Novel approach to assessing residual biomass from pruning: A case study in Atlantic Pinus pinaster Ait. timber forests

Forestry residual biomass from pruning operations is an important, though little studied, potential resource. Residues normally remain in the stand, since tools for their accurate quantification do not exist and it has no particular end use. Traditional tree biomass estimation models consider the whole-tree, but estimating pruned biomass requires the development of more specific equations. This work provides a modelling approach for assessing biomass along the stem and the corresponding residual biomass from forest pruning, and quantitative results from different pruning intensities in Pinus pinaster Ait. are presented. Two types of models were considered: allometric biomass equations (whole-tree) and biomass ratio equations (tree by height along the stem), and the 2-parameter Weibull distribution function resulted in the best characterization. Diameter at breast height was the best explanatory variable in all equations, and model accuracy increased when models were combined with total tree height for the tree stem and thicker branches, or with crown ratio for the remaining tree crown components. This study provides a powerful tool to estimate residual pruned biomass, enabling its better management as a valuable source of bioenergy, as well as the importance in nutrient balance and fire risk which it plays in a sustainable forestry productionWe thank the Forest Services of the Government of the Principality of Asturias for access to the forests used in this study and for financial support. Thank you to people from CETEMAS (L. González, M. García, P. Vallejo) and SERIDA (J.C. Hernández) for their participation in the fieldwork. Thank you to Ronnie Lendrum for reviewing the English and FORRISK project (Interreg IV B SUDOE 2007–2013) for its support during data analysis. Andrea Hevia was financially supported during fieldwork and data analysis by the Spanish Ministry of Education and Science through the FPU scholarship program (Reference AP2006-03890)S

Assessing the effect of pruning and thinning on crown fire hazard in young Atlantic maritime pine forests

Management of fuel to minimize crown fire hazard is a key challenge in Atlantic forests, particularly for pine species. However, a better understanding of effectiveness of silvicultural treatments, especially forest pruning, for hazard reduction is required. Here we evaluate pruning and thinning as two essential silvicultural treatments for timber pine forests. Data came from a network of permanent plots of young maritime pine stands in northwestern Spain. Vertical profiles of canopy bulk density were estimated for field data and simulated scenarios of pruning and thinning using individual tree biomass equations. Analyses of variance were conducted to establish the influence of each silvicultural treatment on canopy fuel variables. Results confirm the important role of both pruning and thinning in the mitigation of crown fire hazard, and that the effectiveness of the treatments is related to their intensity. Finally, models to directly estimate the vertical profile of canopy bulk density (CBD) were fitted using the Weibull probability density function and usual stand variables as regressors. The models developed include variables sensitive to pruning and thinning interventions and provide useful information to prevent extreme fire behavior through effective silvicultureWe thank the Forest Services of the Government of the Principality of Asturias for financial support and access to the forests used in this study. Funding during data analysis was provided by projects SCALyFOR (AGL2013-46028-R), GEPRIF (RTA2014-00011-C06-04), PLURIFOR (SOE1/P4/F0112 Interreg SUDOE) and FORRISK (SOE3/P2/F523 Interreg IV B SUDOE). Andrea Hevia was financially supported during fieldwork and data analysis by the Spanish Ministry of Education and Science through the FPU scholarship program (Reference AP2006-03890)S

Fisiología del cultivo in vitro

The culture procedures described up to the eighties, did not made any mention to the environmental control of in vitro plant development. However, growth rate, development and many of the physiologic-morphologic features of the in vitro grown plants are influenced by the culture vessel. The increasing knowledge about the environmental control of culture vessels under sterile conditions, is helping to change micorpropagation procedures. The in vitro environment with lower rate ventilation, brings about low flow rates of matter and energy, with minimum variations of temperature, high relative humidity and large daily changes of the concentration of CO2 inside the culture vessel. The type of culture vessel (size, shape, fabric and closing system) can influence the evolution of the atmosphere along the time of culture. Although submitted to different stresses factors plant can be grown in vitro, but plants can be faulty in their anatomy, morphology and physiology. As a consequence, these plants shown a phenotype unable to survive to ex vitro conditions. Different strategies can be used to control the atmosphere along the different phases of micropropagation, in heterotrophic, mixotrophic or autotrophic cultures. The election of the best strategy will be based on different factors as species, number of transplantes required, or quality-price relationship.enviromental control, tissue culture, micropropagationKeywords: in vitro enviromental, characteristic physiology,En los procedimientos de cultivo descritos hasta la década de los ochenta, no se hace ninguna referencia al control ambiental en el desarrollo de las plantas in vitro. Sin embargo, las tasas de crecimiento, desarrollo y muchas de las características fisiológicas y morfológicas de las plantas formadas in vitro están influenciadas por el ambiente físico, químico y gaseoso de los recipientes. El incremento de conocimientos acerca del control ambiental del cultivo de tejidos en condiciones estériles, está provocando una evolución de las distintas técnicas empleadas en la micropropagación de plantas. El ambiente in vitro en recipientes con baja tasa de ventilación presenta unas tasas bajas de flujo de materia y energía, con mínimas variaciones de temperatura, elevada humedad relativa y grandes cambios diarios de la concentración de CO2 en el interior de los recipientes. El tipo de recipiente de cultivo (tamaño, forma, material y sistema de cierre) puede condicionar la evolución de la composición gaseosa en su interior durante el período de cultivo. Ante los distintos factores de estrés que tienen que soportar durante las fases de la micropropagación las plantas producidas en recipientes con nulo o escaso intercambio gaseoso, pueden manifestar alteraciones o déficit en cuanto a su estructura anatómica, morfológica y fisiológica. Como consecuencia, estas plantas presentan un fenotipo incapaz de sobrevivir al transplante directo al invernadero o campo. Actualmente se pueden utilizar diferentes métodos para controlar el ambiente en las distintas fases de la micropropagación, ya sean cultivos heterótrofos, mixótrofos o autótrofos. La elección de la mejor estrategia va a depender de varios factores, destacando la especie, el número de transplantes requerido y la relación calidad precio entre otros.Palabras clave: ambiente in vitro, características fisiológicas, control ambiental, cultivo de tejidos, micropropagació

Recursos forestales

Esta publicación editada es la consolidación del trabajo realizado por el Panel de Expertos en Cambio Climático de Asturias CLIMAS. El estudio proyecta el conocimiento científico interdisciplinar de un numeroso grupo de investigadores de distintas instituciones sobre las modificaciones que se vienen produciendo a nivel regional como consecuencia del cambio climático y mejorar la comprensión y la comunicación de las repercusiones que el cambio climático tiene y tendrá en Asturias

Stem taper function for sweet chestnut (Castanea sativa Mill.) coppice stands in northwest Spain

International audience• Context Despite the economic importance of Castanea sativa Mill. in northwest Spain, studies of its growth and yield are practically non-existent. • Aims A compatible system formed by a taper function, a total volume equation, and a merchantable volume equation was developed for chestnut (C. sativa Mill.) coppice stands in northwest Spain. • Methods Data from 203 destructively sampled trees were used for the adjustment. Outliers were removed with a non-parametric local adjustment, providing a final data set of measurements taken from 3,188 sections which was used to test five taper models (compatible and non-compatible). A second-order continuous autoregressive error structure was used to model the error term and account for autocorrelation. Presence of multicollinearity was evaluated with the condition number. Comparison of the models was carried out using overall goodness-of-fit statistics and graphical analysis. • Results Results show that the models developed by Fang et al. in For Sci 46: 1–12, 2000 and Kozak in For Chron 80, N 4: 507–515, 2004 were superior to other equations in predicting diameter for chestnut coppice stands. • Conclusion The compatible volume system developed by Fang et al. in For Sci 46: 1–12, 2000 was finally selected as it provided the best compromise between describing stem pro-file and also estimating merchantable height, merchantable volume, and total volume and therefore provides the first specific tool for more effective management of chestnut cop-pice stands

In vitro culture physiology

The culture procedures described up to the eighties, did not made any mention to the environmental control of in vitro plant development. However, growth rate, development and many of the physiologic-morphologic features of the in vitro grown plants are influenced by the culture vessel. The increasing knowledge about the environmental control of culture vessels under sterile conditions, is helping to change micorpropagation procedures. The in vitro environment with lower rate ventilation, brings about low flow rates of matter and energy, with minimum variations of temperature, high relative humidity and large daily changes of the concentration of CO 2 inside the culture vessel. The type of culture vessel (size, shape, fabric and closing system) can influence the evolution of the atmosphere along the time of culture. Although submitted to different stresses factors plant can be grown in vitro, but plants can be faulty in their anatomy, morphology and physiology. As a consequence, these plants shown a phenotype unable to survive to ex vitro conditions. Different strategies can be used to control the atmosphere along the different phases of micropropagation, in heterotrophic, mixotrophic or autotrophic cultures. The election of the best strategy will be based on different factors as species, number of transplantes required, or quality-price relationship

Modelo de distribución de la carga de combustibles finos en el dosel de copas de rodales regulares de "Pinus Pinaster": efecto de claras combinadas con podas

Los modelos de predicción del riesgo de inicio y propagación de fuegos de copas requieren conocer, entre otros parámetros, la altura de la base de la cubierta de copas (CBH) y la densidad aparente del combustible en la cubierta (CDB), cuyos valores dependen directamente de la distribución de la carga de combustibles finos en el dosel de copas. Estas dos variables no pueden medirse directamente en campo, siendo necesario contar con modelos que permitan estimarlas a partir de variables dasométricas sencillas de obtener. Para el desarrollo de estos modelos, se ha empleado un dispositivo de parcelas de ensayo de podas y claras instalado en cuatro rodales regulares de Pinus pinaster Ait. (cada uno con tres niveles de clara y tres niveles de poda combinados entre sí) en Asturias. Ambos tratamientos modificaron el valor de CBD efectivo, de 0,132 (control) a 0,038 kg.m3 (poda del 40 % con clara fuerte), y CBH, de 0,90 (control) a 3,45 m (poda del 40% con clara fuerte). La función biparamétrica de Weibull fue ajustada para las distribuciones de los combustibles finos, siendo la altura dominante, la altura de la copa y el número de pies por hectárea las variables dasométricas que mejor se relacionaron con los parámetros de dicha función de densidadS