Resumo A estrutura anatômica e as propriedades físicas e mecânicas do lenho variam significativamente entre árvores de uma mesma espécie e mesmo entre diferentes partes de uma mesma árvore. Este ...trabalho teve como objetivo estudar a densidade básica, o comprimento e o diâmetro do lúmen das fibras da madeira de Tectona grandis L., provenientes de dois locais distintos, com idades de 12 e 5 anos. Para tal, foram confeccionados corpos-de-prova obtidos a partir de discos de madeira, retirados de secções feitas entre a medula e a casca. Foram observadas diferenças significativas na variação radial do comprimento das fibras entre as duas procedências/idades analisadas.
We investigated the relationship between the oxygen isotopes in teak (Tectona grandis) tree-ring cellulose and climatic factors, i.e. rainfall, temperature and relative humidity. Four cores of teak ...from northwest Thailand were used to analyse the oxygen isotope values in alpha -cellulose. The oxygen isotopic composition of teak tree-ring alpha -cellulose ranged from 21.38ppt to 25.58ppt. The mean tree-ring alpha -cellulose delta super( 18)O values and standard deviations were 23.4 plus or minus 0.7ppt. The delta super( 18)O value was positively correlated with rainfall in the February to April dry season (r = 0.234, p < 0.5) and negatively correlated with total rainfall (r = - 0.350, p < 0.01), average rainfall (r = -0.321, p < 0.01) and relative humidity (r = -0.282, p < 0.05) in the late rainy season. The delta super( 18)O values were negatively correlated with the annual mean Palmer Drought Severity Index (PDSI) from 1948 to 2005 (r = -0.491, p < 0.001) based on the mean of 4 grids. Oxygen isotope values in the alpha -cellulose of teak from northwest Thailand were significantly related to the hydrological cycle in these areas.
The bark in some forest species may represent a significant volume of the trunk, demanding the use of efficient methods to estimate bark volume indirectly through equations. The aim of this study was ...to evaluate bark volume and thickness in teak (Tectona grandis) trees planted at different densities. Volume data were used to evaluate the percentage of bark in different portions of the trunk. Averages were compared by the Tukey test (p < 0.05%) and regression analysis (polynomial model) was used to predict bark thickness along the trunk. The effect of spacing on bark thickness was compared by the model identity test. The percentage of bark in more densely planted teak trees was higher. The percentage of bark decreases from the base to the top of the tree trunk, with an average volume of green bark reaching 24% to 30% of the total volume. Increasing spacing promotes higher absolute average bark thickness.
Present investigation explores the possible reusability of synthetically contaminated wastewater containing crystal violet (CV) organic dye using Tectona grandis sawdust (TGSD) waste as a very ...low-cost adsorbent. The adsorbent was characterized by proximate, SEM/EDX, FTIR, and XRD analyses. Batch adsorption studies were carried under changing conditions of contact time, the initial concentration of CV, pH, TGSD dose, TGSD particle size, and temperature. The experimental data were tested using Langmuir, Freundlich and Temkin isotherm models, and the data were best followed by Langmuir one. The kinetic results were examined in the light of different models and pseudo-second-order was obtained to be best obeyed. The values of ΔH° (28.642 kJ/mol), ΔG° (-10.776 to -7.080 kJ/mol) and ΔS° (121.8 J/K/mol) in the temperature range of 293-323 K suggested the overall process to be spontaneous, endothermic and associated with an increase in randomness. On the basis of experimental results and their analyses, it has been established that TGSD is one of the most effective adsorbents among those obtained from the domestic, agricultural and industrial wastes. Thus this adsorbent can be effectively utilized to make the impure wastewater reusable.
Bojonegoro Regency has an oil mining location where it is estimated that Indonesia’s crude oil reserves are 25 % of national needs. The location is in Forest Management Unit ( Kesatuan Pengelolaan ...Hutan - KPH) Parengan which has a teak forest ( Tectona grandis L.) with a very close oil mining radius. The aim of the research is to determine the differences in the characteristics of teak growing places and to determine the types of petroleum fractions in active oil mines, former oil mines and those without oil mines. The research method uses a circle plot (17.8 m) with a Sampling Intensity (IS) of 20 % with data analysis results using a one sample test and a Least Significant Difference (LSD) alpha test of 5 %. The characteristics of the teak growing area at each location have different values for height, P content, C content, number of oil fractions and temperature. The types of petroleum fractions in active oil mines are naphtha, kerosene, fuel oil and wax. Ex-oil mines contain gasoline (premium), kerosene, aviation fuel, light gas, fuel oil, lubricating oil, wax and asphalt. In locations without oil mines there is kerosene, aviation fuel, gasoline (premium) and light gas.
Non-English title Sehoueto, Caroline K P; Aoudji, Augustin K N; Avocevou-Ayisso, Carolle ...
Biotechnologie, agronomie, société et environnement,
01/2015, Letnik:
19, Številka:
1
Journal Article
Recenzirano
The present study deals with the production of the seedlings of teak (Tectona grandis L.f.), a species used in forest plantations in southern Benin. The aim of the study was to evaluate the ...techniques and the profitability of teak seedling production in the community nurseries of southern Benin. A survey was carried out in 55 community nurseries selected in the Atlantique department, based on the snowball sampling method. Semi-structured interviews were conducted with nursery holders to collect data on activity organization, techniques of production, costs, and sales revenues. Two types of community nursery were found to be operating: individual nurseries and collective nurseries. Seedling production methods varied widely across the nurseries. The collection of tout venant seeds, and the use of inadequate polyethylene containers might affect seedling quality. A financial analysis showed that nursery holders were receiving a positive return from their activity. The average net revenue from the production of 1,000 seedlings ranged between FCFA 20,603 and 26,649. Improved performance of community nurseries will require the provision of assistance to nursery holders in accessing good quality seeds, and the implementation of further retraining on production techniques.
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