombia date from 1786 through the 1800s. From 1900 until the beginning of World War II, colonization of the agricultural frontier led to extensive deforestation of piedmont and central mountain forests. Forest products such as rubber, balata (a natural gum), quinine, and mahogany were in high demand during this period. From 1940–1952, industrial logging centered on the Pacific region and the central Cauca and Magdalena River valleys. Mahogany was exported from Colombia to the United States from 1953 through the late 1960s. The start of mechanized logging in terra firme forests coincided with federal laws issued in 1959 establishing forest reserves for the management and economic development of forest resources. Widespread deforestation associated with selective logging and the expanding agricultural frontier continued into the 1980s. No production statistics are available for Colombia aside from minor export volumes to the United States beginning in 1954 cited in Lamb (1966).

Little is known about early exploitation patterns in Venezuela. Lamb noted exports to the United States as early as 1908. Exports to France and Germany began before World War I. With Spanish cedar (Cedrela odorata), mahogany was logged beginning in the 1920s from Cojedes and Portuguesa near the cities of Valencea and Cardeas, and from Barinas further southwest beginning in 1939. The 1955 Forestry Law of Soils and Water established four permanent Forest Reserves within mahogany’s range with the objective of building a national wood-processing industry based on sustainable timber production. However, the concession system implemented in Forest Reserves began as simple annual logging permits, and has been poorly regulated; logging practices essentially high-graded high-value species, and future harvests will yield mostly low-value low-density timber. Experts report that commercial mahogany stocks today occur in only two of the original four Forest Reserves. Sawn timber production of mahogany from Venezuela peaked in 1971 at 23,764 cubic meters, falling to 1,919 cubic meters by 1999. This decline was due to reduced supply. Production statistics are unavailable for the period before 1969. [GRAPH]

Mahogany sawn wood production in Venezuela from 1969–1999. From Martinez et al. (2008).

In Mexico and Central America, 64% of mahogany’s historic range had lost forest cover by the mid-1990s, with remaining forest populations severely depleted by logging (Calvo 2000).

SELECTED SOURCES

Browder JO (1987) Brazil's export promotion policy (1980-1984): impacts on the Amazon's industrial wood sector. The Journal of Developing Areas 21: 285-304.

Calvo JC, Bolaños R, Watson V & Jiménez H (2000) Diagnóstico de la caoba (Swietenia macrophylla King) en Mesoamérica: Visión general (Evaluation of Mahogany in Mesoamerica: General Overview). Tropical Science Center / PROARCA / CAPAS, San José, Costa Rica.

Grogan J, Barreto P & Veríssimo A (2002) Mahogany in the Brazilian Amazon: Ecology and Perspectives on Management. IMAZON, Belém, PA, Brazil. 58 pp. Available in Portuguese & English at www.imazon.org.br.

Grogan J, Blundell AG, Landis RM, Youatt A, Gullison RE, Martinez M, Kometter RF, Lentini M & Rice RE (2010) Over-harvesting driven by consumer demand leads to population decline: big-leaf mahogany in South America. Conservation Letters 3: 12-20.

Gullison RE, Panfil SN, Strouse JJ & Hubbell SP (1996) Ecology and management of mahogany (Swietenia macrophylla King) in the Chimanes Forest, Beni, Bolivia. Botanical Journal of the Linnean Society 122: 9-34.

Kammesheidt L, Lezama AT, Franco W & Plonczak M (2001) History of logging and silvicultural treatments in the western Venezuelan plain forests and the prospect for sustainable forest management. Forest Ecology and Management 148: 1-20.

Kometter RF, Martinez M, Blundell AG, Gullison RE, Steininger MK & Rice RE (2004) Impacts of unsustainable mahogany logging in Bolivia and Peru. Ecology and Society 9: http://www.ecologyandsociety.org/vol9/iss1/art12.

Lamb FB (1966) Mahogany of Tropical America: Its Ecology and Management. University of Michigan Press, Ann Arbor, MI, USA.

Martinez M, Blundell AG, Gullison RE & Grogan J (Eds.) (2008) Historic range and current status of big-leaf mahogany (Swietenia macrophylla) in South America. Report for the Center for Applied Biodiversity Science – Conservation International, Washington, DC, USA.

Snook LK (1998) Sustaining harvests of mahogany (Swietenia macrophylla King) from Mexico's Yucatan forests: past, present and future. In: Primack B, Bray DB & Galletti H (Eds.), Timber, Tourists and Temples: Conservation and Development in the Maya Forests of Belize, Guatemala and Mexico, pp. 61-80. Island Press, Washington, DC, USA.

Veríssimo A, Barreto P, Tarifa R & Uhl C (1995) Extraction of a high-value natural resource in Amazonia: the case of mahogany. Forest Ecology and Management 72: 39-60.

White, S. 1978. Cedar and mahogany logging in eastern Peru. The Geographical Review 68: 394-416.

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