Assessing the extent of "conflict of use" in multipurpose tropical forest trees: A regional view

ArticleinJournal of Environmental Management 130C:40-47 · September 2013with 305 Reads
Ad

Do you want to read the rest of this article?

Request full-text
Request Full-text Paper PDF
  • Article
    The Amazon rainforest lies within the most diverse forest ecosystem in the world. However, a large part of the tropical rainforest is being degraded because of timber harvesting without any sustainability criteria, and owing to a limited understanding of the effects of forest exploitation. The Ecuadorian Amazon (EA) is part of the Andes Amazon (AA), an area covered by five countries (Venezuela, Colombia, Ecuador, Peru and Bolivia). This research identified the patterns of legal timber harvesting in the EA and determined current trends with respect to mostly harvested forest species. Two harvesting programs aimed at small farmers prevail in the EA: first, naturally regenerated trees felling program and, simplified timber harvesting programs in native forests. Considering the surface and volume of logging, significant differences were detected between logging procedures and ecosystems in the region. Two hundred and thirty-two genera are registered for harvest and, 51.93% of the total harvesting volume comes from eight genera and ten species. This research shows that in fallows of fragmented forest ecosystems, small farmers are harvesting fast-growing pioneer species. Maintaining a sustainable production in timber harvesting depends, by and large, on the harvesting and felling programs established on small farms.
  • Article
    Full-text available
    Background and Aims: Cedrela odorata (Spanish cedar) is a tropical tree native to America with an important international trade market. In this study, the morphological variation of C. odorata was compared among three conditions: logging, plantations, and natural populations, with the objective to evaluate the current condition of managed populations after harvesting and in plantations, in contrast to relatively well-preserved populations. Methods: Two sites were chosen for each condition. The population density and four morphological attributes were measured: diameter at breast height, height, angle of branch insertion and crown form. A multivariate approach was used to compare the morphological variation among conditions (generalized discriminant factors analysis) and determine total variation distributed among size classes (cluster analysis), as well as assignment of these classes to each condition (canonical correspondence analysis). Key results: Four significantly different size classes were identified among all populations with specific association to condition. Strongest correlations were between highest trees with natural populations and small trees with plantations. Forest management, including harvesting and plantation conditions, reduced the phenotypical variation and modified the dasometrical attributes of C. odorata. The logging of the better shaped phenotypes increased the smaller size trees frequency compared to commercial size individuals, and changed the forest composition favoring small categories. Conclusions: The forest exploitation generates homogenization in median height-class and the plantation in lower height-class. In both cases, the harvestable trees are scarce, even after 20 years of management; and they are non-existent in plantations of 15 years. These results suggest that the removal of the highest trees, as well as forest plantations, are not being effective to wood production since they do not reach commercial sizes in the time of recovery or projected growth.
  • Article
    Full-text available
    Ceratocystis fimbriata Ellis & Halsted recently was recorded causing seed and seedling blight on Carapa guianensis Aubl. (andiroba), a tree species native to the Amazon Rainforest and prized for its valuable timber and medicinal seed oil. C. fimbriata more commonly causes wilt type diseases in woody hosts, especially on non-native host trees. However, on andiroba the disease occurs on seedlings and seeds, affecting the species regeneration. We studied 73 isolates of C. fimbriata on andiroba from three regions of the Amazon Basin to see if they represented natural or introduced populations. Analysis of ITS rDNA sequences and phylogenetic analysis of mating type genes revealed new haplotypes of C. fimbriata from the Latin American Clade that were closely related to other Brazilian populations of the fungus. In mating experiments, andiroba isolates were inter-fertile with tester strains of C. fimbriata from Brazil and elsewhere, confirming that they belong to a single biological species. Using microsatellite markers, 14 genotypes and populations with intermediate levels of genetic variability were found, suggesting that the fungus is indigenous to the Amazon Basin. Inoculation tests indicated that the andiroba isolates are host-specialized on andiroba, supporting the proposition of the special form C. fimbriata f. sp. carapa.
  • Article
    Full-text available
    Products and services provided by trees in forests and farmland support the needs and promote the well-being of hundreds of millions of people in the tropics. Value depends on managing both the diversity of tree species present in landscapes and the genetic variation within these species. The benefits from trees and their genetic resources are, however, often not well quantified because trade is frequently outside formal markets, there is a multiplicity of species and ways in which trees are used and managed, and genetic diversity within species is frequently not given proper consideration. We review here what is known about the value of trees to rural communities through considering three production categories: non-timber products harvested from trees in natural and managed forests and woodlands; the various products and services obtained from a wide range of trees planted and/or retained in smallholders' agro-forestry systems; and the commercial products harvested from cultivated tree commodity crops. Where possible, we focus on the role of intra-specific genetic variation in providing support to livelihoods, and for each of the three production categories we also consider wider conservation and sustainability issues, including the linkages between categories in terms of management. Challenges to 'conventional wisdom' on tree resource use, value and management – such as in the posited links between commercialisation, cultivation and conservation – are highlighted, and constraints and opportunities to maintain and enhance value are described.
  • Article
    Full-text available
    Products and services provided by trees in forests and farmland support the needs and promote the well-being of hundreds of millions of people in the tropics. Value depends on managing both the diversity of tree species present in landscapes and the genetic variation within these species. The benefits from trees and their genetic resources are, however, often not well quantified because trade is frequently outside formal markets, there is a multiplicity of species and ways in which trees are used and managed, and genetic diversity within species is frequently not given proper consideration. We review here what is known about the value of trees to rural communities through considering three production categories: non-timber products harvested from trees in natural and managed forests and woodlands; the various products and services obtained from a wide range of trees planted and/or retained in smallholders' agro-forestry systems; and the commercial products harvested from cultivated tree commodity crops. Where possible, we focus on the role of intra-specific genetic variation in providing support to livelihoods, and for each of the three production categories we also consider wider conservation and sustainability issues, including the linkages between categories in terms of management. Challenges to 'conventional wisdom' on tree resource use, value and management – such as in the posited links between commercialisation, cultivation and conservation – are highlighted, and constraints and opportunities to maintain and enhance value are described.
  • Article
    Full-text available
    Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world's most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however , the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when
  • Article
    Full-text available
    Products and services provided by trees in forests and farmland support the needs and promote the wellbeing of hundreds of millions of people in the tropics. Value depends on managing both the diversity of tree species present in landscapes and the genetic variation within these species. The benefits from trees and their genetic resources are, however, often not well quantified because trade is frequently outside formal markets, there is a multiplicity of species and ways in which trees are used and managed, and genetic diversity within species is frequently not given proper consideration. We review here what is known about the value of trees to rural communities through considering three production categories: non-timber products harvested from trees in natural and managed forests and woodlands; the various products and services obtained from a wide range of trees planted and/or retained in smallholders’ agroforestry systems; and the commercial products harvested from cultivated tree commodity crops. Where possible, we focus on the role of intra-specific genetic variation in providing support to livelihoods, and for each of the three production categories we also consider wider conservation and sustainability issues, including the linkages between categories in terms of management. Challenges to ‘conventional wisdom’ on tree resource use, value and management – such as in the posited links between commercialisation, cultivation and conservation – are highlighted, and constraints and opportunities to maintain and enhance value are described.
  • Article
    The ecosystem services provided by tropical forests are affected by deforestation. Territorial management strat- egies aim to prevent and mitigate forest loss. Therefore, modeling potential land use changes is important for for- est management, monitoring, and evaluation. This study determined whether there are relationships between forest vulnerability to deforestation (potential deforestation distribution) and the forest management policies applied in the Ecuadorian Amazon. Proxy and underlying variables were used to construct a statistical model, based on the principle of maximum entropy that could predict potential land use changes. Entropy can be seen as a measure of uncertainty for a den- sity function. Receiver operating characteristics (ROC) analysis and the Jackknife Test were used to validate the model. The importance of input variables in the model was determined through: Percent Contribution (PC) and Permutation Importance (PI). The results were compared with prevailing regional forest management strategies. The socioeconomic variables that provided the largest amount of information in the overall model (AUC = 0.81) and that showed most of the information not present in other variables were: “Protected areas-Intangible zone” (PC = 24%, PI = 12.4%), “timber harvesting programs” (PC = 21.7%, PI = 4.7%), “road network” (PC = 18.9%, PI = 7.7%), and “poverty rate” (PC = 3.7%, PI = 6.1%). Also, the biophysical variable “temperature” (PC = 7,9%, PI = 22.3%) pro- vided information in the overall model. The results suggested the need for changes in forest management strategies. Forest policies and management plans should consider integrating and strengthening protected areas and intangible zones, as well as restricting timber harvesting in native forest and establishing forest areas under permanent management. Furthermore, the results also suggested that financial incentive programs to reduce deforestation have to be evaluated because their present distribution is inefficient. In this context, conservation incentive plans need to be revised so that they focus on areas at deforestation risk.
  • Article
    Tropical rainforests harbor a high diversity of tree species, offering a potentially rich array of timber (TFP) and non-timber (NTFP) forest products. The supply of such products has been commonly evaluated at the local (plot) scale; however, little is known about how their availability and diversity change at the landscape scale, particularly in heterogeneous environments. This information is critical in designing landscape forest management programs. Here, we assess the extent to which the frequency, abundance, diversity, composition and productivity (aboveground biomass) of tree assemblages with potential forest products (PFPs) change across three landscape units (LUs) that differ in soil and topographic conditions. The study was carried out in a well-conserved old-growth tropical rainforest in southeastern Mexico. Three plots (0.5 ha each) were established per LU, in which all trees ≥ 10 cm were inventoried, taxonomically identified and assigned to eight forest product categories. General linear models, multiple regression and ordination analysis (CCA) were used to assess structural and compositional changes in the tree assemblages supplying different PFPs among LUs and along soil physicochemical gradients. More than half (94 species, 57%) of the total number of identified species (165) had one or more PFPs, mostly related to timber products. Ordination analysis showed that the abundance of species with different PFPs has a heterogeneous distribution among LUs, mostly related to changes in soil nitrogen, pH and aluminum saturation. Variation among LUs in terms of tree biomass was strongly driven by soil available phosphorus and soil physiological depth. Each LU had a different potential to provide forest products, producing a diverse mosaic of PFPs within the landscape. Decisions concerning sustainable forest management should consider such variability in the availability and diversity of forest products across landscapes, as well as the environmental factors that govern this spatial variation.
  • Article
    Full-text available
    Multipurpose NTFP species typically experience higher harvest demand because of their multiple uses, which, when combined with unsustainable land use practices, may threaten population viability. We assessed local knowledge on the uses, habitat, and population status of Mimusops andongensis and Mimusops kummel, both multipurpose NTFP species in Benin, to promote their valorization and conservation and thus sustain local knowledge on their uses for domestication issues. One hundred households were randomly selected for structured interviews for M. andongensis and 500 for M. kummel. The relationship between age, sex, and ethnic groups and the species uses was assessed using comparison and correspondence analyses. Nearly all organs of the species were used. Both species were mainly exploited for medicinal purposes but also in construction and as firewood. We found similarities in some uses of the species organs, although the species occur in different ecological zones and are used by different ethnic groups. This result should be considered for the valorization of the species. Most informants reported that populations of M. andongensis were decreasing, although some felt that they were increasing, whereas less than one-third said that M. kummel was decreasing. There were strong relationships between gender, age, and ethnic affiliation of the users and the exploited organs of both species. Potential uses exist based on both the past and current uses of the species and in comparison to other countries where they are exploited. Local ethnoecological knowledge and practices will help to valorize and conserve the species. However, further research on the species’ seed germination and propagation ability are also necessary.
  • Article
    Full-text available
    Andiroba (Carapa guianensis) is a multiple-use tree species that plays a crucial socioeconomic role across thousands of Amazonian traditional and indigenous communities. In the floodplain forests of the Amazon estuary, we partnered with local forest managers to investigate C. guianensis ecological parameters, addressing seed production rates, tree density, and size class structure across a range of environmental conditions and forest use history. C. guianensis population structure was measured in three forest types: baixio, restinga, and terra preta, differentiated by tidal influence, species dominance and composition, and edaphic conditions. We found significant differences across forest types, whereby seedling and sapling densities were higher in terra preta and adult densities were higher in baixio. Adult densities were 28.7, 23.0, and 19.5 trees/ha, and seedling densities were 22.9, 105, and 151 trees/ha in baixio, restinga, and terra preta forest types, respectively. Seed production rates varied significantly across forest types, year, size class, crown form, and crown illumination. There were higher numbers of viable seeds in terra preta versus baixio (5.5 kg and 2.6 seeds/tree/year, respectively) as well as more trees with better crown forms, more light, and larger diameter sizes. Long-term patterns of community timber management intensity by forest type significantly influenced both population structure and population-level seed production. Nonetheless, assessment of seed production for the total population suggests that the local community was collecting less than 1% of the viable C. guianensis seeds produced annually within community forest lands. This study illustrates the potential of management to impact the sustainability of an important multiple use species and shows the impact that community conservation planning and action can have on future natural resource availability.
  • Article
    Full-text available
    The conservation of ecosystems and associated services depends on an understanding of the ecological process. Research has centered on regulation services with little research in support services such as nursery habitat and provisioning of non-timber forest products (NTFP). We evaluate structural characteristics of 210 trees of ten species of ecological importance from a Colombian oak forest and their relation to Philodendron longirrhizum (Araceae) and its production of aerial roots to obtain fibers. This species was present in the majority of forest tree species, the structural characteristics of the trees were not distinguished between hosts and non hosts and the rugosity of the bark and diameter of the trunk of the host species influenced the number of total and harvestable roots. The nursery habitat offered by the oak forest results from the mechanism that P. longirrhizum uses to climb over a wide variety of hosts, and the provisioning service is fostered by larger host trees that favor the production of roots. For the management of P. longirrhizum we suggest the establishment of individuals over the majority of trees if the aim is the enrichment and the establishment of individuals on larger trees if the aim is to increase the production of fiber.
  • Chapter
    Full-text available
    Globally, 1.5 billion people use or trade non-timber forest products (NTFPs) with the majority of NTFP use and trade occurring at local and regional scales, generally invisible to researchers and policy makers. NTFPs cannot be measured by monetary estimations alone, as they have significant subsistence and sociocultural importance and are commonly one part of multifaceted, adaptive livelihood strategies. In spite of low-cost substitutes, both rural and urban people continue to use select forest resources for medicine, crafts, rituals, and food. And as drought, disease, famine, and conflict escalate globally, growing numbers of displaced and marginalized people depend upon forest resources for survival. In general, forests managed for timber and NTFPs retain more biodiversity and resilience than forest plantations or forests managed for industrial timber. Forests that harbor NTFPs also protect ecosystem services such as hydrological functions and soil retention and act as a buffer against climate variability. Land use change through logging, fire, and agribusiness is contributing to the degradation of forests, resulting in declining access to NTFPs for local communities. Land stewards can mitigate detrimental impacts to NTFPs by employing multiple-use management practices that emphasize ecosystem services and community needs in addition to traditional forestry outputs (timber and non-timber). For multiple-use forestry to be applied broadly, forest policies need to be cross-sectoral and scale sensitive to lessen regulatory obstacles for small holders and for common pool/property systems. In addition, forestry training needs to include a stronger social focus and improved understanding of the ecology, use, and societal and ecosystem service values of NTFPs.
  • Thesis
    Full-text available
    The floodplain forests are dynamic ecosystems energetically open and with a great biodiversity associated with its flora. These forests are producing a variety of timber and non-timber products, this is due mostly species of multiple uses. Pentaclethra macroloba (Willd.) Kuntze is a species of multiple uses, typical of the Amazon estuary, with great potential for oil production because the oil extracted from its seeds has medicinal properties and dermatological. The aim of this work was to study the dynamics and the spatial distribution of populations of P. macroloba to support in strategies of the management and conservation of the species. The study of population dynamics was conducted in permanent plots, linked to the project FLORESTAM, installed in three areas of floodplain forest in the city of Mazagão, southwest state of Amapá. In the area of Embrapa-AP (“Estação Experimental do Mazagão, located in the city of Mazagão, Amapá, Brazil) was conducted study the spatial distribution. For the study of dynamic were conducted four inventories during the years 2011, 2012, 2013 and 2014. In the first inventory were measured all trees with DBH ≥ 5 cm. Was performed one georeferencing of all the trees with the aid of a GPS. To analyze the spatial distribution was used function K univariate Ripley, under the null hypothesis of complete spatial randomness. Were created envelopes of confidence from 1000 permutations. The function k was transformed to the function L. The annual mortality rate was 3.72% and the recruitment was 0.56%. The annual rate of mortality exceeded recruitment, indicating that the natural regeneration of the species may be being suppressed by some environmental force or anthropogenicThe population showed aggregated patterns at all scales. The smaller diameter classes are distributed in the aggregate and larger classes are randomly distributed in the area. Mortality of individuals occurs randomly. The diameter distribution of the population followed an atypical pattern, with fewer individuals in the initial classes. The annual periodic increment obtained was 0.55 cm.ano-1. Conservation strategies should be directed to the management of natural regeneration of the species. The spatial distribution pattern displayed by the population is the result of interactions that occur between the species and its habitat.
  • Article
    Full-text available
    The Special Issue of International Forestry Review, Smallholders and forest landscape transitions: Locally devised development strategies of the tropical Americas brings together a number of papers on the role of smallholders in rural development. Collectively the papers demonstrate that while there is opportunity to more actively engage smallholders in local development and environmental protection of tropical America, this requires major changes in policy design and implementation. Within the prevailing policy frameworks only a smaller proportion of smallholder families can become economically successful, providing they receive the right support. If policy frameworks are better adapted to the needs and capacities of smallholders, their role in regional sustainable development can be significantly boosted. Whether such a shift of the policy framework is likely in a world where relevant policy mechanisms are dominated by decision makers representing the interests of the societies in urban and developed contexts is an open question. The global community will increasingly be faced with the severe effects of climate change, poverty migration, financial crises and food insecurity, which gives grounds for a cautious optimism that more integrative approaches to rural development will be pursued that put smallholders of tropical America and elsewhere, and nature at the centre.
  • Article
    Full-text available
    Contemporary conservation interventions must balance potential trade-offs between multiple ecosystem services. In tropical forests, much attention has focused on the extent to which carbon-based conservation provided by REDD+ policies can also mitigate biodiversity conservation. In the nearly one-third of tropical forests that are community owned or managed, conservation strategies must also balance the multiple uses of forest products that support local livelihoods. Although much discussion has focused on policy options, little empirical evidence exists to evaluate the potential for trade-offs among different tropical forest value components. We assessed multiple components of forest value, including tree diversity, carbon stocks, and both timber and nontimber forest product resources, in forest communities across the trinational frontier of Brazil, Peru, and Bolivia. We installed 69 0.5-ha vegetation plots in local communities, and we characterized 15 components of forest value for each plot. Principal components analyses revealed two major axes of forest value, the first of which defined a trade-off between diversity of woody plant communities (taxonomic and functional) versus aboveground biomass and standing timber volume. The second axis described abundance of commercial species, with strong positive loadings for density of timber and nontimber forest products, including Brazil nut (Bertholletia excelsa) and copaiba oil (Copaifera spp.). The observed trade-off between different components of forest value suggests a potential for management conflicts prioritizing biodiversity conservation versus carbon stocks in the region. We discuss the potential for integrative indices of forest value for tropical forest conservation.
  • Article
    Full-text available
    This study assessed the abundance of and access to tree species (Ozigo, Dacryodes buettneri; and Abam, Gambeya lacourtiana) that yield edible fruits to villagers and timber to the logging industry in and around a logging concession in Gabon. Participatory mapping combining GPS coordinates and interviews was carried out with 5 female and 5 male collectors in each of two villages within or adjacent to the logging concession. Precommercial and harvestable (>70 cm dbh) Ozigo and Abam trees, as well as their stumps, were also quantified on 20 five ha plots in the 2012 cutting area of the concession and on 21 five ha plots on 10 km transects from each village. Distances to 59 Abam and 75 Ozigo from which fruits were collected ranged from 0.7 to 4.46 Km from the village centres. Most collections were by mixed groups made up of men, women and children (54%) at an average of 1.21 ± 0.09 km; or by men and women (18%) at 2.21 ± 0.15 km; or women and children (14%) at 4.03 ± 0.22 km from the village. Almost 28% of all of the collection trees were inside the logging concession boundaries but outside the village agricultural zone, 43% were inside the village agricultural zone, and 29% were outside the logging concession. Only 33% of Ozigo collection trees had reached commercial size while 75% of Abam trees had. No stumps were found on any sample plots, probably reflecting the ban on felling Ozigo which was in effect at the time; and the relatively low commercial value of Abam. Densities of precommercial Ozigo trees in the cutting area were more than double their densities around the villages (236.0 ± 20.3100 ha⁻¹and 96.6 ± 17.2100 ha⁻¹, respectively), while densities of harvestable Ozigo trees were 7 times higher in the cutting area than around villages (120 ± 20.2100 ha⁻¹and 17.1 ± 3.4100 ha⁻¹respectively). This probably reflects past and current anthropogenic pressures around the villages, including logging and land clearance for agricultural fields. Densities of precommercial Abam were almost four times higher around the village (22.3 ± 5.6 and 6.0 ± 2.9) than on the cutting area. Villagers did not record a decline in availability of or access to these fruits over the past 5 years, suggesting little or no immediate conflict between timber production and access to fruits from these trees.
  • Chapter
    Globally, 1.5 billion people use or trade non-timber forest products (NTFPs) with the majority of NTFP use and trade occurring at local and regional scales, generally invisible to researchers and policy makers. NTFPs cannot be measured by monetary estimations alone, as they have significant subsistence and sociocultural importance and are commonly one part of multifaceted, adaptive livelihood strategies. In spite of low-cost substitutes, both rural and urban people continue to use select forest resources for medicine, crafts, rituals, and food. And as drought, disease, famine, and conflict escalate globally, growing numbers of displaced and marginalized people depend upon forest resources for survival. In general, forests managed for timber and NTFPs retain more biodiversity and resilience than forest plantations or forests managed for industrial timber. Forests that harbor NTFPs also protect ecosystem services such as hydrological functions and soil retention and act as a buffer against climate variability. Land use change through logging, fire, and agribusiness is contributing to the degradation of forests, resulting in declining access to NTFPs for local communities. Land stewards can mitigate detrimental impacts to NTFPs by employing multiple-use management practices that emphasize ecosystem services and community needs in addition to traditional forestry outputs (timber and non-timber). For multiple-use forestry to be applied broadly, forest policies need to be cross-sectoral and scale sensitive to lessen regulatory obstacles for small holders and for common pool/property systems. In addition, forestry training needs to include a stronger social focus and improved understanding of the ecology, use, and societal and ecosystem service values of NTFPs.
  • Article
    The Brazilian Amazon is a significant source of timber as well as a rich source of non-timber forest products (NTFPs) such as medicinal barks, oils and fruits. Lack of quantity, quality, uniformity and price as well as a lack understanding of NTFPs socioeconomic, cultural or spiritual value and function in societies relegates them to a marginal economic status eclipsed by timber. The data vacuum for most NTFPs is contrasted by the large amount of timber-specific data available for many logged species. Such data sources can offer insights into the extraction level and locations of a subset of species that are valued for both timber and NTFPs. These are referred to as ‘conflict-of-use’ species. In this article we examine three such species, focusing on the Amazonian state of Pará. Pará is situated in the Brazilian “arc of deforestation” and the state accounts for 47% of all timber produced in the Legal Amazon. We describe three highly-utilized Amazonian NTFPs currently logged commercially: (1) Cumuru, Dipteryx odorata, which bears a seed yielding an essential oil employed in the perfume industry and providing income and medicine to rural families; (2) Amapá amargoso, Parahancornia fasciculata, which produces a powerful exudate used as a treatment of respiratory diseases; and (3) Uxi, Endopleura uchi, which produces a nutritious fruit consumed by humans and wildlife. We analyze data from the timber industry indicating the rate of extraction of these species, as well as data regarding their use and value as NTFPs. Results indicate that extraction of these species in logging frontiers contributes to declining access. However, in communities with links to markets, undocumented management systems supply the increasing demand for NTFPs in urban areas. While there are no formal management plans for these species and few scientific attempts made to manage them, small holders have developed local knowledge and innovative techniques to improve productivity, increase density and create multiple-use systems in the face of growing land use pressures.Highlights► Timber extraction in Amazonia, Brazil includes substantial non-timber forest species (NTFPs). ► Data on timber extraction can shed light on a subset of “conflict of use” species. ► Three widely used NTFPs have been locally exhausted in old logging frontiers. ► Near markets, some small holders have developed innovative multiple use management systems.
  • Book
    Full-text available
    El desarrollo del “Manual de identificación de especies maderables objeto de comercio en la Amazonia colombiana”, es una herramienta técnica que permite a las autoridades ambientales, policivas y judiciales disponer de una serie de elementos que faciliten la identificación de especies maderables objeto de comercio que se encuentran incluidas en los Apéndices de la CITES y/o bajo algún grado de amenaza en el país. En términos generales, cuando las autoridades ambientales realizan controles a la movilización de madera, recurren al nombre comercial o común con que se denota en la región. Posteriormente se pueden conjugar elementos como la procedencia, la información del permiso de movilización y la utilización de características generales de la madera para tener una aproximación al nombre científico de la especie. En todos los casos se evalúa la legalidad de movilización y comercio, este o no listada la especie en los Apéndices de la CITES.
  • Article
    Full-text available
    Millions of people worldwide depend on the harvest of non-timber forest products (NTFP) for their livelihoods, and the importance of understanding the complex relationships between NTFP harvest and conservation is increasingly recognized. This study employs a cross-disciplinary, regional approach to identify some of the links between patterns of harvest, trade, and conservation of one of South India's most heavily harvested resins, Canarium strictum Roxb. (Burseraceae), or black dammar. We focus on indigenous communities in the Nilgiri Biosphere Reserve (NBR) and ask: How is C. strictum tapped and is there variation across communities? How is C. strictum resin sold and bought, and what trade routes are involved? What are the impacts of tapping on C. strictum trees and population structure? We carried out interviews and focus-group discussions with harvesters in eight villages in three different regions, and with buyers and traders inside and outside of the NBR. We also established twenty-two 20 × 20 m plots to document population structure. Three broad resin-harvest strategies were identified: collection from natural fissures, tapping using incisions, and tapping using incisions and fire, each practiced in a different region. However, within each strategy there was large variation in tapping frequency and timing, tenure practices, and resin quality. The loss of tree tenure in some areas has led to a higher frequency of tapping and to the production of lower quality, lower value resin. Factors driving changes in both tenure and tapping strategies include rising commercial demand and value, pressure from outside harvesters, changes in livelihood strategies, and habitat destruction. Tapping leads to elevated mortality of C. strictum adults, with firetapping have a greater negative impact than tapping with no fire. The combination of social and ecological approaches used here provides insight on strategies for better conservation of C. strictum. These include the promotion of tapping and sale of only high-grade resin-which is a good indicator of sustainable harvest - enrichment planting to help address some of the underlying causes of overharvest, and sparing of some trees for increased reproduction. Copyright © 2008 by the author(s). Published here under license by the Resilience Alliance.
  • Article
    Full-text available
    In the upper basin of the Botanamo river, at Imataca Forest Reserve (County Sifontes, Bolívar State) native and indigenous communities live together using non timber forest products (NTFP) as means of subsistence. Personal interviews were conducted in 310 households, using a semi-structured questionnaire to characterize the NTFP tree species. The specific uses were: Medicine (35%), food (32%), fiber and handicrafts (13%), fodder (11%), colorant (7%) and ornamental (2%); near of 75% of the sampled population meets their basic needs using forest products. It is noteworthy that 76% of tree species used as NTFPs are native to local forests, reflecting a high degree of knowledge and use of natural forest by the native communities living in the sector.
  • Article
    In the Atlantic lowland tropical rainforests of the Rio San Juan region, Nicaragua, we are conducting applied vegetation community analyses within an attempt to integrate non-timber forest products with natural forest management. Two long-term sampling plots were evaluated: one primary tropical rainforest plot before and 1 yr after selective logging, and another plot 9 yr after selective logging with and without Hutchinson Liberation Silviculture treatment (in which selected young trees are released from competition for light). The purpose of the study was to evaluate changes in community ecology variables with logging, damage, regeneration, and silviculture, both for useful plant species and for the plant community as a whole, and to evaluate the potential for incorporating non-timber forest product management with silvicultural management. One year after logging there was an increase in species (from $19 \pm 5$ to $33 \pm 10$ species/$10 m^2$) and density (from $42 \pm 19$ to $120 \pm 60$ plants/$10 m^2$) due to establishment or increase of secondary species (vines, grasses, balsa, cecropia) and to seedling regeneration after logging. The more severe the logging damage the more severe were the effects on some variables, particularly increased densities of vines and secondary species. Forest plots 9 yr post-harvest appeared to be returning to pre-harvest levels of species ($28 \pm 6$ species/$10 m^2$) and density ($76 \pm 21$ plants/$10 m^2$). Hutchinson Liberation Silviculture, while promoting growth of desired timber, did not significantly affect either non-timber forest products or the basic physiognomy of the forest. These results are contrasted with other silvicultural systems, particularly the Hartshorn Strip Clearcut, in which regeneration was dominated by resprouts and the proportion of vines was even higher. Hutchinson Liberation Silviculture provides the potential for simultaneous management of non-timber forest products, and moreover, non-timber forest product management holds the potential for significantly reinforcing silvicultural management.
  • Article
    Full-text available
    The main objective of this pape ris to examine the economic dynamics of forest products typically undergoes three distinct development plases: expansion, stagnation, and decline. Four main factor contribute to the decline od forest products extraction: (1) the inelastic supply of forest product, (2) harvest rates that exceed regeneration rates, (3) the domestication of the forest product, and (4) the development of industrial substitutes for the product. Other variables that affect extraction include expansion of the agricultural frontier and population increase which reduce the area of forest cover available for extraction, independently of its profitability. The economic dynamics of forest product extraction must be understood to successfully carry out conservationist and preservationist measures, and to secure equity for future generations.
  • Article
    Full-text available
    Many governmental and non-governmental development organisations (NGOs) invest considerable efforts to support forest dependent people for the extraction and commercialization of non-timber forest products (NTFP) to generate income in an ecologically sustainable way. But success so far has been quite modest. Many of the families abandon these initiatives once the external support ceases. This paper critically reflects on the expectations and concerns regarding this kind of development projects by in-depth analysing a project for the commercialization of vegetal oils by the traditional community of Pedreira, situated in the Eastern Brazilian Amazon, which received intensive government-lead support. The study explores the motivations of the participating families, how the project influenced production schemes, and what have been the specific benefits for participating families and the overall consequences for the entire community. Findings indicate that the analyzed NTFP project, on the basis of overoptimistic expectations, strongly invested in the re-organisation of local production schemes without adequately considering the socio-environmental reality, capacities and interests of the community. As a consequence, the proposed social-productive model was not necessarily meaningful to all local people and even had detrimental effects. Baixando à Terra: uma análise crítica de um projeto de comercialização de produtos florestais não madeireiros em uma comunidade da Amazônia Oriental Resumo -Muitas organizações governamentais e não governamentais (ONGs) investem esforços consideráveis para apoiar as populações dependentes da floresta, na extração e comercialização de produtos florestais não madeireiros (PFNM), para gerar ganhos econômicos de forma ecologicamente sustentável. Porém, o sucesso destes esforços agora tem sido bastante modesto, sendo que muitas das iniciativas que recebem apoio externo são abandonadas quando o apoio acaba. Este artigo é uma reflexão crítica sobre as expectativas e as preocupações que surgem deste tipo de projetos de desenvolvimento, analisando em profundidade um projeto para a comercialização de óleos vegetais pela comunidade de Pedreira, situada na Amazônia Oriental Brasileira, que tem recebido apoio intensivo por parte do governo. O estudo explora as motivações das famílias que participaram do projeto, a forma como o projeto influenciou nos processos de produção e quais foram os benefícios para as famílias participantes assim como as consequências globais para toda a comunidade. Os resultados revelam que o projeto de comercialização de PFNM analisado, baseado em expectativas exageradamente otimistas, investiu fortemente na reorganização dos esquemas de produção locais, sem considerar adequadamente a realidade sócioambiental, as capacidades e interesses das comunidades. Como consequência, o modelo sócio-produtivo proposto não necessariamente teve efeitos significativamente interessantes para todos os atores locais e até causaram prejuízos para eles.
  • Article
    Multiple-use forest management, which includes timber, non-timber forest products, and environmental services, is considered a promising tropical conservation and development strategy. In the tri-national frontier region of Madre de Dios (Peru), Acre (Brazil), and Pando (Bolivia) in Western Amazonia, we evaluated perceptions of representatives from four stakeholder groups – communities, industries (Brazil nut and timber), non-governmental organizations, and government agencies – on integrated management of timber and Brazil nuts (from the tree species Bertholletia excelsa) at multiple scales. A strengths, weaknesses, opportunities, and threats (SWOT) analysis in combination with an analytic hierarchy process (AHP) was used to accomplish this task. Overall, results showed distinct differences in perceptions among stakeholder groups both within and among countries in pursuing multiple-use forestry strategies. Although many stakeholder groups held positive perceptions about multiple use of Brazil nuts and timber, several limitations were associated with implementation of this model. For instance, policy barriers and high management costs were considered the main weaknesses throughout the region. In Madre de Dios and Pando, logging damage to Brazil nut stands was the dominant threat, whereas in Acre, the main threat was reinvestment of forestry income into cattle. Our work shows that despite the high potential for and positive views of many stakeholders in pursuing integrated management of Brazil nut and timber, specific policy, economic, and technical limitations must first be addressed. To this end, we provide recommendations for promoting this multi-use forestry model in the future.
  • Article
    Full-text available
    As a result of government-sponsored colonization, more than 500 000 km 2 of the Brazilian Amazon is managed by settlement households. By law, 80% of this land must remain as standing forest. In this study, we examine the potential for timber harvesting through company–community partnerships (CCPs) as a means to increase forest-based revenue without compromising household use of non-timber forest products (NTFPs). Using participatory rural appraisal, resource diaries, and household questionnaires, we study the impacts of CCP logging contracts on livelihoods, including household income and NTFP harvests. Our results show that annual household income from the CCP logging is equivalent to more than 8 years of household gross income from agricultural production. We also found that there were no significant differences in NTFP harvests between households with CCP logging and those without. In CCP-logging communities, households caught 11.9 ± 13.6 game animals, totaling 74 ± 88 kg of game meat. In the communities without CCP, households caught 9.5 ± 13.0 game animals, totaling 73 ± 172 kg of game meat. Annual forest fruit harvests averaged 9.8 ± 13.2 kg in CCP-logging communities and 13.5 ± 15.9 kg in non-CCP communities. Overall, the CCPs brought improvements in household income without compromising NTFP harvests.
  • Article
    Full-text available
    The potential for combining timber and non-timber forest product extraction has been examined in the context of diversified forest management. Many tropical forests are exploited both commercially for timber and by forest-dependent communities for non-timber forest products (NTFPs). Divergences between these two uses may have significant implications for forest-dependent livelihoods. This article gathers existing examples of conflicts and complementarities between selective logging and non-timber uses of forest from the livelihood perspective. Additionally it draws on three case studies from Brazil, Cameroon and Indonesia to examine by what mechanisms, and to what extent, logging impacts forest resources of livelihood importance, as well as to consider how factors such as logging regime and forest management system may mediate such influences. By doing so we aim to shed further light on a relatively unacknowledged issue in tropical forest management and conservation.Four specific mechanisms were identified; conflict of use and the indirect impacts of logging being those most commonly implicated in negative effects on livelihood-relevant NTFPs. Eighty two percent of reviewed articles highlighted negative impacts on NTFP availability. Examples of positive impacts were restricted to light demanding species that respond to the opening of forest structure and typically represent a small subset of those of livelihood value. Despite considerable impacts on livelihoods, in all three case studies we found evidence to support the potential for enhanced compatibility between timber extraction and the subsistence use of NTFPs. Drawing on this evidence, and findings from our review, we make specific recommendations for research, policy and management implementation. These findings have significant implications for reconciling timber and non-timber uses of tropical forests.
  • Article
    Full-text available
    Foram analisados agrupamentos florísticos entre comunidades arbóreas localizadas em diferentes locais do Estado do Pará, por meio de um banco de dados composto por 24 inventários em florestas de terra firme e 10 em floresta de várzea. Utilizaram-se o índice de Jaccard no cálculo da matriz de similaridade florística, que foi transformada em matriz de distância euclidiana, e o Método de Ward na definição dos grupos. Pelos resultados, foi possível concluir que as composições florísticas das florestas de várzea e terra firme são bem distintas. Poucas espécies ocorrem nos dois ecossistemas; a floresta de terra firme apresenta maior riqueza de espécies arbóreas que a floresta de várzea; houve tendência das florestas de terra firme em se agruparem mais pela situação antrópica e proximidade geográfica do que as florestas de várzea; em geral, as florestas agruparam-se em ordem decrescente de importância dos fatores: saturação hídrica do solo, situação antrópica e proximidade geográfica.
  • Article
    Full-text available
    The aim of this study was to gather information on timber trees occurring in a non-flooded forest near Manaus and to make an attempt to rank these species according to their succession in the forest. The ranking would be helpful in modeling the forest's dynamics, for forest conservation, management and rehabilitation of degraded areas. The group studied was formed by 60 botanical species belonging to 42 genera and 18 families. In a general view, seed size was >0.5cm3 (69% of the species), seed dispersal by animals predominated (60%), germination occurred within a period of up to 3 months (69%) and wood density was high (>0.8 g/cm3 in 52%). However the set of characteristics did not permit a clear ranking of all species, as characteristics thought to be typical for pioneer or climax occurred together on the same species in 24 of the selected trees (40%). Wood density and fruiting regularity showed to be of little use for classification, as well as the presence of seed dormancy, as dormancy was detected in all successional groups. On the other hand, a distinction between the various types of seed dormancy was helpful to separate the groups. The following seed related characteristics may be recommended for classification: dispersal type, reserve quantity, desiccation tolerance and dormancy types. The attempt of ranking the timber species according to their role in natural succession showed that most had a set of characteristics typical of mature forest. Only a few species had earlier successional characteristics, and probably have higher resistance to forest disturbance.
  • Article
    Community perceptions are used to assess the effects of logging on non-timber forest product (NTFP) extraction in a case study Community in the Tapajos-Arapiuns Extractive Reserve, Para, Brazil. Rapid rural appraisal (RRA) is used to explore changes in community harvests of, and access to, the most important NTFPs. Community estimates showed a decline in fruit and nut harvests after conventional logging (CL) (with a forest-gate value reduction of 86%). According to community estimates, hunting rates declined 62%, after CL. Changes in abundance and accessibility of NTFP resources were seen as the key factors affecting harvest rates. Overall, the community held a negative impression of the effects of commercial logging on both NTFP extraction and community life in general.
  • Article
    Full-text available
    Many claims have been made concerning the use of NTFPs as part of development and conservation strategies. Important amongst these is that because NTFPs play an important part in household incomes they can be used to raise the perceived value of forests and thus provide incentives for more sustainable use of the forest estate. However, migrant communities living around forest margins have often been perceived as groups of people most likely to take advantage of the free goods provided by forests in a way that degrades the forest environment as short term benefits are maximised over long-term sustainability. Empirical evidence from the forest zone of south-west Cameroon suggests that for many migrant communities NTFPs are not a significant part (no more than 6%) of household total income and that poorer groups seek diverse livelihood strategies that are not predicated on natural resource use. Whilst richer groups may continue to rely on sources of income from the forest and NTFPs may make up to 15% of household income, for rich and poor alike the value derived from NTFPs is generated by secondary forest and forest fallow rather than less disturbed forest that has been the focus of conservation interest. The view is put forward that forest managers and international donors interested in conservation and development need to reassess the potential contribution of NTFPs in poverty alleviation strategies, and acknowledge that forest conservation priorities of local communities require policies and management systems focused on 'sustainable systems for production of livelihood benefits' rather than protectionist approaches to areas traditionally defined as valuable forest.
  • Article
    Full-text available
    Evaluations of initial attempts at NTFP certification reveal substantial ecological, socioeconomic and administrative obstacles for forest product collectors. However, the problem of lack of sufficient scientific understanding of the ecology of NTFP species can sometimes be addressed by recognition and documentation of traditional ecological knowledge (???). Increasing local input regarding NTFP resource inventories, production/yield, development of criteria and indicators, and monitoring sustainable management can offer valuable contributions to the certification process. Besides benefiting efforts at certification, such attention can foster needed appreciation and local documentation of traditional ecological knowledge. Cases from Namibia, the Philippines and Brazil are used to demonstrate how local initiatives in sustainable resource management strengthened communities understanding of their resource base. The process of sharing ecological knowledge locally can catalyze broader objectives of community empowerment and sustainable management—with or without a seal.
  • Data
    Full-text available
    a b s t r a c t The potential for combining timber and non-timber forest product extraction has been examined in the context of diversified forest management. Many tropical forests are exploited both commercially for tim-ber and by forest-dependent communities for non-timber forest products (NTFPs). Divergences between these two uses may have significant implications for forest-dependent livelihoods. This article gathers existing examples of conflicts and complementarities between selective logging and non-timber uses of forest from the livelihood perspective. Additionally it draws on three case studies from Brazil, Camer-oon and Indonesia to examine by what mechanisms, and to what extent, logging impacts forest resources of livelihood importance, as well as to consider how factors such as logging regime and forest manage-ment system may mediate such influences. By doing so we aim to shed further light on a relatively unac-knowledged issue in tropical forest management and conservation. Four specific mechanisms were identified; conflict of use and the indirect impacts of logging being those most commonly implicated in negative effects on livelihood-relevant NTFPs. Eighty two percent of reviewed articles highlighted negative impacts on NTFP availability. Examples of positive impacts were restricted to light demanding species that respond to the opening of forest structure and typically repre-sent a small subset of those of livelihood value. Despite considerable impacts on livelihoods, in all three case studies we found evidence to support the potential for enhanced compatibility between timber extraction and the subsistence use of NTFPs. Drawing on this evidence, and findings from our review, we make specific recommendations for research, policy and management implementation. These find-ings have significant implications for reconciling timber and non-timber uses of tropical forests.
  • Article
    Full-text available
    This paper deals with growth rates of trees > 5cm dbh over an eight-year period from 257 species at the Tapajós National Forest. The discussion is centred on the behaviour of the forest after logging. Permanent sample plots were established in 1981 and measured at the first time. The area was logged in 1982. Measurements after logging occurred in 1983, 1987 and 1989. Considering all species together, diameter increment was similar for both intensities of logging until five years after logging. Light-demanding species showed significantly higher growth rates than shade-tolerant species in the logged forest, with greater increment in the heavier treatment intensity. Commercial species also had higher growth rates in the heavier logged area, although those were significantly different only in the period from one to five years after logging. In the undisturbed forest, growth rates increased with increasing dbh size. At species level, growth rate varied between and within treatments, as well as between trees within species, depending mainly on degree of canopy opening. The logging favoured the growth of commercial species, chiefly the light-demanders. Therefore, if the same growth conditions continue being given, for example by silvicultural treatments, to those species of commercial interest, the forest would reach a stock available for harvesting around year 30 after logging. However, the high variation in increment rates indicates that an eight-year period is not sufficient to allow predictions on cutting cycles or polycyclic management systems for the study forest.
  • Article
    The success of multiple forest management systems is contingent on a variety of social, economic, biophysical, and institutional factors, including the integration of timber and non-timber forest product (NTFP) extraction and management. Selective logging for timber is increasingly taking place in forests where the collection of Brazil nuts, a high-value Amazonian NTFP, also occurs. We report on logging damage to Brazil nut trees in three certified timber concessions in Northern Bolivia from which timber is harvested using reduced-impact logging (RIL) guidelines and nuts are gathered yearly from the ground by local people. Observed frequencies of logging damage to Brazil nut trees were low, likely mirroring the low intensity of timber harvesting (∼0.5trees/ha and ∼5m3/ha) being currently applied across the study area. Of the trees ≥10cm in diameter at breast height about 0.1 Brazil nut trees and 0.4 timber species per hectare suffered some degree of logging damage. Crown loss was the predominant damage type for Brazil nut trees accounting for 50% of all damage. In spite of the observed low rates of tree damage, we further recommend that RIL guidelines be amended to include the pre-harvest marking of pre-reproductive Brazil nut trees along with the future crop trees of commercial timber species. Further refining directional felling to reduce crown damage to Brazil nut trees would also serve to help maintain nut yields in the long term.
  • Article
    In Bolivia’s Northern Amazon, forests long used for the extraction of non-timber forest products (NTFPs) are now experiencing increased logging. The extraction of timber and economically important NTFPs such as Brazil nuts (from the emergent forest tree Bertholletia excelsa) is occurring in the same forests and provides a clear opportunity to integrate management decisions and planning. Bolivia’s forestry legislation allows, in principle, the management of multiple forest resources. However, there is little evidence that the opportunity has led to greater integration of management decisions and practice. Actually, management of each resource is typically carried out by different stakeholders with resident families responsible for Brazil nut gathering while logging companies carry out the timber harvest. This paper analyzes community forest management plans in Northern Bolivia to examine whether community residents participated in the development and implementation of the timber management plans, and the extent to which proponents of timber management plans attempted to integrate Brazil nut management into timber harvesting. The research draws on analysis of approved timber management plans for community forests and focus group interviews with residents in selected forest communities. Based on observations, the paper concludes that multiple-use management in these forests could be improved by strengthening community level institutions by confirming their authority over timber management operations and by building capacity to oversee and monitor the extraction activities of loggers working on their land.
  • Article
    Developing sustainable extractive industries in otherwise intact tropical forest regions requires a sound understanding of the production potential of key resource populations. The oleoresin extracted from Copaifera trees is an economically important non-timber forest product harvested throughout the lowland Amazon basin. We studied oleoresin extraction from four species of Copaifera trees with known harvest histories within two contiguous extractive reserves in western Brazilian Amazonia. We conducted a large-scale experimental harvest of 179 previously unharvested Copaifera trees, in both seasonally flooded (várzea) and adjacent unflooded (terra firme) forests. The likelihood of trees yielding any oleoresin was principally determined by their species identity: C. multijuga was the only species to regularly yield oleo-resin (70% of trees). Yield volumes varied both amongst species and forest types: C. multijuga (restricted to terra firme forest) had the highest mean yield of 505 ml, whilst C. guyanensis produced higher volumes of oleoresin in várzea (139 ml) than terra firme (15 ml) forest. Intraspecific differences were driven mainly by tree size. To assess extraction sustainability, we reharvested a sample of C. multijuga trees and compared the oleoresin production of 24 conspecific trees that had been initially harvested one year previously with that of 17 trees initially harvested three years previously. Reharvested trees produced just 35% of the oleoresin volume compared to that when originally drilled, but this response was not affected by the time interval between consecutive harvests. We demonstrate that, within a population of Copaifera, both morphological and environmental factors restrict total productivity; consideration of these factors should inform sustainable management practises. We additionally raise methodological considerations that may improve the comparability of studies.
  • Article
    a b s t r a c t Successful management of tropical forest resources depends upon an understanding of their patterns of density and spatial distribution, since these affect the potential for harvesting. The variation in these pat-terns across different spatial scales has rarely been explored. We assessed the extent to which different spatial scales are useful in understanding resource distribution, using the example of an economically-significant tropical tree genus, Copaifera, which is valued across Brazilian Amazonia for its medicinal oleo-resin. We mapped the spatial distribution of Copaifera trees at three nested spatial scales: basin-wide (across Brazilian Amazonia), landscape (across two contiguous extractive reserves) and local (within a 100-ha plot). Using data from our own study and an Amazon-wide forest inventory (Projeto RADAMBRA-SIL), we quantified the population distribution, density and size structure at the genus and species level at all three scales, relating these to two environmental variables – forest type and elevation. Spatial statis-tics were used to further characterize the resource at the landscape and local levels. The distribution, den-sity and adult population structure differed between species and forest types at all three spatial scales. Overall tree densities ranged from 0.37 ha –1 (basin-wide scale) to 1.13 ha –1 (local scale) but varied between forest types, with várzea containing a Copaifera tree density just 43% of that in terra firme forest at the landscape scale. Spatial distribution analyses showed significant clumping of some species, espe-cially C. multijuga which averaged 61 m between neighbouring trees. We compare our cross-scale density estimates and discuss the relative merits of studying the distribution of non-timber forest products (NTFP) at more than one spatial scale. Our results have implications for the management and extraction of this important Amazonian forest resource. Ó 2012 Elsevier B.V. All rights reserved.
  • Article
    El conocimiento ecológico local (CEL) ofrece una gama de información que los conservacionistas, profesionales en desarrollo, organizaciones no gubernamentales e investigadores valoran considerablemente. Sin embargo, CEL tiene un valor intrínseco para quienes lo poseen, ya que representa su capacidad para adaptarse y sobrevivir en áreas remotas, así como también su continuidad cultural en regiones ecológicas específicas. Este artículo describe el conocimiento etnobotánico de la sarrapia (Dipteryx odorata [Aubl.] Willd.) o tonka bean entre los habitantes de tres comunidades no-indígenas de la Cuenca Baja del Río Caura, al sur de Venezuela. Los resultados del estudio sugieren que existe una fuerte asociación entre los modos de vida de los habitantes del Caura y el ciclo anual consecutivo de esta especie. Esta asociación se demuestra en cómo la gente: 1. realiza interconexiones entre el ciclo biológico de la sarrapia y las variables climáticas y ecológicas, 2. discrimina entre los sarrapiales silvestres y cultivados, 3. proporciona estimaciones precisas sobre la producción total de almendras de sarrapia por sarrapial cada año, 4. aplica los conocimientos apropiados en el proceso de extracción y tratamiento de las almendras de sarrapia, y 5. regula el acceso establecido y los derechos de usufructo en los sarrapiales silvestres y cultivados.
  • Article
    Full-text available
    We use a simple scoring system to rank species with regard to their hypothesized ability to withstand logging impacts. Among the species that are potentially susceptible to logging impacts are Euxylophora paraensis (‘Pau Amarelo’) and Swietenia macrophylla (American Mahogany). The sawn lumber from these two species goes principally to European and North American buyers, revealing a direct link between First World consumption and possible biodiversity impoverishment in the Brazilian rain-forest. These two species, and others that might experience population reductions as a result of logging, merit special study.
  • Article
    a b s t r a c t Constraints in making multiple use forest management a more widespread land use type across the tro-pics still prevail. Technical and managerial capacities usually differ for different forest products, market opportunities and degrees of market knowledge. Local communities or small-scale forest operators face difficulties in adjusting traditional practices to implement official forestry regulations, that are usually drafted with little harmonization of different management objectives and also little consideration of local socio-ecological contexts. Strategies that optimize trade-offs, by nature more complex than trade-offs in single-commodity production systems, have been neglected. Although the available evidence suggests that formal management practices favor specialization over integration, studies that attempted to discern or draw lessons learned seem, to date, limited. This Special Issue is intended to further contribute to the knowledge related to biophysical, institutional, regulatory and socio-economic aspects influencing the design, implementation and effectiveness of multiple use management throughout the forested tropics. A few messages emerge. Although the constraints impeding the implementation of multiple use of forests differ little from the constraints in plans that only include timber, the required trade-offs in the former are expected to be more problematic. Refining the scientific basis for assessing and minimizing trade-offs at different spatial scales is warranted. As important as it may be to establish multiple use objectives from the outset and involve different stakeholders in the planning process, social learning and multi-stakeholder dialogue in the context of adaptive management are needed to maintain these objectives over time, both from the top down and the bottom up. For managers and practitioners to work on multi-ple forest use in the tropics they must consider spatial aspects in detail, from the stand to the landscape. Finally, moving from ''concept to reality'' will also require new forestry training and education approaches to keep up with the ever-growing methods for valuing and using tropical forests.
  • Article
    Full-text available
    This article analyses the density, spatial distribution, and diameter structure of two neotropical tree spe-cies, Dipteryx odorata (Aubl.) Willd. and Copaifera reticulata Ducke, in undisturbed forests, logged forests, and forests used for the extraction of Non-Timber Forest Products (NTFPs). Both species are commercially harvested for timber and non-timber products which can fetch high prices on national and international markets. In undisturbed forests, both species display a low tree density, a random adult tree distribution pattern and a flat diameter structure, or one biased towards larger trees. The random spatial distribution pattern did not vary in the three types of forests analysed, whereas individual density and diameter struc-ture did. The NTFP extraction areas exhibited the highest population densities for both species. In the logged forests, there was a lower density of very large D. odorata trees, while the areas used for D. odorata seed extraction showed a drastic reduction in the frequency of young trees. The results of this study seem to suggest that oil extraction from C. reticulata does not have any effect on the regeneration of that spe-cies, whereas D. odorata seed collection could affect the viability of populations. Ó 2012 Published by Elsevier B.V.
  • Article
    Over the past decade, shihuahuaco timber – comprising several species of Dipteryx (Fabaceae) traded internationally as “cumarú” or “Brazilian teak” – has become one of the most highly demanded types of hardwood from Peruvian Amazonia, particularly in the Chinese market. Dipteryx is an ecologically important canopy-emergent genus with widespread distribution in neotropical forests. To assess the response of Dipteryx to logging, we conducted inventories in three logging areas in the Regions of Ucayali and Loreto, Peru. The size-class distributions of Dipteryx populations in recently logged sites showed that initial post-logging conditions enhance recruitment of residual seedlings. These conditions are created by a combination of logging gaps and the activities of farmers migrating into logged lands. Through protection and liberation of shihuahuaco seedlings in post-logged forest as well as within and around agricultural fields, local residents and timber companies could favor the recovery of this valued resource. However, as logged land is increasingly converted to agriculture and pastureland, the reestablishment of mature seed trees is not assured.Research highlights▶ Initial post-logging conditions enhance recruitment of residual Dipteryx spp. seedlings in Peruvian Amazonia. ▶ Protection and liberation of Dipteryx spp. seedlings in post-logged forest as well as within and around agricultural fields could favor the recovery of this valued resource. ▶ As logged land is increasingly converted to agriculture and pastureland, the reestablishment of mature Dipteryx seed trees is not assured.
  • Article
    Full-text available
    The future of tropical forests may lie in integrating different revenue sources, such as timber, non-timber products and environmental services, to make standing forests more economically competitive with other land uses such as pasture. Therefore, analytical techniques that couple economic models with ecological understanding are an increasingly important tool to promote forested landscapes. This study explores the potential revenue associated with different harvest strategies of the multipurpose tropical tree Carapa guianensis, a species valued for both the high quality oil extracted from its seeds and its mahogany-like timber. We calculated the equal annual equivalent (EAE), a measure of profitability that annualizes net present value, of revenues and costs associated with simulations of sustainable seed and timber harvests. Our specific objectives were (1) to simulate and compare the revenue from ecologically viable seed and timber harvests of C. guianensis in stochastically varying environments; and (2) to calculate the EAE of revenues and costs from seed and timber harvest under different market prices and different oil extraction methods. We found profits from both timber and seed harvest of C. guianensis for oil production, though only when seed presses were available for oil extraction; manual oil extraction had negative returns due to intensive labor requirements. Combined profits from C. guianensis press-extracted seed oil and timber harvests were economically competitive with other common forest use activities that provide communities with cash profits. Combining extraction of NTFPs with timber may provide continuous income while forests recover volume between timber harvests. Combining this income with harvest of other resources in the context of multi-use management may be an economically viable management strategy in similar forests in Amazonia.
  • Article
    Considering the pressures on tropical forests from deforestation and the recent expansion of harvesting through forest concessions in the Brazilian Amazon, it is imperative that forest management systems are scrutinized to ensure sustainability. One of the basic problems in forest management is the correct identification of species within the forest stand. While this is a well known issue, little consideration is given to how to mitigate this problem or its affects on management practices and conservation. This paper examines the current practice of forest inventories in the Brazilian Amazon, as part of the mandatory system of reduced impact logging (RIL), using extensive forest inventory verification. The results show that the RIL management plan implemented in the project area was based on a highly inaccurate forest inventory. At least 132 species or 43.5% of all species identified after botanical checking did not appear in the forest inventory and the common practice of matching vernacular names to scientific ones proved to be severely deficient. In contrast, a high percentage of field identifications based on local people's expertise were correct. We suggest changes to current practices, including the training and use of parataxonomists, the collection of samples for verification, and stricter government control over current practices, which will achieve greater accuracy in data collection and forest management planning. Ultimately, we argue that in the current climate of extensive deforestation and forest use, it is essential that all aspects of RIL systems are reevaluated in order to achieve economic and ecological sustainability.
  • Article
    Summary 1 Primate frugivores are important seed dispersers for a large fraction of tree species in many tropical forests. The movement, diet preferences and defecation patterns pro- duced by primates may therefore strongly influence seed dispersion patterns and seed- ling recruitment success. Here we examine the pattern of seed dispersal generated by white-faced monkeys ( Cebus capucinus ) in relation to adult tree distribution in the 50-ha plot on Barro Colorado Island (BCI), Panamá. 2 Diet breadth of Cebus was remarkably wide. Over four months they consumed fruits of 95 out of an estimated 240 species available. Seeds of 67 species passed intact through the gut and 28 were spat out. 3 Dispersal effectiveness of Cebus was also high. Two Cebus groups on average spent < 10 min feeding in individual trees, had large home ranges (> 150 ha), travelled 1-3 km day − 1 and defecated seeds in small clumps throughout the day. 4 Mean dispersal distance of ingested seeds was 216 m (range 20-844 m), with the highest probability of dispersal 100-200 m from the parent plant. For six of nine species studied, the distance between defecation sites and nearest conspecific adults of seeds in faeces was not significantly different from random expectations. 5 The scattered dispersal pattern produced by Cebus suggests that this species contrib- utes relatively little to dispersal limitation ( sensu Nathan & Muller-Landau 2000) com- pared to other dispersers in the community. Long-distance dispersal by Cebus resulted in substantial movement of seeds in and out of the 50 ha plot, and suggests that inverse modelling procedures to estimate dispersal functions from trap data may not ade- quately describe dispersal patterns generated by this primate.
  • Article
    This study builds on earlier quantitative ethnobotanical studies to develop an approach which represents local values for useful forest species, in order to explore factors affecting those values. The method, based on respondents ranking of taxa, compares favourably with more time-consuming quantitative ethnobotanical techniques, and allows results to be differentiated according to social factors (gender and ethnic origin), and ecological and socio-economic context. We worked with 126 respondents in five indigenous and five immigrant communities within a forest-dominated landscape in the Peruvian Amazonia. There was wide variability among responses, indicating a complex of factors affecting value. The most valued family is Arecaceae, followed by Fabaceae and Moraceae. Overall, fruit and non-commercialised construction materials predominate but women tend to value fruit and other non-timber species more highly than timber, while the converse is shown by men. Indigenous respondents tend to value more the species used for fruit, domestic construction and other NTFPs, while immigrants tend to favour commercialised timber species. Across all communities, values are influenced by both markets and the availability of the taxa; as the favourite species become scarce, others replace them in perceived importance. As markets become more accessible, over-exploitation of the most valuable species and livelihood diversification contribute to a decrease in perceived value of the forest.
  • Article
    Full-text available
    In the present study, we describe the temporal and spatial variability in recruitment, growth, and mortality rates of seedlings and saplings of two low-density neotropical tree species, Dipteryx odorata and Copaifera reticulata in Eastern Amazonia, Brazil. As both species have important timber and non-timber uses, for each species we compare regeneration parameters among different management scenarios (sites used for timber logging, non-timber product extraction, and undisturbed forests). Results suggest that both species share similar natural regeneration characteristics. These include temporally and spatially asynchronous germination, existence of individuals that have more abundant and frequent fruit production than the average of the population and a positive influence of the mother tree crown on seedling and sapling density. The management activities analyzed did not influence the regeneration parameters of both species, which suggests that timber logging the way it was performed and current rates of D. odorata seed gathering and C. reticulata tapping at the study site are not sufficiently intense to threaten species population. However, some species characteristics, such as their reproductive strategies, light-demanding syndromes, low-dispersal ranges, and high-mortality rates of seedlings make both species vulnerable to exploitation. KeywordsAmazonia– Copaifera reticulata – Dipteryx odorata –NTFP extraction–Timber logging
  • Article
    Full-text available
    The worlds’ current food production system is focused on a limited number of crops. However, international food demand is increasingly looking for more diversified supplies. In the Venezuelan State Amazonas, the Piaroa indigenous people collect and cultivate several indigenous species with local, regional, national and even international potential. A participatory approach was used to select, in cooperation with these Piaroa people, a list of products for in-depth economic analysis and for introduction in agroforestry trials in a later phase. Seven agroforestry food products of this list were identified as underutilized. Primary data collected through consumer and trader surveys on the local markets and participatory exercises in selected Piaroa communities revealed that the main causes of underutilization are the general lack of transport, processing and market infrastructure in Amazonas; the lack of demand, due to a lack of product information; the lack of market information and cooperation between the different market chain actors; and the low productivity of the traditional slash and burn plots. Solutions to overcome the infrastructural constraints are sought by looking at the example set by a local NGO.
  • Article
    Full-text available
    Although diversified forest management is promoted as a strategy aimed at slowing tropical deforestation, little is known about the viability of integrating timber and non-timber forest products in the same forest management plans. In this study we offer an initial characterization of multi-purpose tree species in the State of Pará, the principal Amazonian logging region. We identify the species used for both timber and non-timber extraction, and classify these according to their commercial value. We relate multi-purpose species to their ecological traits, the type of non-timber forest use and the fraction of the tree harvested. Although a high number of species present a potential conflict of use, this conflict is only relevant in four of them: D. odorata, T. serratifolia, T. impetiginosa and H. courbaril. Nevertheless, the nature and relevance of this conflict will ultimately depend on the importance that the non-timber use has for the livelihoods of forest-dependant people, the commercial value and the ecological resilience of these species.
  • Article
    In the last 10 years the Sri Lankan government has changed its policy regarding its remaining rain forest from one that promoted commercial exploitation to one of conservation. The growing importance of uplands as catchments for water production, biodiversity conservation and other downstream services has been recognized by the Sri Lankan government. It is therefore timely that we review 15 years of research investigating rain forest dynamics of southwest Sri Lanka with the objective of using this knowledge for forest restoration. We provide six common principles for understanding the integrity of rain forest dynamics in southwest Sri Lanka. The principles are: (i) disturbances provide the simultaneous initiation and/or release of a new forest stand; (ii) that disturbances are generally non-lethal to the groundstory vegetation; (iii) disturbances are variable in severity, type and extent across rain forest topography; (iv) guild diversity (habitat diversity) is dependent upon “advance regeneration”; (v) tree canopy stratification is based on both “static” and “dynamic” processes; and (vi) canopy dominant late-successional tree species are site specialists restricted to particular topographic positions of the rain forest. These principles are applied to determine effects of two rain forest degradation processes that have been characterized as chronic (continuous detrimental impacts) and acute (one-time detrimental impacts). Restoration pathways are suggested that range from: (i) the simple prevention of disturbance to promote release of rain forest succession; (ii) site-specific enrichment planting protocols for canopy trees; (iii) sequential amelioration of arrested fern and grasslands by use of plantation analogs of old field pine to facilitate secondary succession of rain forest, and plantings of late-seral rain forest tree species; and (iv) establishment and release of successionally compatible mixed-species plantations. We summarize with a synthesis of the restoration techniques proposed for reforestation using native vegetation on cleared conservation areas and parks, and for the stabilization of eroded upland watersheds. We conclude with a comparative analysis with restoration work done in other tropical forest regions.
  • Article
    Full-text available
    When the goal of natural forest management is to maintain the biodiversity and ecological integrity of the forest while harvesting timber, the silvicultural systems employed must promote timber production and reduce negative impacts on non-timber resources. To foster development of such a system in a seasonally dry tropical forest in Lomerı́o, Bolivia, we classified tree species according to their relative timber value, importance as food for vertebrate frugivores, and vulnerability to population declines when subjected to logging. We used this classification to identify a management system appropriate for the commercial species and to evaluate the compatibility of the system with the regeneration requirements of tree species that produce important food for mammalian wildlife. About half of the tree species in the site are commercially valuable for their timber and a similar proportion are considered of value as food for wildlife. A tree species rating for vulnerability to disturbance appeared to be independent of both timber and wildlife values. A silvicultural system that includes even-aged groups of trees within an uneven-aged matrix appears more suitable to the multiple goals of management in this forest than either an even-aged or uneven-aged (single tree selection) management system.
  • Article
    Tropical forests could satisfy multiple demands for goods and services both for present and future generations. Yet integrated approaches to natural forest management remain elusive across the tropics. In this paper we examine one combination of uses: selective harvesting of timber and non-timber forest product (NTFP) extraction. We analyze the current status of this combination and speculate on prospects and challenges regarding: (i) resource inventory, (ii) ecology and silviculture, (iii) conflict in the use of multipurpose tree species, (iv) wildlife conservation and use, (v) tenure, and (vi) product certification. Our conclusions remain preliminary due to the relative paucity of published studies and lessons learned on what has worked and what has not in the context of integrated management for timber and NTFPs. We propose at least three ways where further research is merited. One, in improving ‘opportunistic’ situations driven by selective timber harvesting that also enhance NTFP values. Two, to explicitly enhance both timber and NTFP values through targeted management interventions. Three, to explicitly assess biophysical, social, regulatory and institutional aspects so that combined benefits are maximized. Interventions for enhancing the compatibility of timber and NTFP extraction must be scaled in relation to the size of the area being managed, applied timber harvesting intensities, and the dynamics of multi-actor, forest partnerships (e.g., between the private sector and local communities). In addition, training and education issues may have to be re-crafted with multiple-use management approaches inserted into tropical forestry curricula.
  • Article
    Full-text available
    Reliable estimates of the biomass of Amazonian forests are needed for calculations of greenhouse gas emissions from deforestation. Interpretation of forest volume data for the region is the most practical means of obtaining representative biomass estimates. The density of the wood used in converting volume data to biomass is a key factor affecting estimates of biomass and of emissions. Interpreting density data for biomass purposes, which is different from the normal use of these data for commercial timber uses, is complicated by a variety of factors. There is variability among individuals of a given species, among geographic locations, and within the vertical and radial dimensions of individual trees. Considerable confusion has resulted from the variety of ways that densities are reported with respect to humidity at time of the weight and volume measurements used in calculating the density value. The most appropriate measure for biomass is basic density, or oven-dry weight divided by wet volume. Corrections for hollow trees and the position of samples within trunks are also needed. Here, available data are brought together for 268 species of trees, with an unweighted mean basic density of 0.65 (range 0.14–1.21). Weighting the mean by the volume of wood of each species in a sample of vegetation types, and weighting the means of the vegetation types by the extent of each in the region, yields a mean density of 0.69. Although the weighted mean density calculated here has a much firmer empirical basis than previously available estimates for this parameter, uncertainty is still considerable, particularly as a result of doubt concerning taxonomic identifications in the forestry surveys. Were the wood density of a small but botanically well-studied plot near Manaus to apply to the region as a whole, Brazil's 1990 emissions of greenhouse gases would be higher by an amount equivalent to two-thirds of the country's annual emission from fossil fuels.
  • Article
    Brazil nut is widely recognized as the cornerstone of the Amazonian extractive economy. Tight linkages between Brazil nut production, regional income, and intact mature forests have thrust this species into focus as a key component of Amazonian conservation and income generation strategies. Nonetheless, a comprehensive synthesis of factors explaining Brazil nut fruit production variation is lacking. We aimed to address this knowledge gap, asking: (1) What are the rates and annual variation of Bertholletia excelsa fruit production at individual and population levels? (2) What factors explain B. excelsa production variation, focusing on spatial and temporal variables, diameter at breast height (dbh), crown attributes, liana loads, and soil attributes? and (3) Does liana cutting affect fruit production?
  • Article
    Carapa guianensis Aublet. is a tropical tree with strong multiple-use characteristics, and is valued for both the high quality oil extracted from its seeds and as a timber resource. This study compares the population structure of this economically important rainforest tree in two contrasting forest types: occasionally inundated and terra firme forests. Main study objectives were (a) to assess the density, spatial distribution, and size class structure of C. guianensis in these two forest types and (b) to use patterns of abundance, distribution and demographic structure to help infer key demographic stages or ecological variables that merit special focus for management. Four 400 m × 400 m plots, two in each forest type, were established to determine distribution and density patterns of C. guianensis ≥10 cm diameter at breast height (dbh) at the landscape level, and 32 10 m × 10 m subplots were randomly nested within each of the larger plots to measure individuals <10 cm dbh. Larger individuals (≥10 cm dbh) were found at higher densities in occasionally inundated forest than in terra firme forest: 25.7 trees ha−1 and 14.6 trees ha−1, respectively. Mean density of C. guianensis individuals <10 cm dbh was also higher in occasionally inundated forests, but variation of regeneration density among the subplots was high. Spatial distribution methods revealed a tendency toward clumping in both forest types, and both had similar size class structures, suggesting that both environments are suitable for C. guianensis. This new finding illustrates the potential for C. guianensis management in terra firme forests. High densities and clumped distributions in both forest types are also indices favorable for sustainable species management. Finally, several ecological variables (tree density and reproductive potential) were sufficiently different between terra firme and occasionally inundated forests to recommend stratification by forest type when conducting further studies on key ecological and management variables of C. guianensis.
  • Article
    Tropical forests are characterized by diverse assemblages of plant and animal species compared to temperate forests. Corollary to this general rule is that most tree species, whether valued for timber or not, occur at low densities (<1 adult tree ha−1) or may be locally rare. In the Brazilian Amazon, many of the most highly valued timber species occur at extremely low densities yet are intensively harvested with little regard for impacts on population structures and dynamics. These include big-leaf mahogany (Swietenia macrophylla), ipê (Tabebuia serratifolia and Tabebuia impetiginosa), jatobá (Hymenaea courbaril), and freijó cinza (Cordia goeldiana). Brazilian forest regulations prohibit harvests of species that meet the legal definition of rare – fewer than three trees per 100 ha – but treat all species populations exceeding this density threshold equally. In this paper we simulate logging impacts on a group of timber species occurring at low densities that are widely distributed across eastern and southern Amazonia, based on field data collected at four research sites since 1997, asking: under current Brazilian forest legislation, what are the prospects for second harvests on 30-year cutting cycles given observed population structures, growth, and mortality rates? Ecologically ‘rare’ species constitute majorities in commercial species assemblages in all but one of the seven large-scale inventories we analyzed from sites spanning the Amazon (range 49–100% of total commercial species). Although densities of only six of 37 study species populations met the Brazilian legal definition of a rare species, timber stocks of five of the six timber species declined substantially at all sites between first and second harvests in simulations based on legally allowable harvest intensities. Reducing species-level harvest intensity by increasing minimum felling diameters or increasing seed tree retention levels improved prospects for second harvests of those populations with a relatively high proportion of submerchantable stems, but did not dramatically improve projections for populations with relatively flat diameter distributions. We argue that restrictions on logging very low-density timber tree populations, such as the current Brazilian standard, provide inadequate minimum protection for vulnerable species. Population declines, even if reduced-impact logging (RIL) is eventually adopted uniformly, can be anticipated for a large pool of high-value timber species unless harvest intensities are adapted to timber species population ecology, and silvicultural treatments are adopted to remedy poor natural stocking in logged stands.
  • Thesis
    Full-text available
    Since only a small area of Guyana's forest can be effectively protected and because timber harvesting is an important source of income, logged forests will play an important role in the conservation of biodiversity in Guyana. Selective logging, in which only a few trees per hectare are harvested and after which forest remains available, is potentially a good way to utilise the forest without destroying it. In Guyana hard wood from selective logging is an important source of income. As in other tropical countries, sustainable forest management should result in sustained timber yields over long periods of time to provide lasting revenues and to secure livelihoods, while on the other hand also diversity should be conserved as much as possible. To be able to define criteria for sustainable forest management, information on the long-term effects of logging is needed. Selective logging creates openings in the forest canopy, which results in increased light availability in the forest understorey. As a consequence of this increased light availability some tree species (the pioneers) are able to grow much faster. On the long term this may result in changes in species composition of the forest. The aim of the investigations described in this thesis was to determine the long-term effects of logging on tree population dynamics, forest composition and tree diversity and to evaluate the sustainability of alternative forest management scenarios for both future timber yields and biodiversity conservation. To investigate these long-term effects, a field study was done in logged and non-logged forests in Guyana and additionally a forest simulation model was developed to evaluate different management scenarios. This population dynamics model simulates growth, mortality and recruitment of trees and makes projections of forest composition and available hard wood in the course of decades. The results of the field study showed that increased light availability after logging is especially advantageous for pioneer species. The abundance of inherently slow growing tree species decreased, but recovered again in the course of years after logging. Model simulations showed, however, that selective logging did not severely affect forest composition. Even in simulations of the most intensive way of logging (12 trees ha-1, every 25 years) forest composition remained rather intact. This is probably due to the fact that in forests in central Guyana, pioneer species are very rare and thus will not easily dominate the forest after logging. After logging once using high harvest intensities of 12 trees ha-1, it took, however, more than 100 years before harvestable timber volumes were comparable again with a baseline (non-logging) situation. For slow growing tree species it even took more than 160 years after logging before the abundance of stems was comparable again with the baseline situation. Projected recovery periods were, however, substantially longer than the currently in Guyana advised length of felling cycle of 60 years. Highest total timber yields were achieved if trees were harvested every 25 years using high harvest intensities. At the same time this approach also resulted in a fast depletion of the available commercial timber volumes in the forest and thus reduced timber yields. The results of the investigations in this thesis can be used to determine criteria for sustainable forest management in Guyana.
  • Article
    Full-text available
    A comparative analysis of 23 populations of the Brazil nut tree (Bertholletia excelsa) across the Brazilian, Peruvian, and Bolivian Amazon shows that the history and intensity of Brazil nut exploitation are major determinants of population size structure. Populations subjected to persistent levels of harvest lack juvenile trees less than 60 centimeters in diameter at breast height; only populations with a history of either light or recent exploitation contain large numbers of juvenile trees. A harvesting model confirms that intensive exploitation levels over the past century are such that juvenile recruitment is insufficient to maintain populations over the long term. Without management, intensively harvested populations will succumb to a process of senescence and demographic collapse, threatening this cornerstone of the Amazonian extractive economy.
  • Article
    Full-text available
    Tree architecture is an important determinant of the height extension, light capture, and mechanical stability of trees, and it allows species to exploit the vertical height gradient in the forest canopy and horizontal light gradients at the forest floor. Tropical tree species partition these gradients through variation in adult stature (Hmax) and light demand. In this study we compare 22 architectural traits for 54 Bolivian moist-forest tree species. We evaluate how architectural traits related to Hmax vary with tree size, and we present a conceptual scheme in which we combine the two axes into four different functional groups. Interspecific correlations between architecture and Hmax varied strongly from negative to positive, depending on the reference sizes used. Stem height was positively related to Hmax at larger reference diameters (14-80 cm). Species height vs. diameter curves often flattened toward their upper ends in association with reproductive maturity for species of all sizes. Thus, adult understory trees were typically shorter than similar-diameter juveniles of larger species. Crown area was negatively correlated with Hmax at small reference heights and positively correlated at larger reference heights (15-34 m). Wide crowns allow the small understory species to intercept light over a large area at the expense of a reduced height growth. Crown length was negatively correlated with Hmax at intermediate reference heights (4-14 m). A long crown enables small understory species to maximize light interception in a light-limited environment. Light-demanding species were characterized by orthotropic stems and branches, large leaves, and a monolayer leaf arrangement. They realized an efficient height growth through the formation of narrow and shallow crowns. Light demand turned out to be a much stronger predictor of tree architecture than Hmax, probably because of the relatively low, open, and semi-evergreen canopy at the research site. The existence of four functional groups (shade-tolerant, partial-shade-tolerant, and long- and short-lived pioneer) was confirmed by the principal component and discriminant analysis. Both light demand and Hmax capture the major variation in functional traits found among tropical rain forest tree species, and the two-way classification scheme provides a straightforward model to understand niche differentiation in tropical forests.
  • Article
    Wood density is a crucial variable in carbon accounting programs of both secondary and old-growth tropical forests. It also is the best single descriptor of wood: it correlates with numerous morphological, mechanical, physiological, and ecological properties. To explore the extent to which wood density could be estimated for rare or poorly censused taxa, and possible sources of variation in this trait, we analyzed regional, taxonomic, and phylogenetic variation in wood density among 2456 tree species from Central and South America. Wood density varied over more than one order of magnitude across species, with an overall mean of 0.645 g/cm3. Our geographical analysis showed significant decreases in wood density with increasing altitude and significant differences among low-altitude geographical regions: wet forests of Central America and western Amazonia have significantly lower mean wood density than dry forests of Central and South America, eastern and central Amazonian forests, and the Atlantic forests of Brazil; and eastern Amazonian forests have lower wood densities than the dry forests and the Atlantic forest. A nested analysis of variance showed that 74% of the species-level wood density variation was explained at the genus level, 34% at the Angiosperm Phylogeny Group (APG) family level, and 19% at the APG order level. This indicates that genus-level means give reliable approximations of values of species, except in a few hypervariable genera. We also studied which evolutionary shifts in wood density occurred in the phylogeny of seed plants using a composite phylogenetic tree. Major changes were observed at deep nodes (Eurosid 1), and also in more recent divergences (for instance in the Rhamnoids, Simaroubaceae, and Anacardiaceae). Our unprecedented wood density data set yields consistent guidelines for estimating wood densities when species-level information is lacking and should significantly reduce error in Central and South American carbon accounting programs.