Composição florística e estrutural da regeneração natural em uma floresta manejada no município de Itacoatiara (AM)

The regeneration of vegetation is a natural process in which each species develops its own characteristics. Knowing the process of natural regeneration, when subjected to selective logging is of fundamental importance for the success of forest management. Aiming to analyze natural regeneration after such interventions, six plots of 10 x 100 (level 2 = 2.4 ha) were allocated divided into sub plots of 2 x 2 m (level 1 = 0.288 ha) in three areas with different ages of exploration and a witness in the logged forest of the timber company Precious Woods Amazon Ltda, located in Itacoatiara (AM). At each level were taken three size classes, level 1 (C1 = 0.50 m ≥ height < 1.50 m; C2 = 1.50 m ≥ height < 3 m; C3 = height ≥ 3 m and DBH < 5 cm), level 2 (C1 = 5 cm ≥ DBH < 10 cm; C2 = 10 cm ≥ DBH < 15 cm; C3 = 15 cm ≥ DBH ≤ 20 cm). Plant height was measured with a ruler graduated in meters and the diameter was measured with a diameter tape, the identification of plants was made in the field and in the laboratory and much of the plant material was collected, pressed, dried and identified by comparison with the herbarium material. The floristic composition consisted with 4365 individuals (level 1 = 2278, level 2 = 2087), 49 families (level 1 = 44, level 2 = 46), 154 genera (level 1 = 125, level 2 = 126) and 416 species ( level 1 = 341, level 2 = 268). The Shannon diversity index was 5.24 (level 1 = 4.97, level 2 = 4.95) and floristic similarity of 0.38 (38%) with 193 species common to both levels. The vertical structure of the natural regeneration showed a decrease in the number of individuals at both levels, according to the amplitude of the class size adopted. The first class of each level (C1) detained most of the individuals, when compared to the last two classes. At both levels of approach, the different areas analyzed were dominated by individuals belonging to family Burseraceae, as to the number of species, the families differed among the areas examined at the two levels. For the size classes at the two levels of approach, 35 (8.41%) species covered all size classes. Among those that occurred in all classes, for both levels, are the species that are exploited by the company: Goupia glabra Aubl. (cupiúba), Scleronema micranthum (Ducke) Ducke (cardeiro) and Zygia racemosa (Ducke) Barneby & J.W. Grimes (angelim rajado). Regarding the vertical structure analyzed for the level one species Duguetia flagellaris Huber (envira amarela) was the most important in the parameter on natural regeneration. The most important species in the horizontal structure forest of the for level 2 was Protium sp. 2. (breu vermelho). The forest is considered non-stocked for the species exploited by the company for level 1, because the stock index was 18.43% as in the level 2 was considered the forest stocked because the stock index was 72.50%.A regeneração da vegetação é um processo natural em que cada espécie desenvolve características próprias. Conhecer o processo da regeneração natural, quando submetida ao corte seletivo é de fundamental importância para o sucesso do manejo florestal. Objetivando analisar a regeneração natural após tais intervenções, foram alocadas seis parcelas de 10 x 100 m (nível 2= 2,4 ha) subdivididas em subparcelas de 2 x 2 m (nível 1= 0,288 ha) em três áreas com diferentes idades de exploração e uma testemunha na floresta manejada da empresa madeireira Precious Woods Amazon Ltda, localizada no município de Itacoatiara (AM). Em cada nível foram adotadas três classes de tamanho, nível 1 (C1=0,50 m ≥ altura < 1,50 m; C2=1,50 m ≥ altura < 3 m; C3=altura ≥ 3 m e DAP < 5 cm), nível 2 (C1=5 cm ≥ DAP < 10 cm; C2=10 ≥ DAP < 15 cm; C3=15 cm ≥ DAP ≤ 20 cm). A altura das plantas foi medida com uma trena graduada em metros e o diâmetro, com fita diamétrica; a identificação das plantas foi feita tanto no campo quanto em laboratório e boa parte do material botânico foi coletado, prensado, seco e identificado por comparação com material de herbário. A composição florística constou de 4365 indivíduos (nível 1= 2278; nível 2= 2087), 416 espécies (nível 1= 341; nível 2= 268), 154 gêneros (nível 1= 125; nível 2= 126) e 49 famílias (nível 1= 44; nível 2= 46). Cinquenta e três espécies são exploradas pela empresa, as quais encontram-se distribuídas em 37 gêneros e 20 famílias. O índice de diversidade de Shannon foi de 5,24 (nível 1= 4,97; nível 2= 4,95) e similaridade florística de 0,38 (38%) com 193 espécies comuns aos dois níveis. A estrutura vertical da regeneração natural apresentou um decréscimo no número de indivíduos nos dois níveis, conforme a amplitude de tamanho da classe adotada. A primeira classe de cada nível (C1) foi detentora da maior parte dos indivíduos, quando comparada às duas últimas classes. Nos dois níveis de abordagem, as diferentes áreas analisadas foram dominadas por indivíduos pertencentes à Burseraceae, quanto ao número de espécies as famílias diferiram entre as áreas analisadas nos dois níveis. Para as classes de tamanho nos dois níveis de abordagem, 35 (8,41%) espécies contemplaram todas as classes de tamanho. Dentre as que ocorreram em todas as classes, nos dois níveis, estão as espécies exploradas pela empresa: Goupia glabra Aubl. (cupiúba), Scleronema micranthum (Ducke) Ducke (cardeiro) e Zygia racemosa (Ducke) Barneby & J.W. Grimes (angelim rajado). Quanto a estrutura vertical analisada para o nível 1, Duguetia flagellaris Huber (envira amarela) foi a mais importante quanto ao parâmetro regeneração natural relativa. A espécie mais importante na estrutura horizontal da floresta para o nível 2 foi Protium sp. 2 (breu vermelho). A floresta é considerada não estocada em relação às espécies exploradas pela empresa para o nível 1, pois o Índice de Estoque foi de 18,43%, já para o nível 2 a floresta foi considerada estocada, pois o Índice de Estoque foi de 72,50%

Composição florística e análise estrutural da floresta primária de terra firme na bacia do rio cuieiras, Manaus-Am

This study dealt with vegetation characterization and horizontal structure analysis of a plant species community, and it was carried out at ZF-2 Tropical Forestry Experimental Station of the National Institute for Research in the Amazon (INPA). The climate is characterized as “Amw”, which means warm and humid all year long. Floristic and phytosociologic surveys were done over two transects (East-West and North-South) measuring 20 x 2500 m each, which were stratified by plateau and “baixio”. Each transect was divided into 125 sample units of 20 x 20 m each, where botanical samples were collected for identification besides information related to diameter at breast height (dbh) of 10 cm. For this study only plateau and “baixio” were used for further comparisons, therefore, 7 hectares were used instead of 10 ha of the two transects together. The floristic composition of the 7-ha (plateau + “baixio”) site is represented by 737 species, 238 genera and 59 botanical families. The richest families in terms of species are: Sapotaceae (69 species), Chrysobalanaceae (44), Lauraceae (44), Lecythidaceae (39), Fabaceae (39) and Mimosaceae (38). In terms of individual species, the most important are: Oenocarpus bataua Mart., Eschweilera wachenheimii (Benoist) Sandwith, Eperua glabriflora (Ducke) R.S. Cowan, Hevea guianensis Aubl., and Scleronema micranthum Ducke. The floristic composition in plateau is represented by 533 species, 187 genera and 53 families with 623 individuals per hectare and basal area equivalent to 28.3 m2ha-1. The richest families in plateau are: Sapotaceae (61 species), Lecythidaceae (36) and Burseraceae (27). The three most important families are: Lecythidaceae, Sapotaceae and Fabaceae. The most important species are: Eschweilera wachenheimii (Benoist) Sandwith, Eschweilera truncata A.C. Sm., Micrandropsis scleroxylon W.Rodr., Eschweilera coriacea (DC.) Mart. ex Berg. and Eschweilera pseudodecolorans S.A. Mori. The floristic composition in “baixio” is represented by 461 species, 177 genera and 50 families with 624 individuals per hectare and basal area equivalent to 29.1 m2ha-1. The richest families in “baixio” are: Sapotaceae (37 species), Fabaceae (33) and Chrysobalanaceae (28). The two most important families are: Arecaceae and Euphorbiaceae. The most important species are: Oenocarpus bataua Mart., Eperua glabriflora (Ducke) R.S. Cowan, Micrandra siphonioides Benth. and Vitex sprucei Briq.. In terms of occurrence exclusivity, plateau presented 9 families, 60 genera and 281 species, while “baixio” presented 6 families, 54 genera and 212 species.O presente estudo descreve a caracterização da vegetação e análise da estrutura horizontal da comunidade arbórea em floresta de terra firme na bacia do rio Cuieiras, região de Manaus, localizada na Estação Experimental de Silvicultura Tropical do INPA, núcleo ZF-2. O clima da região é do tipo “Amw”, caracterizado como quente e úmido durante o ano inteiro. Para o levantamento florístico e fitossociológico foram utilizados os dados de transectos (Norte-Sul e Leste-Oeste) de 20 x 2.500 m cada, subdivididos em 125 unidades amostrais quadradas de 20 x 20 m, ao longo de um gradiente topográfico estratificado em platô e baixio. Nas unidades amostrais presentes no platô e baixio foram observados os indivíduos arbóreos com DAP ≥ 10 cm, dos quais obteve-se amostras botânicas para identificação. A composição florística nos sete hectares (platô + baixio) constou de 737 espécies, pertencentes a 238 gêneros e 59 famílias. As famílias mais ricas em espécies foram: Sapotaceae (69 espécies), Chrysobalanaceae e Lauraceae (44), Lecythidaceae e Fabaceae (39) e Mimosaceae (38). As famílias mais importantes, em ordem decrescente de IVIf, foram: Sapotaceae, Lecythidaceae e Euphorbiaceae. As espécies que mais se destacaram em valor de importância foram: Oenocarpus bataua Mart., Eschweilera wachenheimii (Benoist) Sandwith, Eperua glabriflora (Ducke) R.S.Cowan, Hevea guianensis Aubl. e Scleronema micranthum Ducke. No platô a composição florística constou de 533 espécies, pertencentes a 187 gêneros e 53 famílias, apresentando uma densidade total de 623 ind./ha e área basal de 28,3 m².ha-1. As famílias mais ricas em espécies foram: Sapotaceae (61 espécies), Lecythidaceae (36) e Burseraceae (27). As famílias mais importantes, em ordem decrescente de IVIf, foram: Lecythidaceae, Sapotaceae e Fabaceae. As espécies que mais se destacaram em valor de importância (IVI) foram: Eschweilera wachenheimii (Benoist) Sandwith, Eschweilera truncata A.C.Sm., Micrandropsis scleroxylon W.Rodr., Eschweilera coriacea (DC.) Mart. ex Berg. e Eschweilera pseudodecolorans S.A.Mori. No baixio a composição florística constou de 461 espécies, pertencentes a 177 gêneros e 50 famílias, apresentando uma densidade total de 624 ind./ha e área basal de 29,1 m² ha-1. As famílias mais ricas em espécies foram: Sapotaceae (37 espécies), Fabaceae (33) e Chrysobalanaceae (28). As famílias mais importantes, em ordem decrescente de IVIf, foram: Arecaceae e Euphorbiaceae. As espécies que mais se destacaram em valor de importância foram: Oenocarpus bataua Mat., Eperua glabriflora (Ducke) R.S.Cowan, Micrandra siphonioides Benth. e Vitex sprucei Briq.. Quanto a exclusividade de famílias, gêneros e espécies, o platô sobressaiu-se com 9 famílias, 60 gêneros e 281 espécies, enquanto que o baixio apresentou 6 famílias, 54 gêneros e 212 espécies

Biomass stock and structural analysis of a secondary forest in Manaus (AM) region, ten years after clear cutting followed by fire

In Amazonia, fire is widely used for soil preparation in the agriculture and cattle ranching, either by small or big farmers. The combination of low fertility of the soil and low price of the land usually leads to typical shift cultivation as soon as the natural sources of nutrients are exhausted, when new primary forests are felled and burned. Due to that, secondary forests originated from abandoned agriculture or pasture activity projects cover huge areas in the Brazilian Amazônia. This study was carried out in the Tropical Forestry Experimental Station (EEST/INPA), around 50 kilometers north of Manaus, the capital of Amazonas State. A secondary forest capoeira"), 10 years old, was selected for this study; its land use history includes clear cutting followed by fire. Two different samples of primary forests were included as control plots for the "capoeira". All individuals with diameter at breast height (DBH) greater than 5 cm were measured and recorded in a single area of 0,4 ha for each treatment. Ten years after burning, the secondary forest is still very different in comparison with primary forest, in terms of important parameters of the vegetation structure, such as floristic composition, abundance, frequency, dominance, index of value of importance (IVI) and the diameter distribution. In "capoeira" studied the dominant species are mainly of the following botanical families: Annonaceae, Arecaceae, Burseraceae, Cecropiaceae, Euphorbiaceae, Fabaceae, Lecythidaceae, Melastomataceae, Mimosaceae, Sapindaceae and Sterculiaceae. The estimates of dry biomass were 56.2 t. ha-1 ± 12 (CI 95%) and 339.7 t.ha-1 ± 66.7 (CI 95%) for "capoeira" and primary forest, respectively.Na Amazônia, o fogo é ainda o principal trato cultural utilizado no preparo de solo para agricultura e pecuária, tanto pelos pequenos como pelos grandes fazendeiros. Combinando à baixa fertilidade do solo e ao baixo preço da terra, assim que as fontes naturais de nutrientes são exauridas, as áreas são abandonadas e novas florestas primárias são derrubadas e queimadas. Por conta disso, grandes extensões de área da Amazônia são cobertas por florestas secundárias originadas de áreas abandonadas pela agricultura ou pastagem. Este estudo foi conduzido em uma área experimental usada em uma pesquisa sobre eficiência de combustão e emissão de gás carbônico da floresta amazônica, localizada aproximadamente 50 km ao norte de Manaus. A vegetação da área experimental foi derrubada e queimada em 1991, simulando as condições em que o pequeno agricultor prepara o solo para plantios de subsistência. Dez anos após a queimada, a floresta secundária ainda é bastante diferente da floresta original. As espécies vegetais dominantes são, principalmente, das famílias botânicas Annonaceae, Arecaceae, Burseraceae, Cecropiaceae, Euphorbiaceae, Fabaceae, Lecythidaceae, Melastomataceae, Mimosaceae, Sapindaceae e Sterculiaceae. O estoque de biomassa recuperado, dez anos após a formação da capoeira estudada, é de aproximadamente 16%, ou seja, a capoeira apresenta um estoque médio de 56,2 t.ha-1 ± 12 (IC 95%), enquanto que o estoque da floresta primária é de 339,7 t.ha-1 ± 66,7 (IC 95 %)

Avaliação da estrutura de uma floresta submetida a diferentes intensidades de anelamento, 28 anos após a intervenção

In the Brazilian Amazon Area there is no long-term research reporting on the forest structural response to thinning by girdling. This study was conducted in the Tropical Forestry Experimental Station of the National Institute of Amazonian Research. The objective was to evaluate the structure of an upland forest which had a reduction of basal area by annealing by different intensities. The study was conducted 28 years after the girdling intervention. The experiment was installed in 1985 on 15 hectares. The statistical design was randomized blocks with three replications and four treatments (T1, T2, T3 and T4) and one control (T0). As for the number of trees per hectare (trees.ha-1), the ringed area showed a high capacity for resilience, even when subjected to high levels of intervention. In treatments T1, T2 and T3 the annealing benefited both commercial and non-commercial species. In T4, there was a reversal of this trend, an increase in the proportion of commercial species was detected when compared with T0. The diameter distribution of T1 (χ2 = 16.1) and T2 treatments (χ2 = 15.4) were statistically equal to T0 and the treatments T3 (χ2 = 29.9) and T4 (χ2 = 55.3) were different. The results suggest that the forest structure still has signs of the different interventions. The silvicultural treatment used in T4 has great potential to increase the forest dynamics and tree growth without compromising the forest structure and ecological processes

Dynamics of the Terra-firme primary forest in Manaus-AM region using the Markov probabilistic transition matrix

To combine protection and utilization of forest resources in the tropics, the understanding of forest dynamics is essential. It is also important in the definition of strategies for rehabilitation of degraded areas. In Forestry, forest dynamics could be translated as the understanding of recruitment, mortality and biomass increment rates over time. For this study, these rates were estimated based on measurements carried out in 2000 and 2004 over two transects measuring 20 by 2500 m (5 hectares) each, in Manaus region. This paper deals with forest dynamics of a pristine forest based on the probabilistic transition matrix (the first-order Markov Chain) approach. The main objective is to report 4-year (2000 to 2004) changes in the forest structure. Diameter distribution and tree mortality will be projected ahead to 2008 (t+2), based upon a 4-year period of observations completed in 2004 (t+1) and its immediate past in 2000 (t). In terms of fresh aboveground biomass, this site accumulated 8.34 t.ha-1.ano-1. The chi ² test has shown no statistical difference (p = 0.01) between observed diameter frequency and the expected projected by Markov Chain. This result indicates that the Markov Chain approach is a reliable tool to project the forest dynamics on a short-term basis. In 2008, the total number of individuals will have a decrease of 2.7%, and the mortality rate will 15% higher than in 2004.Os fatores que envolvem os processos da dinâmica da floresta influenciam a sua biodiversidade e, portanto, a qualidade da floresta. A definição de estratégias que envolve a proteção e o uso adequado da floresta manejada e a recuperação de áreas já degradadas tornam-se possível com o estudo da estrutura e dinâmica da floresta primária por meio de informações como a mortalidade, o recrutamento e a permanência das árvores no sistema florestal. Este trabalho teve como objetivo avaliar a dinâmica de uma floresta não perturbada e fazer projeções da dinâmica florestal usando a matriz de transição probabilística (Cadeia de Markov). As taxas de recrutamento, mortalidade e incremento foram determinadas a partir de inventários florestais realizados em dois transectos, nos sentidos Norte-Sul e Leste-Oeste (20 x 2500 m cada, totalizando 10 ha), localizados no km 50 da BR 174, na estrada vicinal ZF-2, Manaus/AM, nos anos de 2000 e 2004. A floresta acumulou 8,34 t.ha-1.ano-1 de biomassa fresca acima do solo. De acordo com projeção para 2008, o número total de árvores diminuirá em 2,67% (de 5987 indivíduos (2004) para 5827 (2008)) e a mortalidade será 15% maior (de 264 (2004) para 311 (2008)). O teste Qui-quadrado mostrou que não há diferença significativa (1% de probabilidade) entre as informações coletadas e projetadas. Esses resultados permitem concluir que a Cadeia de Markov é um eficiente instrumento para projetar a dinâmica da floresta natural, contribuindo para o planejamento em curto prazo das atividades que utilizam os recursos florestais

Highly reactive light-dependent monoterpenes in the Amazon

Despite orders of magnitude difference in atmospheric reactivity and great diversity in biological functioning, little is known about monoterpene speciation in tropical forests. Here we report vertically resolved ambient air mixing ratios for 12 monoterpenes in a central Amazon rainforest including observations of the highly reactive cis-β-ocimene (160 ppt), trans-β-ocimene (79 ppt), and terpinolene (32 ppt) which accounted for an estimated 21% of total monoterpene composition yet 55% of the upper canopy monoterpene ozonolysis rate. All 12 monoterpenes showed a mixing ratio peak in the upper canopy, with three demonstrating subcanopy peaks in 7 of 11 profiles. Leaf level emissions of highly reactive monoterpenes accounted for up to 1.9% of photosynthesis confirming light-dependent emissions across several Amazon tree genera. These results suggest that highly reactive monoterpenes play important antioxidant roles during photosynthesis in plants and serve as near-canopy sources of secondary organic aerosol precursors through atmospheric photooxidation via ozonolysis. © 2015. The Authors

Soil fertility and drought interact to determine large variations in wood production for a hyperdominant Amazonian tree species

Introduction: The productivity of the Amazon Rainforest is related to climate and soil fertility. However, the degrees to which these interactions influence multiannual to decadal variations in tree diameter growth are still poorly explored. Methods: To fill this gap, we used radiocarbon measurements to evaluate the variation in tree growth rates over the past decades in an important hyperdominant species, Eschweilera coriacea (Lecythidaceae), from six sites in the Brazilian Amazon that span a range of soil properties and climate. Results: Using linear mixed-effects models, we show that temporal variations in mean annual diameter increment evaluated over a specific time period reflect interactions between soil fertility and the drought index (SPEI-Standardized Precipitation and Evapotranspiration Index). Discussion: Our results indicate that the growth response of trees to drought is strongly dependent on soil conditions, a facet of forest productivity that is still underexplored, and which has great potential for improving predictions of future tropical tree growth in the face of projected climate change

Hyperspectral remote detection of niche partitioning among canopy trees driven by blowdown gap disturbances in the Central Amazon

Advanced recruitment and neutral processes play important roles in determining tree species composition in tropical forest canopy gaps, with few gaps experiencing clear secondary successional processes. However, most studies are limited to the relatively limited spatial scales provided by forest inventory plots, and investigations over the entire range of gap size are needed to better understand how ecological processes vary with tree mortality events. This study employed a landscape approach to test the hypothesis that tree species composition and forest structural attributes differ between large blowdown gaps and relatively undisturbed primary forest. Spectral mixture analysis on hyperspectral satellite imagery was employed to direct field sampling to widely distributed sites, and blowdown plots were compared with undisturbed primary forest plots. Tree species composition and forest structural attributes differed markedly between gap and non-gap sites, providing evidence of niche partitioning in response to disturbance across the region. Large gaps were dominated by classic Neotropical pioneer genera such as Cecropia and Vismia, and average tree size was significantly smaller. Mean wood density of trees recovering in large gaps (0.55 g cm-3) was significantly lower than in primary forest plots (0.71 g cm-3), a difference similar to that found when comparing less dynamic (i.e., tree recruitment, growth, and mortality) Central Amazon forests with more dynamic Western Amazon forests. Based on results, we hypothesize that the importance of neutral processes weaken, and niche processes strengthen, in determining community assembly along a gradient in gap size and tree mortality intensity. Over evolutionary time scales, pervasive dispersal among colonizers could result in the loss of tree diversity in the pioneer guild through competitive exclusion. Results also underscore the importance of considering disturbance processes across the landscape when addressing forest carbon balance. © 2009 Springer-Verlag