40 resultados para above ground biomass
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
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Current estimates of the total biomass in tropical rainforests vary considerably; this is due in large part to the different approaches that are used to calculate biomass. In this study we have used a canopy crane to measure the tree architectures in a 1 ha plot of complex mesophyll vine forest at Cape Tribulation, Australia. Methods were developed to measure and calculate the crown and stem biomass of six major species of tree and palm (Alstonia scholaris (Apocynaceae), Cleistanthus myrianthus (Euphorbiaceae), Endiandra microneura (Lauraceae), Myristica insipida (Myristicaceae), Acmena graveolens (Myrtaceae), Normanbya normanbyi (Arecaceae)) using the unique access provided by the crane. This has allowed the first non-destructive biomass estimate to be carried out for a forest of this type. Allometric equations which relate tree biomass to the measured variable 'diameter at breast height' were developed for the six species, and a general equation was also developed for trees on the plot. The general equation was similar in form to equations developed for tropical rainforests in Brazil and New Guinea. The species equations were applied at the level of families, the generalized equation was applied to the remaining species which allowed the biomass of a total of 680 trees to be calculated. This has provided a current estimate of 270 t ha-1 above-ground biomass at the Australian Canopy Crane site; a value comparable to lowland rainforests in Panama and French Guiana. Using the same tree database seven alternative allometric equations (literature equations for tropical rainforests) were used to calculate the site biomass, the range was large (252-446 t ha-1) with only three equations providing estimates within 34 t ha-1 (12.5%) of the site value. Our use of multiple species-specific allometric equations has provided a site estimate only slightly larger (1%) than that obtained using allometric equations developed specifically for tropical wet rainforests. We have demonstrated that it is possible to non-destructively measure the biomass in a complex forest using an on-site canopy crane. In conjunction the development of crown maps and a detailed tree architecture database allows changes in forest structure to be followed quantitatively. © 2007 Ecological Society of Australia.
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Questions: Grasslands are usually neglected as potential carbon stocks, partially due to the lack of studies on biomass and carbon dynamics in tropical grasslands. What is the importance of Brazilian tropical wet grasslands as carbon sinks? Does fire frequency and season affect biomass and carbon allocation in Brazilian wet grasslands? Location: Wet grasslands, tropical savanna, Jalapão, Tocantins, northern Brazil. Methods: We determined biomass above- and below-ground, estimated carbon stocks in biennially burned plots (B2) and plots excluded from fire for 4 yr (B4). Moreover, we determined biomass in both rainy and dry seasons. Samples were 0.25 m × 0.25 m × 0.2 m (eight samples per treatment, applying a nested design, total of 48 samples). The biomass was classified in above-ground graminoids, forbs and dead matter, and below-ground roots and other below-ground organs. We used ANOVA to compare variables between treatments and seasons. Results: More than 40% of the total biomass and carbon stocks were located below-ground, mostly in roots. A high proportion of dead biomass (B4) was found in the above-ground material, probably due to low decomposition rates and consequent accumulation over the years. Although these grasslands do not experience water stress, we found significant evidence of resource re-allocation from below-ground organs to the above-ground biomass in the rainy season. Conclusions: We found more dead biomass in the rainy season, probably due to low decomposition rates, which can increase fire risk in these grasslands during the following dry season. These tropical wet grasslands stored high amounts of carbon (621 to 716 g C.m-2), mostly in the roots. Thus, policymakers should consider tropical grasslands as potential carbon stocks, since they are one of the most threatened and unprotected ecosystems in Brazil. © 2012 International Association for Vegetation Science.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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To evaluate the growth and pattern of nutrient absorption (N, P, K, Ca, Mg and S amongst others) in three berry cultivars (treatments), four plants by treatment in different phonological stages were harvested. The experiment was arranged in randomized design of factorial 3x5 with three replicates. There cultivars were used FM Shima-Miura, IZ 56/4 and Miura and above ground biomass was harvested in five occasions 45, 60, 75, 90 and 115 days after plantation. It was observed that the accumulation of nutrients presented different pattern and cv. IZ 56/4 was superior compared with PM Shima-Miura for N, P, K, Ca, Mg and S and N, P, K and S for Miura. For example, the accumulation of N expressed on mg plant"(1) per berry plant cultivar PM Shima-miura, IZ 56/4 and Miura was respectively 4,21; 8,14 and 5,56, for K 2,71; 5,22 and 2,64 and for Ca 2,47; 4,52 and 3,59.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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O objetivo deste trabalho foi realizar caracterização física e avaliar o efeito de substratos à base de serragem e dois recipientes no crescimento de mudas de cacaueiro. O delineamento experimental foi em blocos casualizados, em esquema fatorial 2 x 4 x 2. Os tratamentos foram obtidos da combinação de serragens originadas de dois locais: municípios de Una e Camacan, no Estado da Bahia, quatro proporções (v:v) de serragem e areia: 1:0; 8:1; 4:1 e 2:1 e dois recipientes de crescimento (tubetes de 288 cm³ e sacos de polietileno de 840 cm³). Antes do plantio, amostras dos substratos foram retiradas para análises físicas. Foram usadas miniestacas de 4 a 6 cm de comprimento do clone Trinidad Select Hybrid (TSH 1188). Inicialmente, as miniestacas foram tratadas na base com AIB 6.000 mg kg-1, em seguida foram inseridas em tubetes preenchidos com os substratos e mantidas em câmara de nebulização. Após quarenta dias, as miniestacas foram retiradas da câmara e transferidas para crescimento, em casa de vegetação, onde parte foi mantida nos respectivos tubetes e outra transplantada em sacos de polietileno de 840 cm³ preenchidos com os mesmos tratamentos. Após cinco meses, em casa de vegetação, as mudas foram avaliadas quanto à altura da planta, diâmetro do caule, massa da matéria seca da parte aérea e das raízes, número de folhas e área foliar das plantas. Na análise física dos substratos, verificou-se que a distribuição do tamanho de partículas foi diferenciada entre as serragens e a proporção de areia. As densidades seca, úmida e de partícula aumentaram, enquanto o teor de matéria orgânica e a porosidade total foram reduzidos pela adição de areia às serragens. O transplante de miniestacas enraizadas de cacaueiro, clone TSH 1188, para sacos com substrato preparado com serragem coletada no município de Una-BA, nas proporções serragem:areia 4:1 e 2:1, possibilitou maior crescimento das plantas, sendo,portanto, recomendados para produção de mudas.
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In order to evaluate growth characteristics, adaptability, biomass production, nutrient recycling, nutrient distribution and the ability to regenerate degraded land, a trial using four multipurpose tree species (Leucaena leucocephala, Leucaena diversifolia, Acacia melanoxylon and Mimosa scabrella) was undertaken over two years in a distrophic red yellow latosol (oxisol) following a randomized block experimental design with four replications. At the age of two years, A. melanoxylon and L. diversifolia were the tallest species (5.25 and 4.97 m, respectively) and A. melanoxylon and M. scabrella had the largest diameters at 20 cm from tree base. Mimosa scabrella and A. melanoxylon had the highest dry matter production and quantity of nutrients in the above ground biomass. In all species, the highest nutrient contents were found in the leaves, followed by branches and stems. From all species, the highest Nutrient Utilization Efficiency Indexes were obtained for sulphur, phosphorous, and magnesium; L. diversifolia was the most efficient for nitrogen, potassium, calcium, sulphur, and manganese, while A. melanoxylon was the most efficient for phosphorus, magnesium, boron, iron, and zinc. Litter production levels over a three month period were as follows: M. scabrella > A. melanoxylon > L. diversifolia > L. leucocephala. Litter nutrient content was higher in M. scabrella than in the other species.
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Lianas play a key role in many tropical forests ecosystems, contributing to community abundance, diversity and structure. Techniques to census lianas and estimate biomass have been used mainly in tropical forests. The aim of this study was to verify if different measurement location on the stem and inclusion criteria influence the estimations of liana abundance and biomass in Cerrado. The study was carried out at Itirapina fragment (ca 260 ha) located in Sao Paulo, Southeast Brazil. We measured all apparent ramets of rooted lianas by using different inclusion criteria: >= 0.5 cm in diameter at 30 cm basal area (D_30), and at 130 cm diameter breast height (DBH), in 36 transects (10 x 25 m). We compared the biomass using the allometric equation based on data from tropical florest take at 130 cm (DBH) and other The allometric biomass equation development to estimate the aboveground biomass of live lianas in tropical forests (DAP = 130 cm) was used. We tested the liana biomass, based on measurements taken at (D_30) using two different conversion equations. The results did not show significant differences in liana abundance and above ground biomass estimated applying the different criteria of inclusion However the biomass estimated from data collected at D_30 and converted into DAP showed a tendency to increase in biomass. Our findings suggest that the protocol used to the census of liana and the allometric biomass equation proposed to forests can be applied in the Cerrado.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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QuestionsWe aimed to analyse the effect of fire on flowering in subtropical grasslands, by addressing the following questions: will fire history affect flowering? If yes, do fire feedbacks influence flowering or is it just the removal of above-ground biomass? Are there differences in burned and mowed plots?LocationSubtropical grasslands in Southern Brazil (30 degrees 03S, 51 degrees 07W).MethodsWe established plots in areas with different fire histories: 30d (30 plots: five replicates), 1yr (14 replicates), 3yr (30 plots: five replicates) since the last fire, in experimentally burned and mowed plots (14 replicates each). We counted the number of flowering species, as well as the number of flowering stalks.ResultsGraminoid species flowered in highest numbers 1yr after fire, whilst forbs had more species flowering just after fire, indicating different reproductive strategies in post-fire environments. Mowing was not as efficient as fire in stimulating flowering. Finally, the different functional groups showed different flowering responses to time since last fire and to the different types of management.ConclusionsOur results show fire stimulated flowering. Although mowing can be a good alternative for maintaining plant diversity, our study showed that this practice is not as efficient as fire in stimulating flowering. However, fire season should be noted as a limiting factor to the recovery of C-3 grasses in these subtropical grasslands, and annual burns may be harmful to C-4 grasses, since they delay their flowering to the next post-fire growing season.
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Pós-graduação em Agronomia - FEIS
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)