Juan Lucas Cellini

Se trabajo con 60 arboles de Nothofagus pumilio seleccionados a lo largo de un gradiente de sitios entre calidades 1 a 3 en Tierra del Fuego (Argentina). Con estos datos se desarrollaron ecuaciones de prediccion de perfil del tronco del arbol para bosques secundarios (originados a partir de la regeneracion de un bosque intervenido), comparando cuatro modelos tradicionales con otro no tradicional que utiliza la calidad de sitio como variable predictora. Por otra parte, a partir de los resultados obtenidos con los modelos, se incorporo la forma a ecuaciones de volumen comunmente utilizadas para N. pumilio, evaluando su ajuste mediante un analisis de comportamiento de residuos. El modelo de perfil de Muhairwe de exponente variable, que utiliza como variables el diametro a 1,3 m de altura, la altura total y la altura del tronco a la que se encuentra un diametro determinado, tiene el mejor comportamiento general, adecuandose a diferentes calidades de sitio, diametro y alturas relativas. ...

El efecto de la competencia se refleja en la reduccion del crecimiento de los individuos que se encuentran en una situacion competitiva mas desfavorable. El conocimiento de esos procesos es utilizable en el manejo para optimizar las condiciones de crecimiento. Se estudio la competencia entre cohortes en un bosque de Celtis tala regenerado por rebrote. Se obtuvieron muestras de barreno de 48 individuos pertenecientes a 2 cohortes distintas en 3 parcelas. Se analizaron los diametros a las edades de 5, 10 y 15 anos. Los datos se analizaron mediante tecnicas parametricas y no parametricas para un diseno de medidas repetidas. La cohorte mas joven presento diametros menores para todas las edades. No se hallo interaccion cohorte x parcela indicando un comportamiento homogeneo en los 3 sectores. La interaccion cohorte x edad determino la existencia de diferencias de pendiente en las curvas de diametro en funcion del tiempo, lo que refleja menores tasas de crecimiento para los individuos de ...

Tree growth is one of the main variables needed for forest management planning. The use of simple models containing traditional equations to describe tree growth is common. However, equations that incorporate different factors (e.g. site quality of the stands, crown classes of the trees, silvicultural treatments) may improve their accuracy in a wide range of stand conditions. The aim of this work was to compare the accuracy of tree diameter growth models using (i) a family of simple equations adjusted by stand site quality and crown class of trees, and (ii) a unique global equation including stand and individual tree variables. Samplings were conducted in 136 natural even-aged Nothofagus antarctica (Forster f.) Oersted stands in Southern Patagonia (Argentina) covering age (20–200 years), crown class and site quality gradients. The following diameter growth models were fitted: 16 simple equations using two independent variables (age and one equation for each stand site quality or cro...

Se cita por primera vez para la Provincia de Buenos Aires Tillandsia myosura, coleccionada en las inmediaciones del arroyo Pereyra, Parque Provincial y Reserva de la Biosfera Parque Pereyra Iraola (Partido de Berazategui, Buenos Aires, Argentina). Esta especie, conocida hasta el presente sólo para el sur de Uruguay y las provincias de Catamarca, Córdoba, Jujuy, La Rioja, La Pampa, Mendoza, Salta, San Juan, San Luis, Santiago del Estero y Tucumán en Argentina es citada por primera vez para la Provincia de Buenos Aires, ampliándose su límite sur de distribución. En el presente trabajo se describe e ilustra la especie, y se presenta una clave para diferenciarla de especies afines de distribución congruente.

La regeneración es un proceso dinámico basado en la incorporación de nuevos individuos a medida que otros desaparecen como resultado de la mortalidad natural. Sus fases comprenden la producción de semillas, la dispersión y la germinación. Nothofagus pumilio (Poepp. et Endl.) Krasser es considerada una especie de tolerancia media, ya que la regeneración presenta una tolerancia a la luz, no puede reproducirse ni sobrevivir por largos períodos bajo una alta cobertura y por sus habilidades de colonización. La disminución de la cobertura forestal, tras el aprovechamiento en bosques productivos sin intervención, produce una modificación significativa de las características micro-climáticas, que repercuten en la producción de semillas, la instalación de la regeneración y el crecimiento en altura. Este trabajo de Tesis evalúa la relación entre diferentes coberturas forestales remanentes luego de la intervención de bosques de N. pumilio y la producción de semilla y dinámica de la regeneració...

Estimation of stand growth is crucial for forest planning. Estimations were usually done using fixed values, and recently growth equations have been used. An alternative is through stand growth models. The objective was to develop a simple model for Nothofagus pumilio stands with full density along site quality and age gradients. The sample was obtained from 125 stands. Data on forest structure and samples for tree-ring measurement were taken in all trees to estimate growths using biometric models previously developed. The growth values of each plot during the last twenty years were calculated to fit the model, using the ratio of total volume increment/basal area as an independent variable. The developed model gives a ratio between stand volume increment and basal area (m/year) in relation to the site quality and stand age. The statistics (r2 = 0.819, mean error = 0.019, absolute mean error = 0.033), residual analysis and biological performance were satisfactory. The obtained stand ...

Recent advances in heterogeneous configurations and autonomous technology interact in order to accomplish information retrieval systems [9]. In fact, few computational biologists would disagree with the construction of symmetric encryption. Our focus in our research is not on whether lambda calculus can be made decentralized, semantic, and heterogeneous, but rather on proposing an application for collaborative symmetries (Web). This follows from the emulation of simulated annealing.

1 Ing. Forestal; 2 Proyecto Espacios Periféricos y Territorios Emergentes frente a las Dinámicas de la Mundialización (UNPA–UARG). Correspondencia a: Vélez Sarsfield 557, 1°Piso (9400) Río Gallegos, Argentina.; 3 CADIC– CONICET, Ushuaia (Tierra del Fuego); 4 Facultad Ciencias Agrarias y Forestales – UNLP, La Plata (Buenos Aires). II°Taller de Dinámicas Mundiales, Integración Regional y Patrimonio en Espacios Periféricos. 12–13 Agosto (UNPA–UARG), Río Gallegos RESUMEN Desde un enfoque ganadero, dominante en Patagonia desde finales del siglo XIX, ambientes cordilleranos como la Cuenca Río de las Vueltas, han sido considerados marginales para la producción. Una combinación particular de factores en años recientes ha resultado en la exploración de nuevas alternativas productivas entre las que el turismo es una de las más importantes. Ésta presenta en la cuenca una importante tasa de crecimiento, tanto de la oferta como de la demanda de servicios turísticos. El crecimiento de la activida...

Nothofagus pumilio forests are managed by shelterwood cuts and thinning, producing impacts on the original forest, transforming the primary forest on managed secondary forests with high timber productivity. The aim of this work is to analyze the management schemes, and propose an alternative that improves conservation taking into account current research on forest structure components, remnant tree stability and regeneration. The application of variable retention as alternative regeneration method minimizes the impacts of harvest on abiotic and biotic variables and in particular changes in forest structure, structural stability and regeneration. Natural regeneration is analyzed at all stages in the various sectors of the method and suggests guidelines for post-harvest monitoring, using results of long term research plots and publications.

ABSTRACT Biodiversity conservation is usually implemented only at a regional level in Patagonia (Argentina) and its effectiveness is poorly known regarding other landscape level units (local and stand), since little information exits. Therefore, we studied vascular plant diversity in Nothofagus forests and their associated environments distributed throughout Tierra del Fuego Island at three landscape levels. Floristic surveys (richness and cover) were conducted at 535 sites, and 230 vascular plant species were analysed at the (1) regional level, considering 2-3 zones depending on forest types (N. pumilio-NP, N. antarctica-NA or N. betuloides-NB); (2) local level, considering 5-6 vegetation types for each zone (grasslands, peat-bogs, shrublands, NP, NA and NB); and (3) stand level, considering a control-C and different tree retention types (aggregated-AR and dispersed retention-DR) on NP forests at three ranches. Data were analysed using multivariate techniques (nonmetrical multidimensional scaling and multi-response permutational procedure). At the regional level, differences were found for zones considering each forest type (NA > NP > NB). At the local level, forests plant diversity differed from non-forested associated environments in the three zones. At the stand level, harvesting produces changes in plant diversity of NP forests for the three ranches, where C was more similar to AR than DR. Plant conservation strategies in Nothofagus forests should take into account these landscape levels, since vascular plant diversity differs within a region (between different zones), a locality (vegetation types) or harvested stands (retention types). Implications of the analyses for management and conservation strategies at different landscape levels are discussed.

ABSTRACT At regional scale, large areas are preserved as natural reserves; at local scale, protection forests are left according to legal restrictions; and at stand scale, variable retention systems are used to improve conservation. This work evaluates the conservation effectiveness at different landscape scales, using Nothofagus pumilio forests (NPF) as a study case. There were used 535 vascular plant surveys (richness and cover) as conservation status indicator in Tierra del Fuego (Argentina), which were analysed using multivariate techniques. At regional scale, NPF plant diversity differed along landscape, where natural reserves are deficient for a regional conservation. At local scale, NPF differed from associated environments, where their preservation does not ensure full conservation. At stand level, aggregates better conserved plant communities than dispersed retention, retaining more structural micro-environmental components of the primary forests. Conservation programs to achieve sustainable NPF management must include different landscape scales, since differences were observed among scales.

ABSTRACT RESUMEN Las propuestas de manejo forestal para Tierra del Fuego y Patagonia Sur se basan en el manejo silvopastoril para Nothofagus antarctica (ñire), y cortas de protección y raleo para Nothofagus pumilio (lenga). Ambas propuestas producen impactos sobre los componentes bióticos y abióticos del bosque original. El objetivo de este capítulo es analizar las propuestas de manejo, planteando alternativas que prioricen el equilibrio entre producción y conservación a partir de las investigaciones actuales. Se analizan diferentes escalas en la planificación del manejo forestal y estrategias de conservación (macro, meso y micro-escala), describiendo ventajas y costos incrementales de su aplicación. En particular, se describe la aplicación de la retención variable como técnica complementaria de las cortas de protección, para minimizar los impactos de la cosecha a escala de rodal sobre las variables abióticas y bióticas. Asimismo, se analiza la regeneración natural como la variable de mayor importancia en los monitoreos post-cosecha, junto con los factores limitantes del ciclo y la posterior dinámica en parcelas de investigación a largo plazo, así como los resultados de ensayos de raleos y podas comerciales. Finalmente, se describen las carencias en el conocimiento científico y técnico desarrollado hasta el presente, a fin de mejorar la implementación del manejo 8 La producción forestal y la conservación de la biodiversidad en los bosques de Nothofagus en Tierra del Fuego y Patagonia Sur. Timber production and biodiversity conservation in Nothofagus forests of Tierra del Fuego and southern Patagonia. 156 forestal actual. A partir de este análisis se proponen diez desafíos a tener en cuenta para la próxima década. Palabras clave: manejo forestal, silvicultura, conservación, retención variable, regeneración, impacto, lenga, ñire. SUMMARY Forest management for Tierra del Fuego and southern Patagonia are based mainly on silvopastoral use of Nothofagus antarctica (ñire), and shelterwood cuts and thinnings for Nothofagus pumilio (lenga). Both proposals had impacts over biotic and abiotic components of the original forests. The objective of this chapter was to analyze these management practices by introducing a concept of equilibrium between timber production and conservation. Different planning scales (macro-, meso-and micro-scale) were analyzed for forest management and conservation including advantages and implementation. In particular, variable retention implementation was described as complementary technique of the shelterwood cuts, where harvesting impacts over abiotic and biotic scale at stand level were minimized. Natural regeneration, as one of the most important variable in the post-harvesting monitoring, also was analyzed. Limiting factors in the whole reproductive cycle, their natural dynamics in long-term research plots, commercial thinnings and prunings were described. Finally, it was identified the main actual scientific and technical knowledge gaps in order to improve the future research and implementation in the current forest management.

Summary The estimation of forest productivity is carried out using the tree volume, which is estimated directly or by using relationships or equations. Foresters must design methodologies that increase the precision and diminish the costs of carrying out a forest ...

... PABLO PERI 1, 2 , GUILLERMO MARTINEZ PASTUR 3 , RICARDO VUKASOVIC 4 , BORIS DIAZ 2 , MARIA VANESSA LENCINAS 3 , JUAN MANUEL CELLINI 3. 1 Instituto Nacional de Tecnología Agropecuaria, cc 332 (9400) Río Gallegos, Santa Cruz, Argentina. ...

ABSTRACT A random and complex task is to estimate the timber volume to be harvested in a Lenga forest, or to predict the yield of the logs to be sawed in a sawmill. The aims of this work were: to develop an equation system to estimate the timber volume of a Nothofagus pumilio forest (site quality III) from easy measured variables on standing-trees, and to construct a function to predict the yield of a middle-production sawmill of Tierra del Fuego. Using forest survey current variables (DAP, crown classes, health, stem shape and number of logs) and yield measurements (diameter and length of logs), it is possible to construct easy models. These equations give some of the neccesary information for a better planification in the management of our forest resouce.

ABSTRACT Although it is true that ecotourism may contribute to the conservation of protected areas, its secondary impact on the environment is often neglected and specifically the impact of ecotourism on wildlife has been little studied. In the arrayanes forest (Luma apiculata (DC.) Burret) in Arrayanes National Park, Quetrihue peninsula, intense tourism occurs since 1971. Even though the National Park has an area of 1840 ha tourism is almost wholly concentrated within the approximately 20 ha of arrayanes forest on its southern tip. The forest of L. apiculata as a dominant species is so unusual as to turn it into a site of scientific interest. On the basis of these considerations we decided to study the impact of noise on birds in this site. We did not find significant relation between bird behaviour and noise, nor noise levels over regulations or which could generate harm to the hearing system of birds.