DURABILIDAD DE LA MADERA DEL Pinus taeda L. IMPREGNADO CON ARSENIATO DE COBRE CROMATADO, FRENTE A HONGOS XILÓFAGOS, MISIONES, ARGENTINA

Abstract

ResumenEl objetivo del trabajo fue estudiar el comportamiento de la madera de Pinus taeda L. sin impregnar e impregnada con CCA tipo C, con retenciones de 5, 10 y 15 kg/m 3 , frente a la acción de los hongos xilófagos, Pycnoporus sanguineus, Laetiporus sulphureus, Plerotus sajor caju, Ganoderma applanatum, Glophyllum sp. en ensayos de laboratorio. Las maderas fueron obtenidas de seis árboles seleccionados al azar, e impregnadas con CCA en una autoclave de laboratorio. Para determinar la eficacia del preservante fueron utilizadas, 5 probetas de 3 x 1 x 0,5 cm por retención y por cepa de hongos y 5 de madera sin impregnar, testigo. Las probetass fueron puestas en ambiente de laboratorio para climatización y fueron pesadas. Los hongos fueron cultivados en tubos de ensayos de 20 mm de diámetro y 200 mm de largo, y sobre los mismos se colocaron las probetas, permaneciendo en estufa a 28 ºC por 12 semanas. Luego de este período las probetas fueron retiradas y puestas en ambiente de laboratorio, hasta obtener el contenido de humedad del inicio del ensayo. La degradación fue evaluada a través de la pérdida de peso. La madera de Pinus taeda L. fue moderadamente resistente con retenciones de 5 y 10 kg/m 3 de CCA, por lo tanto la retención de 5 kg/m 3 es suficiente. Palabras claves: Pinus taeda; CCA; durabilidad; hongos xilófagos. Abstract Durability of Pinus taeda L. wood, impregnated with chromated copper arsenate to the xylophagaus fungi action. Misiones, Argentina.The objective of this work was to study the behavior of Pinus taeda L. wood without and with impregnation with retentions of 5, 10 and 15 kg/m 3 of chromated copper arsenate, type C, preservative against Pycnoporus sanguineus, Laetiporus sulphureus, Plerotus sajor caju, Ganoderma applanatum, Glophyllum sp. in laboratory conditions. The wood was obtained from six trees chosen at random, and impregnated with C.C.A. in laboratory autoclave. To determine the efficiency of preservative 5 samples were used 5 samples of 3x 1 x 0,5 cm of no treated wood, were used. The wood samples were sterilized and put on a xylophagaus fungi staying in oven at 28°C for 12 weeks; after this period, the samples were taken away and put on a laboratory environment, until the moisture content of the beginning of the experiment was attained. The degradation was evaluated through the weight loss. The Pinus taeda L. wood was moderately resistant with retentions of 5 and 10 kg/m 3 of CCA, therefore retention of 5 kg/m 3 is enough.

Durability of Pinus elliottii Wood Impregnated with Quebracho Colorado (Schinopsis balansae) Bio-Protectives Extracts and CCA

“…Bobadilla et al (2007) found similar values in P. taeda L. The results obtained are in accordance with the IRAM 9600 (1998) regulation that classifi es the resinous pine wood as Class 3: not very durable against fungi. According to Findlay scale, ASTM D-2017(1981, wood with fungal weight loss > to 30 % (Table 1) is classifi ed as perishable or without resistance.…”

“…The weight loss in the treatment with CCA type c disagrees with the values obtained by Bobadilla et al (2007), with a weight loss of 9.51 %.…”

“…Moreno et al (2002) registered in Caribbean pine wood boards 18.51 % weight loss by white rot fungi. Bobadilla et al (2007) found 34.63 % weight loss in P. taeda L. wood. These percentages are high taking into consideration that conifers contain only guayacil lignin (Highley 1983;Blanchette et al 1990) and that Pycnoporus sanguineus has preference for hardwoods that have lignin of the syringyl type (Eaton and Hale 1993) that is more easily degraded than conifer lignin (Eriksson et al 1990).…”

Eficiência de preservantes fungicidas em madeiras de duas espécies florestais submetidas à deterioração por fungo

“…Já para a espécie de Pinus taeda submetida ao ensaio de deterioração pelo mesmo fungo apodrecedor, Bobadilla et al (2007) determinaram uma perda de massa média de aproximadamente 37% para a madeira in natura. Submetendo madeiras de Pinus elliottii à deterioração pelo fungo de podridão branca Pycnoporus sanguineus, Bernardis;Popoff (2009) obtiveram uma perda de massa de 25%.…”