Celso Paulo de Azevedo

Estudo fitossociológico nas regiões de Carajás e Marabá - Pará, Brasil

O estudo fitossociologico levou em consideracao duas areas localizadas em Carajas e Maraba, na regiao sul do Para. A amostragem abordou dois niveis: 1) Individuos com DAP ≥ 20cm em parcelas de 20m x 200m e, II) Individuos com 5cm ≤ DAP ≤ 20cm em duas sub-parcelas de 10m x 10m no inicio c final das parcelas. Todos os individuos do segundo nivel foram considerados como regeneracao natural do povoamento adulto. Em Carajas utilizou-se 35 (trinta e cinco) unidades amostrais (parcelas) e em Maraba 22 (vinte c duas). Do ponto de vista de composicao floristica, as areas estudadas apresentaram-se heterogeneas, com indices de Shanon-Weaver estimados em 3,66 e 3,71, respectivamente, para Carajas e Maraba. A equacao hipsometrica comum que melhor ajustou os dados observados foi: h = [ d 2.38 + 0.1387 h ] 2 As abundâncias medias foram 131,92 e 127,85 individuos/ha, respectivamente, para Carajas e Maraba. As estimativas de area basal foram 15,41 e 17,35 m2/ha nas regioes de Carajas e Maraba, respectivamente. A funcao de densidade I (Meyer) que melhor ajustou os dados de frequencia por classe de diâmetro (Fi) em funcao do centro de classe (DAP), para Carajas, foi Fi= e(9,56330614 - 0,07139847d) e Fi =e(8,96125691 - 0,06937877d) para Maraba. Tambem estimou-se que cerca de 36% das especies existentes nas regioes estudadas possuem valor economico no mercado madeireiro.

Carbon recovery dynamics following disturbance by selective logging in Amazonian forests

When 2 Mha of Amazonian forests are disturbed by selective logging each year, more than 90 Tg of carbon (C) is emitted to the atmosphere. Emissions are then counterbalanced by forest regrowth. With an original modelling approach, calibrated on a network of 133 permanent forest plots (175 ha total) across Amazonia, we link regional differences in climate, soil and initial biomass with survivors’ and recruits’ C fluxes to provide Amazon-wide predictions of post-logging C recovery. We show that net aboveground C recovery over 10 years is higher in the Guiana Shield and in the west (21 ±3 Mg C ha-1) than in the south (12 ±3 Mg C ha-1) where environmental stress is high (low rainfall, high seasonality). We highlight the key role of survivors in the forest regrowth and elaborate a comprehensive map of post-disturbance C recovery potential in Amazonia. DOI: http://dx.doi.org/10.7554/eLife.21394.001

Uso de banda dendrométrica na definição de padrões de crescimento individual em diâmetro de árvores da bacia do rio Cuieiras

Este trabalho tem como objetivo analisar padroes de crescimento individual de diversas arvores que ocorrem em duas topossequencias (direcoes Norte-Sul e Leste-Oeste), de uma amostra representativa da floresta de terra-firme na Amazonia Central. Foram selecionados de forma aleatoria, aproximadamente, 300 individuos, sendo 150 em cada topossequencia, distribuidos em mesmas proporcoes nas tres classes topograficas (plato, encosta e baixio) e nas tres classes de diâmetro (10 ≤ DAP < 30 cm; 30 ≤ DAP< 50 cm e DAP≥ 50 cm). Em cada uma dessas arvores foi instalada uma fita metalica, com extremidades parcialmente sobrepostas e ligadas por uma mola; o avanco de uma das pontas, dentro de uma abertura, representa o crescimento em circunferencia, que foi medido com um paquimetro digital. As medicoes foram realizadas mensalmente ao longo de 19 meses, de junho/1999 a dezembro/2000; neste estudo foram considerados apenas os 12 meses do ano 2000. O padrao individual de crescimento em diâmetro varia muito com o passar dos meses (p = 0,00) e apenas razoavelmente quando os meses sao interagidos com as classes de diâmetro (p 0,08); por outro lado, ha fraca uma evidencia (p = 0,25) quando as classes topograficas sao acrescentadas na interacao anterior e praticamente nenhuma evidencia (p = 0,89) quando e analisada a interacao meses e classes topograficas. Dentre todas as arvores selecionadas (300 individuos), foram mantidas na analise 272 individuos. A media do incremento anual em diâmetro, considerando as 272 arvores monitoradas, foi de 1,64 ± 0,21 mm (p = 0,05), ficando dentro do intervalo dos incrementos obtidos no BIONTE e FLONA Tapajos, que e de 1,5 a 2 mm por ano.

Comportamento de espécies florestais em plantios a pleno sol e em faixas de enriquecimento de capoeira na Amazônia

Foram avaliadas especies florestais nativas e exoticas em duas condicoes de plantio: a pleno sol e em faixas de enriquecimento de capoeira, a fim de gerar tecnologias para incorporacao ao processo produtivo de areas alteradas na regiao amazonica para minimizar a pressao do desmatamento sobre a floresta natural. Os dados analisados (DAP, altura, volume por hectare e sobrevivencia) referem-se a idade de seis anos. No plantio a pleno sol, a especie que apresentou o melhor desempenho foi Ceiba pentandra, com medias de DAP de 19,6 cm, altura de 10,2 m e volume de 390,9 m3 ha-1. Hymenaea courbaril tambem apresentou crescimento satisfatorio, com medias de 11,5 cm de DAP, 10,8 m de altura e 144,8 m3 ha -1 de volume. Nos plantios de enriquecimento de capoeira, a Carapa guianensis foi a especie que apresentou o melhor desempenho, com 8,3 cm de DAP, 6,4 m de altura e volume de 54,8 m3 ha -1. Acacia mangium e Sclerolobium paniculatum apresentaram crescimento superior, mas as taxas de sobrevivencia foram muito baixas nas duas condicoes de plantio.

Simulação de estratégias de manejo florestal na Amazônia com o uso do modelo SYMFOR

The SYMFOR model was used to simulate the ecological processes of tree growth, mortality and recruitment, and the forest management processes, in the terra firme forests of the eastern Amazon. The simulation utilized all the trees that have a diameter greater than 5 cm, from 40 permanent sample plots of 1 ha each (36 logged and 4 unlogged). The stand was measured in 1984, logged in 1985 and remeasured in 1986, 1988, 1990, 1994, 1996 and 2004. Ten species groups are used to describe the natural processes affecting tree behavior. Model performance compares the simulation results with real data describing the forest recovery for 19 years following logging. The treatments, combinations of logging intensities (15%, 25% and 35% of the total volume of the trees higher than 60 cm of DBH had been tested) and thinning intensities (0%, 30%, 50% and 70% of the original basal area) were analyzed as management strategies. The model was applied to simulate current forest management practice in the Brazilian Amazon, with 30 m3 ha−1 of timber extracted with a cutting cycle of 30 years. Results show that the similarity among observed and simulated data for SYMFOR validated the model to represent the dynamics of the unlogged forest. In the simulation of the current management practice applied in the Amazon forest, it is suggested that the financial benefits decrease with successive harvests and, consequently, the timber volume cannot be sustained.

Predição da distribuição diamétrica de uma floresta manejada experimentalmente através de um Sistema de Equações Diferenciais

The aim of this study was to evaluate the prognosis of the diameter structure of an experimentally managed forest, utilizing a system of differential equations of the first order, adjusted for each treatment. The basic data were obtained from the Bom Manejo Projet (Embrapa Eastern Amazon/CIFOR/ITTO), carried out in the Monte Dourado Forest Company (Jari) area, Vitoria do Jari, Amapa, Brazil. The statistical delineation was designed as random blocks with three replications. The treatments applied were combinations of logging intensities (15%, 25% and 35% of the total volume of the trees larger than 60 cm of DBH) and thinning intensities (0%, 30%, 50% and 70% of the original basal area). The non-logged forest was used for the control plots. Stand development was monitored through 40 permanent sample plots of 1 ha each (36 logged and 4 unlogged). The stand was measured in 1984, logged in 1985 and remeasured in 1986, 1988, 1990, 1994, 1996 and 2004. All the trees with DBH ≥ 20 cm were measured. While keeping the same simplicity of transition matrix based models, the proposed model allows for determining the state of the system for any given point in time, not being confined just for multiplying time intervals as was the former. This method was verified for different evaluation periods and the results showed that not even the longer periods of projections (break-even point) will be enough to restore the initial conditions of the stand.

Dinâmica e estoque de carbono em floresta primária na região de Manaus/AM

This study analyzed data from three forest inventories conducted in the Experimental Forest, which belongs to Embrapa Western Amazon basin and is located at km 54 on BR-174, Manaus / AM. The aim was to study forest dynamics - the rates of recruitment, growth and mortality - in addition to carbon storage in an area of primary forest, without any intervention. The surveys were conducted in the years 2005, 2007 and 2010 in 15 permanent plots of 1 hectare each. There, all trees with diameter at breast height (DBH) above 10 cm were measured. We calculated the rates of recruitment and mortality, the periodic annual increments (PAIs) in terms of DBH, basal area and volume, fresh and dry biomass above the soil and total carbon storage in the vegetation. The recruitment rates were 2.0 percent and 1.8 percent, and mortality were 0.95 percent and 1.3 percent for the periods between 2005 and 2007 and 2007 and 2010, respectively. The volume was 345.62 m3 ha-1 for the year 2005, rising to 360.67 m3 ha-1 in 2010 with PAIs of 4.32 m3 ha-1 yr-1 between 2005 and 2007 and 1.31 m3 ha-1 yr-1 between 2007 and 2010. The total carbon storage increased from 173.63 t C ha-1 in 2005 to 181.01 t C ha-1 in 2010, confirming that the forest accumulated carbon in the period, acting as a sink.

Carbon stock and dynamics in a managed forest in Central Amazon

The Amazon forest has been in evidence in global discussions about their role in control of global climate change, both by the ability to emit greenhouse gases into the atmosphere via burning or thinning, how to absorb carbon from the atmosphere by through the growth of the stand. This study analyzed data from a forest managed in 1987, in Manaus/AM. This work aimed to study the carbon stock and dynamics. The forest inventories were conducted in 15 hectares of permanent plots. The average rates of recruitment were 4.9%, 4.8%, 3.7% and 5% for control treatments and logging of 1/3, 1/2 and 2/3, respectively, and the average mortality rates were 3.1%, 6%, 4.8% and 6.7%, for control treatments and logging of 1/3, 1/2 and 2/3, respectively. The basal area (23.1 m2 ha-1 in 2005, 23.6 m2 ha-1 in 2007 and 23.7 m2 ha-1 in 2010), the volume (345 m3 ha-1 in 2005, 351.3 m3 ha-1 in 2007 and 353.7 m3 ha-1 in 2010) and the carbon content (149.2 t ha-1 in 2005, 151.8 t ha-1 in 2007 and 152.6 t ha-1 in 2010) increased in all measurements. However, the statistical difference between these values was not significant, so it was concluded that the forest was in equilibrium with the atmosphere during the period evaluated. A comparison of the carbon stock of the years measured with the stock pre-exploratory, in 1986, showed that in 2010 the carbon stock equaled the content before logging, meaning the forest recovery.

STRUCTURE OF 15 HECTARES PERMANENT PLOTS OF TERRA FIRME DENSE FOREST IN CENTRAL AMAZON

Terra Firme dense forest occurs in 65% of the Amazonian region and is characterized by the high diversity of plant species and high occurrence of rare plant species. The objective of this work was to analyze the horizontal structure of 15 hectares of plots, randomly chosen from a set of 400 ha of permanent plots situated at the Experimental Site of Embrapa, Manaus, Amazonas State, Brazil. All individuals with DBH ≥ 10 cm were identified at the level of species in 2005. The VI values (Values of importance) were separated in classes of range with one (01) standard deviation and the individuals distributed according to DBH classes of 10 cm in amplitude. In total, 8771 individuals were identified, distributed into 264 species and 53 families. A larger number of individuals is concentrated in a few number of species, such as Protium hebetatum D.C. Daly, Eschweilera coriacea (DC.) S.A. Mori and Licania oblongifolia Standl, which sum up 21% of the total number of individuals and 12% of the VI. There is a high occurrence of rare species (36%). The families Sapotaceae, Lecythidaceae and Burseraceae together accounted for 39% of the total number of individuals. The diametric structure in an inverse-J shape shows that 80% of the individuals are concentrated in the DBH classes ranging from 10 to 30 cm. The results highlight the high occurrence of rare species and those with low density, and with distribution restricted to some plots, particularly those belonging to the lowest classes of VI, which deserve special attention in actions for biodiversity conservation and forest management.

ECOLOGICAL AND FUNCTIONAL CLUSTERING OF FORESTAL SPECIES IN THE SOUTH WESTERN AMAZONIA

A floresta amazonica e uma mistura de centenas de especies, com diferentes idades e taxas de crescimento, o seu conhecimento, tanto para pesquisadores quanto para as populacoes amazonicas, e um grande desafio. O objetivo deste estudo foi efetuar o agrupamento ecologico e funcional de especies presentes na floresta do Estado do Acre. Este trabalho foi desenvolvido a partir de dados de 95 parcelas permanentes, com area de um hectare cada (100 x 100m), subdividida em subparcelas de 10 x 10 e instaladas no Projeto de Colonizacao (PC) Pedro Peixoto, Floresta Estadual do Antimary (FEA) e ST Manejo. Nestas sub-parcelas todos os individuos com diâmetro a altura do peito (DAP) maior ou igual a 10 cm foram medidos. O periodo de coleta foi de 1996 ate 2007, com medicoes em intervalos de tempo nao regulares. O processo de agrupamento ocorreu em tres estagios: (1) analise de Cluster para fazer o agrupamento das especies mais populosas. Para esse processo foram empregadas as variaveis Incremento Periodico Anual em diâmetro - IPADAP medio em Alta, Media e Baixa competicao e percentil 95% da distribuicao de frequencia cumulativa dos diâmetros pelo metodo hierarquico Ward; (2) analise Discriminante, para alocar as especies menos populosas aos grupos formados, utilizando-se as variaveis percentil 95% da distribuicao de frequencia cumulativa dos diâmetros e os incrementos periodicos medios anuais em diâmetro (IPADAP) e o metodo de Fisher; (3) estagio subjetivo, utilizado para alocar as especies com poucos individuos aos grupos formados. O metodo Ward utilizado na analise de Cluster e o metodo de Fisher usado no discriminante demonstraram-se eficazes na criacao e formacao dos grupos. A utilizacao destes metodos resultou na formacao de dez grupos de especies com crescimentos de alta similaridade entre individuos do mesmo grupo e baixa similaridade entre grupos. As variaveis: IPADAP para o povoamento e IPADAP em baixa, media e alta competicao e P95 da distribuicao de frequencia cumulativa dos diâmetros demonstraram-se variaveis uteis para a realizacao do agrupamento de especies. As variacoes nas taxas de crescimento relativas a media total dos dados foram reduzidas quando calculada para cada grupo de especies.