Carlos Roberto de Lima

Natural resistance of nine woods of Brazilian semi-arid region to wood-destroying fungi under laboratory conditions

The objective of this research was to evaluate the natural resistance of nine semi arid region Brazilian woods to wood-destroying fungi under laboratory conditions. The studied woods were the Prosopis juliflora, Anadenanthera macrocarpa, Myracrodruon urundeuva, Schinopsis brasiliensis, Senna siamea, Tabebuia aurea, Amburana cearensis, Tabebuia impetiginosa and Aspidosperma pyrifolium. Test samples measuring 2.54 x 2.00 x 1.00 cm, with the largest measure taken fiber-wise were obtained from four pith-to-bark positions. The samples were submitted to action of the Postia placenta and Neolentinus lepideus fungi for 14 weeks. Species resistance, with exception of those of Prosopis juliflora and Anadenanthera macrocarpa (P. placenta), Tabebuia aurea (N. lepideus) and Senna siamea (P. placenta and N. lepideus), was affected by pith-to-bark position, not been associated to density wood. The Tabebuia impetiginosa wood and the heartwood of Myracrodruon urundeuva and Schinopsis brasiliensis showed the greatest resistance to the tested fungi. The natural resistance disparity, except in Myracrodruon urundeuva and Schinopsis brasiliensis, has not been associated to content of soluble substances in hot-water present in the wood of each species studied.

CARACTERIZAÇÃO FÍSICO-MECÂNICA DO LAMINADO COLADO DE BAMBU (Dendrocalamus giganteus)

The purpose of this work was to evaluate the preservative treatment effect and the adhesive type in physical-mechanical properties of glue laminated bamboo (GLB) of Dendrocalamus giganteus . Thus, the bamboo stems were treated by immersion method with chemical product (solution of 1% of active ingredients of copper chrome borate - CCB) and water by 15 days. Before treating the stems, the external and internal parts were removed to obtain the flat strips of bamboo with 4 mm of thickness, 45 cm of length and 5 cm of width. The “Cascophen RS” (resorcinol-formaldehyde) and “Cascorez-extra” (polyvinyl acetate) commercial adhesives were used to bond the flat strips. The resorcinol-formaldehyde adhesive showed superior moisture resistance than polyvinyl resin to GLB, and the samples obtained of pieces treated with CCB were more stable than treated with water. Among the mechanical properties tested, the adhesive factor was significant for the resistance to shear parallel to glue line and the preservative treatment for the rigidity. The interaction of the factors adhesive and treatment was significant for the rigidity, resistance to parallel compression and shear parallel to glue line. The pieces treated with water and adhered with resorcinol-formaldehyde presented better results for the rigidity and parallel compression to the fibers and those treated with CCB, for the shear parallel to glue line.

Efeitos dos extrativos e cinzas na resistência natural de quatro madeiras a cupins xilófagos

This study tested the natural resistance of wood of four tree species to Nasutitermes corniger Motsch. xylophogous termite attack and correlate the resistance with the amount of extract and ash in the chemical composition of the tested species. The species evaluated were Anadenanthera colubrina (Vell.) Brenan. var. cebil (Gris.) Alts., Tabebuia aurea (Mart.) Bureau., Amburana cearensis (Allem.) A.C.Sm. and Eucalyptus camaldulensis Dehnh. Test samples with dimensions of 2.00 x 10.16 x 0.64 cm (radial x longitudinal x tangential) were obtained at two positions (external heartwood and sapwood) of each species. The samples were exposed to action of termites for 45 days in food preference assay. The content of wood extractives was obtained through the sawdust that went through sieve of 40 mesh and were retained in the 60 mesh. The natural resistance was not associated with wood extractive contents. The wood more resistant to termite attack was the Anadenanthera colubrina var. cebil in the two positions (external heartwood and sapwood) and Eucalyptus camaldulensis wood presented the greatest wear. The biological resistance of wood was correlated with ash content, i.e., the species with the highest levels was the most resistant to termite attack.

Eficiência dos óleos de nim e mamona contra cupins xilófagos em ensaio de alimentação forçada

The research aimed to evaluate the efficiency of neem (Azadirachta indica) and castor oil plant (Ricinus communis) oils to improvement of Ceiba pentandra wood resistance to Nasutitermes corniger xilophogous termite under forced food assay. The neem and castor oil plant oils were extracted with absolute ethyl alcohol and employees in the preparation of oil solutions. Wood samples with dimensions of 2.0 x 2.54 x 0.64 cm (radial x longitudinal x tangential) were treated to reach a nominal retention of 10 to 16 kg of solution/m3 of wood. A part of treated samples was submitted to the weathering test (volatily and leaching tests). The treated samples were submitted to termite action under forced food assay. The neem and castor oil plant oils, on employed retention, did not contribute to improvement of Ceiba pentandra wood resistance to xylophogous termites. Among the tested solutions, the pure castor oil plant oil was more efficient. The weathering test of samples did not influence the wood resistance. The neem and of pure castor oil plant oils and their solutions, even presenting some repulsive effect to termites, their effect are not durable, indicating that they should not be used in wood treatment in order to improve its resistance to xylophogous termites.

VIABILIDADE TÉCNICA DOS TANINOS DE QUATRO ESPÉCIES FLORESTAIS DE OCORRÊNCIA NO SEMI-ÁRIDO BRASILEIRO NO CURTIMENTO DE PELES

Vegetable tannins are found in several forest species. Actually, the Northeast Brazilian tanners have, on Anadenanthera colubrina var. cebil , their only source of vegetable tannins. This study aimed to evaluate the tanning capacity of tannins extracted from four vegetable species of Brazilian Semi-arid region, seeking to make possible the diversification of species to be used in tannings in the region. Thus, physical and mechanical characteristics of bovid treated skins with extract tannic of Anadenanthera colubrina var . cebil , Anacardium occidentale , Mimosa tenuiflora and Mimosa arenosa were analyzed. The bovid skins were tanned with extracted tannins of those species and compared to tanned skins by tannins of Acacia mearnsii (“Seta Natur” commercial tannin). The samples of tanned skins were submitted to tension, lengthening and progressive tear resistance tests. Good results were verified to tanned skins by Mimosa tenuiflora and Mimosa arenosa . Due to the abundance of these species in Brazilian Semi-arid region, they showed potential to exploration of tannins. However, researches are necessaries to indicate the best forms of application of obtained tannins.

Eficiência do óleo de candeia na melhoria da resistência da madeira de sumaúma a cupins

The research evaluated the efficiency of Eremanthus erythropappus (DC.) Macleish. oil to improve the resistance of Ceiba pentandra (L.) Gaertn. wood to Nasutitermes corniger Motsch. termite under laboratory condition. Wood samples with nominal dimensions of 0.7 x 2.0 x 2.5 cm (thickness x width x length), forcedfeeding assay and of 0.7 x 2.0 x 10.2 cm (thickness x width x length), alimentary preference assay were treated by cold immersion process and reached medium retentions of 10.61; 16.73; 22.04; and 26.94 kg of oil/m3 of wood (force feeding) and of 38.35; 58.22; 87.53; e 108.36 kg of oil/m3 of wood (preference feeding) and submitted to Nasutitermes corniger termite attack during 28 (force feeding) and 20 days (alimentary preference). The results showed that the Eremanthus erythropappus oil in the retentions of 10.61 kg/m3 (forced feeding) and 38.35 kg/m3 (preference feeding) inhibited the attack and in the retentions of 16.73 kg/m3 (force feeding) and of 58.22 kg/m3 (preference feeding) prevented the attack in wood samples, making unfeasible the access of the termites to the food source.

Eficiência dos óleos de nim (Azadirachta indica) e de mamona (Ricinus communis) na proteção da madeira de sumaúma (Ceiba pentandra)contra cupins xilófagos em ensaio de preferência alimentar

The objective of this work was to evaluate the efficiency of oils from neem (Azadirachta indica) and castor plant (Ricinus communis) in improving the resistance of Sumauma wood (Ceiba pentandra) to Nasutitermes corniger xylophogous termite under feed preference assay. Oils from neem and castor oil plant were extracted with absolute ethyl alcohol and used in preparing preservative solutions. Wood samples with dimensions of 2.0 × 10.16 × 0.64 cm (radial × longitudinal × tangential) were treated to reach a nominal retention of 10 to 16 kg of solution by m 3 of wood, and some treated samples were submitted to the weathering test (volatily and leaching tests). The treated samples were submitted to termites in feed preference assay. Oils from neem and castor oil plant did not contribute much to improvement of Sumauma wood resistance to the tested termite. Among the tested solutions, the pure castor oil plant oil was the most efficient. Weathering of samples little influenced wood resistance. Although neem and pure castor oil plant oils presented some repulsive effect to termites, their effects are not durable, indicating that these products should not be used in wood treatment in order to improve its resistance to xylophogous termites.

Resistência natural de nove madeiras do semiárido brasileiro a fungos xilófagos em simulares de campo

The objectives of this research were to evaluate the natural resistance of nine woods from the Brazilian semi-arid region to fungi under field simulator condition and to correlate the wood natural resistance with the wood density and the content of extractives soluble in hot water. The studied woods were Prosopis juliflora, Anadenanthera colubrina var. cebil, Myracrodruon urundeuva, Schinopsis brasiliensis, Senna siamea, Tabebuia aurea, Amburana cearensis, Tabebuia impetiginosa and Aspidosperma pyrifolium. Test samples measuring 0.5 x 1.5 x 15.0 cm, with the largest measure taken on fiber direction, were obtained from four positions on pith to bark direction in the stem. The samples were submitted to the action of natural micro-flora of three soils; forest, agricultural use and gramineous plant soils, for 180 days. Wood resistance to decay was affected by the bark-heart wood position. Just for M. urundeuva, the wood resistance was associated to wood density and extractives content soluble in hot water. The resistance of P. juliflora, A. columbrina, T. aurea, and T. impetiginosa woods was not associated to density nor the extractive content. The sp-wood was the most attacked position for all soils. Among the tested soils, the one for agricultural use presented the lowest biological activity, presenting lower deterioration for the tested woods.

Eficiência dos óleos de nim ( Azadirachta indica A. Juss.) e mamona ( Ricinus communis L.) na resistência da madeira de sumaúma ( Ceiba pentandra (L.) Gaerth.) a fungos xilófagos em simuladores de campo

The research aimed to evaluate the efficiency of neem (Azadirachta indica) and castor oil plant (Ricinus communis) oils for the improvement of Ceiba pentandra wood resistance to xilophagous fungi in soil bed condition (field simulator). The neem and castor oil plant oils were extracted with absolute ethyl alcohol and employed in the preparation of oil solutions. Wood samples with dimensions of 1.5 x 0.5 x 15 cm (radial x tangential x longitudinal) were treated to reach a nominal retention of 10 to 16 kg of solution/m³ of wood. The samples were submitted to the action of natural micro-flora of three soils; forest, agricultural use and natural pasture soils, for 180 days. Among the tested soils, the agricultural presented greater biological activity, which damaged the samples even more. Among the tested solutions, the pure neem oil provided increased protection to samples. The prepared solutions using neem and castor oil plant oils did not protect the wood from the attack of xylophagous fungi existing in the ground

Yield and Physical Characteristics of Neem (Azadirachta indica) and Castor (Ricinus communis) Oils

This work aimed to evaluate the yield and viscosity of neem (Azadirachta indica) and castor (Ricinus communis) oils. Neem fruits were collected at the ‘Nucleo de Pesquisa do Semi-Arido’, municipality of Patos, Paraiba state, and castor plants were collected along the Espinharas River margins, municipalities of Patos and Igaracy, Paraiba state, Brazil. The fruits were beneficiated at the Forest Products Technology Laboratory in Patos. Seed samples were used for determination of moisture content and yield of oils from the studied species. The oils were extracted with absolute ethyl alcohol and employed in the preparation of neem and castor oil solutions. The density and viscosity of solutions were determined. Castor oil presented lower moisture content and yield compared with neem oil. The density and viscosity of neem oil were lower than those of castor oil. A larger amount of castor oil provided an increase in the density and viscosity of the prepared solutions.