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La evaluación del combustible superficial es una necesidad perentoria en la prevención y control de incendios forestales. El objetivo de este trabajo fue realizar una estimación de la cantidad de acículas en plantaciones de pino de diferentes edades. Se evaluaron rodales con 16 y 22 años de edad y en ellos se tomaron sub-parcelas de 1 m2 para cuantificar las acículas; además se midió la masa plantada mediante sub-parcelas circulares de 250 m2. Se encontró un volumen de acículas de 316 m3/ha en 16 años y 487 m3/ha en 22 años. El peso seco a los 16 años es 28 t/ha y 34 t/ha a los 22 años; para este estadígrafo no hay diferencias estadísticamente significativas (p= 0,05) entre las edades. En las características estructurales tampoco hubo diferencias significativas entre las edades; el dap promedio es 22 cm, la densidad oscila entre 530 y 590 árboles/ha, el área basal está alrrededor de 24 m2/ha y la altura total es 21 m. Se interpreta que los rodales analizados están en competencia, no presentan un incremento importante en el crecimiento y eso se refleja en la mencionada ausencia de diferencias significativas. Esta masa de acículas es muy elevada si se compara con resultados reportados para otras plantaciones similares. Se concluye que esta elevada cantidad de combustible amerita estudios más detallados que indiquen con más precisión su masa en las edades de 5, 10, 15 y 20 años, con el fin de optimizar los programas de prevención y control de incendios de la plantación. The evaluation of surface fuel is a critical need in the prevention and control of forest fires. The aim of this study was to estimate the amount of needles in pine plantations of different ages. 16 and 22 years old stands were evaluated and needles were assessed by mean of 1 m2 square sub-plots; in addition, 250 m2 circular sub-plots were used to measure the mass planted. A volume of 316 m3/ha of needles at 16 years and 487 m3/ha in 22 years was found. The needles dry weight at age 16 is 28 t/ha and 34 t/ha at age 22; for this statistics no statistically significant differences (p= 0,05) between the ages was found. in a similar way, no significant differences between the ages were for the structural characteristics; average dbh is 22 cm, the density ranges between 530 and 590 trees/ha, basal area is about 24 m2/ha and total height is 21 m. it is interpreted that these stands are in competition, do not present an important increase in growth and this is reflected in such absence of significant differences. This mass of needles is very high when compared to results reported for similar plantations. it is concluded that this high amount of fuel justifies further detailed studies addressed to get more precisely its mass at ages 5, 10, 15 and 20 years, in order to optimize fire prevention and control programs in these plantations. 105-114 jolozada@ula.ve Semestral

Se detectaron diferencias significativas, en el primero y el segundo aclareo en plantaciones de 7 y 12 años, en la plantación de Cabuya entre los tratamientos de aclareo y el testigo, pero el tercer aclareo realizado a los 21 años, no presentó diferencias significativas. Los aclareos realizados en Puerto Carrillo, que dejó 500 árboles/ha a los seis años, mostraron un mayor crecimiento diamétrico que los realizados tomando en cuenta el área basal, en sitios de similar calidad. Las altas densidades a temprana edad afectan el crecimiento en diámetro, altura y hasta la productividad del sitio. Las plantaciones de teca en la península de Nicoya, se clasificaron entre los índices de sitio 23 y 27, con una edad clave de 16 años, estas plantaciones se consideran como sitios de clase media y alta, de acuerdo al crecimiento exhibido por la teca en Costa Rica. Results are presented of two thinning experiment carried out with different goals in teak plantations (Tectona grandis L.f.), in two sites, at the Nicoya Peninsula: Puerto Carillo with 10 years of records and Cabuya with 23 years of research. Strong early thinnings, were done, based on the number of trees in intensively managed plantations with a shorter rotation and lighter thinning using basal area as a parameter, in the longer rotation plantations. A completely randomized block design with two replication was using. Thinnings were done at 7, 12 and 21 years in Cabuya and at 5, 6, and 10 years in Puerto Carrillo. Significant differences were detected in the first and the second thinning at the ages of 7 and 12, at Cabuya plantation, between the different thinning treatments and the control plot, but the third thinning done at 21 years of age, the differences were not significant. The thinning carried out at Puerto Carrillo, taking as a reference the number of trees, in order to leave 500 trees/ha at the age of 6, showed a superior growth in diameter that those carried out taking into account the basal area, in sites of similar quality. The high densities at early ages affect the growth in diameter and height, and also affect stand productivity. The teak plantations at the Nicoya Peninsula, classified among site indexes of 23 and 27, with a 16 yearold base age, and are considered as middle class and high class sites, according to the growth exhibited by teak in Costa Rica. 131-145 echaves1@ice.co.cr Semestral

Se evaluó el efecto de los preservantes hidrosolubles CCA, ACQ y Ecoplus sobre la madera de la especie Caryodaphnopsis cogolloi van der Werff mediante el ensayo acelerado de laboratorio para la durabilidad inducida utilizando la metodología agar block y los hongos de pudrición Trametes versicolor y Gloeophyllum trabeum establecido por la norma EN 350-1. La durabilidad fue determinada mediante pérdida de peso y estudio de las características de degradación de los hongos durante cuatro meses de incubación en la madera. Al finalizar el periodo de exposición se observó que en todas las probetas tratadas hubo pérdida de peso, registrándose las mayores en la muestras preservada con ACQ y Ecoplus, alcanzando un valor promedio de 10,5% y 11,1%, respectivamente, bajo la acción del hongo T. versicolor y de 10,4% y 10,9% bajo la de G. trabeum, lo que determinó que la limitada absorción y retención de los preservantes, debido a la presencia de tilides y contenidos de sílice en la mayoría de las estructuras anatómicas, no garantizó la inhibición de los procesos de biodegradación como consecuencia del ataque de los hongos T. versicolor y G. trabeum. The effect of water-borne preservatives CCA, ACQ and Ecoplus on wood species Caryodaphnopsis cogolloi van der Werff was evaluated using agar block method and rot fungi Trametes versicolor and Gloeophyllum trabeum, according to EN 350-1 Accelerated laboratory test for induced durability. The durability was determined by weight loss and study of the characteristics of degradation of fungi for four months of incubation in the wood. At the end of the exposure period there was weight loss in all treated samples, with highest in samples preserved with ACQ and Ecoplus, reaching an average value of 10.5% and 11.1%, respectively, with T. versicolor and 10.4% and 10.9% with G. trabeum, which determined the limited absorption and retention of the preservative, since tyloses and silica contained in most anatomical structures, did not ensure the inhibition of biodegradation processes in the attack of tested fungi. 147-156 oencinas@ula.ve diegodistrital@gmail.com Semestral

Se presenta el estudio de las características ecoanatómicas de los elementos de conducción del xilema secundario para 87 especies de bosque húmedo tropical, colectadas en la Reserva Forestal Ticoporo (Barinas, venezuela). Para cada especie se determinó el diámetro, frecuencia y longitud de elementos de vasos y se procedió a calcular los índices de vulnerabilidad y mesomorfía. Se realizaron comparaciones con estudios en otras áreas de transición bosque seco tropical a húmedo tropical (Caparo), seco tropical (El Caimital), muy seco tropical (Mamo) y húmedo premontano (La Mucuy). Las especies estudiadas desarrollan un sistema de conducción de comportamiento mesomórfico y con orientación hacia la eficiencia, excepto en el caso de los representantes de la familia Rubiaceae cuyo comportamiento es de tipo xeromórfico y el sistema de conducción se orienta hacia la seguridad. Ecoanatomical features in conductive system of secondary xylem from 87 species in tropical wet forest were studied. Samples were collected in Ticoporo Forest Reserve (Barinas, venezuela). For each species, vessel diameter, vessel frequency and vessel element length were measured. vulnerability and mesomorphy index were calculated. Comparative analysis with others studies in transition between dry tropical forest and wet tropical forest (Caparo), dry tropical forest (El Caimital), very dry tropical forest (Mamo) and premontane wet forest (La Mucuy) was done. Species studied presents a mesomorphic conductive system oriented to efficiency, except in Rubiaceae that shows a xeromorphic type behaviour oriented to efficiency. 115-129 wleon@ula.ve Semestral

O presente estudo teve por objetivo principal determinar e comparar os valores das principais propriedades físico-mecânicas da madeira e do LVL de Pinus merkussi, visando quantificar possíveis ganhos em resistência, rigidez e estabilidade dimensional do LVL em relação à madeira. Para o desenvolvimento do estudo foram utilizadas 20 toras de 10 árvores coletadas aos 26 anos de idade. A partir desse material, corpos-de-prova de madeira sólida e de LVL (Laminated Veneer Lumber) foram obtidos e ensaiados conforme as prescrições da Norma Brasileira NBR 7190 (ABNT, 1997). Posteriormente, os dados obtidos para os dois conjuntos (madeira e LVL) foram submetidos a uma análise de variância. Os resultados indicaram que a retratibilidade máxima radial (R) foi superior para o LVL e na direção tangencial (T) verificou-se o contrário. O valor da relação T/R foi mais favorável ao LVL. Em resistência, os ganhos médios do LVL foram de 11% a 18%, conforme a propriedade considerada. Em rigidez, os ganhos médios do LVL foram de 14% a 29%. A variabilidade dos dados das propriedades do LVL foi menor que a da madeira. Concluiu-se que além de apresentar maior resistência e rigidez, o LVL tornou-se mais homogêneo que a própria madeira que lhe deu origem. The main objective of this study was to determine and to compare the physical-mechanical properties values of the wood and of LVL of Pinus merkussi, seeking to quantify possible gain in strength, rigidity and dimensional stability of LVL in relation to the wood. 20 logs of 10 trees with 26 years old were used on this research. From this material, solid wood and LVL (Laminated Veneer Lumber) samples were obtained and tested according to Brazilian Norm NBR 7190 (ABNT, 1997). Later, the obtained data for wood and LVL were submitted to variance analysis. The results indicated that the maximum radial shrinkage (R) was superior to LVL and in the tangential direction (T) the opposite was verified. The T/R relation was more favorable to LVL. In strength, the LVL average values were superior from 11% to 18%, according to the considered property. In rigidity, the LVL average values were superior from 14% to 29%. The LVL properties data variability was smaller than the one of the wood. It is concluded that in addition to superior strength and rigidity, the LVL became more homogeneous than the own wood that gave its origin. 191-195 gbortoll@esalq.usp.br semestral