https://hdl.handle.net/2238/11165 2026-05-20T12:55:50Z 2026-05-20T12:55:50Z Moya, Roger Quesada-Román, Adolfo Quesada-Monge, Ruperto https://hdl.handle.net/2238/16384 2025-10-17T16:15:42Z 2025-01-01T00:00:00Z

Distinctiveness of annual-ring and its relationship with altitudinal and life zones, and climate type Moya, Roger; Quesada-Román, Adolfo; Quesada-Monge, Ruperto Costa Rica tiene un clima tropical compuesto por diferentes zonas de vida donde crecen muchas especies arbóreas. Este estudio busca establecer diferentes tipos de distintividad de los anillos anuales (AR) y potencial dendrocronológico (DP) de 320 datos de madera para Costa Rica, un país neotropical. Además, se estableció la relación entre la distintividad y el DP con el tipo de especie, condición de crecimiento, nivel altitudinal, zonas de vida, y tipo de clima. Los resultados indicaron que 70 especies (21.9%) no presentaron límite de AR (con ningún DP), 104 especies (32.5%) presentaron AR bien definido (+) (con alto DP) y las especies restantes (146 especies o 45.6% del total) presentaron AR más o menos distintivo (+/-), luego el DP varió de medio a bajo. Las 8 especies que crecen exclusivamente en condiciones tropicales secas y presentaron una AR bien definida (con un DP alto), pero 137 especies (73,3%) que crecen en condiciones tropicales lluviosas presentaron una AR ausente o poco definida, por lo que el DP varió de medio a bajo. Muchas especies (67) que crecen en zonas bajas y altas (basales y premontanas) presentaron un DP nulo, mientras que muchas especies presentaron un DP positivo (DP medio) y 41 especies mostraron un DP alto. Pocas especies crecen en zonas altas (cordilleras y subalpinas), pero presentaron una AR poco distintiva, por lo que se presentaron DP altos. Finalmente, muchas especies presentan DP medio y alto, por lo que las aplicaciones de la dendrocronología fueron limitadas.; Costa Rica has a tropical climate composed by diverse life zones with large quantity of tree species. This study aims to establish different types of the annual rings (AR) distinctiveness, and dendrochronological potential (DP) of 320 wood data for Costa Rica, a neotropical and central America country. Besides it was established the relation among distinctiveness and DP species type, growing condition, altitudinal level and life zones, and climate type. So, it can serve as a basis for a proposal of tree species with dendrochronological potential in South America and the neotropics region. The results indicated 70 species (21.9%) did not present AR boundary (with any DP), 104 species (32.5%) presented well-defined (+) AR (with high DP) and the remaining species (146 species or 45.6% of the total) presented more or less distinctive (+/-) AR, then DP varied from medium to low. The 8 species that grow exclusively in dry tropical conditions presented well-defined AR (with high DP), but 137 species (73.3%) that grow in rainy tropical condition presented absent or poor defined AR, then DP varied from medium to low. Many species (67) that grow in low high (basal and premontane) presented null DP and many species presented (+/-) (medium DP) and 41 species shown high DP. Few species grow in high part (montane and subalpine), but barely presented distinctive AR, then high DP are presented. Finally, many species present medium and high DP, the applications of dendrochronology were limited. Artículo (Preimpresión: versión no revisada por pares) Instituto Tecnológico de Costa Rica (ITCR). Escuela de Ingeniería Forestal, Universidad de Costa Rica (UCR). Departamento de Geografía, 2025

2025-01-01T00:00:00Z Calvo-Alvarado, J. Jiménez, V. Calvo-Obando, A. Castillo, M. https://hdl.handle.net/2238/14913 2025-09-05T23:42:03Z 2019-01-01T00:00:00Z

Current perspectives on forest recovery trends in Guanacaste, Costa Rica Calvo-Alvarado, J.; Jiménez, V.; Calvo-Obando, A.; Castillo, M. The main goal of this study was to evaluate whether the trends in the recovery of forest cover in Guanacaste continued during the past decade and to evaluate if the socioeconomic drivers of recovery have been altered. Our analysis found that forest cover in Guanacaste province increased marginally from 48.14% in 2005 to 50.74% in 2012. This implies that the forest recovery process during this period has continued but with a much smaller pace, showing signs of stagnation. The province landscape has changed since the 1970s, when it was dominated by livestock ranching and was the most deforested province with only 23.6% of forest cover. Today Guanacaste is a good example of an economic development forest transition region, with a matrix of land use that is dominated by new forests in different successional stages, which has resulted in great benefits to society given the ecosystem services that this landscape provides. Artículo. Instituto Tecnológico de Costa Rica. Escuela de Ingeniería Forestal, Ministerio del Ambiente, Energía y Minas. Sistema Nacional de Áreas de Conservación, 2019

2019-01-01T00:00:00Z Rodriguez-Solís, María Berrocal-Jiménez, Alexander Starbird-Pérez, Ricardo Muñoz-Acosta, Freddy Moya-Roque, Róger https://hdl.handle.net/2238/9840 2025-09-24T15:52:18Z 2016-01-01T00:00:00Z

Surface chemical and color characterization of juvenile tectona grandis wood subjected to steam-drying treatments Rodriguez-Solís, María; Berrocal-Jiménez, Alexander; Starbird-Pérez, Ricardo; Muñoz-Acosta, Freddy; Moya-Roque, Róger The color of Tectona grandis wood is an attribute that favors its commercialization, however, wood color from fast-growth plantation trees is clear and lacks uniformity. The aim of this work is to characterize steamed teak wood by means of the Fourier transform infrared spectroscopy (FTIR) and L a b color systems. Two moisture conditions (green and 50%) and two grain patterns (°at and quarter) of boards were analyzed through the application of di®erent steaming times (0, 3, 6, 9, 12, 15 and 18 h). The FTIR results showed that the bands at 1158, 1231, 1373 and 1419 cm 1 did not show any change with steaming, whereas the bands at 1053, 1108, 1453, 1506, 1536, 1558, 1595, 1652, 1683, 1700 and 1733 cm 1 presented a decrease in the intensity with the steaming time. The band at 1318 cm 1 was the only one that increased. Lightness (L ) was the most a®ected parameter, followed by yellowness (b ), while redness (a ) showed the smallest change. Surface color change ( E ) presented the lowest value between 3 h and 6 h of steam-drying in the boards with °at grain, whereas for boards with quarter grain, the smallest E value was obtained after 18 h of steaming. Artículo

2016-01-01T00:00:00Z Aragón-Garita, Stephanie Moya-Roque, Róger Bond, Brian Valaert, Jorre Tomazello-Filho, Mario https://hdl.handle.net/2238/9832 2025-06-26T15:30:26Z 2016-01-01T00:00:00Z

Production and quality analysis of pellets manufactured from five potential energy crops in the Northern Region of Costa Rica Aragón-Garita, Stephanie; Moya-Roque, Róger; Bond, Brian; Valaert, Jorre; Tomazello-Filho, Mario Modifications to a pellet manufacturing process must be made based on the characteristics of raw material used. The purpose of this work was to determine the alternations required to a wood pellet manufacturing process and the quality of the pellets produced using this process from five energy crops. Quality measurements include: the caloric value, the loss of moisture content in each production stage, the efficiency index of particle-pellet, ash content and quality as defined using the quantity of cracks and the transversal density and longitudinal density determined using X-ray radiography. The crops analyzed were rhizomatous plants, with caloric values ranging between 17.1 and 20.3 MJ kg 1. This work determined that it was possible to produce pellets with Gynerium sagittatum and Phyllostachys aurea using the same production process for wood; however, Arundo donax and Pennisetum purpureum needed pre-airdrying and the Sorghum bicolor required mechanical dewatering before drying. A. donax, P. purpureum and G. sagittatum provided the highest efficiency index. When evaluating the pellet quality P. aurea and G. sagittatum hard a large quantity of cracks, unlike A. donax, P. purpureum and S. bicolor. The transversal and longitudinal pellet density varied from 1129 to 1294 kg m 3. The highest values of bulk density were obtained in A. donax and P. purpureum, followed by G. sagittatum and P. aurea, and the lowest bulk density was obtained in S. bicolor. Althogh out, some species produced cracks and high ash content, this work demonstrated that it is possible to produce pellets with moderate quality. Artículo científico

2016-01-01T00:00:00Z