Análisis florístico de dos poblaciones de árboles en diferentes altitudes en un Bosque Primario en San Isidro, San Ramón, Costa Rica

Proyecto de Graduación (Licenciatura en Ingeniería Forestal) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Forestal, 2015.Weather conditions may cause a change in the structure of plants in the altitudinal gradient. The objective of this study was to relate the floristic composition in populations of trees in two altitudinal floors in a primary forest. Four permanent plots were established: two plots on high altitude floor to 710 m and two plots on the ground floor to 570 m, of 2500 m2 each plot, we measured the diameters, total height and tree species were identified within sample plots. We analyze the horizontal and vertical structure of the forest through the basal area, average total height and aboveground biomass, it were compared between each altitudinal floor with a homogeneity test Chi square. 48 families were found, with 110 genera and 145 species, to 579 individuals identified. For basal area and average total height there are not significant differences between the altitudinal floors. While, for above-ground biomass on the ground altitude floor was significantly higher in the high floor, may be due to climatic conditions of the site. By having a low sampling intensity of 0.11, we cannot explain what happens at the ecosystem level, by a high sampling bias.Instituto Tecnológico de Costa Rica. Escuela de Ingeniería Forestal

Dinámica del crecimiento del bosque húmedo tropical, 19 años después de la cosecha bajo cuatro sistemas de aprovechamiento forestal en la Península de Osa, Costa Rica.

ArtículoWithin the project “Monitoring of forest ecosystems to strengthen conservation strategies and forest use: a contribution to Costa Rica carbon neutral initiative”, the dynamic growth of the tropical rainforest was studied, nineteen years after harvest under four systems of forest use. Through the measurement of all trees (d ≥ 10 cm), three revenue sites were botanically identified in the Peninsula de Osa (Estero Guerra, Dos Brazos de Río Rincón and Los Mogos). Four permanent sampling parcels (PPM) of 1 HA were installed in 1990. At that time and subsequently, fifteen and nineteen years later (2007 and 2011, respectively), the status of the primary forest was examined after applying four logging systems: oxen harvesting system (SACB), improved harvesting system (SATM), traditional harvesting system (SATT) and oxen-tractor system (SABT). The analysis of the forest dynamic was made based on growth, mortality, recruitment and replacement rate. The current annual increment (ICA) average for the period under review ranged from 2,47 to 3,56 mm / year. Statistical analysis showed that the ICA value has a normal distribution and homoscedasticity and the analysis of variance indicated no significant differences between the ICA of each logging system (p = 0,3410). The average mortality rate of the four logging systems is 1,301%, the recruitment rate is 1,869%. The annual turnover rate is 0,569%. Statistical analysis found that mortality; recruitment and replacement rates show a normal distribution and homoscedasticity. On the other hand, analysis of variance showed that differences between the different logging systems are not significant (mortality: P = 0,2412; recruitment: p = 0,0675; parts: p = 0,1159). Paired t tests showed that the mortality and recruitment rates are statistically the same within each logging (SACB: p = 0,4992; SATM: p = 0,9238; SATT: p = 0,9080; SABT: p = 0,8065), confirming the dynamic equilibrium of the forests under study.Instituto Tecnológico de Costa Rica

ESTRUCTURA HORIZONTAL DE BOSQUE CADUCIFOLIO, OBSERVADA EN UNA PARCELA AL SUR DE LA PENÍNSULA DE AZUERO

  A horizontal structure study was made on deciduous forest plot, in Achotines Laboratory, Provincia de Los Santos, Panama Republic. In this study was mesure a rectangular plot of one hectarea and this was split in 10 subplot of the same size each one (10X100 m). All the trees with DAP ≥ 10 cm, then all the trees were mesure and identified. With this information was calculed the Importance Valor Indice (IVI) of each tree species. The trees wth most IVI value were madroño (Calycophyllum candidissimum) with 34.04, then zorro (Astronium graveolens) with 32.48, nisperillo (Pouteria Campechiana) with 32.04, roble de sabana (Tabebuia rosea) with 29. 36, guayacán (Tabebuia guayacan) with 25.09 and cedro amargo (Cedrela odorta) with 20.06. The most important tree species is Calycophyllum candidissimum, because is the most abundant and frequent in the plot.  Se realizó un estudio de la estructura horizontal en una parcela de bosque caducifolio, en los terrenos del laboratorio de Achotines, Provincia de Los Santos, República de Panamá. Se estableció una parcela rectangular de una hectárea dividida en 10 subparcelas de igual tamaño (10 x 100 m). Se midieron todos los árboles con un DAP ≥ 10 cm, a los cuales se les anotó la altura total y características vegetativas que ayudasen en su identificación. Se calculó el Índice de Valor de Importancia (IVI) de las especies arbóreas. Las especies arbóreas que mostraron los mayores valores del IVI fueron: madroño (Calycophyllum candidissimum) con 34.04, seguido por zorro (Astronium graveolens) con 32.48, nisperillo (Pouteria campechiana) con 32.04, roble de sabana (Tabebuia rosea) con 29. 36, guayacán (Tabebuia guayacan) con 25.09 y cedro amargo (Cedrela odorta) con 20.06. La importancia del Calycophyllum candidissimum se debe principalmente a su abundancia y dominancia relativa dentro de la parcela

Demografía de Especies Maderables de la Península de Osa

Proyecto de investigación (Código 5402-1401-8401) Instituto Tecnológico de Costa Rica. Escuela de Ingeniería Forestal. Centro de Investigación en Integración Bosque; Universidad de Costa Rica. Escuela de Biología, 2010This project is supported by 20 years of research and previous projects that have been carried out in the Osa Peninsula by researchers at the TEC Forestry School, all with the common interest of generating baseline information for the management of the forests in the Osa Peninsula. The main objective was to “determine the population demographics of the most intensively harvested merchantable tree species in the Osa Peninsula”. Three research sites within the Golfo Dulce Forest Reserve were selected. Within each site four 1-ha permanent plots were established during the “Forest Management Alternatives” project conducted in 1990 and 1993 (Castillo, 1990, Cordero, 1990). Demographic parameters are presented for five merchantable species in the Osa Peninsula (Peltogyne purpuea, Caryocar costaricense, Copaifera camibar, Qualea polychroma y Aspidosperma spruceanum). Growth rate, mortality and recruitment for early and late successional species were determined using data collected in three censuses within the permanent plots. Additionally, demographic matrices were built to predict the size of the populations in 45 years and the effect of selectively logging 50% of all trees was determined for a 15-year cutting cycle which is the norm for management plans usually approved by the Osa Conservation Area. Predictions of tree demographics after harvestings in which 50% of all trees are selectively logged every 15 years show a rapid decrease in the late successional species in the short term (<30 years), and would also cause depletion of important merchantable species in all successional stages due to the low recruitment of advanced regeneration. Particularly, this negatively affects P. purpurea, C. costaricense y C. Camibar and results show that this management regime could cause the local extinction of these species. On the contrary, A. spruceanum and Q. poylchroma were observed to recover more quickly after harvestings and this is due to their higher growth rates and their population structure. Overall, it is recommended that the current Forestry Law should be modified to decrease the extraction rate of these tree species. Thus, cutting cycles should be extended and harvesting intensities should be modified in order to increase the time period in between harvestings. This analysis was based on several silvicultural treatments implemented in the simulations, which are based on three different silvicultural systems (Cordero and Howard, 1990; Castillo, 1991). 1. Improved traditional system: it is the traditional harvesting method of felling and skidding. The planning of forestry operations can thus reduce damage to the forest. Because of this, directional felling should be practiced to reduce the amount of damage to standing trees, the forest floor and extracted logs. During the skidding process, the machinery should remain in the skid trails and all logs must be extracted by using cables (i.e. winched) in order to reduce road distance and the damaged cause by machinery in the forest. 2. Skidding with oxen: the oxen are equipped with chains and a skidding wooden frame. The damaged cause by machinery in the forest is thus reduced. 3. Traditional skidding system with tractors: most common method employed in the country which is highly damaging to the forest, and without prior planning can cause great deterioration of the ecosystem. From the above described skidding methods the different silvicultural systems are derived: Oxen skidding method (SACB), Improved traditional system (SATM), Traditional skidding system with tractors (SATT) and Improved skidding method with oxen and tractors. Regarding tree density (N/ha), there is a tendency to increase with time, which suggests a recovery of the forest after harvestings. In primary forests tree density was 435,6 trees/ha. Tree density also varied from 350 trees/ha in the SATT treatment to 435 trees/ha in the SACB treatment, with a difference between treatments of 85 trees/ha. Nonetheless, 15 years after the first harvesting tree density changed to 520 trees/ha in the SACB and 569 trees/ha in the SABT treatment, reducing the difference between treatments by 50%. There is an increase in the basal area (m2 /ha) 15 years after the harvesting, although values similar to those in primary forests have not been reached yet. In primary forests the average basal area was 30,12 m2 /ha and, specifically for 2007 it was 29,43 m2 /ha. Basal area (m2 /ha) was high regardless of its decrease due to the silvicultural treatments, and when compared with other humid forests this site ranks high. For example, in Northern Costa Rica primary forests have been reported to present 23,8 m2 /ha, and in logged forests it may ranged from 17 to 21,2 m2 /ha. In the development curve analysis, it is important to notice the problem with the abundance of individuals according to their DBH distribution. Not all species reach the canopy or are very abundant so the strategies for their survival/permanence change. In this way, the development curves vary dramatically and are related to the autoecology of the species, which are in turn affected by forest management practices. Tree growth is influenced by many factors, nonetheless, when forests are being assessed for forest management the degree of disturbance caused by the harvestings becomes an important factor since it modifies the standing vegetation and this is tailored according to the particular growth rates of the species. In these experiments, current annual growth (ICA) was 2,88- 3,21 cm/year and the highest current annual growth value of 3,1 cm/year was reported for the most severe treatment. For a 12-year period, and related to the silvicultural treatments implemented, certain tendencies in species’ behaviors have been observed: current annual growth tends to be greater in the 30-39,9 cm at DBH and the 50-59,9 cm at DBH categories, but then decreases considerably in larger categories; this trend is clear in all four treatments. The species with the highest diameter increment by treatment are: Vochysia ferruginea with 15,58 mm/year in treatment 1, Vochysia allenii with 18,17 mm/year, and 12,72 mm/year in treatments 2 and 4, respectively, and Tachigali versicolor with 13,3 mm/year in treatment 2. The proceeding demonstrates these species’ potential for growth. Growth rates are high, Vocyhsia alleni was shown to have the highest growth rate at 12,53 mm/year. This highlights the 12-year growth interval considered in this analysis, which is highly significant. Other equally important within this forest are: Brosium utile, Qualea polychroma, Simarouba amara, Symphonia globurifera, Tapirira myriantha and Vochysia megalophylla were present in all four treatments and present high current annual growth rates. At the other extreme, 67 species are only found in one of the treatments and demonstrate current annual growth rates of 5mm per year. This demonstrates the high variability in terms of growth rates that exists within tropical forests. Growth curves of species with high importance or economic values are presented. These species are Qualea polychroma, Peltogyne purpurea, Calophyllum brasiliense, Carapa nicaraguensis, Brosimun utile, Symphonia globulifera. Species in different genera but with similar ecological charactgeristics were grouped: Vochysia (V. allenii, V, ferruginea, V. guatemalensis, V. megalophyla), Virola (V. koschny, V. sebifera), and at the family level: Sapotaceae (géneros Pouteria, Elaeoluma, Micropholis, Manilkara), and lastly the shade-intolerant and fast-growing species: Trattinnicka aspera, Laetia procera, Apeiba membranaceae, Cecropia obtusifolia, C. insignis, Jacaratia spinosa, Casearia arborea, Jacaranda caucana, and Castilla tunu. All of these present the typical hyperbole curve in their distributions. With respect to mortality among treatments, results indicate that treatment III SATT presented the highest mortality rates, and treatment IV SABT presented the highest recruitment rates. The current tendency is where disturbances were greater mortality was high. Ecological guilds are used in grouping species presenting similar autoecological characteristics in relation to their shade-tolerance. From a silvicultural perspective, this classification allows to assess forest growth after the treatments by means of DBH growth. From the disturbance viewpoint, treatment 4 was the most severe, and it is to be expected that shade-intolerant species present the highest current annual growth rates. This was confirmed and for the fast-growing shade-intolerant species and the pioneer species which attained 4,22 – 4,29 mm/year of DBH growth per year, respectively. It was also observed that the shade-intolerant group presents the highest current annual growth in all treatments, which was also to be expected. An important objective in this project was to translate demographic information into practical recommendations for extraction rates and harvesting methods for the study species. Being able to monitor species for 17 years provides very valuable information that sheds light on the ecology of the tree species, on their growth rates, and silviculturally by studying their response to different silvicultural regimes. This information together is useful when designing sustainable forestry practices for the forests in the Osa Peninsula. After the publication of the Standards for Sustainable Natural Forest Management, according to the Executive Decree 34559-MINAE, published in the Gaceta 115 on June 16th, 2008, the use of the Practices Code and the Manual of Procedures is enforced thereon. This decree demands the application of reference values for two very important variables: basal area (m2 /ha) and the ranges of absence/presence of species according to their ecological guild. Because this decree enforces its implementation in the country, data from two very specific sites was used to establish these guidelines: Northern Costa Rica and the area of influence of FUNDECOR (Foundation for the Development of the Central Cordillera), and there are differences in the variables discussed here between sites. To have more specific parameters of forest dynamics in this region, the Osa Conservation Area (ACOSA) has planned to generate new reference values for this region, and for this reason this study’s results become very valuable, because it provides up to date information which has been requested to the researchers working in the area by ACOSA. Given the importance of this request, the dissemination of the findings in this study can be readily distributed and incorporated into the different government sectors. Meetings were carried out between the ACOSA officials and the researchers, with the objective of designing a strategy that could be submitted to the National Commission of Sustainable Forestry in order to modify the current Executive Decree 34559-MINAE. This project’s results suggest that the reference values set by the Executive Decree 34559-MINAE are small compared to the values reported in the Osa Peninsula’s forests. This represents a disadvantage for these forests because they are harvestable according to the decree. This is mainly due to the fact that the Peninsula’s forests are more productive than most forests in the country.Instituto Tecnológico de Costa Rica. Universidad De Costa Rica. Programa Conjunto INBio-SINAC con fondos del Banco Mundial-Proyecto Desarrollo de Recursos de la Biodiversidad

Monitoreo fenológico de árboles semilleros de diez especies forestales nativas del bosque seco tropical, estación experimental forestal horizontes, área de conservación Guanacaste, Costa Rica

Proyecto de Graduación (Licenciatura en Ingeniería Forestal) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Forestal, 2013.Se estudió la fenología vegetativa y reproductiva de 239 árboles semilleros de diez especies forestales nativas del Bosque Seco Tropical, dentro de la Estación Experimental Forestal Horizontes, Guanacaste, Costa Rica. Los objetivos de este trabajo fueron elaborar y establecer un protocolo para el monitoreo fenológico de árboles semilleros; cuantificar la fenología vegetativa y reproductiva de las especies; elaborar un mapa de ubicación de los individuos estudiados; brindar información para una mejor comprensión de la fenología; aportar recomendaciones para la conservación de fuentes semilleras y la toma de decisiones en actividades de recolecta. La selección de las especies se realizó de acuerdo al periodo de recolección de semillas y al valor comercial de las especies. Los individuos se identificaron, seleccionaron y ubicaron cerca de los caminos. A cada individuo se midió el diámetro a 1.3 m del suelo, se tomaron sus coordenadas con GPS, se determinó la forma y posición de copa, estado fitosanitario y grado de infestación por lianas. Se evaluaron los patrones fenológicos mensualmente de enero a marzo del 2013 según la metodología de Fournier (1974). Se realizó un análisis para datos categóricos utilizando tablas de contingencia. El follaje y la fructificación mostraron una tendencia decreciente conforme aumentó la época seca; se presentó un pico de floración en el mes de febrero. Los porcentajes de foliación, floración y fructificación fueron 87.2%, 19.9% y 35.4%, respectivamente. Durante el periodo de observación, los valores de máxima foliación se registraron en todas las especies, mientras que la floración y fructificación mostraron variabilidad en la cantidad de especies que manifestaron estas fenofases. La infestación de lianas no mostró una aparente afectación en la productividad de las especies arbóreas. La presencia de hojas, flores y frutos fue mayor en los árboles emergentes. Se presentó variación fenológica entre individuos, sitios y especies

Uso de ImageJ y R para la digitalización de datos de ubicación de árboles en inventarios forestales

Este tutorial muestra el uso de código R para leer los mapas de cuadrantes (formularios croquis) en inventarios de árboles. Primero, se presenta la digitalización de píxeles, de una imagen escaneada del croquis dibujado en campo, con el programa ImageJ (Schneider et al., 2012); y segundo, la conversión de los píxeles digitalizados en coordenadas dentro de un cuadrante o lo que se conoce como coordenadas locales. Aquí, se muestra paso a paso una técnica computacional para obtener los datos de ubicación de los árboles inventariados en cuadrantes de 20m x 20m utilizando código R (R Core Team, 2021).Este tutorial muestra el uso de código R para leer los mapas de cuadrantes (formularios croquis) en inventarios de árboles. Primero, se presenta la digitalización de píxeles, de una imagen escaneada del croquis dibujado en campo, con el programa ImageJ (Schneider et al., 2012); y segundo, la conversión de los píxeles digitalizados en coordenadas dentro de un cuadrante o lo que se conoce como coordenadas locales. Aquí, se muestra paso a paso una técnica computacional para obtener los datos de ubicación de los árboles inventariados en cuadrantes de 20m x 20m utilizando código R (R Core Team, 2021)

Diversidad de mariposas diurnas y especies con potencial productivo en un paisaje fragmentado, reserva námaku, Sierra Nevada de Santa Marta.

Se realizó una caracterización del ensamblaje de mariposas diurnas en un fragmento de bosque secundario, borde de bosque y área abierta en la Reserva Námaku y finca las mercedes, ubicadas en el sector noroccidental de la Sierra Nevada de Santa Marta. Los atributos examinados fueron, la diversidad, riqueza, abundancia, composición, y potencial de las especies para su cría sostenible y comercialización. Un total de 71 especies, 55 géneros y 16 subfamilias de Papilionoidea fueron registrados. La riqueza y diversidad en el bosque fue baja en comparación al borde y área abierta que presentaron mayor heterogeneidad ambiental y disponibilidad de microhabitats. La composición de especies reflejo los cambios en el grado de intervención de cada sitio; con especies propias de ambientes húmedos en el bosque, como, Pseudoscada timna, Hypoleria lavinia, Morpho helenor y Mechanitis polymnia. En el borde predominaron Pareuptychia ocirrhoe, Hermeuptychia hermes, Cissia terrestris, e Historis odius, y en la zona abierta hubieron especies indicadoras de áreas degradadas, siendo más abundantes Eurema albula, E. elathea, Anartia amathea, Janatella leucodesma y Hermeuptychia hermes. Un total de 25 especies son utilizadas en actividades de zoocria y venta de mariposas, representando un potencial para enfocar esta actividad hacia el ecoturismo de la Sierra Nevada o en la liberación de mariposas en eventos sociales

Efecto del cambio climático sobre el patrón de distribución de las especies de plantas en el Parque Nacional Volcán Irazú (PNVI) basado en simulaciones a mediano y largo plazo

Proyecto de Investigación. Código del proyecto: VIE-5402-1401-1031Actualmente son escasos los estudios sobre las modelaciones a mediano y largo plazo y es incierto si las especies de plantas en nuestro país, o al menos en algunos ecosistemas específicos, serán capaces de evolucionar y adaptarse a tiempo al cambio climático. Pocos estudios en Costa Rica dan seguimiento a estos efectos, a pesar que se poseen espacios geográficos muy particulares para llevar a cabo estudios sobre el impacto del cambio climático en las poblaciones naturales. Uno de estos espacios es el Parque Nacional Volcán Irazú (PNVI), un área protegida que resguarda el volcán activo más alto de Costa Rica, mantiene uno de los pocos reductos de vegetación de páramo presentes en nuestro país, preserva los sitios de origen de varias cuencas hidrográficas, abriga varias zonas de vida del país y es una importante zona de protección de flora y fauna, que incluye al menos nueve especies de plantas endémicas de Costa Rica. El presente estudio estableció 10 parcelas de medición permanentes dentro del PNVI, dentro de un sistema montañoso que reúne características muy particulares que la convierten en un sitio ideal para monitorear el efecto del cambio climático sobre el patrón de distribución de sus especies de plantas. Adicionalmente, los ciclos fenológicos en las plantas se están viendo significativamente afectados; un cambio previsto es el predominio de "malas hierbas" o especies oportunistas a expensas de la escasez de especies con más exigencias ecológicas; también, ya se registran migraciones altitudinales de especies y se proyectan extinciones locales a un plazo muy corto. Se ha considerado que "las temperaturas globales previstas para los próximos siglos, puede poner en marcha un nuevo evento de extinción masiva”, donde más del 50% de las especies de animales y plantas podrían extinguirse. Este trabajo atendió como objetivo principal la evaluación del efecto del cambio climático sobre el patrón de distribución de las especies de plantas presentes en el Parque Nacional Volcán Irazú, basado en simulaciones a mediano y largo plazo”. Este objetivo se cumplió satisfactoriamente mediante las simulaciones en el patrón de distribución de 47 especies de plantas presentes en el PNVI, en función del cambio climático, lo que permitió valorar su riesgo de extinción local, capacidad de desplazamiento o adaptación a las nuevas condiciones climáticas; también se valoró la probabilidad de ingreso al PNVI, por cambios en los patrones del clima, de especies de plantas actualmente consideradas como arvense, evaluando al menos 10 taxones distintos que en el presente no se encuentran pero tienen alto potencial de inserción en el sitio. Finalmente el proyecto define acciones a seguir en procura de mitigar el efecto del cambio climático en el patrón de distribución de las especies de plantas presentes en el PNVI, donde la principal recomendación es que el Parque, realice el pago de los terrenos que aún no han sido despropiados en el sector sureste; ya que según la modelaciones realizadas es en este sector donde se concentra el nicho potencial para las especies modeladas. Dar seguimiento a las especies Crassocephalum crepidioides, Rumex obtusifolius, Ulex europaeus, Achillea millefolium y Ranunculus repens, como especies con 6 potencial de invadir las áreas del PNVI. Un producto a resaltar aparte de las publicaciones científicas, es un libro sobre la flora en la PNVI