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

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

Effects of selective logging on the abundance, regeneration and short-term survival of Caryocar costaricense (Caryocaceae) and Peltogyne purpurea (Caesalpinaceae), two endemic timber species of southern Central America

In this study, we determined the effects of selective logging on the abundance of the last remnant populations of two tropical timber species with a restricted distribution, Caryocar costaricense and Peltogyne purpurea. We conducted a census of adult tree densities for these species on 94 selectively logged sites located in a tropical rain forest on the Osa Peninsula, Costa Rica. We compared the abundance of juveniles and seedlings for both tree species on 11 logged and unlogged sites. In addition, we analyzed the growth and mortality rates of adult trees of P. purpurea (>10 cm dbh) in a 4 ha permanent plot that was selectively logged once in 1992. Both species presented a heterogeneous density distribution over the Osa Peninsula (166,668 ha) and the highest density of both species is located in the region of the highest logging activity. For C. costaricense, seedling (height 50 cm, dbh < 2 cm) abundance was greater in unlogged areas, while trees 2–10 cm dbh were more abundant in logged areas. For P. purpurea, seedlings were more abundant in unlogged areas, but small and large juvenile abundance did not differ between selectively logged treatments. The density of P. purpurea adult trees remained constant 15 years after selective logging but the density of trees 10–30 cm dbh decreased in the same period. We predict that recurrent 15 year cutting cycles of 50% of timber trees with restricted distribution, as it is practiced by conventional logging in Costa Rica, may lead a significant reduction of the main reproductive individuals, decreasing the regeneration of the populations subjected to exploitation and fragmentation.Programa conjunto INBio-SINAC (Programa Integrado Desarrollo de Recursos de Biodiversidad, World Bank), Vicerrectoría de Investigación de la Universidad de Costa Rica (Programa Institucional Osa-Golfo Dulce) and the Consejo Nacional de Investigacio ́n y Tecnologia de Me ́xico (CONACYT)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Environmental gradients and the evolution of successional habitat specialization: A test case with 14 Neotropical forest sites

https://www.scopus.com/inward/record.url?eid=2-s2.0-84939570316&partnerID=40&md5=fcadae8e6c274e8b7efca96099304a7cSuccessional gradients are ubiquitous in nature, yet few studies have systematically examined the evolutionary origins of taxa that specialize at different successional stages. Here we quantify successional habitat specialization in Neotropical forest trees and evaluate its evolutionary lability along a precipitation gradient. Theoretically, successional habitat specialization should be more evolutionarily conserved in wet forests than in dry forests due to more extreme microenvironmental differentiation between early and late-successional stages in wet forest. We applied a robust multinomial classification model to samples of primary and secondary forest trees from 14 Neotropical lowland forest sites spanning a precipitation gradient from 788 to 4000 mm annual rainfall, identifying species that are old-growth specialists and secondary forest specialists in each site. We constructed phylogenies for the classified taxa at each site and for the entire set of classified taxa and tested whether successional habitat specialization is phylogenetically conserved. We further investigated differences in the functional traits of species specializing in secondary vs. old-growth forest along the precipitation gradient, expecting different trait associations with secondary forest specialists in wet vs. dry forests since water availability is more limiting in dry forests and light availability more limiting in wet forests. Successional habitat specialization is non-randomly distributed in the angiosperm phylogeny, with a tendency towards phylogenetic conservatism overall and a trend towards stronger conservatism in wet forests than in dry forests. However, the specialists come from all the major branches of the angiosperm phylogeny, and very few functional traits showed any consistent relationships with successional habitat specialization in either wet or dry forests. Synthesis. The niche conservatism evident in the habitat specialization of Neotropical trees suggests a role for radiation into different successional habitats in the evolution of species-rich genera, though the diversity of functional traits that lead to success in different successional habitats complicates analyses at the community scale. Examining the distribution of particular lineages with respect to successional gradients may provide more insight into the role of successional habitat specialization in the evolution of species-rich taxa

Educación ambiental y sociedad. Saberes locales para el desarrollo y la sustentabilidad

EL LIBRO PERMITE REFLEXIONAR SOBRE LA IMPORTANCIA DE FOMENTAL LA EDUCACIÓN AMBIENTAL PARA RESOLVER LA PROBLEMÁTICA AMBIENTALEL LIBRO PRESENTA DIFERENTES TRABAJOS QUE ESTUDIAN EL TEMA D ELA SUSTENTABILIDAD, ENFATIZANDO LA IMPORTANCIA DE LA EDUCACIÓN AMBIENTAL Y LA TRANSDISCIPLINANINGUN

Consideraciones silviculturales de ocho especies forestales con poblaciones reducidas o en peligro de extinción en la provincia de Guanacaste, Costa Rica

Se evaluó el estado actual de las poblaciones y producir la información básica técnica y legal que permita orientar el manejo de especies forestales, incluyéndose la veda parcial o total, que contribuya a la permanencia de sus poblaciones en condiciones in situ, las especies estudiadas fueron guanacaste blanco (Albizia niopoides (Spruce ex Benth.) Burkart), espavel (Anacardium excelsum (Bert. & Bald.) Skeels.), ron ron (Astronium graveolens Jacquin), cedro amargo (Cedrela odorata L.), ceiba (Ceiba pentandra (L.) Gaertn.), cocobolo (Dalbergia retusa Helmsl.), guapinol (Hymenaea courbaril L.) y tempisque (Sideroxylon capiri (A.DC.) Pittier). La selección de las especies forestales se basó en: la disminución visible de sus poblaciones, la tasa de aprovechamiento comercial es aún elevada, criterios biológicos y ecológicos, como lo son los mecanismos de polinización y dispersión de las semillas, requerimientos edáficos, distribución a escala regional, diocismo, endemismo, crecimiento, abundancia, frecuencia, distribución de las especies en los ecosistemas forestales y regeneración. La situación actual de las poblaciones de las especies estudiadas es crítica, principalmente considerando la abundancia/ha, en toda el área muestreada los valores fluctuaron entre 0,04 y 0,46 árboles/ha. Las especies se presentan bajo una matriz de bosques fraccionados y muy dispersos, fuertemente afectados por actividades humanas, como los incendios y aprovechamientos de diferentes productos. Todas las especies presentan valores de abundancia más bajos que los establecidos en los Principios, Criterios e Indicadores para el Manejo Forestal y la Certificación en Costa Rica (menores a 0,3 árboles/ha). Se concluye que, bajo las condiciones actuales de aprovechamiento, las especies estudiadas tienen pocas probabilidades de continuar formando parte del bosque. Sin embargo, por los serios problemas de regeneración, producción de semillas, vitalidad de los individuos, aislamiento de poblaciones, no se tiene garantía que las áreas protegidas realmente estén cumpliendo su rol en la conservación de las especies y del ecosistema. Se propone una veda regional para Dalbergia retusa, Sideroxylon capiri, Astronium graveolens, Hymenaea courbaril, y restricciones de uso a Ceiba pentandra, Anacardium excelsum y Cedrela odorata y un decreto especial de protección para Albizia niopoides

Evaluación silvicultural para ocho especies forestales con poblaciones reducidas o en peligro de extinsión en el bosque seco de Guanacaste, Costa Rica.

En Costa Rica se estiman más de medio millón el número de especies de plantas, animales y microorganismos. Las plantas conocidas se estiman en aprox. en 10 000 especies. El componente arbóreo está representado por 2000 especies, de las cuales 300 han sido utilizadas por su madera

Recuperación de áreas degradadas por medio de un proceso natural: el bosque secundario

La pérdida de cobertura forestal en todo el mundo es un problema de grandes proporciones, por sus efectos sobre el medio ambiente, la sociedad y la economía de los países. Junto con la desaparición de bosques, surge automáticamente el efecto contrario, cuando las áreas descubiertas dejan de cumplir un rol dentro del contexto por el cual fue destruido el bosque original. Este efecto es larecuperación en forma natural de los sitios, siempre que se reúnan algunas características: eliminación del incendios y pastoreo, principalmente. En forma natural, y sin costo alguno, la naturaleza, por medio del proceso conocido como sucesión secundaria, cubre con el pasar de los años las áreas descubiertas de una vegetación arbórea. Este proceso permite al hombre recuperar no solo la cobertura forestal de un sitio, sino mejorar las características del suelo y, en general, mejorar el medio ambiente. Costa Rica posee un potencial muy grande de recuperación, por localizarse dentro de la faja tropical. Ello favorece el establecimiento del bosque secundario en todas las áreas que perdieron por diferentes razones la vegetación original, de tal manera que se puedan manejar con el fin de satisfacer diferentes necesidades para la sociedad

Recuperación de áreas degradadas por medio de un proceso natural: el bosque secundario

La pérdida de cobertura forestal en todo el mundo es un problema de grandes proporciones, por sus efectos sobre el medio ambiente, la sociedad y la economía de los países. Junto con la desaparición de bosques, surge automáticamente el efecto contrario, cuando las áreas descubiertas dejan de cumplir un rol dentro del contexto por el cual fue destruido el bosque original. Este efecto es larecuperación en forma natural de los sitios, siempre que se reúnan algunas características: eliminación del incendios y pastoreo, principalmente. En forma natural, y sin costo alguno, la naturaleza, por medio del proceso conocido como sucesión secundaria, cubre con el pasar de los años las áreas descubiertas de una vegetación arbórea. Este proceso permite al hombre recuperar no solo la cobertura forestal de un sitio, sino mejorar las características del suelo y, en general, mejorar el medio ambiente. Costa Rica posee un potencial muy grande de recuperación, por localizarse dentro de la faja tropical. Ello favorece el establecimiento del bosque secundario en todas las áreas que perdieron por diferentes razones la vegetación original, de tal manera que se puedan manejar con el fin de satisfacer diferentes necesidades para la sociedad

"Caracterización y evaluación de productos no maderables en bosque secundario"

Proyecto de investigación. Instituto Tecnológico de Costa Rica. Vicerrectoría de Investigación y Extensión (VIE). Escuela de Ingeniería Forestal. Centro de Investigación Integración Bosque Industria (CIIBI), 2004El conocimiento de la dinámica de las poblaciones de la (s) especie (s) vegetal (es) productoras de productos no maderables de bosque (pnmb) es información fundamental, sobre la cual se deben sustentar la toma de decisiones sobre el manejo de un recurso. Sin el conocimiento de esta dinámica población dentro del marco social, político y económico, del usuario del recurso, se pueden cometer errores de gran magnitud, principalmente por la sobreexplotación de un producto, planta o parte de la misma. La valoración de los pnmb, es quizás la información más importante con la que debe contarse, para elaborar un plan de manejo para el aprovechamiento de los pnmb, tendiente al aprovechamiento y uso racional de los mismos, en donde el análisis de la abundancia y frecuencia, así como el potencial productivo de los pnmb, son la base para planificar la cosecha que brindara beneficios económicos a una comunidad rural, basado en el aprovechamiento sostenible del recurso. Se presentan los resultados de la cuantificación de plantas productoras de productos no maderables, en dos bosque secundarios de la Región Huetar Norte de Costa Rica. Dichas evaluaciones indican que las poblaciones de las plantas productoras son bajas, en función de la abundancia que presentan. Por otro lado la cantidad de elementos de las plantas que se podría aprovechar es grande, en términos de diversidad no así en cantidades (abundancia). Por lo cual es sumamente difícil poder sustentar un aprovechamiento sostenido de productos no maderables bajo las condiciones existentes actualmente en dichos bosques. Por lo contrario, su condición de bosque secundario, da un enfoque particular hacia el aprovechamiento de lianas para la elaboración de cestería, principalmente. Aspecto que debe explotarse según la edad del bosque o fase de desarrollo.Instituto Tecnológico de Costa Rica. Vicerrectoría de Investigación y Extensión (VIE). Escuela de Ingeniería Forestal. Centro de Investigación Integración Bosque Industria (CIIBI)