Artículos
https://hdl.handle.net/2238/11165
2024-03-28T09:52:09ZCurrent perspectives on forest recovery trends in Guanacaste, Costa Rica
https://hdl.handle.net/2238/14913
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
2019-01-01T00:00:00ZSurface chemical and color characterization of juvenile tectona grandis wood subjected to steam-drying treatments
https://hdl.handle.net/2238/9840
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
2016-01-01T00:00:00ZProduction and quality analysis of pellets manufactured from five potential energy crops in the Northern Region of Costa Rica
https://hdl.handle.net/2238/9832
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
2016-01-01T00:00:00ZPopulation status of the tree Sacoglottis holdridgei (Humiriaceae) at Isla del Coco National Park, Costa Rica
https://hdl.handle.net/2238/9830
Population status of the tree Sacoglottis holdridgei (Humiriaceae) at Isla del Coco National Park, Costa Rica
Acosta-Vargas, Luis Guillermo
Isla del Coco is the only oceanic island in the Eastern Pacific with humid tropical climate. Its forests
have a particular structure with a unique array of plant species and high endemism. There are few studies on
the flora or forest monitoring on the island. The population structure of Sacoglottis holdridgei was analyzed
using data from six years with data points taken in 2006 and 2012, including sampling of regeneration in 2012.
Sacoglottis holdridgei was the most important tree species, presenting in 2012 the highest Importance Value
Index (190.7±21.8), abundance (158.5±40.3 Nha-1 or 39.5 % of the forest) and basal area (15.6 m2ha-1 or 72.9
% of the forest). It was present in all three height strata with dominance in the highest. Annual mortality was
reported at 3.3 % and recruitment at 1.2 %. The diameter distribution of forest fits the inverted J model, but
not for the reported species of which only S. holdridgei tends to adjust for DBH>40 cm. Regeneration fitted
the inverted J model with values below those reported for continental forests. Even though it was the dominant
species, S. holdridgei showed low regeneration values. This particular condition, give way hypotheses related to
the introduction of species, species biology and climate change which could influence the future development
of S. holdridgei and forests of Isla del Coco. Rev. Biol. Trop. 64 (Suppl. 1): S263-S275. Epub 2016 Febrary 01.
Artículo científico
2016-01-01T00:00:00Z