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Kometter, R. F., M. Martinez, A. G. Blundell, R. E. Gullison, M. K. Steininger, and R. E. Rice. 2004. Impacts of unsustainable mahogany logging in Bolivia and Peru. Ecology and Society 9(1): 12. [online] URL: http://www.ecologyandsociety.org/vol9/iss1/art12/
Report Impacts of Unsustainable Mahogany Logging in Bolivia and Peru Roberto F. Kometter1, Martha Martinez2, Arthur G. Blundell3, Raymond E. Gullison4, Marc K. Steininger2, and Richard E. Rice2
1Universidad Nacional Agraria La Molina; 2Center for Applied Biodiversity Science, Conservation International; 3EGAT Forest Team, USAID; 4Hardner & Gullison Associates
Although bigleaf mahogany [Swietenia macrophylla King (Meliaceae)] is the premier timber species of Latin America, its exploitation is unsustainable because of a pattern of local depletion and shifting supply. We surveyed experts on the status of mahogany in Bolivia and Peru, the world's past and present largest exporters. Bolivia no longer has commercially viable mahogany (trees > 60 cm diameter at breast height) across 79% of its range. In Peru, mahogany's range has shrunk by 50%, and, within a decade, a further 28% will be logged out. Approximately 15% of the mahogany range in these two countries is protected, but low densities and illegal logging mean that this overestimates the extent of mahogany under protection. The international community can support mahogany conservation by funding park management and by encouraging independent verification of the legality of mahogany in trade. Our findings demonstrate that a systematic expert survey can generate reliable and cost-effective information on the status of widespread species of concern and help to inform appropriate management policy.
KEY WORDS: Bolivia, Latin America, Peru, expert survey, forest conservation, forest inventories, forest regeneration, mahogany, protected areas, questionnaire, range, sustainable forestry.
Published: April 28, 2004
Mahogany logging has attracted international concern because it is commercially unsustainable (CITES 2002a). It can also harm indigenous peoples (Watson 1996), catalyze subsequent deforestation (Veríssimo et al. 1995), and threaten the viability of the species (Snook 1996). Attempts to improve the management and secure the conservation of mahogany have included boycotts (Hering and Tanner 1998), logging moratoria, and the promotion of sustainable forest management (CITES 2002a, Grogan et al. 2002). Despite these efforts, the threat to mahogany populations remains, and concerned parties have attempted to secure protection for the species under the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES) four times since 1990. This objective was finally realized in November 2002, when bigleaf mahogany was listed on CITES Appendix II (CITES 2002b). CITES scientific authorities in exporting countries will now be required to verify that mahogany shipments are not detrimental to the survival of the species (CITES 2002b: Article IV, Paragraph 2) and do not harm mahogany's ability to maintain itself throughout its range at a level consistent with its role in the ecosystem (CITES 2002b: Article IV, Paragraph 3).
One of the main obstacles to generating the international will to take action to reverse the plight of mahogany has been the difficulty in accurately assessing the status of mahogany populations. Typically, an assessment of the population status of a tree species would require on-the-ground inventories across its range. However, because mahogany's range is very large, i.e., from Mexico to the southern Amazon basin (Lamb 1966), traditional systematic forest inventory techniques would be prohibitively expensive. In the absence of systematic assessments, a wide range of divergent and contradictory claims about the status of mahogany populations has prevented scientific consensus and the subsequent formulation of appropriate policies.
In this paper, we present a systematic and rigorous expert-survey methodology that can be used to collect information over large areas at a low cost. We applied this methodology to assess the conservation status of mahogany in Bolivia and Peru. These two countries represent different snapshots in the logging trajectory of local depletion and shifting supply that has typified mahogany's exploitation across its entire range (Robbins 2000). Mahogany logging began in Bolivia in the late 1960s. As a result of overharvest and increasing regulation (Management Authority of Bolivia 2001, TRAFFIC 2001a), Bolivia's exports dropped precipitously in the late 1990s (Fig. 1). Logging has now shifted to Peru, where exports have increased dramatically. Our study documents a species depleted or under threat across its entire range in the two countries, providing significant support for the decision to list bigleaf mahogany on Appendix II.
To conduct our surveys, we designed a structured questionnaire to assess the current status of mahogany, land use history, and planned anthropogenic activities in particular areas (Appendix 1). A steering committee that included scientists with experience in the forest ecology and management of mahogany and in related fields provided input to the design. Our project team included an in-country researcher who conducted the survey and gathered other relevant information such as the history of exploitation, production statistics, and the legal situation of the species. This article focuses on the results of the survey and forest cover analyses.Historic range
Prior to implementing our survey, we delineated mahogany's historic range. Using Lamb's (1966) map of mahogany's historic distribution, local researchers gathered information from the literature, herbarium specimens, government documents, vegetation and elevation maps, and personal knowledge to produce a more accurate historical distribution for each country.
The historic range was then divided into a tractable number of relatively homogenous forest units referred to in the questionnaire as "mahogany conservation units" or MCUs. Of these, 68 were located in Peru (Fig. 2) and 40 in Bolivia (Fig. 3). The division was made based on administrative and land use boundaries as well as forest cover. For each forest unit, we used the questionnaire to interview individuals who had a direct knowledge of the status of mahogany. These experts included foresters, loggers, ecologists, community representatives, leaders of indigenous communities, and nongovernmental organizations (Appendix 2). For Peru, 124 experts completed 301 questionnaires, a mean of 4.4 questionnaires per forest unit (SD = 1.4). In Bolivia, 59 experts completed 134 questionnaires, a mean of 3.4 per forest unit (SD= 0.6). As a check on the experts, we examined the correlation among responses for each forest unit (see section below on Concordance of results).
Forest cover within mahogany's range
To determine where mahogany could still be present, we used satellite imagery to identify areas that still retained forest cover within mahogany's historic range. For this purpose, we combined information from two data sets: (1) percent tree cover from the MODIS satellite, which is based on images collected from October 2000 to December 2001 at 500-m resolution (Global Land Cover Facility 2003), and (2) a global land-cover grid of 1000-m resolution, with data from 2000 produced by the Joint Research Centre (2003), the European Union's scientific and technical research laboratory. The MODIS data had more recent and accurate tree-cover data for Bolivia and Peru, and the Joint Research Centre grid provided a more extensive land-cover classification, making it possible to distinguish between natural nonforested and deforested areas. Combining the two sources provided the most accurate description of forest cover in Bolivia and Peru.Definition of terms used in this study
Unless otherwise stated, we use "density" to refer to the average density of mahogany over the entire forest unit, recognizing that there may be smaller areas with higher and lower densities within the unit. We divided density into the following categories, which represent the number of trees per hectare: absent (0), very low (< 0.01), low (0.01–0.1), medium (0.1–1), and high (> 1).
Commercial tree size
Trees equal to or greater than 60 cm diameter at breast height (dbh) are considered to be of commercial size. Although the legal minimum commercial size varies by country, for the purpose of this study we used 60 cm as the smallest tree size that should be harvested under a sustainable management regime. The legal minimum diameter for harvest is 75 cm dbh in Peru and 70 cm dbh in Bolivia.
Reproductive tree size
Trees greater than 30 cm dbh are considered to be of reproductive size, based on data from Gullison (1996) and Grogan (2001).
Commercially viable population
Commercial viability depends on a number of factors, including: (1) the density of commercial-sized trees, (2) the value of mahogany, and (3) the cost of harvest and transport. For the purpose of this study, however, we conservatively focused on the first factor: experts considered a forest unit to be commercially viable if it contained stands of commercial-sized mahogany trees. Price and site accessibility were not considered in this definition because both may change rapidly given the nature of the logging infrastructure and technology.
Commercially depleted population
A forest unit with an average density of zero commercial-sized trees was considered to be commercially depleted. These units may have some commercial-sized trees, but experts felt that they lacked sufficient stands of commercial mahogany for viable economic activity.
Our survey results indicated a high degree of agreement among respondents' answers when describing any given forest unit. For Bolivia, respondents were unanimous for 86% of the 1520 questions asked (40 forest units x 46 questions in the questionnaire). In only two cases did more than one respondent differ for a given question. In the case of Peru, respondents' answers were unanimous for 88% of the 3128 questions asked (68 forest units x 46 questions). In only 4% of the responses did more than one respondent differ. We also used correlation tests to determine the similarity in respondents' answers for four key questions. For each question, we randomly selected two responses for each of the 68 forest units in Peru and 40 units in Bolivia. For all four questions in both countries, responses were highly correlated, with r > 0.87 for Bolivia and r > 0.90 for Peru (Table 1). These findings suggest high confidence in the accuracy of the responses.
Sources of data used by respondents
Although published reports on the status of mahogany are scant, a great deal of knowledge is held by individuals who have direct experience with the species. Thus, in Bolivia and Peru we supplemented the 7% of total responses based on field plots (question 4b in Appendix 1) with the personal experience of respondents.
To evaluate a respondent's level of experience, we examined the number, length, and frequency of his or her visits to the forest unit, as well as how much of the area he or she was familiar with. For Bolivia, we found that 96% of respondents had visited the forest unit one or more times during the previous 2 yr, and 23% were year-round residents or had spent at least a year in the area. In addition, 63% of the surveys were completed by respondents who were familiar with more the 25% of the forest unit. In Peru, 99% of respondents had visited the forest unit within the previous 2 yr, 42% were year-round residents, 11% visited one to 12 times per year, and 74% had visited more than 25% of the forest unit (Appendix 2).Range reduction
As of 2001, 4% of mahogany's original range of approximately 55 x 106 ha in Peru and 8% of the Bolivian range of 30 x 106 ha had been deforested. Although forest cover in these two countries is relatively intact, our expert survey revealed that decades of selective mahogany logging have dramatically reduced the areas with commercially viable populations. In Peru, mahogany is already commercially depleted in 50% of its historic range (Table 2, Fig. 4A); compared to 20 yr ago, the experts said that mahogany density was either lower or much lower across 92% of its range. Furthermore, as mahogany populations diminish, loggers often resort to harvesting smaller size classes to maintain harvest volumes (e.g., Weaver and Sabido 1997). Unless harvest rates are rapidly reduced, experts predict that within 10 yr an additional 28% of the historic range in Peru will lose populations of mahogany > 30 cm dbh (Figs. 4A and 5), leaving few stands of reproductive-sized mahogany outside of protected areas. Logging has proceeded to an even greater degree in Bolivia. The experts said that over the past 20 yr mahogany has been reduced across 97% of its historic range and is no longer commercially viable in 79% of its range (Fig. 4A).
Given the uncertain contribution of logged populations to the long-term survival of mahogany (Appendix 3), we include only the mahogany populations located in protected areas in our assessment of the long-term conservation status of the species. Protected areas that prohibit logging, such as national parks, reserved zones, and protected forests, total 15% of mahogany's historic range in Bolivia and Peru (Fig. 4B, Table 2). Although these areas seem sufficiently large to ensure the conservation of mahogany in both countries, commercial-size mahogany (> 60 cm dbh) does not occur at high densities (> 0.1 tree/ha) in all of the protected areas, nor have all protected areas been effective at preventing illegal logging within their borders.
For example, Bolivia has approximately 4.5 x 106 ha of protected areas that fall within mahogany's historic range (Table 2), but mahogany occurs at densities > 0.1 tree/ha in only 36% of this area (Fig. 4B). In the past, both small-scale and industrial logging has occurred to varying degrees in all of the protected areas within mahogany's historic range. Illegal logging is currently occurring in at least two protected areas in Bolivia, representing 5% of the country's total range under protection.
Peru has approximately 8.5 x 106 ha of protected areas, but in only 35% of this area is mahogany found at densities > 0.1 tree/ha (Fig. 4B). Most of these populations are located in the Alto Purus Reserved Zone and the northwestern part of Manu National Park. Fourteen percent of the total protected area is currently being logged, and an additional 7% has been logged previously, including logging that may have occurred prior to the establishment of the protected area. Where logging is occurring, respondents indicated that commercial depletion is likely within 5 yr. In all but the remotest protected areas, ongoing vigilance and enforcement will be required to prevent neighboring logging from spreading into the protected areas.Local depletion, shift in supply, and social impacts
Our systematic survey of mahogany populations suggests that Peru is set to follow the pattern of Bolivia, where the vast majority of mahogany's range has been overexploited to the point of commercial depletion, thus supporting the decision to list bigleaf mahogany on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora.
Such an unfortunate outcome will not only impede Peru's ability to create a long-term sustainable forest industry, but it will also likely produce negative social impacts because the remaining large mahogany populations in Peru are found in areas of uncontacted indigenous cultures (Forero 2003). As logging increases in these areas, so will social disruption and violence. Such was the case in 2002 in the Peruvian Department of Madre de Dios. In June, the implementation of stricter terms for logging concessions caused violent protests against the government's National Institute of Natural Resources (INRENA) and the environmental group ProNaturaleza in Puerto Maldonado. The following month, a skirmish between loggers and Amerindians left a number of people wounded when the loggers invaded an indigenous reserve near Rio Las Piedras (Powers 2002a, 2002b).
Peru has two basic options to halt the unsustainable exploitation of its mahogany and meet its obligations under the new regulations in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). It may emulate Bolivia's example, greatly increasing investment in the forestry sector to eradicate the 30–40% of all harvests that are illegal (Traffic 2001b) and to implement management plans that are consistent with the production of sustainable volumes of mahogany. Alternatively, Peru may follow Brazil's lead. Since 2001, when Brazil was faced with widespread illegal harvesting of mahogany, it has banned all trade until illegal logging can be brought under control and the basic requirements for sustainable forest management can be enacted. However, given the pace and scale at which illegal harvesting is occurring in Peru, whichever alternative is chosen must be implemented very quickly, or the opportunity to maintain commercially viable populations outside of protected areas will be lost.
On a more positive note, both Bolivia and Peru's protected areas still have the potential to maintain intact mahogany populations, provided that long-term support sufficient for effective management is available (Bruner et al. 2001). The situation will become increasingly urgent as new roads expand the frontier, increasing the vulnerability of remote protected areas. The threat of illegal logging in protected areas can be reduced by implementing a system that tracks mahogany logs so that illegally logged trees can be eliminated from the marketplace, e.g., chain of custody, which independent forest certification such as by the Forest Stewardship Council may provide. Such tracking would support compliance with the listing of mahogany on CITES Appendix II. International buyers, who are mainly from the United States, should demand that suppliers provide such verification of legality. Further, the international community should provide financial assistance to help secure effective management of protected areas in the region (Gullison et al. 2000), which, in addition to providing a safety net for mahogany, also ensures the survival of thousands of other plant and animal species.
Our study has also demonstrated that prohibitively expensive field surveys should no longer be an excuse for failing to generate consensus on the conservation status and appropriate policy responses for any species, even one as widespread as mahogany. Expert surveys such as the one used in this study are rapid and inexpensive. In this case, it required only a few months for a small team to interview experts to assess the status of mahogany across some 85 x 106 ha of its historic range in Bolivia and Peru. The results are also robust, as indicated by the high degree of concordance among a broad range of experts, including biologists, foresters, loggers, and community leaders. We expect that the application of expert surveys will become common in the future to assess and monitor commercial species of concern.
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We would like to express our gratitude to the respondents, Peru's National Institute of Natural Resources (INRENA), and Bolivia's forest agency (Superintendencia Forestal). We also thank the members of our scientific advisory board: Alfonso Argüelles, Trópica Rural Latinoamericana, Mexico; Kamaljit Bawa, University of Massachusetts, Boston; Ximena Buitrón, TRAFFIC-South America; Julio Calvo, Tropical Science Center; Jimmy Grogan, Yale University; James Hamrick, University of Georgia; Tim Killeen, CI-CABS; Susan Minnemeyer, Global Forest Watch; Patricia Negreros Castillo, Iowa State University; Adrian Newton and Gemma Smith, World Conservation Monitoring Centre; Roberto Smeraldi, Friends of the Earth - Amazonia; Laura Snook, Center for International Forestry Research; John Terborgh, Duke University; and Adalberto Veríssimo, Amazon Institute of People and the Environment. The comments of Drs. Jimmy Grogan, Ariel Lugo, Michael Mascia, Laura Snook, Shirlee Tan, and two anonymous reviewers were also appreciated.
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Address of Correspondent:
Arthur G. Blundell
AAAS Diplomacy Fellow and
EGAT Forest Team
US Agency for International Development
3426 16th St NW #308
Washington D.C. 20010 USA
Phone: (202) 387-1299
Fax: (202) 387-1299
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