Papers by Julio César Calvo-Alvarado
Poster: Calvo-Alvarado J. y R. Moya. 2009. Factores biofísicos que controlan el color de madera d... more Poster: Calvo-Alvarado J. y R. Moya. 2009. Factores biofísicos que controlan el color de madera de Teca. En: XVIII Congreso Latinoamericano de la Ciencia del Suelo. 16-20 Nov, 2009. Sociedad Latinoamericana de la Ciencia del Suelo/Asociación Costarricense de la Ciencia del Suelo. (Memoria en CD). San José, Costa Rica
Understanding the causes of Tropical Dry Forest disturbance and their cascading effects on many c... more Understanding the causes of Tropical Dry Forest disturbance and their cascading effects on many components of this ecosystem are important to identifying negative effects on biophysical resources and human development, and for elaborating policies and strategies for conservation and sustainable management. Our current understanding of the impacts of land use/cover change on human dominated landscapes is strongly linked to a clear understanding of the socio-economic and biophysical forces driving land use and land cover change. These forces, acting at different scales (from the production land unit to the regional and international levels), contribute to regional environmental deterioration trends. In many cases, these trends cannot be fully understood because of a lack of spatial databases of socio-economic and biophysical landscape characteristics. Traditionally Land Use Cover Change (LUCC) studies have focused on processes of negative land-cover change, primarily deforestation, pa...
Duke Environment.
Duke University, School of the Environment, PO Box 90328, Durham, NC 27708-0328, US E-mail: drich... more Duke University, School of the Environment, PO Box 90328, Durham, NC 27708-0328, US E-mail: drichter@env.duke.edu E-mail: jucalvo@itcr.ac.cr. ... Reforestation of cutover lands in Southern Costa Rica. Reforestación de tierras taladas en el sur de Costa Rica. ... PLANTS; SPERMATOPHYTES; MAGNOLIOPHYTA; MAGNOLIOPSIDA. COMBRETACEAE; TERMINALIA AMAZONIA; EUPHORBIACEAE; HYERONIMA OBLONGA; CLUSIACEAE; CALOPHLLUM BRASILIENSE; FABACEAE/PAP.; PLATYMISCIUM PINNATUM; VOCHYSIACEAE; ...
A trial was established to evaluate the effect of five soil treatments in the growth, foliar nutr... more A trial was established to evaluate the effect of five soil treatments in the growth, foliar nutrient concentration and chlorophyll concentration (SPAD-502 values) of three tree species. The selected soil treatments were three types of soils ((Ultisol, Andisol, Inceptisol) and two improved soils: Ultisol+CaCO3+NPK and Andisol+NPK. The tree species were Gmelina arborea (L.) Roxb. (Gmelina), Tectona grandis L.F. (Teak) and Swietenia macrophylla King. (Mahogany). Clones of Teak and Gmelina were also included in the trial. It is concluded that the Ultisol+CaCO3+NPK treatment can result in similar or better growth rates than the other soil treatments, corroborating that the management of Ultisols is possible for reforestation. The soil and plant interactions are different among species but in general the trend indicates that soil pH, sum of base, exchangeable acidity in % (SA%) and K, are important factors that control plant growth and foliar nutrient concentrations. Teak is the species ...
IEEE Workshop on Advances in Techniques for Analysis of Remotely Sensed Data, 2003, 2003
... Roger Bonilla, Luis Coronado-Chacón, April Mitchell and Denis Ortiz for their field assistanc... more ... Roger Bonilla, Luis Coronado-Chacón, April Mitchell and Denis Ortiz for their field assistance as well as Jaime Viquez and Patricia Murillo ... Measurement of Forest Structure,” in Methods forRemote Sensing of Forests: Concepts and Case Studies, M. Wulder and S. Franklin, Eds. ...
Science for Conservation and Management, 2011
Within the framework of a larger project studying the hydrologic impacts of converting tropical m... more Within the framework of a larger project studying the hydrologic impacts of converting tropical montane cloud forest to pasture in the Tilarán range of northern Costa Rica, physical and hydraulic properties of various volcanic soils were compared in two small watersheds covered with mature lower montane cloud forest and pasture, respectively. In situ and laboratory experiments were conducted to determine trends in soil texture, bulk density, porosity, water retention characteristics, infiltration, and (un)saturated hydraulic conductivities with depth under the two types of land cover. Despite their predominantly sandy texture, the soils were rich in organic matter and non-crystalline material such as allophane. Bulk densities were very low and similar between sites for corresponding soil horizons, except for the pasture top-soil which was more compacted, particularly on cow trails. Soil porosity was very high throughout the profile and dominated by macro-and mesopores, again with the exception of the pasture top-soil and the cow trails. Water retention at a suction of 1500 kPa (permanent wilting point) was very high, except in gravelly C-horizons which had low retention capacity. Amounts of plant-available water (i.e. held at suctions between 10 and 1500 kPa) were also high. Surface infiltration rates were relatively high and dominated by "bypass"
Science for Conservation and Management, 2011
ABSTRACT Fog and wind-driven rain (WDR) are difficult to measure separately and reported measurem... more ABSTRACT Fog and wind-driven rain (WDR) are difficult to measure separately and reported measurements of “fog” often represent a combination of fog and WDR. In this chapter the term “horizontal precipitation” (HP) is used instead. Understanding of “typical” amounts of HP intercepted by different types of cloud forest is hampered by a lack of comparative information on local fog climatology. Usually some kind of “fog gage” is used to characterize fog occurrence and amounts. Collection efficiencies of three passive fog gages, viz. a wire harp, a modified cylindrical gage (Juvik-type), and a tunnel gage (Daube-type), were derived by comparing the volumes of water collected by the respective gages with cloud water fluxes derived from fog liquid water content (LWC) as measured by a cloud particle spectrometer during conditions of fog at a windward cloud forest site in northern Costa Rica. The collection efficiency of the three gages proved linearly related to the horizontal cloud water flux as measured by the gages themselves. Therefore, no additional information on wind speed, droplet size, and fog LWC was needed. During conditions of HP, relative collection efficiencies were derived by comparing the volumes collected by the respective gages. The modified Juvik gage had an efficiency close to 100%, independently of wind speed and direction. The efficiency of the wire harp depended critically on wind speed,whereas the tunnel gage collected additional precipitation at small precipitation angles and low wind speeds.
... Autor : Jiménez-Ramón, Jorge A; González-Jiménez, Eugenio; Calvo-Alvarado, Julio César. ... P... more ... Autor : Jiménez-Ramón, Jorge A; González-Jiménez, Eugenio; Calvo-Alvarado, Julio César. ... PROYECTO TAMARINDO; PARQUE NACIONAL PALO VERDE; AREA DE CONSERVACION TEMPISQUE; LA BOCANA LAGOON; OTS; MINAE; SENARA; FUNDACION CR-USA ...
... Autor : Calvo-Alvarado, Julio César; Arias-Aguilar, Dagoberto; Sibaja-Villegas, A; Camacho-Mo... more ... Autor : Calvo-Alvarado, Julio César; Arias-Aguilar, Dagoberto; Sibaja-Villegas, A; Camacho-Mora, P; Fisher, RF. ... BIOLOGICAL STATION; AREA DE CONSERVACION CORDILLERA VOLCANICA CENTRAL; BUENOS AIRES (CANTON); PEREZ ZELEDON (CANTON); AREA DE ...
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Papers by Julio César Calvo-Alvarado