& Key message LiDAR data (low-density data, 0.5 pulses m −2) represent an excellent management resource as they can be used to estimate forest stand characteristics in short-rotation willow coppice (SRWC) with reasonable accuracy. The technology is also a useful, practical tool for carrying out inventories in these types of stands. & Context This study evaluated the use of very low-density airborne LiDAR (light detection and ranging) data (0.5 pulses * María Castaño-Díaz

Resumen Modelización de las distribuciones diamétricas en masas de abedul (Betula alba L.) y de roble (Quercus robur L.) en el noroeste de España con la distribución betaSe han modelizado con la distribución beta las distribuciones diamétricas de 125 y 172 parcelas permanentes instaladas respectivamente en masas puras de abedul (Betula alba L.) y de roble pedunculado (Quercus robur L.) en Galicia (noroeste de España). Se ha empleado el método basado en los momentos de la distribución para ajustar el modelo a las distribuciones reales de frecuencias relativas de árboles, considerando los siguientes estadísticos en la comparación de resultados: sesgo, error medio absoluto, error medio cuadrático y número de parcelas rechazadas por el test de Kolmogorov-Smirnov (KS). En los ajustes de la función, el porcentaje de rechazos por el test KS fue del 0,8% del número total de casos en las masas de abedul y de un 1,2% en las masas de roble pedunculado, con un nivel de significación del 5%.A continuación los parámetros de la distribución fueron recuperados con modelos de recuperación de parámetros (PRM) a partir del primero y del segundo momento de la distribución (diámetro medio y varianza, respectivamente). Los extremos de la función (diá-metro mínimo y máximo de las distribuciones) fueron modelizados con modelos lineales sencillos, empleando variables de masa fáci-les de obtener de las tablas de producción existentes para las especies en el noroeste de España (diámetro medio cuadrático, altura dominante, número de pies por hectárea, edad, área basimétrica e Índice de Hart-Becking). Los modelos recuperados y calibrados en masas de Quercus robur L. fueron más precisos en términos del error medio cuadrático (con un valor medio de 0,00055 en frecuencias relativas del número de árboles). Sin embargo, los modelos fueron más precisos en las masas de Betula alba L. en términos de rechazos por el test de Kolmogorov-Smirnov: 21 parcelas rechazadas en masas de abedul (16,8% del total de parcelas) y 33 parcelas en masas de roble (19,2% del total).Palabras clave: Modelo de clases diamétricas, método de los momentos, modelo de recuperación de parámetros, Galicia. AbstractThe diameter distribution of 125 and 172 permanent plots installed respectively in birch-dominated (Betula alba L.) and pedunculate oak-dominated (Quercus robur L.) stands in Galicia (northwest Spain) were modelled with the beta distribution. The method based on the moments of the distribution was used to fit the model to real distributions of relative frequencies of trees with the following statistics considered in the comparison of results: bias, mean absolute error (MAE), mean square error (MSE) and number of plots rejected by the Kolmogorov-Smirnov (KS) test. In the fits of the function, the percentage of rejections by the KS test was 0.8% of the total number of cases in birch stands and 1.2% in pedunculate oak stands, at a significance level of 5%.Then, the parameters of the distribution were recovered with the parameter recovery models (PRM) from the first and t...

Abstract:A willow short rotation coppice (SRC) trial was conducted on former mining land in northern Spain over a period of five years, with the purpose of evaluating the effects on yield of two planting densities (9876 and 14,815 cuttings ha −1 ), three treatments (control, two levels of nitrogen, phosphorus and potassium compound fertilizer (NPK) plus weed control) and three willow clones (Björn, Inger, Olof). The area was subsoiled, ploughed, harrowed and fertilized with NPK before trial establishment. A randomized block design was applied, with three replications of each treatment in a total of 54 plots, each of an area of 400 m 2 . The effects of the interactions between the various factors on yield and other growth parameters were also studied. The clone factor significantly affected the number of shoots per stool (greatest for the Inger clone) and the Olof clone, which showed the lowest mortality rate and produced the largest trees and largest quantity of biomass. The combined application of fertilizer and herbicide also significantly increased the values of all response variables considered, except the mortality rate. The planting density did not significantly affect the response variables. Clone × treatment interactions were significant for the shoots per stool, height, diameter and biomass variables, and the Olof clone displayed the highest height and diameter growth and yield. The results obtained in the first rotation indicate that the Olof clone adapted well to the trial conditions and therefore would be appropriate for producing biomass in abandoned mine land in Asturias. These findings will help in the development of strategies for the establishment and management of SRC on marginal land.

Aim of study: To evaluate agronomic performance and changes on soil chemical properties in two types of managements: conventional or sustainable.Area of study: Principality of Asturias, Spain.Material and methods: On a loam-clay texture soil, three winter forage legumes (faba bean, red clover and white lupin), in monoculture or mixed with Italian ryegrass and with organic fertilization (sustainable management) versus Italian ryegrass in monoculture and inorganic fertilization (conventional management) were evaluated during three consecutive years. After the harvest in spring, the rotations were completed with maize crop with the purpose to evaluate the effect of the sustainable management on forage yield and soil chemical parameters.Main results: The results showed that faba bean and red clover in monoculture and mixed with Italian ryegrass had better edaphic quality than Italian ryegrass in monoculture, and white lupin in monoculture or mixed with Italian ryegrass. Faba bean in monoculture and mixed with Italian ryegrass, both with organic fertilization, could be competitive crops since both had yields comparable to Italian ryegrass in monoculture with inorganic fertilization.Research highlights: Current agricultural practice could be changed for a more sustainable management system, including organic fertilization and legume crops.

The relationships among soil parameters, tree nutrition and site index were examined in Pinus radiata D. Don stands in a climatically homogeneous area of NW Spain. Thirty-eight even-aged stands, ranging from 10 to 54 years, were sampled. In each stand, a representative plot of 0.1 ha was selected and different stand variables and parent material were considered. The soils in the study area are strongly acidic, with high proportions of organic matter, high C/N ratios, and low exchangeable base cation and available P concentration extracted by Mehlich 3 method (PM3). Although foliar N was sufficient in every stand studied, widespread deficiencies of K, P and, to a lesser extent, Mg and Ca were diagnosed. The foliar concentrations of P were positively correlated with PM3 and effective cation exchange capacity. The SI values ranged between 9.5 and 28.8 m and were positively correlated with foliar P and extractable K in soil. In the stands developed on quartzite and sandstone lithologies, the SI was negatively correlated with slope and foliar N respectively. The results suggest the importance of site selection and fertilizer treatment in reforestation programmes.Key words: age-height relationship, needle analysis, Pinus insignis, soil analysis. Resumen Influencia de los factores edáficos en el índice de sitio y estado nutricional de Pinus radiata D. Don en Asturias, noroeste de EspañaSe estudia en 38 parcelas de 0,1 ha cada una las propiedades del suelo que más influyen en el índice de sitio (IS) de plantaciones de Pinus radiata D. Don de 10 a 54 años de edad y en su estado nutricional en Asturias, considerando diferentes variables de masa y distinto material parental. Los suelos estudiados presentaron un carácter fuertemente ácido, alto contenido de materia orgánica, relación C/N elevada, bajo contenido en bases y P disponible extraído por el método de Mehlich 3 (PM3). Las deficiencias más extendidas fueron en K y P, observándose en algunas parcelas deficiencias en Mg y Ca. Sin embargo, las concentraciones en N fueron siempre superiores al nivel crítico. El P foliar se correlacionó positivamente con la capacidad de intercambio catiónico efectiva y con PM3. El IS osciló entre 9,5 y 28,8 m y estuvo positivamente correlacionado con la concentración de P en acículas y con el K intercambiable en el suelo en todas las parcelas y negativamente con la pendiente y el N foliar en las parcelas desarrolladas sobre cuarcitas y areniscas respectivamente. Los resultados revelan la importancia de la elección del sitio y la necesidad de fertilización en los programas de reforestación.Palabras clave: análisis de acículas, análisis de suelo, pino insigne, relación altura-edad.