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Given its complexity, directional felling is considered one of the most dangerous activities in the exploratory phase of forest management projects for timber obtention. Therefore, detailed studies of the variables influencing its execution are necessary. The present research was conducted in the Tapajós National Forest, Brazilian Amazon, and analyzed 1,075 trees logged using the directional felling technique in a 504.30 ha area. To better understand directional felling, the studied variables were subjected to descriptive analyses and principal component analysis, a multivariate procedure that enables the simultaneous evaluation of several variables. While the diameter, basal area, and stem and branch volume explained most of the variability concerning directional felling, the commercial height influenced the least. Trees of the species Hymenolobium petraeum (angelim pedra) strongly correlated with the dendrometric variables diameter and stem and branch volume. Those of the species Hymenaea courbaril (jatobá) showed a strong correlation with the commercial height. Pseudopiptadenia psilostachya (fava timborana), Dipteryx odorata (cumaru), Hymenaea parvifolia (jutai mirim), and Astronium lecointei (muiracatiara) had a strong correlation with the basic wood density. Trees of the species Couratari guianensis (tauari), Lecythis pisonis (sapucaia), Astronium lecointei (muiracatiara), Mezilaurus itauba (itaúba), and Goupia glabra (cupiúba) showed lower correlations with the time needed for planning, cutting, and felling. They also had a reduced correlation with the angular differences between the natural and effective and the intended and effective felling directions. The latter results suggest that these species do not follow a defined pattern concerning the directional felling technique. However, trees of the other species followed a different tendency. In general, the logged trees lacked correlation with the directional felling cutting and total operation time. The analyses suggest that as the diameter of a tree increases, the chances of completing its directional felling decrease. Made available in DSpace on 2022-06-21T13:19:22Z (GMT). No. of bitstreams: 1 FactorsInfluencingDirectional.pdf: 2448488 bytes, checksum: 7ea6039404c86d87e19b42b89f094475 (MD5) Previous issue date: 2022

To reduce the damage caused by logging in the Amazon rainforest, new metaheuristics have been implemented and tested to ensure the sustainability of this economic segment. Therefore, this study aimed to compare alternatives for road sizing and log deck allocation. In a forest management unit, the skidding to log decks was evaluated in two diff erent areas. To determine the skidding/log deck relation, georeferenced points were generated equally spaced every 50 m. In area 1, the Integer Linear Programming (ILP) model and the Multi-Objective Evolutionary Algorithm (MOEA) were compared. In area 2, only the MOEA was considered. In both areas, these models were also compared to the current planning used in the forest management unit. Solutions were then generated to identify the best management alternative. In both areas, the MOEA showed greater efficiency regarding the processing time, as well as the reduction of log decks number and the road sizing. The multi-objective evolutionary approach assists the decision-making process, due to the presentation of alternatives based on Pareto-optimal solutions, making the choice more flexible and well supported. Com o objetivo de reduzir os danos causados pela exploração madeireira na floresta amazônica, novas meta-heurísticas vem sendo implementadas e testadas para garantir a sustentabilidade desse segmento econômico. Assim, este trabalho tem como objetivo comparar alternativas para o dimensionamento de estradas e para alocação de pátios de estocagem de madeira. Em uma unidade de manejo florestal, o deslocamento da exploração de árvores para os pátios de estocagem de madeira foi avaliado em duas diferentes áreas. Para determinar a relação exploração de árvores / pátios de estocagem de madeira, pontos georreferenciados foram gerados igualmente espaçados a cada 50 m. Na área 1, o modelo de Programação Linear Inteira (ILP) e o Algoritmo Evolutivo Multiobjetivo (MOEA) foram comparados. Na área 2, apenas o MOEA foi considerado. Em ambas as áreas, esses modelos também foram comparados com o planejamento executado na unidade de manejo florestal. Soluções foram geradas para identificar a melhor alternativa de manejo. Em ambas as áreas, o MOEA apresentou maior eficiência quanto ao tempo de processamento, bem como na redução do número de pátios de estocagem de madeira e no dimensionamento das estradas. A abordagem evolutiva multiobjetivo auxilia o processo de tomada de decisão, devido à apresentação de alternativas baseadas em soluções Paretoótimas, tornando a escolha mais flexível e bem fundamentada. Made available in DSpace on 2021-10-20T18:00:24Z (GMT). No. of bitstreams: 1 27210.pdf: 1549544 bytes, checksum: 8a845c598d88f6f19fa5074e75e52351 (MD5) Previous issue date: 2021

Knowledge about the activity of the timber sector and local industries assists in the management of a forest economy based on sustainable use in the Amazon. In this study, the situation of the timber sector of the municipality of Porto Grande-AP was examined to detail the extraction and processing of native wood from the Amazon and the sustainable use of this resource by the local sector. Forms were applied in all sawmills of the municipality, which collected information on factors of production and commercialization of native wood for the year 2017. In addition, interviews with local merchants were done and secondary data collection from several institutions related to the sector was conducted. All sawmills in the municipality exercise licensed activity and processed 69,300 m3 of wood in the period, with an average extraction of 21 m3/ha. The sawmills productive income was 55%, above of the 35%, maximum recently established by CONAMA. There is no destination for productive of residual waste generated by most sawmills and lumber is marketed mainly to the Northeast of Brazil for use in civil construction. Thus, in order to guarantee better economic and environmental performance of the sector, it is recommended that sawmills search for new forest areas as sources of raw material, participate in forest certification programs, and seek ways to use residual waste for bioenergy generation. The government recommends that new forests be managed through actions that solve land tenure problems and increase the supply of public forests, and for certified management units the recommendation is to reduce licensing costs, and simplify the bureaucratic processes of environmental agencies. Made available in DSpace on 2020-12-16T09:07:02Z (GMT). No. of bitstreams: 1 CPAF-AP-2020-Harvesting-and-processingof-native.pdf: 530423 bytes, checksum: 59c134f1c189d9be94ad3033eb74d0a0 (MD5) Previous issue date: 2020

International audience; AbstractKey messageReduction in the aboveground biomass of larger trees is the main consequence of disturbances in open forests dominated by bamboo. Because these trees are of central importance both for ecosystem function and for the economic value of the forest for management, the impact on these trees due to the increase of bamboo abundance following anthropogenic disturbances is both an environmental and a commercial concern.ContextBamboo-dominated forests in southwestern Amazonia are increasingly exposed to the combined impacts of fire and selective logging. Although the climbing bamboos (Guadua spp.) are considered native species of these forests, disturbances contribute to a discontinuous canopy, which is an ideal scenario for an increase in abundance of these opportunistic plants. The regeneration of tree biomass is limited in these cases, decreasing the carbon stock of the forest.AimsThis study compares changes in bamboo abundance and forest structure in the face of forest fire and post-burn logging in the municipality (county) of Rio Branco, Acre state, Brazil.MethodsThe study was conducted on the Transacreana Highway (AC 090) in the eastern portion of Acre state, Brazil. We compared changes in bamboo abundance and aboveground biomass (AGB) of an area of forest with no known recent disturbances to areas in the same forest that had been disturbed by fire and post-burn logging, which are frequent sources of disturbance in this region. The live and dead AGB values were estimated by field inventory in 2016, which was 11 years after a fire and 9 years after selective logging. The AGB values for trees and palms were estimated by allometric equations in three 2-ha areas. Bamboo abundance was expressed both by bamboo biomass (Mg ha−1) and culm density (culms ha−1), sampled by direct measurements in three 200-m2 areas.ResultsBamboo abundance was over 20% higher in forest that had been burned but not logged, as compared to undisturbed forest. Compared to undisturbed plots, aboveground forest biomass (live + dead) was 34% lower in plots exposed to fire but not logging, and 36% lower if exposed to both. Live trees and palms represented 77% of the total forest biomass (live + dead), and almost a half of this contribution (41%) was in individuals in the largest diameter class (diameter at breast height > 50 cm).ConclusionIncrease in the level of impact led to a reduction in aboveground carbon stock of the forest. One of the main consequences of disturbances in open forests dominated by bamboo is reduction of live trees and palms, especially in the diameter at breast height (DBH) class over 50 cm.

Around 30Mm3 of sawlogs are extracted annually by selective logging of natural production forests in Amazonia, Earth?s most extensive tropical forest. Decisions concerning the management of these production forests will be of major importance for Amazonian forests? fate. To date, no regional assessment of selective logging sustainability supports decision-making. Based on data from 3500 ha of forest inventory plots, our modelling results show that the average periodic harvests of 20m3 ha?1 will not recover by the end of a standard 30 year cutting cycle. Timber recovery within a cutting cycle is enhanced by commercial acceptance of more species and with the adoption of longer cutting cycles and lower logging intensities. Recovery rates are faster in Western Amazonia than on the Guiana Shield. Our simulations suggest that regardless of cutting cycle duration and logging intensities, selectively logged forests are unlikely to meet timber demands over the long term as timber stocks are predicted to steadily decline. There is thus an urgent need to develop an integrated forest resource management policy that combines active management of production forests with the restoration of degraded and secondary forests for timber production. Without better management, reduced timber harvests and continued timber production declines are unavoidable. Made available in DSpace on 2019-11-14T18:23:27Z (GMT). No. of bitstreams: 1 CPAFAP2019CantimberprovisionfromAmazonian.pdf: 1180878 bytes, checksum: 1ac13277d4e677177e64186cd7c04ace (MD5) Previous issue date: 2019 Supplementary material for this article is available online.

Reduced-impact logging is a well known practice applied in most sustainable forest management plans in the Amazon. Nevertheless, there are still ways to improve the operational planning process. Therefore, the aim of this study was to create an integer linear programming (ILP) to fill in the knowledge gaps in the decision support system of reduced impact logging explorations. The minimization of harvest tree distance to wood log landing was assessed. Forest structure aspects, income and wood production were set in the model, as well as the adjacency constraints. Data are from a dense ombrophylous forest in the western Brazilian Amazon. We applied the phytosociological analysis and BDq method to define the selective logging criteria. Then, ILP models were formulated to allow the application of the constraints. Finally, 32 scenarios (unbalanced forest, UF, and balanced forest, BF) were generated and compared with real executed plans (RE). Robust results were achieved and the expected finding of each scenario was met. The feasibility to integrate ILP models in uneven-aged forest management projects was endorsed. Consequently, the UF and BF scenarios tested were efficient and concise, introducing new advances for forest management plans in the Amazon. The proposed models have a high potential to improve the selective logging activities in the Amazon forest. A exploração de impacto reduzido é uma prática bem conhecida e aplicada na maioria dos planos de manejo florestal sustentável na Amazônia. Todavia, ainda há a possibilidade de melhoria do processo de planejamento da operação. Diante da falta de métodos auxiliares à tomada de decisão, o objetivo do trabalho foi desenvolver modelos de programação linear inteira (PLI) para suprir esta demanda. Considerou-se a minimização da distância entre as árvores exploradas e os pátios de estocagem de madeira. Aspectos estruturais, econômicos e produtivos foram incorporados ao modelo, bem como restrições de adjacência. Os dados derivam de uma floresta ombrófila densa na Amazônia Ocidental. Previamente, utilizou-se uma análise fitossociológica e o método BDq como critério de remoção. Posteriormente, modelos de PLI foram formulados para exemplificar as aplicações. Finalmente, 32 cenários (para floresta desbalaceada, UF, e floresta balanceada, BF) foram gerados e comparados com o plano executado no campo (RE). Resultados robustos foram obtidos e atenderam às expectativas de cada cenário. A viabilidade da integração dos modelos de PLI em projetos de manejo de florestas ineqüiâneas foi testado. Os cenários UF e BF testados foram eficientes e concisos, confirmando seu potencial para aumentar a eficiência de planos de exploração madeireira e manejo florestal na Amazônia. Made available in DSpace on 2018-03-09T00:33:13Z (GMT). No. of bitstreams: 1 26524.pdf: 1789976 bytes, checksum: a9973a85aea009a5c922b786128312da (MD5) Previous issue date: 2018-03-08

We evaluated the impacts of selective logging on tree regeneration one, four, and eight years after harvests in Antimary State Forest in the State of Acre, Brazil. We inventoried tree seedlings, saplings, and poles (>50 cm tall to

O objetivo deste trabalho foi estimar o valor econômico e a margem de comercialização da madeira em tora oriunda de áreas manejadas. Essa cadeia, além de produzir margem positiva, os valores são relativamente superiores aos gerados nas atividades que concorrem para o desmatamento na Amazônia para se estabelecerem. Adicionalmente, determinou-se o coeficiente médio de desdobramento de 37,3% (2,68 m³ de madeira em tora para cada 1,0 m³ de madeira serrada), o qual revelou baixo grau tecnológico das empresas. O valor econômico médio da extração e comercialização da madeira em pé no mercado local foi de R$ 23,48/m³, tendo um valor mínimo de R$ 9,06/m³ para as espécies da categoria C4 (madeira branca) e um máximo de R$ 55,63/m³ para as espécies da categoria C1 (madeira especial). Assim, para um fluxo de 30 anos e extração de 25 m³/ha nos planos de manejo das áreas de concessão florestal do Estado do Pará, gera-se um valor médio de R$ 587,00/ha, ou R$ 19,56/ha/ano. No fluxo de 30 anos, esse resultado é relativamente superior ao gerado pelas atividades de pecuária extensiva (em torno de R$ 180,00/ha) e das lavouras de grãos (em torno dos R$ 420,00/ha), principais responsáveis pelo desmatamento da Amazônia. Também, apresenta maior rentabilidade do que o reflorestamento com paricá, que gera R$ 192,26/ha. A margem de comercialização indicou que a sociedade tende a se apropriar de 14,3% do valor econômico gerado na cadeia da madeira oriunda dos contratos de concessão florestal. The objective of this study was to estimate the economic value and the trade margin of roundwood from managed areas. Besides generating a positive margin values, they are relatively higher In this chain than those generated in activities contributing to deforestation in the Amazon. Additionally, the unfolding mean rate of 37.3% was achieved (2.68 m³ of logs for each 1.0 m³ of sawn timber), which revealed a low technological level of companies. At the lower Amazon, the average economic value from the extraction and sale of standing timber in the local market was R$ 23.48/m³, with a minimum value of R$ 9.06/m³ for the species in category C4 (softwood) and a maximum of R$ 55.63/m³ for the species of category C1 (special wood). Thus, considering an extraction flow of 30 years and assuming the extraction of 25 m³/ha in management designs of forest areas from concession contracts in the state of Pará, it is generate an average economic value of R$ 587.00/ha or R$ 19.56/ha/year, which is relatively higher than the profit generated by the activities of extensive livestock (around R$ 180.00 per hectare or R$ 6.00/ha/year) and grain crops (approximately R$ 420.00 per hectare or R$ 14.00/ha/year), which are the main responsibles for deforestation in the Amazon. It also presents a higher profitability than the reforesting with Paricá, whose income is R$ 192.26/ha or R$ 7.12/ha/year. The marketing margin showed that society tends to appropriate of 14.30% of the economic value generated in the wood chain from the transition contracts.

We evaluated the survival and growth of Amburana cearensis, Cedrela fissilis, and Sterculia striata seedlings in three seasonally tropical dry forest fragments that were subjected to different logging levels (intact, intermediately and heavily logged). In each fragment, we planted 40 seedlings of each species and monitored these over a period of 1 year. The highest seedling survival rate (64%) occurred in the heavily logged fragment, which, however, also had the highest mortality risk for all species during the dry season. Only S. striata seedlings had different survival rates among the fragments. Height and diameter growth were higher at sites with higher canopy openness in the wet season. The survival and growth rates of seedlings planted in logged fragments indicate that this technique can be applied to restore and enrich logged forests of the Paranã River Basin.

A demanda por madeira tropical na Amazônia dita uma pressão na conservação deste bioma, especialmente pelas práticas em desacordo com as normas ambientais. A atividade madeireira no Amazonas vem sendo incentivada pelo Estado como política de desenvolvimento da economia local. No entanto, vários fatores contribuem para um cenário nada promissor em relação ao manejo florestal sustentável. Embora a produção madeireira seja inferior em relação aos outros estados da Amazônia brasileira, muita madeira ainda é de origem ilegal. E as unidades de conservação se tornam alvo fácil devido à ausência de políticas públicas robustas para a gestão ambiental e as dificuldades logísticas de fiscalizar um território tão grande. Diante deste cenário, este trabalho buscou caracterizar o comportamento e a dinâmica das práticas florestais licenciadas e não licenciadas para produção madeireira dentro e na zona de amortecimento da Reserva de Desenvolvimento Sustentável do Juma (RDS do Juma). Foram utilizadas informações de licenciamento ambiental, assim como imagens de satélites OLI/Landsat-8 e RapidEye para identificar e mapear áreas com sinais de exploração seletiva de madeira. No Amazonas, é licenciado em média o volume de 413.327m 3 de madeira em tora por ano proveniente de planos de manejo florestal. A região sul do Amazonas concentra 59% das indústrias consumidoras de matéria-prima florestal e boa parte da produção legal. Por sua vez, a RDS do Juma sofre forte pressão pela atividade madeireira do entorno. Por meio de técnicas de interpretação visual das imagens RapidEye foram identificados 437,035 hectares de áreas com sinais de exploração florestal dentro da RDS do Juma para os an os de 2011 e 2013, e 1.740,605 hectares de exploração ilegal na zona de amortecimento da UC para o mesmo período. Não se obteve sucesso no emprego das imagens OLI/Landsat-8 para a detecção de exploração madeireira, no entanto, a partir da interpretação das imagens fração -solo derivadas do modelo linear de mistura espectral pôde-se mapear estradas endógenas na região de estudo. O uso de sensoriamento remoto pode ser aplicado no monitoramento da atividade de exploração florestal no Amazonas. Demand for tropical wood in the Amazon adds urgency to the conservation of this ecosystem, especially by preventing practices that are at odds with environmental regulations. Logging in the state of Amazonas is being encouraged by the state government as development policy for the local economy. However, several factors contribute to an unpromising scenario for “sustainable” forest management. Although less timber is harvested in the state of Amazonas than in other states in the Brazilian Amazon, there is still a large amount of wood of illegal origin in the state. Protected areas are easy targets because of the absence of robust public policies for environmental management and because of the logistical difficulties of supervising such a large territory. This study sought to characterize the behavior and the dynamics of licensed and unlicensed practices for timber production in the Juma Sustainable Development Reserve (Juma Reserve) and in its buffer zone. Environmental-licensing information and satellite images (OLI/Landsat-8 and RapidEye) were used to identify and map areas with signs of selective logging. An average of 413.327m 3 of logs is harvested per year from forest management plans in Amazonas. The southern Amazonas region accounts for 59% of the industries consuming forest raw materials in the state and supplies much of the legal production. The Juma Reserve is under strong pressure from logging in the surrounding area. Using visual-interpretation techniques with RapidEye images, we identified 437.0 hectares with signs of logging in the Juma Reserve for the years 2011 and 2013 and 1740.6 hectares of illegal logging in the buffer zone for the same period. We were not successful in using the OLI/Landsat-8 images for the detection of logging; however, based on interpretation of images using a linear spectral mixing model, we were able to use the soil-derived fraction to map endogenous roads in the study area. The use of remote sensing can be applied in monitoring logging in the state of Amazonas, Brazil.

Em 1995, a Embrapa Acre iniciou o desenvolvimento do sistema de manejo florestal madeireiro comunitario do Projeto de Colonizacao Pedro Peixoto (PC Peixoto), no Estado do Acre, propondo metodos acessiveis a produtores rurais de baixa renda. Originalmente, nesse sistema, o transporte primario da madeira da floresta as vias de escoamento e praticado com animais (bois de carga), no entanto, a eficiencia desse metodo e baixa e exige demasiado esforco dos animais. Diante dessa limitacao, foi proposto substituir os animais por microtratores, acoplados a carretas basculantes. Este trabalho objetiva apresentar indices tecnicos operacionais e economicos da colheita de madeira do PC Peixoto com a insercao de microtrator em substituicao aos animais de carga. O equipamento utilizado foi o microtrator Yanmar Agritech TC-14 (14 cv). Os indices tecnicos e economicos apresentados sao relativos a todas as operacoes de colheita da madeira – abertura e manutencao de carreadores na floresta, derrubada da arvore, processamento e transporte primario – e aos insumos utilizados – mao-de-obra, material de consumo e os equipamentos, como motosserras e serraria portatil. Comparado aos animais, o microtrator mostrou desempenho operacional superior em varios aspectos, com destaque a produtividade, que alcancou, em media, 4,1 m3 d–1, acima do dobro. O custo operacional utilizando serraria portatil e microtrator foi de R$ 114,11 m–3, empregando 23,25 homens d–1 para colher 36 m3 de madeira em tora ao ano. Os resultados obtidos apontam para a viabilidade tecnica e economica do uso do microtrator no sistema de manejo comunitario do PC Peixoto.

The western Amazon supports the largest formation of neotropical bamboo forests. This forest ecosystem is neglected due to its low commercial timber volume and fragile forest structure that amplifies the damage caused by logging operations. This study was conducted in a lightly logged bamboo-dominated forest in Brazilian western Amazon, with the objective to evaluate the sustainability of the applied forest management regime in terms of tree density, above-ground dried biomass and tree bole volume stocks recovery rates and species groups. The forest dynamics were monitored over a period of 12 years in 10 permanent sample plots of 1 ha. Two main results of this study are important to the establishment of cycle lengths, logging intensities and silvicultural treatments for tropical forest management in bamboo-dominated forest: the rapid increment of the above-ground biomass (AGB) observed in the area after logging, and the slow growth of commercial and logged species. In addition, although no climate data was collected in this study, the reported 2005 and 2010 atypical climate events strongly affected forest dynamics and productivity. These results indicate that short cutting cycles and light logging intensities, and the rotation of logged species, should produce the appropriate combination in terms of the disturbance frequency and scale to promote sustainable timber production in bamboo-dominated forests. Made available in DSpace on 2020-04-18T00:54:44Z (GMT). No. of bitstreams: 1 24797.pdf: 942524 bytes, checksum: 943dd7f80ae4480fcbdc5557026acda8 (MD5) Previous issue date: 2013

As mudanças ambientais causadas pela fragmentação florestal podem modificar o fluxo de carbono de um ecossistema florestal e contribuir para maiores emissões de dióxido de carbono (CO 2 ) para a atmosfera. Considerando que o solo possui um grande estoque de carbono (138 Gt de carbono até 8 m de profundidade na Amazônia Legal), a emissão desse carbono em forma de CO 2 poderia acelerar as mudanças climáticas. Para melhor compreender o efeito de borda e da extração de madeira sobre o carbono no solo, medimos a variação espacial do efluxo de CO 2 e do estoque de carbono do solo superficial em relação à distância até 200 m da borda. Além disso, mensuramos variáveis ambientais que pudessem explicar tal variação espacial dentro de uma parcela de 20 x 200 m, posicionada perpendicularmente à margem da borda de dez áreas sob efeito de exploração madeireira. A complexa variação espacial do efluxo de CO 2 pelo solo de áreas alteradas está relacionada a diversos fatores ambientais, tais como: percentual de carbono total e da fração leve livre do solo superficial, temperatura do solo, espessura da camada de liteira e densidade do solo. O efeito de borda sobre o efluxo de CO 2 do solo mostrou-se complexo e difícil de ser mensurado, mas encontramos evidências de que a presença de borda aumenta o estoque de carbono no solo superficial. Extração seletiva de madeira sem controle e por períodos prolongados também aumenta o estoque de carbono do solo superficial, mas aumenta a emissão de CO 2 pelo solo. Estes resultados sugerem que, apesar do estoque de carbono do solo superficial aumentar com a deposição de material vegetal sobre o solo em virtude do efeito de borda e da atividade de extração de madeira, este estoque tem sido decomposto, aumentando as emissões de CO 2 para a atmosfera. The environmental changes caused by forest fragmentation may affect the forest carbon fluxes and increase the efflux of CO 2 to the atmosphere. The emission of stored soil carbon can accelerate the global warming because of the large amount of soil carbon (138 Gt carbon up to 8 m of depth in Legal Amazon). To understand the edge and logging effects on the forest soil carbon, we analyzed the soil efflux of CO 2 and topsoil carbon stock spatial variation in relation to the edge distances (0-200 m) at ten sites in the Central Amazon. Furthermore, some environmental variables that could explain this spatial variation were measured to get a better understanding of this spatial variation. The complex spatial variation of soil CO 2 efflux is related to many environmental variables as total carbon and free light fraction carbon in topsoil, soil temperature, depth of the litter layer and soil density. The edge effect on soil CO 2 efflux was complex and difficult of be measured, but we find evidences of edge effect increases the top soil carbon stock. Logging without control and during by long time also increases the top soil carbon stock, but increases the soil CO 2 efflux too. These results suggest that despite increase of top soil carbon stock by deposition of vegetal material on soil caused by edge effect and logging, this stock has been decomposed, increasing the soil CO 2 emission to atmosphere.

WWF - World Wildlife Fund CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico Este trabalho apresenta um estudo comparativo entre as comunidades de formigas, existentes em uma floresta primária e dois tipos de sistemas de extração de madeira (Manejado e Tradicional) em uma área Tropical localizada em Paragominas, PA. Formigas foram amostradas através de pitfall-traps (Majer & Delabie 1994) em transetos de 200m separados 100m entre si. Diferenças na diversidade da fauna de formigas entre estes hábitats foram testadas por meio de Índices de Diversidade (Shannon, Simpson and Fisher's Alpha), e Protocolos de Estimativa de Riqueza (Colwell & Coddington 1994). A composição de espécies foi avaliada empregando Análises de Afinidade (Scheiner 1992) e índices de Similaridade (Jaccard and Morisita-florn). No total, 134 espécies de formigas, pertencentes a sete subfamílias e 42 gêneros foram identificadas em na área toda. Destas, 90 foram encontradas na Floresta Primária, 90 no Corte Manejado e 84 no Sistema de Corte Tradicional. Diferenças entre na Diversidade e Similaridade entre hábitats apenas puderam ser detectadas quando comparados transectos/hábitats. Quando os índices foram comparados através dos valores absolutos calculados para cada hábitat, a diferença desaparece. Os resultados dos Protocolos de Estimativa de Riqueza empregados indicam que a fauna de formigas foi igual entre os hábitats e sugerem que a fauna está subestimada. Variações periódicas na temperatura e umidade podem ter um forte efeito, igualmente nas estimativas de Diversidade e de Riqueza nos hábitats estudados. Análises na composição mostram que a fauna de formigas é similar entre os hábitats, e apesar desta similaridade, pudemos detectar através da Análise de Afinidade uma alta Diversidade de Mosaico, a qual sugere que a comunidade é composta por gradientes muito complexos, assim diferenças na composição poderão estar ocorrendo em escalas menores. This work presents a comparative study of ant fauna communities inhabiting in a primary tropical forest and two types of logging systems (Managed and Traditional) located in Paragominas, PA, Brazil. From each area, ants were sampled using pitfall traps (Majer & Delabie 1994) in six 200m transects separated from each other by 100m. Differences in ant fauna diversity in the three forest types were tested using índices of diversity (Shannon, Simpson and Fisher's Alpha) and richness estimates protocols (Colwell Coddington 1994). Species composition was evaluated through affinity analysis (Scheiner 1992) and indices of similarity (jaccard and Morisita-Horn). A total of 134 ant species belonging to seven subfamilies and 42 genera were identified in the entire area. From these, 90 species were found in Primary Forest, 90 in Managed logged forest and 84 in the Traditional logged Forest. Differences between habitats could be detected by comparing diversity and similarity indices in different transects/habitats. There were no differences in índices when absolute values were compared for each habitat. Results from richness estimate protocols indicate that ant fauna was similar between habitats and suggests that ant fauna diversity was underestimated. Periodic variations on pluviosity had a strong effect on diversity and richness estimates in the three forest types. The ant fauna composition was similar between habitats; however, a high mosaic diversity could be detected by using affinity analysis, suggesting that the ant community is composed of complex gradients. Thus differences in ant composition would be detectable at smaller scales.