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Kolb R.M.,Paulista University | Pilon N.A.L.,University of Campinas | Durigan G.,Instituto Florestal Do Estado Of Sao Paulo
Acta Botanica Brasilica | Year: 2016

Few studies address the ecology of herbs of Cerrado grasslands, which are ecosystems where the long dry season, high temperatures, insolation, fire and invasive grasses greatly influencing germination and the establishment of plants. We assessed germination of 13 species of Poaceae from Cerrado grasslands under nursery conditions or in germination chambers, the latter with i) recently collected seeds and seeds after six months storage, ii) under constant and alternating temperatures, and iii) in the presence and absence of light. Germinability, mean germination time (MGT) and required light were quantified to elucidate factors involved in successful germination. Germinability was low for most grasses, probably because of low seed viability. For most species, germinability and MGT were not altered by seed storage. Germination percentages were higher at alternating temperatures and in the presence of light, factors that are more similar to natural environmental situations compared with constant temperature or the absence of light. Our findings indicate that alternating temperatures and light incidence are key factors for germination of species of Poaceae. The maintenance of these environmental factors, which are crucial for the conservation of Cerrado grasslands, depends on appropriate management interventions, such as fire management and the control of biological invasion. © 2016, Sociedade Botanica do Brasil. All rights reserved.

de Miranda D.L.C.,Federal University of Mato Grosso | de Melo A.C.G.,Instituto Florestal Do Estado Of Sao Paulo | Sanquetta C.R.,Federal University of Parana
Revista Arvore | Year: 2011

The objective of this study was to develop and to fit allometric models to estimate dry biomass and total carbon in trees planted in forest restoration areas. Fit data are from 107 trees of 44 species planted in Médio Paranapanema Vale, SP, Brazil, located in the Atlantic Forest and Cerrado Biomes. Dry biomass and carbon mass were obtained by destructive sampling taken from aerial and underground sections of the trees. For model test and fitting, stratification of the initial data set was made in growth rhythms of the sampled species. Adjust was done by using eight linear models of each dependent variable and two were obtained from Stepwise-Forward method. The best models to estimate dry biomass and carbon stock presented adjusted determination coefficient above 0.95 and standard error below 32%. Models based on growth rate of the species presented the best statistical results, reaching R 2= 0.985 and Syx%=16.15 for dry biomass of low growth species. Models created by Stepwise procedure produced the best equations for estimates of dry biomass and total carbon, and data stratification of different growth rates of the sampled species was suitable for improving performance of the models.

Tiberio F.C.S.,Federal University of Sao Carlos | Sampaio-E-Silva T.A.,Federal University of Sao Carlos | Matos D.M.S.,Federal University of Sao Carlos | Antunes A.Z.,Instituto Florestal Do Estado Of Sao Paulo
Brazilian Journal of Biology | Year: 2016

The introduction of a species may alter ecological processes of native populations, such as pollination and dispersal patterns, leading to changes in population structure. When the introduced and the native species are congeners, interference in pollination can also lead to hybridization. We aimed to understand the ecological aspects of Euterpe oleracea introduction in the Atlantic forest and the possible consequences for the conservation of the native congener Euterpe edulis. We analysed the population structure of palm populations, including hybrids, and observed the interaction with frugivorous birds of both palm species after E. oleracea introduction. We observed that E. edulis had significantly lower density and a smaller number of seedlings when occurring with E. oleracea. Native and introduced Euterpe species shared nine frugivorous bird species. E. oleracea and hybrids had dispersed outside the original planting area. Consequently, the risks of introduction of E. oleracea may mostly be related to the disruption of interactions between E. edulis and frugivorous birds and the spontaneous production of hybrids. Finally, the cultivation of E. oleracea and hybrids in Atlantic rainforest could affect the conservation of the already endangered E. edulis. © 2016, Instituto Internacional de Ecologia. All rights reserved.

The Eucalyptu grandis stands apart for its productivity and quality wood. The ideal forest management where a greater wood ratio and better quality are obtained is one of the questions to be considered in the research of the E. grandis. The present work had as its general objective the study of the variation of the specific gravity and the resistance to the compression as a function of the thinning intensity, fertilization and diameter classes in the radial position in trees of a 21-year old population of E. grandis, managed under the system of selective thinning, with the application of fertilizers. The factors used in this study were: three intensities of selective thinning (37, 50 and 75%), presence or absence of fertilizers, three diameter classes and five radial positions. The influences of the factors and of their combinations were evaluated regarding specific gravity and compression strength. The specific gravity and compression strength of the wood were influenced by factors such as fertilizer and diameter class in almost all radial positions, increasing significantly from the pith to bark. A good positive relationship was found to exist among the specific mass, compression strength and radial position.

Kunz S.H.,Federal University of Vicosa | Martins S.V.,Federal University of Vicosa | Ivanauskas N.M.,Instituto Florestal Do Estado Of Sao Paulo | Stefanello D.,Instituto Cuiabano Of Ensino | Silva E.,Federal University of Vicosa
Revista Arvore | Year: 2010

The Southern Amazon forests, where the Seasonal Perennial Forest occurs, has great influence on the maintenance of the regional physical equilibrium and they are among forests most threatened by anthropic action and are little known in relation to their structure. In this context, the objective of this work was to study phytosociological structure of a Seasonal Perennial Forest area in the Rio das Pacas Basin at Querência, state of Mato Grosso, Brazil. The vegetation sampling was composed of the distribution of 200 center quarter points, all individuals with DAP (diameter to height breast) equal or superior to 10 cm were considered. The total density of the sampled area was 736 ind./ha distributed into 58 species, 45 genera and 31 families. The species of highest Importance Value (IV), Ocotea leucoxylon (Sw.) Laness., Trattinickia glaziovii Swart, Ouratea discophora Ducke, Xylopia amazonica R.E. Fr. and Myrcia multiflora (Lam.) DC. corresponded to 28.45% of the total IV and occurred in other Seasonal Perennial Forest areas in Gaucha do Norte, state of Mato Grosso; however, not with the same representativity. The Shannon index (3.51) may be considered as low in relation to the Amazon Forest; however, the Pielou equability (0.86) suggests that this arborous community presents high floristic heterogeneity. mudanças morfológicas nas raízes relacionadas ao metabolismo secundário, constituindo sistema-modelo para o estudo da genética, da fisiologia e dos processos morfogenéticos envolvidos na formação de ectomicorriza entre Pisolithus e Eucalyptus.

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