144 resultados para Reforestation.


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Hardness is a property largely used in material specifications, mechanical and metallurgical research and quality control of several materials. Specifically for timber, Janka hardness is a simple, quick and easy test, with good correlations with the compression parallel to grain strength, a strong reference in structural classification for this material. More recently, international studies have reported the use of Brinell hardness for timber assessment which resumes the advantages previously mentioned for Janka hardness and make it easier to be performed in the field, especially because of the lower magnitude of the involved loads. A first generation of an equipment for field evaluation of hardness in wood - Portable Hardness tester for wood - based on Brinell hardness has already been developed by the Research Group on Forest Products from FCA/UNESP, Brazil, with very good correlations between the evaluated hardness and several other mechanical properties of the material when performing tests with different species of native and reforested wood (traditionally used as ties - sleepers - in railways). This paper presents results obtained in the experimental program with the first generation of this equipment and preliminary tests with its second generation, which uses accelerometers to substitute the indentation measurements in wood. For the first generation of the equipment functional and calibration tests were carried out using 16 native and reforestation timber lots, among there E. citriodora, E. tereticornis, E. saligna, E. urophylla, E. grandis, Goupia glabra and Bagassa guianenses, with different origins and ages. The results obtained confirm its potential in the classification of specimens, with inclusion errors varying from 4.5% to 16.6%.

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Piptadenia moniliformis Benth. is a tree species which is important for beekeeping, as well as being recommended for soil restoration, reforestation, wood production for small civil construction projects, and cattle and sheep forage. Information on how to evaluate seed physiological quality is still scarce and in this was the study aimed to adapt the procedures of the tetrazolium test to assess the viability of P. moniliformis seeds. Four seed lots were scarified in sulphuric acid for 30 min, and soaked between paper towels at 25 °C for 24 hours. The seed coat was then removed and the naked seeds immersed in tetrazolium solutions with concentrations of 0.05, 0.075 and 0.1% for 2, 3, and 4 hours at 35 oC in the dark. Each treatment consisted of four replications of 25 seeds. The embryos were classified according to viability based on the staining patterns. The previous soaking of the seeds for 24 hours at 25 oC between paper towels, followed by the removal of the seed coat and staining of the naked seeds for 4 hours in a 0.075% tetrazolium solution at 35 oC was the most efficient method for evaluating the viability of P. moniliformis Benth seeds.

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Understanding basic information on weed biology contributes to the implementation of appropriate management and control strategies. Thus, this work was developed to evaluate the germination of Spermacoce latifolia Aubl. seeds, an important weed in reforestation areas. The seeds were subjected to dormancy break treatments, in which the mechanical scarification, chemical treatment (H2SO 4 and KNO 3), heat treatment, and control, were evaluated. Three more tests were done determinate the effects of temperature (10, 15, 20, 25, 30 and 35°C), light filters (absence of light and red, green, yellow, distant red, blue, orange and clear light) and water availability (0.0, -0.2, -0.4, -0.6, -0.8 and -1.0 MPa) on the seeds germination and vigor. The treatments were arranged in a completely randomized design with four replications, and the experimental plot was constituted by gerbox plastic boxes with 50 seeds. The mechanical scarification (sanding) provided the best dormancy break, indicating that Spermacoce latifolia seeds have tegument water impermeability. The seeds showed higher germination percentage under conditions of mild water stress (-0.2 MPa) and the optimal temperature was 25°C. The blue light reduced seed germination.

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Studying the physical environment of a watershed is the basic condition for a successful planning of the riparian forest preservation, and for water production and conservation. The aims of the present study were to analyze and quantify the spatial and temporal evolution (1984 and 2010) using Landsat-5 satellite images of Cintra Stream sub-watershed, Botucatu, São Paulo State, Brazil, processed by the software IDRISI Andes, as well as to analyze the water quality through the parameters pH, EC, DO and BOD5 at 4 different sites in the years 1999, 2008 and 2009. Considering the 1076.48ha area of the sub-watershed, the pasture class of 1984 was reduced by 25.55% in 2010, resulting in an increase in the remaining classes. The most important class was native forest and reforestation since it had an increase of 5.08%, which indicates recovery of the riparian forest. Degraded areas were identified close to the inferior limit of the sub-watershed (P3 and P4), as well as local contamination (P1 and P2) with worsening of the water quality in the remaining sites in the periods 2008 and 2009. Recovery and management of the ecological succession of degraded areas and water quality monitoring at 1 and 2 sites will be necessary to reestablish the natural condition of the area studied.

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The rapid growth of agriculture, promoted by public government initiatives, favored an out of control deforestation of our forests; today, reforestation of permanent preservation areas are necessary for the conservation of our natural resources, and recovery of such areas are required by public laws. In an area of 5.26 acres of riparian reforestation in the savanna soil chemical properties were evaluated after twenty years of planting. It was analyzed the following variables: (P, organic matter (MO), pH, K, Ca, Mg, H+Al, Al and S) in 13 modules, with three replicas in two depths (0 - 20 and 20 - 40 cm) in a randomized block design in hierarchical scheme. Reforestation with tree species on the edge of Parana river in Selvíria (MS) contributes to chemical soil attributes, under riparian reforestation, as similar as a soil without human disturbance in this region; it is also possible to verify that forestry plantation promotes deposition of organic material which is essential for nutrient cycling, which keep the chemical properties of such soil in good condition for the establishment of riparian vegetation.

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Anthropogenic changes in the reproductive population density can affect the mating system and result in an increase in selfing and correlated matings. This study investigated the mating system in small fragmented populations of the insect pollinated tropical tree species Copaifera langsdorffii, using microsatellite loci and the mixed and correlated mating models. Open-pollinated seeds were collected from 15 seed-trees located in a small forest fragment (4.8 ha), denominated Bosque and from 14 other seed-trees located in other small forest fragments of the north-western region of São Paulo State. No significant differences were observed between the seed-trees from Bosque (tm=0.933±0.028) and other fragments (tm=0.971±0.032), although these estimates were significantly different from 1.0, suggesting that selfing was occurring. Differences between multilocus and unilocus outcrossing rate were significantly high in both seed-trees of Bosque (tm -ts=0.478±0.05) and other forest fragments (tm -ts=0.475±0.018), suggesting a spatial genetic structure in those stands. The results also showed high rates of correlated mating in the samples, indicating that a good part of the offspring were full-sibs. As a consequence of selfing, mating among relatives and correlated matings, the coancestry within families was equally high in the seed-trees of Bosque ((Θ=0.237) and in the seed-trees of the other forest fragments (Θ=0.241) and the effective population size was lower than expected in panmitic populations (Ne<4). The results were discussed, focusing on the sample size of seed-trees to collect seeds for genetic conservation and enviromental reforestation.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The study aimed to assess the moisture and density of the soil, the amount of water stored in the profile, and the average soil's porosity with Eucalyptus grandis reforestation, compared to bare soil. The study areas are located in the Paulista region, in São Paulo, Brazil. The samples were collected in layers of 0, 20, 40, 60, 100 and 300 cm, in the months of April, June, August and October 2008. The results show that the density is lower and the porosity is higher in Eucalyptus forest soil compared to bare soil, due to the higher content of organic matter in forest leaf litter. Furthermore, the forest soil has a lower amount of water stored in profile than the bare soil without vegetation.

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More than 80% of the 29600 km of the Brazilian railroad mesh employs wooden sleepers. The problem of hard availability of native wood for this purpose leads to the alternative use of reforestation species to produce sleepers. Considering the great difficulty to, in field condition, evaluate characteristics that are of major importance to define its suitability to sleeper production the Research Group on Forest Products from FCA/UNESP - Brazil had developed equipment for field evaluation of hardness in wood - Portable Hardness Tester. This paper reports the functional validation tests, performed with different species of Eucalyptus. Results revealed the equipment great functionality, easy-to-use characteristics and applicability to Eucalyptus wood. Moderate to strong relationships between laboratory and validated values of hardness were found. The best validation model was obtained using the data provided by the experimental dispositive 3 (R2=0.74 and SSE= 7.71 kJ/m2) while the experimental dispositive 1 gave the worse validation (R2=0.55 and SSE= 13.46 kJ/m2).

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In São Paulo state, deforestation and agriculture activities are increasing soil losses processes, especially in areas of susceptible soils where soil conservation practices are not adopted. Environmental adequacy at property level regarding Permanent Protection Areas and Legal Reserves is considered a potential factor for reducing soil losses and it was based on this fact that we assessed soil losses of different scenarios of environmental adequacy. Simulations of erosive processes were carried out in 15 catchments of the Corumbataí river basin, with different forest restoration scenarios, as well as the current situation of land use/ land cover. The scenarios include reforestation of Permanent Preservation Areas (PPA); the reforestation hydrological sensitive areas; and two scenarios, the Legal Reserve installation in 20% of each catchment, being one of them for most critical areas in terms of erosion and the other at random. It was observed that the establishment of PPA and the reforestation of hydrological sensitive areas (HSA), offered a small contribution to the control of the erosive process, resulting in a reduction of 10% and 7.4%, respectively, while the legal reserve in critical areas has the significant reduction of 69.8%. The random scenario, in turn, resulted in a reduction of 21.4% of erosion. Results show that reforestation can reduce soil losses, but previous studies of land prioritization and planning could significantly increase its efficiency.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Agricultura) - FCA

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Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)