Regulation of woody plant development by gibberellin catabolic and signaling genes

Gibberellin (GA) is a growth promoting hormone implicated in regulating a diversity of plant processes. This dissertation examines the role of GA metabolic and signaling genes in woody plant growth and development. Transgenic modifications, expression analysis, physiological/biochemical assays, biometric measurements and histological analysis were used to understand the regulatory roles these genes play in the model woody plant, Populus. Our results highlight the importance of GA regulatory genes in woody perennial growth, including: phenology, wood formation, phenotypic plasticity, and growth/survival under field conditions. We characterize two putative Populus orthologs of the SHORT INTERNODES (SHI) gene from Arabidopsis, a negative regulator of GA signaling. RNAi-mediated suppression of Populus SHI-like genes increased several growth-related traits, including extent of xylem proliferation, in a dose-dependent manner. Three Populus genes, sharing sequence homology to the positive regulator of GA signaling gene PHOTOPERIOD-RESPONSIVE 1 (PHOR1) from Solanum, are up-regulated in GA-deficient and insensitive plants suggesting a conserved role in GA signaling. We demonstrate that Populus PHOR1-like genes have overlapping and divergent function(s). Two PHOR1-like genes are highly expressed in roots, predominantly affect root growth (e.g., morphology, starch quantity and gravitropism), and induced by short-days (SD). The other PHOR1-like gene is ubiquitously expressed with a generalized function in root and shoot development. The effects of GA catabolic and signaling genes on important traits (e.g., adaptive and productivity traits) were studied in a multi-year field trial. Transgenics overexpressing GA 2-oxidase (GA2ox) and DELLA genes showed tremendous variation in growth, form, foliage, and phenology (i.e., vegetative and reproductive). Observed gradients in trait modifications were correlated to transgene expression levels, in a manner suggesting a dose-dependent relationship. We explore GA2ox and DELLA genes involvement in mediating growth responses to immediate short-term drought stress, and SD photoperiods, signaling prolonged periods of stress (e.g., winter bud dormancy). GA2ox and DELLA genes show substantial up-regulation in response to drought and SDs. Transgenics overexpressing homologs of these genes subjected to drought and SD photoperiods show hypersensitive growth restraint and increased stress resistances. These results suggest growth cessation (i.e., dormancy) in response to adverse conditions is mediated by GA regulatory genes.

On the road through the Bolivian Amazon: a multi-level land governance analysis of deforestation

Previous studies have shown that collective property rights offer higher flexibility than individual property and improve sustainable community-based forest management. Our case study, carried out in the Beni department of Bolivia, does not contradict this assertion, but shows that collective rights have been granted in areas where ecological contexts and market facilities were less favourable to intensive land use. Previous experiences suggest investigating political processes in order to understand the criteria according to which access rights were distributed. Based on remote sensing and on a multi-level land governance framework, our research confirms that land placed under collective rights, compared to individual property, is less affected by deforestation among Andean settlements. However, analysis of the historical process of land distribution in the area shows that the distribution of property rights is the result of a political process based on economic, spatial, and environmental strategies that are defined by multiple stakeholders. Collective titles were established in the more remote areas and distributed to communities with lower productive potentialities. Land rights are thus a secondary factor of forest cover change which results from diverse political compromises based on population distribution, accessibility, environmental perceptions, and expected production or extraction incomes.

Declining pine growth in Central Spain coincides with increasing diurnal temperature range since the 1970s

Growing evidence suggests environmental change to be most severe across the semi-arid subtropics, with past, present and projected drying of the Mediterranean Basin posing a key multidisciplinary challenge. Consideration of a single climatic factor, however, often fails to explain spatiotemporal growth dynamics of drought-prone ecosystems. Here, we present annually resolved and absolutely dated ring width measurements of 871 Scots pines (Pinus sylvestris) from 18 individual plot sites in the Central Spanish Pinar Grande forest reserve. Although comprising tree ages from 6 to 175 years, this network correlates surprisingly well with the inverse May–July diurnal temperature range (r = 0.84; p < 0.00011956–2011). Ring width extremes were triggered by pressure anomalies of the North Atlantic Oscillation, and the long-term growth decline coincided with Iberian-wide drying since the mid-1970s. Climate model simulations not only confirm this negative trend over the last decades but also project drought to continuously increase over the 21st century. Associated ecological effects and socio-economic consequences should be considered to improve adaptation strategies of agricultural and forest management, as well as biodiversity conservation and ecosystem service.

Temporal Changes in Randomness of Bird Communities across Central Europe

Many studies have examined whether communities are structured by random or deterministic processes, and both are likely to play a role, but relatively few studies have attempted to quantify the degree of randomness in species composition. We quantified, for the first time, the degree of randomness in forest bird communities based on an analysis of spatial autocorrelation in three regions of Germany. The compositional dissimilarity between pairs of forest patches was regressed against the distance between them. We then calculated the y-intercept of the curve, i.e. the ‘nugget’, which represents the compositional dissimilarity at zero spatial distance. We therefore assume, following similar work on plant communities, that this represents the degree of randomness in species composition. We then analysed how the degree of randomness in community composition varied over time and with forest management intensity, which we expected to reduce the importance of random processes by increasing the strength of environmental drivers. We found that a high portion of the bird community composition could be explained by chance (overall mean of 0.63), implying that most of the variation in local bird community composition is driven by stochastic processes. Forest management intensity did not consistently affect the mean degree of randomness in community composition, perhaps because the bird communities were relatively insensitive to management intensity. We found a high temporal variation in the degree of randomness, which may indicate temporal variation in assembly processes and in the importance of key environmental drivers. We conclude that the degree of randomness in community composition should be considered in bird community studies, and the high values we find may indicate that bird community composition is relatively hard to predict at the regional scale.

Tree Species Composition and Harvest Intensity Affect Herbivore Density and Leaf Damage on Beech, Fagus sylvatica, in Different Landscape Contexts

Most forests are exposed to anthropogenic management activities that affect tree species composition and natural ecosystem processes. Changes in ecosystem processes such as herbivory depend on management intensity, and on regional environmental conditions and species pools. Whereas influences of specific forest management measures have already been addressed for different herbivore taxa on a local scale, studies considering effects of different aspects of forest management across different regions are rare. We assessed the influence of tree species composition and intensity of harvesting activities on arthropod herbivores and herbivore-related damage to beech trees, Fagus sylvatica, in 48 forest plots in three regions of Germany. We found that herbivore abundance and damage to beech trees differed between regions and that – despite the regional differences - density of tree-associated arthropod taxa and herbivore damage were consistently affected by tree species composition and harvest intensity. Specifically, overall herbivore damage to beech trees increased with increasing dominance of beech trees – suggesting the action of associational resistance processes – and decreased with harvest intensity. The density of leaf chewers and mines was positively related to leaf damage, and several arthropod groups responded to beech dominance and harvest intensity. The distribution of damage patterns was consistent with a vertical shift of herbivores to higher crown layers during the season and with higher beech dominance. By linking quantitative data on arthropod herbivore abundance and herbivory with tree species composition and harvesting activity in a wide variety of beech forests, our study helps to better understand the influence of forest management on interactions between a naturally dominant deciduous forest tree and arthropod herbivores.

Exploring Growth Variability and Crown Vitality of Sessile Oak (Quercus Petraea) in the Czech Republic

Unraveling climatic effects on growth of oak - Europe’s most ecologically and economically important forest species - has been the subject of many recent studies; however, more insight based on field data is necessary to better understand the relationship between climate and tree growth and to adapt forest management strategies to future climate change. In this report, we explore the influence of temperature, precipitation and drought variability on the productivity and vitality of oak stands in the Czech Highlands. We collected 180 cores from mature oaks (Quercus petraea) at four forest stands in the Czech Drahany Highlands. Standard dendromethods were used for sample preparation, ring width measurements, cross-dating, chronology development, and the assessment of growth-climate response patterns. Crown vitality was also evaluated, using the modified ICP Forests methodology. Late spring precipitation totals between May and June as well as the mean July temperature for the year of ring formation were found to be the most important factors for oak growth, whereas crown condition was significantly affected by spring and summer drought. This study is rep-resentative for similar bio-ecological habitats across Central Europe and can serve as a dendroclima-tological blueprint for earlier periods for which detailed meteorological information is missing .

Contrasting growth and water use efficiency after thinning in mixed Abies pinsapo–Pinus pinaster–Pinus sylvestris forests

Foresters frequently lack sufficient information about thinning intensity effects to optimize semi-natural forest management and their effects and interaction with climate are still poorly understood. In an Abies pinsapo–Pinus pinaster–Pinus sylvestris forest with three thinning intensities, a dendrochronologial approach was used to evaluate the short-term responses of basal area increment (BAI), carbon isotope (δ13C) and water use efficiency (iWUE) to thinning intensity and climate. Thinning generally increased BAI in all species, except for the heavy thinning in P. sylvestris. Across all the plots, thinning increased 13C-derived water-use efficiency on average by 14.49% for A. pinsapo, 9.78% for P. sylvestris and 6.68% for P. pinaster, but through different ecophysiological mechanisms. Our findings provide a robust mean of predicting water use efficiency responses from three coniferous species exposed to different thinning strategies which have been modulated by climatic conditions over time.

Implications of Longterm Diameter-Limit Harvesting: Effects on Radial Growth of Red Spruce (Picea rubens) and Genetic Diversity of White Pine (Pinus strobus)

For over 3 centuries, diameter-limit harvesting has been a predominant logging method in the northeastern United States. Silvicultural theory asserts that such intensively selective harvesting can lead to genetic degradation. A decrease in softwood productivity has recently been reported in Maine - has a long history of dysgenic selection degraded the genetic resources of Maine softwoods, contributing to a decrease in growth and productivity? This study examines two aspects of potential implications of diameter-limit harvesting: effects on residual phenotypes of red spruce and impacts on genetic diversity of white pine. Radial growth of residual red spruce trees in stands experiencing 50 years of fixed diameter-limit harvesting was measured using annual increment rings and compared with residual red spruce trees in positive selection stands. Trees remaiaing after several rounds of diameter-limit harvesting exhibited sigdicantl y smaller radial sizes throughout their lives, and displayed significantly slower growth rates for the first 80 years of measured growth. These results strongly suggest that the largest and fastest-growing genotypes and their respective gene complexes determining good radial growth have been removed from the diameter-limit stand. Dysgenic selection can be observed in fixed diarneter-limit stands, resulting in a diminished genetic resource and decreased residual stand value. To examine more direct genetic implications of long-term diameter-limit harvesting, microsatellite DNA markers were implemented to study genetic diversity of eastern white pine in Maine. Three age groups of trees were studied: mature trees older than 200 years, juvenile trees 5-30 years old, and embryos. Trees were genotyped at 10 microsatellite loci. Overall genetic diversity levels of eastern white pine in Maine were extremely high, with an average observed heterozygosity of 0.762. Genetic differentiation was minimal among and between all three age groups, although an excess of heterozygotes was shown in the mature and juvenile groups that was not reflected in the embryo group, which actually had a slight heterozygote deficiency. Allele frequencies did not differ significantly between age groups, but did reveal more rare and low frequency alleles in the embryo groups than in the mature group. Overall, low frequency alleles comprise the largest portion of alleles in the sample population, with no common alleles evident overall. These results suggest that significant genetic degradation has either not occurred for white pine, or that the results of dysgenic selection have not yet emerged. It is clear, however, that selective harvesting could result in a loss of low frequency alleles, which are a primary reserve of evolutionary potential in a species. Implications of these studies affect industrial forestry, regional economics, and ecological concerns for the northeast. Long-term diameter-limit harvesting can lead to a degradation of residual phenotypes, and an overall decrease in stand quality. Potentially, a loss of low frequency, locally adapted alleles could result in a decrease of allelic richness and degradation of the regidnal genetic resource. Decreased genetic variation can lead to seriously limited evolutionary potential of species and ecosystems, particularly in rapidly changing environments. Based on these findings, I recommend a reassessment of any harvesting prescription that includes fixed diameter-limit removals, particularly for species that have low natural genetic diversity levels or a limited natural range, such as red spruce. Maintenance of a healthy genetic reserve can avoid effects of dysgenic harvesting.

Re.Sa.Ma.Ja.V - Patrimonio, Historia y Turismo: Plan Estratégico Situacional (PES) del Territorio de las Misiones del Uruguay. 16H282

Durante el transcurso del proyecto que se informa el equipo ha desarrollado múltiples actividades consistentes en las programadas y otras que son el resultado de los proyectos aprobados con financiamiento de múltiples instituciones. Las principales actividades a mencionar son de investigación, formación de recursos humanos y extensión. Cabe citar las actividades de formación de recursos humanos desarrolladas en el marco del programa de fortalecimiento a la extensión universitaria PROFAE, el Voluntariado Universitario, las becas CIN (Consejo Interuniversitario Nacional) Beca de estímulo a las vocaciones científicas 2012 y las becas del CEDIT (Comité Ejecutivo de Desarrollo e Innovación Tecnológica). En cuanto a investigación y extensión hemos trabajado con la Agencia Española de Cooperación Internacional para el Desarrollo, las actividades de Voluntariado Universitario con fondos de la SPU y actividades financiadas por el Programa de fortalecimiento a la extensión universitaria SPU: Redes y Promoción de las actividades de la Universidad en el exterior. Las actividades que se han desarrollado durante 2009/11 se informan en el punto 2.1.2 Acciones de transferencia que resulten del Proyecto de Investigación y que estén acreditados a través de convenios, disposiciones, contratos, etc. Otras actividades realizadas en el período: En el transcurso del período se han efectuado numerosas actividades tendientes a generar vínculos e interactuar con diversos actores locales. Salidas de reconocimiento del área de estudio y encuentros con actores locales en Concepción de la Sierra: Se han visitado las localidades de Concepción de la Sierra y Santa María. Se llevaron a cabo contactos y entrevistas con vecinos de Concepción de la Sierra, el párroco que atiende toda el área, directivo del área de Deportes del municipio, visita a la casa de la cultura y algunos sitios de interés relacionado al patrimonio jesuítico. Los agentes con quienes se ha contactado, manifestaron su preocupación por los bienes patrimoniales que se fueron perdiendo a lo largo de su historia reciente o que se llevaron para formar parte de museos de otras ciudades, la cual se plantean como una tarea pendiente su recupero. A raíz de esta situación, quienes poseen bienes encontrados o heredados, mantienen su apropiación hasta tanto no consideren políticas y espacios de exposición seguros y adecuados para su conservación y protección. Asimismo, se ha observado en la visita a la ciudad, la excavación por parte de particulares de restos misionales para construcciones privadas sin la presencia evidente de ninguna figura legal que proteja o regule el uso o restricción de dichos elementos. Cabe señalar, que los encuentros con los habitantes, fueron de carácter espontáneo, quienes se acercaron por iniciativa propia a los miembros del equipo de investigación, para expresar su desazón por la falta de política e inacción de sectores que tienen la facultad de decisión. También se ha observado un clima hostil de algunos manifestantes hacia el intendente de Concepción (2010) debido a gestiones poco claras según expresaron los actores con quienes se ha contactado, lo cual era evidente en el panorama de disconformidad que se presentaba en la ciudad y que se venía sosteniendo desde el mes de diciembre de 2009. Al mismo tiempo, el párroco señaló que tenían expectativas de planificar y organizar el espacio donde se erige la Iglesia, pero sus proyectos llevaban largo tiempo de espera por parte del organismo de cultura de la provincia, a quienes expusieron dichos proyectos. Observación: Los habitantes de Concepción de la Sierra, expresa su interés por el pasado, su historia y su identidad basado en la apropiación de los procesos que se desarrollan en el territorio. Están ansiosos y ávidos de dar a conocer ese pasado bajo condiciones viables de exposición y decisiones políticas acorde para la protección y seguridad. Es necesario un ordenamiento del territorio, regulación y zonificación con fines de protección, conservación y exposición del patrimonio local, incluyendo el legado jesuítico. Conversaciones en Santa María: Continuando con el recorrido por la zona, se visitó en varias oportunidades la Escuela de Familia Agrícola en el municipio de Santa María, establecimiento educativo con quien ya se han desarrollado otras actividades en proyectos anteriores, tanto de Investigación como de Extensión. De estos encuentros surgen solicitudes vinculadas a la posible construcción de la Represa Garabí, que afectaría a propiedades de familias de alumnos quienes desconocen el impacto ambiental resultante y las tierras que se inundarían si se concretase dicha obra. Requieren en ese sentido charlas y reuniones informativas con especialistas para que clarifiquen la situación derivada. También se visitó un emprendimiento familiar de elaboración, envasado y distribución de rapadura artesanal en el Paraje La Corita. El proceso consiste en la adquisición de leche de ordeñe que provee una vecina y de otro productor local, para luego iniciar la cocción, reservar y luego prepararlo para la distribución en la zona, incluyendo a la localidad San Javier y otros compradores de otros lugares que conocían el producto y se acercaban periódicamente a comprar cierta cantidad para revenderlo. El producto presenta dos variantes: 1. De leche y azúcar, 2. De leche, azúcar y maní. Según indicaron, cada vez es mayor la demanda y se encuentran analizando el modo de aumentar la producción. La difusión se dio básicamente bajo la modalidad del boca a boca o boca oreja. La Misión de Santa María La Mayor, amerita una visita toda vez que concurrimos al área, tanto por las acciones llevadas a cabo en este sitio, como también para recabar información y mantener el vínculo e interactuar con los gestores del patrimonio. Un dulce encuentro en San Javier: El 15 de abril de 2010 se concurrió a la localidad de San Javier, ocasión en la que se visita el Cerro que evoca la batalla de Mobororé sobre el río Uruguay en el que se construye la casa del bicentenario, el deteriorado hotel del ACA (Automóvil Club Argentino), el ingenio azucarero, el museo jesuítico, el Cerro Monje, y un camping. En el Cerro, conocido como “el cerrito” sobre el río Uruguay, el intendente explicó las acciones llevadas a cabo y los proyectos en vías de desarrollo. En la casa en construcción de la casa del bicentenario, se llevarían a cabo diversas actividades culturales, allí también existe un anfiteatro que se recuperaría teniendo en cuenta la vista excepcional del río y el entorno paisajístico desde este espacio en altura. Inmediatamente anexo se halla el viejo edificio del Hotel del ACA, que se encuentra en planes de concesionarlo para su restauración. Asimismo, el intendente explicó que se ha trabajado en forma conjunta con una escuela especial creándose una comisión para la redacción de una ordenanza que ya se ha aprobado para favorecer a personas con capacidades especiales, en el que se reglamenta aspectos constructivos en toda la ciudad. También se ha impulsado la creación y promoción de un frigorífico cooperativo con productores de ganado de la zona, contemplando aspectos de calidad y posterior comercialización, y que está encaminándose exitosamente. En el ingenio azucarero, el Ingeniero a cargo, explicó las diversas actividades que se realizaba en esos momentos de desarme de las maquinarias, debido a que no se realizaba la zafra en esa época. Aclaró también las posibilidades de ampliar la producción de azúcar si se pudiera adquirir moderna maquinaria sin un costo excesivo. A la vez explicó de qué manera se controlan a los productores de caña de azúcar que se inscriben para cumplir con los requisitos para la producción orgánica, considerando que San Javier forma parte de la cuenca orgánica, un programa del Ministerio del Agro y la Producción. Ello redunda en un precio más elevado para dichos productores. También se llevan a cabo otras investigaciones para la producción de derivados, a través de convenios con Cuba, como la elaboración de ron, licores, entre otros usos. El museo jesuítico que se halla en la plaza principal, se encuentra poco organizado y no adecuado para la contención de los bienes patrimoniales, así como el diseño, la exposición e interpretación para la visita. El camping de San Javier, sobre el río Uruguay, se enseñorea de un paisaje de excepcional belleza, ofreciendo la posibilidad de alojarse en cabañas y carpas y realizar actividades en el río, paseos en canoa y pesca en épocas permitidas. San Javier es también, un centro de peregrinación que convoca a miles de fieles en Semana Santa, provenientes de localidades aledañas. El punto culminante es el Cerro Monje, en cuya cima se erige una capilla y espacio para acampar. Desde este lugar, se tiene una amplia visión panorámica del río y del lindero país, Brasil. Con las localidades próximas de este país, se realiza un encuentro de integración anual entre miembros y funcionarios de municipios de ambas orillas. El puerto de San Javier, con el servicio de balsa entre Porto Xavier y Porto Xavier (Brasil), desarrolla una intensa actividad comercial, destacándose la exportación de cebolla, papa y ajo, con largas esperas de un centenar de camiones que van y vienen continuamente. La distancia a recorrer entre ambas orillas es muy corta, lo que permite el cruce en pocos minutos. En verano además, es una de las principales vías de comunicación hacia las playas del sur de Brasil. A su paso, es posible observar, los cultivos de la planta que emana dulzura al saborear alguna infusión, la caña de azúcar, y que distingue a San Javier, la dulce. El desvío de la Ruta provincial N° 30, un proyecto de largo caminar: La Ruta provincial N° 30 que atraviesa la Misión de Santos Mártires del Japón, luego de una sostenida gestión de poco más de una década por parte del equipo de investigación ante autoridades locales, de Vialidad Provincial, del Programa Misiones Jesuíticas, finalmente concretó el desvío. El trazado se realizó mediante la gestión del Intendente para la cesión de tierras de los propietarios que circundan el Cerro para la ejecución de dicho desvío evitando circular sobre el mismo, y apaciguar el continuo deterioro de los restos pétreos protegidos por la selva de dicha misión, de importancia notable para estudios e investigaciones científicas que pudiera dar cuenta de informaciones relevantes secretamente guardados bajo la vegetación. En la presentación del nuevo trazado, se sumó una vecina y una concejal del municipio, además del referido intendente municipal, quienes amablemente nos brindaron un almuerzo de trabajo, además del apoyo para realizar otras actividades de indagación y puesta en escena de circuitos turísticos locales en bicicleta por la Ruta provincial N° 30. Durante 2011, también se recorrió la zona advirtiéndose que no están concluidas las obras de consolidación del desvío por lo que el acceso por el nuevo camino se hace muy dificultoso.

Memorias del contacto. Relaciones indios-blancos en Misiones 1920-1960. 16H290

En el presente trabajo de investigación nos proponemos incursionar en un tema poco analizado en la historia de Misiones: el contexto y la forma en que se produjeron los primeros contactos entre inmigrantes de origen europeo e indígenas mbya en la provincia en el periodo correspondiente a 1920-1960. Nos interesa también conocer cómo eran las relaciones entre los mbya y la población de origen paraguayo y criolla en general, quienes trabajaban como mano de obra en yerbales y obrajes, constituyendo, por lo tanto, los primeros en tomar contacto con los indígenas. Indagaremos acerca de las características de esas primeras relaciones interétnicas, si existían intercambios de objetos y alimentos, si hubo violencia para expulsarlos de sus territorios a medida que se formaban las colonias destinadas a los inmigrantes, los conflictos derivados de la ocupación de las tierras. Si hubo intentos de contratarlos como peones para desmontar la selva y desde cuándo comienzan los mbya a trabajar para los colonos. Como contraparte, nos interesa conocer la visión indígena de aquellos primeros contactos, viva aún en la memoria de los ancianos. Cómo fueron los primeros contactos con los blancos y en qué contextos ocurrieron. También realizaremos la búsqueda y recopilación de material fotográfico inédito producido en la provincia durante las primeras décadas del siglo XX a los fines de análisis documental.

Forestry Sector Reform and Distributional Change of Natural Resource Rent in Indonesia

After the collapse of the centralized Soeharto regime, deforestation caused by over-logging accelerated. To tackle this problem, an IMF/World Bank-led forestry sector reform program adopted a market-friendly approach involving the resumption of round wood exports and raising of the resource rent fee, with the aim to stop rent accumulation by plywood companies, which had enjoyed a supply of round wood at privileged prices. The Indonesian government, for its part, decentralized the forest concession management system to provide incentives for local governments and communities to carry out sustainable forest management. However, neither policy reform worked effectively. The round wood export ban was reimposed and the forest management system centralized again with cooperation from a newly funded industry-led institution. In the midst of the confusion surrounding the policy reversal, the gap between the price of round wood in international and domestic markets failed to contract, although rent allocations to plywood industries were reduced during 1998-2003. The rents were not collected properly by the government, but accumulated unexpectedly in the hands of players in the black market for round wood.

A silviculture-oriented spatio-temporal model for germination in Pinus pinea L. in the Spanish Northern Plateau based on a direct seeding experiment

Natural regeneration in Pinus pinea stands commonly fails throughout the Spanish Northern Plateau under current intensive regeneration treatments. As a result, extensive direct seeding is commonly conducted to guarantee regeneration occurrence. In a period of rationalization of the resources devoted to forest management, this kind of techniques may become unaffordable. Given that the climatic and stand factors driving germination remain unknown, tools are required to understand the process and temper the use of direct seeding. In this study, the spatio-temporal pattern of germination of P. pinea was modelled with those purposes. The resulting findings will allow us to (1) determine the main ecological variables involved in germination in the species and (2) infer adequate silvicultural alternatives. The modelling approach focuses on covariates which are readily available to forest managers. A two-step nonlinear mixed model was fitted to predict germination occurrence and abundance in P. pinea under varying climatic, environmental and stand conditions, based on a germination data set covering a 5-year period. The results obtained reveal that the process is primarily driven by climate variables. Favourable conditions for germination commonly occur in fall although the optimum window is often narrow and may not occur at all in some years. At spatial level, it would appear that germination is facilitated by high stand densities, suggesting that current felling intensity should be reduced. In accordance with other studies on P. pinea dispersal, it seems that denser stands during the regeneration period will reduce the present dependence on direct seeding.