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Introduction: Inventories are essential for forest management, but, in the Amazon region, the absence of standardization produces information loss, low accuracy, and inconsistent measurements. This prevents valid comparisons and compromises the use of information in networks and software. Sampling unit size is of key importance in the inventory of native forests, particularly regarding accuracy and costs. Objective: To identify a plot size that provides adequate precision for dendrometric parameters in the Amazon. Methods: In Cotriguaçu, Mato Grosso, Brazil, we tested four plot sizes with six repetitions each: 2 500, 5 000, 7 500, and 10 000 m². We measured diameter at breast height, population density, basal area, and biomass. We applied Shannon and Jaccard indexes; Weibull 2P and Gamma functions to fit the diametric distribution; and the Akaike Information Criterion for the best model. Results: There was a directly proportional relationship between plot area and population similarity, but diversity did not indicate significant alterations. Plot size did not affect dendrometric attributes and diametric distribution. Larger plot areas led to lower coefficients of variation and smaller confidence intervals. The Gamma function was the best model to represent the distributions of different plot sizes. Conclusions: For similar forests, we recommend the 2 500 m² plot to evaluate diameter at breast height, population density, basal area, and biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • We estimated recruitment after logging using a transition matrix model and an individual-tree model. • Tree recruitment was adequately predicted by the two evaluated models. • Predicting recruitment is important for estimating the future development of forests. • The DII BAL (Basal Area of Larger trees) index more accurately estimates the mortality of recruited trees. Recruitment models in rainforests are important for studies on forest management sustainability and can guide the assessment of remaining stocks and timber harvesting. Therefore, the objective of this study was to estimate recruitment after Reduced Impact Logging (RIL) by using two categories of models: a distance-independent individual-tree model (ITM) and a matrix model of forest dynamics or transition matrix (TMM). Data from continuous inventories conducted in a Dense Ombrophilous Forest in Paragominas, Pará state, Brazil, were utilized. Two transects of 9 ha each were installed at an area with Reduced Impact Logging, the data was collected in 2005 (nine months after logging), then in 2006, 2008, 2010 and 2012. Considering a period of 8 years after RIL, the individual tree-based model and transition matrix give consistent predictions of the recruitment in the study area. However, we observed slight superiority by the ITM, which presented values closer to the real ones for the total number of trees per hectare. [ABSTRACT FROM AUTHOR]

The Amazon has a range of species with high potential for sustainable timber harvesting, but for them to be utilized globally, the merchantable wood volume must be accurately quantified. However, since the 1950s, inadequate methods for estimating merchantable timber volumes have been employed in the Amazon, and Brazilian Government agencies still require some of them. The natural variability of the Amazon Forest provides an abundance of species of different sizes and shapes, conferring several peculiarities, which makes it necessary to use up-to-date and precise methods for timber quantification in Amazon Forest management. Given the employment of insufficient estimation methods for wood volume, this study scrutinizes the disparities between the actual harvested merchantable wood volume and the volume estimated by the forest inventory during the harvesting phase across five distinct public forest areas operating under sustainable forest management concessions. We used mixed-effect models to evaluate the relationships between inventory and harvested volume for genera and forest regions. We performed an equivalence test to assess the similarity between the volumes obtained during the pre-and post-harvest phases. We calculated root mean square error and percentage bias for merchantable volume as accuracy metrics. There was a strong tendency for the 100% forest inventory to overestimate merchantable wood volume, regardless of genus and managed area. There was a significant discrepancy between the volumes inventoried and harvested in different regions intended for sustainable forest management, in which only 22% of the groups evaluated were equivalent. The methods currently practiced by forest companies for determining pre-harvest merchantable volume are inaccurate enough to support sustainable forest management in the Amazon. They may even facilitate the region's illegal timber extraction and organized crime., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Concerns about the sustainability of tropical forestry motivated this study on post-logging timber and carbon dynamics over a 20-year period in Paragominas, Pará, Brazil. Previously unlogged forest was subjected to conventional logging (CL), reduced-impact logging (RIL), or was set aside as an unlogged control. All trees ⩾25 cm DBH and all trees of commercial species ⩾10 cm DBH were monitored in a 24.5 ha plot in each treatment, with a 5.25 ha subplot in each for monitoring all trees ⩾10 cm DBH. Above-ground biomass and bole volumes of merchantable species were tracked based on 10 inventories made between 1993 and 2014. Pre-logging biomass and bole volumes of commercial species were estimated as 237, 231, and 211 Mg ha −1 , and 78, 80, and 70 m 3 ha −1 , in the RIL, CL, and unlogged plots, respectively. One year after logging, biomass was reduced 14% by RIL and 24% by CL with corresponding merchantable species volume reductions of 21% and 31%. By 2014, biomass and bole volumes of commercial species had recovered 95% and 98% of their pre-logging stocks in the RIL plot but only 76% and 72% in the CL plot, respectively; timber volumes from large trees (⩾50 cm DBH) were only recovered to 81% in the RIL plot and to 53% in the CL plot. Over the first twenty years after logging, average volume increments from commercial species were substantially higher in the RIL plot (0.72 m 3 ha −1 year −1 ) than in the CL plot (0.08 m 3 ha −1 year −1 ). Recovery of both biomass and timber volumes were temporarily reversed between 2009 and 2014 due to a 4-fold increase in annual mortality rates in the RIL plot and a 5.5-fold increase in the CL plot (as well as a 3-fold increase in the control plot), all presumably related to the extreme drought of 2010. Our findings support the claim that use of RIL techniques accelerates rates of biomass and timber stock recovery after selective logging. [ABSTRACT FROM AUTHOR]

The impacts of selective harvesting in tropical forests on population recovery and future timber yields by high-value species remain largely unknown for lack of demographic data spanning all phases of life history, from seed to senescence. In this study, we use an individual-based model parameterized using 15 years of annual census data to simulate population dynamics of big-leaf mahogany Swietenia macrophylla King in southeast Amazonia in response to multiple harvests and in the absence of harvesting., The model is based on regression equations of stem diameter growth, mortality, and fruit production estimated as a function of stem diameter and prior growth; it includes functions for germinating seeds, growing trees from seedling to adult senescence, producing seeds, and creating disturbances at specified spatial scales and return intervals, including logging. We simulate six harvest scenarios by varying the minimum diameter cutting limit (60 cm, 80 cm) and the retention rate requirement (20%, 40% and 60% commercial population retained)., Without logging, simulated populations grew over 100 years by 182% from observed densities, indicating that one or more parameters in the model may overestimate long-term demographic rates on this landscape. However, 100-year densities did not far exceed values reported from forests across this region, and other modelled demographic parameters resembled observed behaviours., Under current harvest regulations for mahogany in Brazil (60 cm minimum diameter cutting limit, 20% commercial-sized tree retention rate, minimum 5 commercial-sized trees 100 ha−1 retained after harvest, 30-year cutting cycle), commercial densities at the study site would decline from 39·7 to 11·3 trees 100 ha−1 before the fourth harvest in year 90, yielding an estimated 16·4% of the initial harvest volume during the fourth harvest. Increasing retention rates caused first-cut harvest volumes to decline but improved population recovery rates between harvests. Under both minimum diameter cutting limit scenarios, increasing retention rates led to more robust population recovery compared with the current 20% rate, and higher subsequent harvest yields relative to initial (first-cut) values., Synthesis and applications. These results indicate that current harvest regulations in Brazil for mahogany and other high-value timber species with similar life histories will lead to commercial depletion after 2-3 cutting cycles. Increasing commercial-sized tree retention rates improved population recovery at the cost of reduced initial harvest volume yields. Sustainable harvests will require, in combination, a moderate increase in the retention rate, investment in artificial regeneration to boost population recovery, and implementation of silvicultural practices designed to increase growth rates by future crop trees. [ABSTRACT FROM AUTHOR]

The Public Forest Management Law represents great change in Brazil's forest policy. Law 11,284/2006, which regulates public forest management for sustainable production, establishes that the Government and its agencies may grant forest concessions to private companies for promoting sustainable logging. Such law, designed mainly for the exploration of areas in the Amazon, has the purpose of bringing together forest conservation and sustainable development, and yet to undermine illegal logging, illegal land appropriation land grabbing and tax evasion. Through forest concessions, the Public Administration would give responsibilities to the concessionaires, declaring that it is unable to provide inspection itself. The approval of Law 11,284/2006 reumed quickly, despite several opinions against its creation. Its constitutionality is being discussed on the Federal Supreme Court. In this study we analyze the Management Law in its socio-legal aspects, in the scope of constitutional, administrative, environmental and civil processual law; as well as its factual outcomes regarding the FLONA Jamari licitation in Rondônia, the first public forest concession on Amazon. [ABSTRACT FROM AUTHOR]

1. Current efforts to model population dynamics of high-value tropical timber species largely assume that individual growth history is unimportant to population dynamics, yet growth autocorrelation is known to adversely affect model predictions. In this study, we analyse a decade of annual census data from a natural population of big-leaf mahogany Swietenia macrophylla King to quantify the strength and duration of growth autocorrelation, and experimentally investigate the role of crown vine coverage, a major predictor of performance. 2. The sample population consisted of 358 trees >10 cm diameter. The relative contributions of predictor variables including diameter, crown vine coverage and growth history to models of growth and mortality were evaluated using Akaike’s Information Criterion. Autocorrelation among trees was incorporated into growth models using generalized least squares. We experimentally removed vines from heavy-laden trees to test the strength and persistence of their impact on stem diameter growth. 3. Previous growth explained the highest amount of variation in annual diameter growth; the best-fitting model of autocorrelation was an AR(7) autoregressive model, indicating that autocorrelation persisted throughout the study period. Other factors explaining variation in growth were, in decreasing order of importance: year of measurement, crown vine coverage, diameter, crown illumination and fruit production. The best logistic regression model for mortality retained diameter growth plus crown vine coverage as predictors of risk. 4. The vine release experiment strongly supported these results. Released trees grew faster than control trees but required ≥5 years to approach growth rates of trees with minimal vine coverage. Trees with heavy vine coverage also experienced higher mortality rates. 5. Synthesis and applications. These results indicate that growth autocorrelation is strong, persistent, and an important predictor of future performance; demographic models for tree growth and yield projections can be improved by accounting for growth history. Our results also indicate that targeted silvicultural practices such as vine cutting can increase long-term growth and timber yield. These findings further current understanding of tropical tree growth and survival, and offer improved management tools for sustainable harvest practices for mahogany and similar species. [ABSTRACT FROM AUTHOR]

Understanding the forces that drove policy in the past can inform expectations of the effectiveness of policy implementation today. Forest policies of countries with forested frontiers transition through stages of forest management, reflecting the orientation of governments toward economic development. The article follows Brazilian national forest policy from the early 20th century from colonization to protectionism, during which extrasectoral policies largely served to marginalize forest policy. More recently, profound changes in Brazil's governance structures, civil society's progressively important role in influencing policy, and recognition of the biophysical importance of forests have fostered an emerging vision of the Amazon as a region whose primary vocation is sustainable forest management. The sustainable management phase of forest policy development and the approval of Brazil's first Public Forest Management Law, given the current socioeconomic, political, and environmental context, present an unprecedented opportunity for increasing the relevance of forest policy in shaping land use. [ABSTRACT FROM AUTHOR]

Abstract: There is more to sustainable forest management than reduced impact logging. Partnerships between multiple actors are needed in order to create the institutional context for good forest governance and sustainable forest management and stimulate the necessary local community involvement. The idea behind this is that the parties would be able to achieve more jointly than on their own by combining assets, knowledge, skills and political power of actors at different levels of scale. This article aims to demonstrate by example the nature and variety of forest-related partnerships in Brazilian Amazonia. Based on the lessons learned from these cases and the authors’ experience, the principal characteristics of successful partnerships are described, with a focus on political and socioeconomic aspects. These characteristics include fairly negotiated partnership objectives, the active involvement of the public sector as well as impartial brokers, equitable and cost-effective institutional arrangements, sufficient and equitably shared benefits for all the parties involved, addressing socioeconomic drawbacks, and taking measures to maintain sustainable exploitation levels. The authors argue that, in addition to product-oriented partnerships which focus on sustainable forest management, there is also a need for politically oriented partnerships based on civil society coalitions. The watchdog function of these politically oriented partnerships, their awareness-raising campaigns regarding detrimental policies and practices, and advocacy for good forest governance are essential for the creation of the appropriate legal and political framework for sustainable forest management. [Copyright &y& Elsevier]

Abstract: The sustainability of current harvest practices for high-value Meliaceae can be assessed by quantifying logging intensity and projecting growth and survival by post-logging populations over anticipated intervals between harvests. From 100%-area inventories of big-leaf mahogany (Swietenia macrophylla) covering 204ha or more at eight logged and unlogged forest sites across southern Brazilian Amazonia, we report generally higher landscape-scale densities and smaller population-level mean diameters in eastern forests compared to western forests, where most commercial stocks survive. Density of trees ≥20cm diameter varied by two orders of magnitude and peaked at 1.17ha−1. Size class frequency distributions appeared unimodal at two high-density sites, but were essentially amodal or flat elsewhere; diameter increment patterns indicate that populations were multi- or all-aged. At two high-density sites, conventional logging removed 93–95% of commercial trees (≥45cm diameter at the time of logging), illegally eliminated 31–47% of sub-merchantable trees, and targeted trees as small as 20cm diameter. Projected recovery by commercial stems during 30 years after conventional logging represented 9.9–37.5% of initial densities and was highly dependent on initial logging intensity and size class frequency distributions of commercial trees. We simulated post-logging recovery over the same period at all sites according to the 2003 regulatory framework for mahogany in Brazil, which raised the minimum diameter cutting limit to 60cm and requires retention during the first harvest of 20% of commercial-sized trees. Recovery during 30 years ranged from approximately 0 to 31% over 20% retention densities at seven of eight sites. At only one site where sub-merchantable trees dominated the population did the simulated density of harvestable stems after 30 years exceed initial commercial densities. These results indicate that 80% harvest intensity will not be sustainable over multiple cutting cycles for most populations without silvicultural interventions ensuring establishment and long-term growth of artificial regeneration to augment depleted natural stocks, including repeated tending of outplanted seedlings. Without improved harvest protocols for mahogany in Brazil as explored in this paper, future commercial supplies of this species as well as other high-value tropical timbers are endangered. Rapid changes in the timber industry and land-use in the Amazon are also significant challenges to sustainable management of mahogany. [Copyright &y& Elsevier]

Timber harvest is one of the main causes of degradation of Amazonian tropical forests, where bats represent important components of biodiversity. In addition, bats may represent keystone taxa in the Neotropics, as they are primary agents of pollination and seed dispersal for many pioneer plants. We assessed the impact of low harvest (18m3/ha), reduced impact logging (RIL) on population and community characteristics of phyllostomid bats in Amazonian terra firme forest of Brazil at 20–42 months post-harvest. Based on 103,680 net-meter-hours of netting in Tapajós National Forest, 2341 phyllostomids were captured, representing 42 species, 25 genera, and 4 broad feeding guilds. Population-level responses of common phyllostomids to RIL were minor, with 10 of 15 species evincing no change in mean abundance. Of those taxa responding to RIL (mean difference in number of individuals per site), three increased (Artibeus concolor [0.46 individuals], Artibeus lituratus [3.88], and Glossophaga soricina [0.71]) and two decreased (Carollia brevicauda [0.96] and Carollia perspicillata [14.04]) in abundance. Compositional (species distributions) and structural (rank distributions) aspects of bat assemblages differed between cut and control forests. More specifically, bat assemblages in cut forest had increased diversity and decreased dominance compared to control forest. Nonetheless, the proportional abundance of the five most common species, as a group, was similar in cut (86%) and control forest (88%), and frugivores dominated assemblages in both management types. Mean abundance of frugivores decreased (10.59 individuals per site) in response to RIL; however, this response was driven by decreases in C. perspicillata, the most abundant species in terra firme forest. Although RIL had only minor effects on biodiversity in the short-term, extrapolation to a long-term prospectus should be exercised with caution when applied to conservation or policy issues. [Copyright &y& Elsevier]

Abstract: The sustainability of a range of forest management scenarios were evaluated for the Tapajós region of the Brazilian Amazon using the growth and yield simulation model, Simflora, a derivative of the model SYMFOR developed for application in Indonesia. A simulation of current management regulations based upon a maximum extracted volume of 35m3 ha−1 and a 30-year cutting cycle was found to be unsustainable. A range of alternative specifications for the control (regulation) of harvested timber yield were compared, along with associated estimates of timber increment and description of the ecological composition of the stand. The alternative scenarios included cutting cycles ranging from 10 to 60 years and maximum yields from 10 to 40m3 ha−1. The maximum commercial volume increment predicted in this study was 0.33m3 ha−1. It was observed that the highest rates of volume increment were associated with high logging intensities. The study produced a limited number of potentially sustainable options for the Tapajós forest. The best of these were the combinations of 10m3 ha−1 yield and a cutting cycle of 30 years or 20m3 ha−1 with a 60-year cutting cycle. The analysis suggested that the sustainability of both of these options was “marginal” and suggested adopting a precautionary approach of an additional limit for yield to be no more than 33% of standing commercial volume until more data are available. Analysis of the ecological data from the simulations clearly demonstrated that the composition of the managed forest is likely to differ significantly from that observed in primary forest. The most significant likely change is a reduction in the proportion of trees in the emergent ecological group. This observation raises the issue that stakeholders should not expect tropical forests that are managed for production to ever be identical in structure or composition to primary forests. It also suggests that additional technical measures will be required to promote the regeneration and growth of current emergent species if these are to be maintained in managed forests in the Amazon. The study concludes that there cannot be a single system of yield regulation or forest management that will fit all contexts (social, ecological, environmental and economic) or management objectives held by various stakeholders in the Amazon. [Copyright &y& Elsevier]

Illegal logging and trade is a global problem that undercuts attempts to sustainably manage forests. While data is not consistently or comprehensively available, existing studies highlight a large problem in both tropical and non-tropical timber producing countries. This paper presents the results of a literature review on the extent of the problem. Results indicate that most nations with significant portions of forest cover suffer some level of illegal logging. Estimates range from 80 percent for the Brazilian Amazon, to over 90 percent for Cambodia and over 70 percent for Indonesia. Further studies at both national and local levels will help to identity the complex set of factors that contribute to the problem and appropriate solutions. [ABSTRACT FROM AUTHOR]

The ecosystem services provided by tropical forests are affected by deforestation. Territorial management strategies aim to prevent and mitigate forest loss. Therefore, modeling potential land use changes is important for forest 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 density 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%) provided 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., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Premise of the Study: Flowering phenology is a crucial determinant of reproductive success and offspring genetic diversity in plants. We measure the flowering phenology of big-leaf mahogany (Swietenia macrophylla, Meliaceae), a widely distributed neotropical tree, and explore how disturbance from logging impacts its reproductive biology., Methods: We use a crown scoring system to estimate the timing and duration of population-level flowering at three forest sites in the Brazilian Amazon over a five-year period. We combine this information with data on population structure and spatial distribution to consider the implications of logging for population flowering patterns and reproductive success., Key Results: Mahogany trees as small as 14 cm diam flowered, but only trees > 30 cm diam flowered annually or supra-annually. Mean observed flowering periods by focal trees ranged from 18-34 d, and trees flowered sequentially during 3-4 mo beginning in the dry season. Focal trees demonstrated significant interannual correlation in flowering order. Estimated population-level flowering schedules resembled that of the focal trees, with temporal isolation between early and late flowering trees. At the principal study site, conventional logging practices eliminated 87% of mahogany trees > 30 cm diam and an estimated 94% of annual pre-logging floral effort., Conclusions: Consistent interannual patterns of sequential flowering among trees create incompletely isolated subpopulations, constraining pollen flow. After harvests, surviving subcommercial trees will have fewer, more distant, and smaller potential partners, with probable consequences for post-logging regeneration. These results have important implications for the sustainability of harvesting systems for tropical timber species.