Kiln drying behavior utilizing drying rate of lumber from six fast-growth plantation species in Costa Rica

Artículo científicoThe objective was to study the effect of the drying time and moisture content variations on the drying rate during kiln drying. The moisture content is a good predictor of the variation in drying rate; to determine the drying rate, the model DR =a * t + b (where DR is the drying rate, t is the drying time, and a and b are constants) was used. Cordia alliodora, Dipterix panamensis, Hieronyma alchorneoides, and Vochysia ferruginea show a unique tendency, whereas Enterololium cyclocarpum and Samanea saman showed two tendencies. Drying rate in relation to time showed that it is possible to define the various stages during drying and the inflexion points in time where a change in the drying rate occurs. Two types of tendencies are shown in the drying rate vs. time relation in C. alliodora, E. cyclocarpum, and S. saman, whereas three tendencies appear in D. panamensis, H. alchorneoides, V. ferruginea. C. alliodora, E. cyclocarpum, and S. saman presented only one inflexion in the drying rate, which can be maintained at an average of 24.5, 11.64, and 7.83%/day, respectively, for those species. On the other hand, D. panamensis, H. alchorneoides, and V. ferruginea showed two inflexions

Optical performance of finished and unfinished tropical timbers exposed to ultraviolet light in the field in Costa Rica

Artículo científicoThis study evaluated wood color change (ΔE*) and the surface quality in 10 tropical wood species painted with three finishes (composed of wax and polyurethane). Two weathering conditions were tested: natural weathering (NW) and artificial weathering (AW). The results showed that the application of these finishes, decreased the luminosity (L*), increased the redness (a*) and the yellowness (b*) parameters in all species. ΔE*, after weathering exposure, was affected significantly by L*, a*, and b, whereas for finished or pretreated wood, L* and b* are the main parameters affecting ΔE* in the 10 tropical species studied. ΔE* values found in different finishes and pretreatments are cataloged as total change of color. Other important results were that tropical light colored timber with natural pretreatment produced higher ΔE* than dark colored timber. The stains and fungal development were observed in polyurethane finishes in NW, but not in AW. The irregular and mosaic flaws were not observed in any kind of finish or pretreatment of surface. The values of the quality index created, which considered long and short lines and switch flaws, were lowest in NW and in waxy finish, while the highest value was obtained with the polyurethane finish

Estimating the Sustainability of Managed Natural Forests in Costa Rica—A Hybrid Delphi & Choice Experiment Approach

Management of natural forests in Costa Rica allows timber extraction in so far as it is guaranteed that the logging activities comply with diverse Sustainability Principles, Criteria and Indicators (PCIs). These are hierarchical and complex systems used, ex-ante in the formulation and approval of the Management Plan but have not been used for ex-post evaluation of managed forests. Development of sustainability evaluation systems that include few criteria is highly recommended. In that sense, the choice experiments contribute to simplification of the initial system of decision making, complementing a complex system of PCIs that permits detailed analysis of the management units. In this study, a choice experiment was included in a Delphi application and 5 key variables were identified to evaluate the sustainability of managed natural forests. These variables are, in order of importance—technical, legal and administrative conditions; external financing conditions; production performance; costs of preparing the Management Plan; and payment mechanisms for environmental services. The definition of these variables confirms not only that the technical, legal and administrative conditions are critical for sustainability but also that they could reflect the type of governance involved in sustainability forest management

Estudio de propiedades de la madera de seis especies nativas en plantaciones de Costa Rica

Artículo científicoThis study details information about physical, chemical and mechanical properties, drying, preservation and workability of wood from Cordia alliodora, Dipteryx panamensis, Enterolobium cyclocarpum, Hieronyma alchorneoides, Samanea saman and Vochysia ferruginea trees, growing in forest plantations in Costa Rica. Variation of the general properties in relation to height showed that heartwood percentage decreases, bark percentage increases and pith percentage is not affected. Dipteryx panamensis showed both the highest values for specific gravity and the highest mechanic resistance. Both chemical properties and extractives presence were different among species. Heartwood was not possible to preserve in any of the species, though sapwood was. Penetration varied from partial irregular or vascular in the species. The highest durability was for Hieronyma alchorneoides and Vochysia ferruginea, species classified as of high durability. Finally, all species had good performance in the workability tests. The previous results indicate that these species, used for trading reforestation in Costa Rica, have acceptable characteristics to be commercialized and used in wooden products

Analizan los efectos de los acabados en la durabilidad de la madera

Las condiciones ambientales presentes en toda la franja tropical, por sus altas temperaturas y la presencia de precipitaciones a lo largo del año, propician que en países como Costa Rica se pueda desarrollar una gran variedad de especies arbóreas maderables. Muchas de estas especies se han utilizado en programas de reforestación con fines comerciales

Secadoras solares de madera aserrada

El valor agregado en productos de madera, utilizando material seco, es un factor limitante para la mayoría de los productores forestales nacionales, quienes no cuentan con la tecnología para secar madera en forma económica y eficiente.Por años, la única técnica utilizada ha sido el secado de madera aserrada al aire. Algunos pocos productores secan en hornos convencionales; sin embargo, este método de secado se caracteriza por un costo elevado que de momento los productores prefieren evitar

Diseño de una metodología para evaluar el manejo sostenible de los bosques naturales de la Zona Norte, Costa Rica

Doctorado en Ciencias Naturales para el Desarrollo con énfasis en Gestión de Recursos NaturalesA partir de un conjunto de indicadores de referencia, se diseñó una herramienta para la evaluación “ex post” de la sostenibilidad de unidades de bosques naturales manejados en Costa Rica. Este conjunto se desarrolló utilizando una estructura jerárquica de principios, criterios e indicadores de sostenibilidad. La lista de referencia resultante consta de 5 principios, 12 criterios y 30 indicadores, clasificados como esenciales por un grupo de expertos en manejo forestal en Costa Rica. El conjunto de indicadores permite estudiar las dimensiones y atributos que delimitan la sostenibilidad de los ecosistemas. El procedimiento de selección y la probable contribución de este conjunto al manejo forestal aborda, en primer lugar, las condiciones económicas, sociales, ecosistémicas e institucionales de Costa Rica. Sin embargo, el conjunto de indicadores es útil para otras regiones del mundo, previa adaptación de los umbrales a las condiciones locales del ecosistema. Adicionalmente, la dimensión ecosistémica (productividad, estabilidad, adaptabilidad) se ratifica como condición de primer orden para la sostenibilidad, pero los expertos refuerzan la idea de que la dimensión institucional (equidad y gobernanza) es un desafío para la evaluación de la sostenibilidad.Based on a set of reference indicators, a tool was designed for the evaluation “ex post” of sustainability of units of managed natural forests in Costa Rica. This set was developed using a hierarchical structure of principles, criteria and indicators of sustainability. The resulting reference list consists of 5 principles, 12 criteria and 30 indicators, classified as essential by a group of experts in forest management in 19 Costa Rica. The set of indicators allows studying the dimensions and attributes that delimit the sustainability of the ecosystems. The selection procedure and the likely contribution of this set to forest management addresses, firstly, the economic, social, ecosystemic and institutional conditions of Costa Rica. However, the set of indicators is useful for other regions of the world, previous adaptation of the threshold values to the local conditions of the ecosystem. Additionally, the ecosystemic dimension (productivity, stability, adaptability) is ratified as a condition of first order for the sustainability, but the experts reinforce the idea that the institutional dimension (equity and governance) is a challenge for the evaluation of sustainability.Instituto Tecnológico de Costa RicaUniversidad Nacional, Costa RicaUniversidad Estatal a DistanciaDoctorado en Ciencias Naturales para el desarrolloDepartamento de Físic

Secadoras solares de madera aserrada

El valor agregado en productos de madera, utilizando material seco, es un factor limitante para la mayoría de los productores forestales nacionales, quienes no cuentan con la tecnología para secar madera en forma económica y eficiente.Por años, la única técnica utilizada ha sido el secado de madera aserrada al aire. Algunos pocos productores secan en hornos convencionales; sin embargo, este método de secado se caracteriza por un costo elevado que de momento los productores prefieren evitar

Cuantificación de los indicadores sociales, económicos y ecosistémicos que permiten evaluar la sostenibilidad en los bosques manejados

In Costa Rica, natural forest management has been regulated rigorously using a hierarchical scheme of Principles, Criteria, and Indicators of Sustainability (PCI's). These systems are complex and have traditionally been used in the ex-ante evaluation of forest management in Costa Rica but have not been used in the ex-post evaluation of managed forests. Creating evaluation systems that allow evaluating sustainability with few criteria is very desirable, but it is more important to have validated systems. In the present study we proceeded to quantify and validate a hierarchical scheme of indicators to use in ex-post evaluation; the first step was the quantification of 30 sustainability indicators defined in previous studies as possible to use in the evaluation of this type. Each indicator was then validated using 3 criteria: accessibility to information, cost of access, and relevance of the indicator in relation to the management unit. From the quantification of the indicators, a total of 25 indicators were validated which represent the ecosystem, social, institutional, and economic dimensions on which sustainability is based. The ecosystem baseline was also defined for the variables basal area above 30 cm in diameter (dbh) and proportion of ephemeral heliophic species above 10 cm in diameter (dbh), this baseline was constructed by forest types according to the minimum and maximum reference values.En Costa Rica se ha regulado el manejo forestal de los bosques naturales de manera rigurosa utilizando un esquema jerárquico de Principios, Criterios e Indicadores de Sostenibilidad (PCI´s). Estos sistemas son complejos y tradicionalmente se han utilizado en evaluación ex-ante del manejo forestal, pero no se han utilizado en la evaluación ex-post de los bosques manejados. Crear sistemas de evaluación que permitan evaluar la sostenibilidad con pocos criterios es muy deseable, pero es de relevancia contar con sistemas validados. En el presente estudio se procedió a cuantificar y validar un esquema jerárquico de indicadores para utilizar en evaluación ex post. El primer paso fue la cuantificación de 30 indicadores de sostenibilidad definidos en estudios previos como posibles de utilizar en evaluación de este tipo.  Luego, cada indicador se sometió a validación utilizado 3 criterios: accesibilidad a la información, costo de acceso y pertinencia del indicador en relación con la unidad de manejo forestal. A partir de la cuantificación de los indicadores se logró validar un total de 25 indicadores. Los indicadores validados representan las dimensiones ecosistémica, social, institucional y económica sobre las que se fundamenta la sostenibilidad. Se definió; además, línea base de ecosistema para las variables área basal arriba de 30 cm de diámetro y proporción de especies heliófitas efímeras arriba de 10 cm de diámetro, esta línea base se construyó por tipos de bosque según los valores de referencia mínima y máxima que establecen la normativa costarricense

Manejo forestal sostenible del bosque y monitoreo ecológico en dos bosques muy húmedos tropicales de Zona Norte de Costa Rica

An ecological monitoring was carried out on two properties subject to sustainable forest management (SFM), located in the Northern Zone of Costa Rica. For monitoring purposes, the basal area was chosen as the gross filter indicator, and the composition and diversity of diurnal butterflies of the Nymphalidae, Papilionidae and Pieridae families was chosen as a fine filter indicator. The results indicate that forests subjected to SFM , which were also affected by the passage of Hurricane Otto, suffered a significant loss of basal area, which implies adjustments in the new cutting cycle to ensure the recovery of forest areas. It was found that as lower forest cover, the greater abundance, richness and composition of butterflies. In order to use the monitoring of butterflies as an indicator of sustainability, a greater effort is required to achieve the construction of reference lines for this indicator. Se realizó un monitoreo ecológico en dos propiedades sometidas a manejo forestal sostenible (MFS), ubicadas en la Zona Norte de Costa Rica. Para el monitoreo se eligió como indicador de filtro grueso el área basal y como indicador de filtro fino la composición, y diversidad de mariposas diurnas de las familias Nymphalidae, Papilionidae y Pieridae. Los resultados indican que los bosques sometidos a MFS, que además fueron afectadas por el paso del Huracán Otto, sufrieron una pérdida importante de área basal, lo que implica ajustes en el nuevo ciclo de corta que aseguren la recuperación de las áreas de bosque. Se comprobó que a menor cobertura forestal mayor abundancia, riqueza y composición de mariposas. Para lograr utilizar los monitoreos de mariposas como indicador de la sostenibilidad se requiere de un esfuerzo mayor para lograr construir líneas de referencia para este indicador