Efecto de la fertilización sobre la producción de un fruto forestal comestible: el piñón de pino piñonero (Pinus pinea L.) en Andalucía Occidental

The pine nut from the stone pine (Pinus pinea L.) is the most important edible fruit in mediterranean forests. Despite this fact, there is a lack of knowledge regarding the application of agronomy techniques in stands of this species to increase pine nut production. Our study focuses on the effect of mineral fertilization on cone production and size, which in turn, are closely related to nut yield and quality. Cone production and quality was analysed in a randomized experiment installed in south west Spain, comparing the effect of different doses of lime superphosphate, dolomite and potassium. A significant short term increase in cone production and quality exists as a consequence of fertilization, especially in those treatments involving the addition of larger quantity of dolomite. Nevertheless, effect of mineral fertilization on cone yield and quality was lower than expected, so further increments might be achieved through nitrogenous and organic fertilizations to improve soil structure in these sandy soils.El piñón de Pinus pinea L. es el fruto forestal comestible más importante en los bosques mediterráneos. Pese a esto, existe una falta de conocimiento científico acerca de la aplicación de prácticas agronómicas sobre las masas forestales de la especie al objeto de mejorar la producción de piñón. Nuestro trabajo se centra en el análisis del efecto de la fertilización mineral sobre la producción y el tamaño de las piñas, variables muy relacionadas con la cantidad y calidad de piñón. Entre 1993-1999 se realizó el seguimiento de la producción y la calidad de la piña en un experimente aleatorizado instalado en el SO de España, donde se comparaban diferentes dosis de superfosfato de cal, dolomita y cloruro potásico. Se ha detectado una respuesta positiva a la fertilización en la cantidad y calidad de las piñas producidas, especialmente en los tratamientos que planteaban la incorporación de una mayor cantidad de dolomita. El efecto de la fertilización mineral sobre la cantidad y calidad de piña ha sido menor que el esperado, por lo que futuros trabajos deben plantear la necesidad de incorporar fertilizantes nitrogenados y materia orgánica para mejorar la estructura en estos suelos arenosos

Interactions between directly and parametrically driven vibration modes in a micromechanical resonator

The interactions between parametrically and directly driven vibration modes of a clamped-clamped beam resonator are studied. An integrated piezoelectric transducer is used for direct and parametric excitation. First, the parametric amplification and oscillation of a single mode are analyzed by the power and phase dependence below and above the threshold for parametric oscillation. Then, the motion of a parametrically driven mode is detected by the induced change in resonance frequency in another mode of the same resonator. The resonance frequency shift is the result of the nonlinear coupling between the modes by the displacement-induced tension in the beam. These nonlinear modal interactions result in the quadratic relation between the resonance frequency of one mode and the amplitude of another mode. The amplitude of a parametrically oscillating mode depends on the square root of the pump frequency. Combining these dependencies yields a linear relation between the resonance frequency of the directly driven mode and the frequency of the parametrically oscillating mode.Comment: 5 pages, 4 figure

Modelling the spatio-temporal pattern of primary dispersal in stone pine (Pinus pinea L.) stands in the Northern Plateau (Spain)

Natural regeneration in stone pine (Pinus pinea L.) managed forests in the Spanish Northern Plateau is not achieved successfully under current silviculture practices, constituting a main concern for forest managers. We modelled spatio-temporal features of primary dispersal to test whether (a) present low stand densities constrain natural regeneration success and (b) seed release is a climate-controlled process. The present study is based on data collected from a 6 years seed trap experiment considering different regeneration felling intensities. From a spatial perspective, we attempted alternate established kernels under different data distribution assumptions to fit a spatial model able to predict P. pinea seed rain. Due to P. pinea umbrella-like crown, models were adapted to account for crown effect through correction of distances between potential seed arrival locations and seed sources. In addition, individual tree fecundity was assessed independently from existing models, improving parameter estimation stability. Seed rain simulation enabled to calculate seed dispersal indexes for diverse silvicultural regeneration treatments. The selected spatial model of best fit (Weibull, Poisson assumption) predicted a highly clumped dispersal pattern that resulted in a proportion of gaps where no seed arrival is expected (dispersal limitation) between 0.25 and 0.30 for intermediate intensity regeneration fellings and over 0.50 for intense fellings. To describe the temporal pattern, the proportion of seeds released during monthly intervals was modelled as a function of climate variables – rainfall events – through a linear model that considered temporal autocorrelation, whereas cone opening took place over a temperature threshold. Our findings suggest the application of less intensive regeneration fellings, to be carried out after years of successful seedling establishment and, seasonally, subsequent to the main rainfall period (late fall). This schedule would avoid dispersal limitation and would allow for a complete seed release. These modifications in present silviculture practices would produce a more efficient seed shadow in managed stands

Modelling non-wood forest products in Europe: a review.

Non-wood forest products (NWFP) like cork, edible mushrooms, pine nuts, acorns, resins, medicinal plants, and floral greens, among others, provide important recreational and commercial activities in the rural forested areas of the world, being in certain regions more profitable than traditional timber harvesting. Despite the importance of non-wood forest products and services, forest management and planning methods and models in Europe have been traditionally wood oriented, leading to a lack for tools helping forest management based on optimizing these products. In the present work we’ll show and discuss the main factors and challenges limiting the development of classical empirical models for NWFP, and we will review the existing models for the main NWFP in Europe: cork, pine nuts, berries, mushrooms and resins.Los productos forestales no maderables (PFNM), como el corcho, los hongos coemstibles, piñones, bellotas, resinas y plantas medicinales u ornamentales, entre otros, son fuente tanto de servicios recreativos como de actividad económica en una parte importante de los bosques del mundo. En muchas de estas zonas, el aprovechamiento de estos productos supone un ingreso superior al obtenido en el aprovechamiento maderable tradicional. Sin embargo, y pese a la importancia de estos productos y servicios no maderables, la gestión forestal, las herramientas de apoyo y los modelos forestales existentes en Europa han sido normalmente desarrollados desde una perspectiva centrada en la producción de madera. Esto se ha traducido en la escasez de herramientas de apoyo a la decisión de la gestión basadas en la optimización de la producción no maderable. En el presente trabajo se exponen y discuten los principales factores que limitan el desarrollo de los modelos para productos no maderables, y se revisan los modelos existentes para los principales productos no maderables en Europa: corcho, piñones, frutos del bosque, hongos y resina

Hacia el manejo sostenible de los bosques de araar (Tetraclinis articulata (Vahl.) Mast.) en Túnez: modelos para las principales variables de árbol

The thuya (Tetraclinis articulata (Vahl.) Mast.) forests are one of the most important ecosystems in semiarid environments in north-western Africa, providing important economic profit and social services to local populations. However, lack of tools aiding sustainable management of these forests is detected. In the present work models for the main tree attributes as total height, crown diameter, height to crown base and stem form are developed for the species, using data from a net of plots installed in JbelLattrech region, in the NE Tunisia. Presented models allow characterizing the actual state and timber production of forests by using variables measured in typical forest inventories and conform a preliminary step for the future development of dynamic growth models.Los bosques de araar (Tetraclinis articulata (Vahl.) Mast.) constituyen uno de los ecosistemas más importantes de los ambientes semiáridos del noroeste de África, siendo además fuente de importantes beneficios económicos y servicios sociales a las poblaciones rurales. Pese a este interés, hasta el momento no se han desarrollado herramientas que faciliten la gesitón sostenible de estas masas forestales. En el presente trabajo se presentan modelos para los principales atributos de árbol individual: altura total, diámetro de copa, altura hasta la base de la copa y ecuación de perfil, desarrollados para la especie a partir de datos obtenidos en una red de parcelas permanentes instalada en la región de JbelLattrech, en el NE de Túnez. Los modelos presentados permiten caracterizar el estado y producción maderera actual de los bosques de thuya a partir de las variables medidas habitualmente en los inventarios forestales para la gestión, y constituyen además un paso preliminar para el desarrollo futuro de modelos dinámicos de crecimiento para la especie

Exploring the transferability of large supramolecular assemblies to the vacuum-solid interface

We present an interplay of high-resolution scanning tunneling microscopy imaging and the corresponding theoretical calculations based on elastic scattering quantum chemistry techniques of the adsorption of a gold-functionalized rosette assembly and its building blocks on a Au(111) surface with the goal of exploring how to fabricate functional 3-D molecular nanostructures on surfaces. The supramolecular rosette assembly stabilized by multiple hydrogen bonds has been sublimed onto the Au(111) surface under ultra-high vacuum conditions; the resulting surface nanostructures are distinctly different from those formed by the individual molecular building blocks of the rosette assembly, suggesting that the assembly itself can be transferred intact to the surface by in situ thermal sublimation. This unanticipated result will open up new perspectives for growth of complex 3-D supramolecular nanostructures at the vacuum-solid interface

Modelling Pinus pinea forest management to attain natural regeneration under present and future climatic scenarios

Natural regeneration-based silviculture has been increasingly regarded as a reliable option in sustainable forest management. However, successful natural regeneration is not always easy to achieve. Recently, new concerns have arisen because of changing future climate. To date, regeneration models have proved helpful in decision-making concerning natural regeneration. The implementation of such models into optimization routines is a promising approach in providing forest managers with accurate tools for forest planning. In the present study, we present a stochastic multistage regeneration model for Pinus pinea L. managed woodlands in Central Spain, where regeneration has been historically unsuccessful. The model is able to quantify recruitment under different silviculture alternatives and varying climatic scenarios, with further application to optimize management scheduling. The regeneration process in the species showed high between-year variation, with all subprocesses (seed production, dispersal, germination, predation, and seedling survival) having the potential to become bottlenecks. However, model simulations demonstrate that current intensive management is responsible for regeneration failure in the long term. Specifically, stand densities at rotation age are too low to guarantee adequate dispersal, the optimal density of seed-producing trees being around 150 stems·ha−1. In addition, rotation length needs to be extended up to 120 years to benefit from the higher seed production of older trees. Stochastic optimization confirms these results. Regeneration does not appear to worsen under climate change conditions; the species exhibiting resilience worthy of broader consideration in Mediterranean silviculture

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