Respuesta inicial del aporte de cenizas de biomasa arbórea en el estado nutricional de una plantación joven de Pinus radiata D. Don

The aim of the present study was to evaluate the effects of the application of wood-bark ash as a amendment and fertilizer of a young plantation of Pinus radiata grown on an acid soil. Two different doses of ash (5.000 and 10.000 kg ha-1) and one dose of 8:24:16 NPK fertilizer (200 g in hole) were applied at establishment. The response of the soil solid fraction and foliar chemical composition was studied throughout 28 months. Fertilization of the soil with wood-bark ash produced an increase in soil pH, at the same time increasing the availability of Ca, Mg, P and K. Related to this increase, the needle levels of Ca and, in a lower extent, Mg were also higher. Possible diagnosis of vector analysis of foliar nutrient contents and concentrations showed that these two elements limited the species growth.El objetivo del presente ensayo fue evaluar la respuesta del empleo de cenizas de corteza de madera como enmendante y fertilizante de una plantación joven de Pinus radiata que se desarrolla sobre un suelo forestal ácido. El trabajo consistió en un ensayo de campo, con aporte de dos dosis de cenizas en cobertera (5.000 kg ha-1 y 10.000 kg ha-1) y una dosis de fertilizante mineral NPK 8:24:16 (200 g en hoyo) en el momento del establecimiento de la plantación. Durante 28 meses se evaluó la respuesta de la fracción sólida del suelo y de la composición química de las acículas. El aporte de cenizas derivó en aumentos temporales del pH y de la concentración de Ca, Mg, P y K disponible en el suelo. Esta mejora de las propiedades químicas del suelo se tradujo en incrementos temporales en la concentración de Ca y, en menor medida, de Mg en las acículas. Como posible diagnóstico, el análisis de vectores de los contenidos y concentraciones de nutrientes foliares mostró que estos dos elementos limitaban el crecimiento de la especie

Secuestro de C en plantaciones de Eucalyptus spp establecidas en terrenos agrícolas en el norte de España

Una de las estrategias que se ha planteado para fijar gases con efecto invernadero (CO2, CH4 y N2O) es el aumento de la superficie forestal. España es uno de los países que más han contribuido a incrementar la superficie forestal en Europa, lo que se debe en buena parte al establecimiento de parcelas en tierras agrarias en situación de marginalidad. Durante el período de 11 años, transcurridos entre el segundo y el tercer inventarios forestales (1987 y 1998), el almacenamiento de C en biomasa arbórea en el norte de España ha aumentado en un 50 %. En este trabajo se realiza una primera estimación de las ganancias de C en biomasa y suelo en plantaciones de eucalipto establecidas en terrenos agrícolas. Para ello se seleccionaron un total de 25 pares de parcelas. Se trata de parcelas agrarias en las cuales parte de la superficie se transformó a plantación de Eucalyptus sp. En estas parcelas se determinó la acumulación de C en biomasa arbórea, mantillo y suelo en tres profundidades 0-5, 5-15 y 15-30 cm. Dado las mejores condiciones de fertilidad y mayor profundidad, que promueven el crecimiento arbóreo, la tasa de acumulación de C en biomasa es considerablemente superior a las plantaciones establecidas en suelos forestales. Los datos de este trabajo muestran acumulaciones superiores a 17 Mg ha-1 año-1. La acumulación de C en el mantillo también es superior a 1 Mg ha-1 año-1. En cuanto al suelo mineral, las pérdidas de C se reducen con los años desde el cambio de uso, fundamentalmente a partir de los 15 años del establecimiento y en plantaciones sobre esquistos y pizarras. Hasta ese momento se produjeron ligeras pérdidas.____________________________________One of the strategies proposed for fixing gases that contribute to the greenhouse effect (CO2, CH4 and N2O) is to increase the extension of land covered by forest. Spain is one of the countries that has contributed most to the increase in the forest area in Europe, largely due to the establishment of forest plots on marginal agricultural land. During the 11- year period between the second and third forest inventories (1987 and 1998), there has been a 50% increase in the storage of C in tree biomass in northern Spain. In the present study, a first estimate was made of the increase in C in biomass and soil in eucalyptus plantations established on agricultural land. A total of 25 pairs of plots were selected for the study. The plots are on agricultural land, part of which has been transformed by plantation of Eucalyptus sp. The amount of C accumulated in the tree biomass, humus and three different depths of soil (0-5, 5-15 and 15-30 cm) was determined. Given the more fertile conditions and the greater depth of the soil, which favour tree growth, the rate of accumulation of C in the biomass was considerably higher than in plantations established on forest soils. The data obtained in the present study revealed accumulations of C of more than 17 Mg ha-1 year-1. Accumulation of C in the humus was also higher than 1 Mg ha-1 year-1. The losses of C in the mineral soil decreased since the change in land use, generally from 15 years after establishment onwards, and in plantations on schists and slates. Slight losses of C were observed up until this time

Carbon balance for different management practices for fast growing tree species planted on former pastureland in southern Europe: a case study using the CO2 Fix model

Although it is known that forestry mitigates carbon emissions to some degree, there is still a need to investigate the extent to which changes in forest management regimes affect the carbon cycle. In a climate-change scenario, forest management schemes must be optimized to maximize product supply and minimize environmental impacts. It is difficult to predict the mitigating effects of different silvicultural regimes because of differences in the growth characteristics of each species, destination of products, and industrial efficiencies. The objective of the present study was to use a modeling approach to evaluate the effects of different management regimes for fast growing species in southern temperate Europe in relation to mitigating climate change. A comprehensive study was carried out considering the C sink effect in biomass, soil and wood products, the substitutive effect of bioenergy, and particular conditions of the forest industry in southern Europe. The mechanistic CO2Fix model was parameterized for three species used in fast growing plantations in southern Europe: Eucalyptus globulus, Eucalyptus nitens, and Pinus radiata. Data from 120 plots covering the complete age range observed for each species were used to calculate changes in C stocks in aboveground biomass and organic and mineral soil and to validate the parameterized model for these conditions. Additional information about the efficiency of forest industry processes in the region was also considered. A strong bias in soil organic carbon estimation was observed and attributed to overestimations in the decomposition rates of soil compartments. Slight bias was also observed in the carbon biomass estimation when forest-specific yield models were used to simulate afforestation over former pastureland. As regards the model sensitivity, the Yasso model was strongly robust to turnover of leaves, roots, and branches. The chip wood production alternative yielded higher carbon stock in biomass and products, as well as in bioenergy substitution effect, than the sawn wood production alternative. Nevertheless, the sawn wood alternative was the most effective as regards the C stock in the soil. Site index had an important effect for all species, alternatives, and compartments, and mitigating effects increased with site index. Harvesting of clearcutting and thinning slash for bioenergy use led to a slight decrease in the soil carbon equilibrium but significantly increased the mitigation effect through bioenergy use

Efecto de la selvicultura en la extracción de nutrientes a lo largo del turno en plantaciones de tres especies de crecimiento rápido en el norte de España

This paper deals with the evaluation of the amount of nutrients removed and reincorporated after clearcut or thinning in the tree main commercial species of northern Spain: Eucalyptus globulus, Pinus pinaster and Pinus radiata. A simulation of different sylvicultural alternatives was done using stand growth models integrated with control functions which allow to cope with an individual-tree level of detail and a determination of the components of the total aboveground biomass. The high annual rates of extraction in the eucalypts plantations and the adaptation of maritime pine to poor sites where low amounts of nutrients were removed are demonstrated. Heavy thinning sylvicultural regimes give a better nutrient economy for pines. The harvest of no debarked wood is very important for the amount of extractions, particularly in eucalypts.Se realiza en el presente trabajo una simulación de diferentes regímenes selvícolas para tres especies de crecimiento rápido de importancia comercial en el norte de España. A partir de modelos de crecimiento y de la desagregación de las variables dasométricas de masa se determina la composición en distintas fracciones de biomasa y las acumulaciones totales de nutrientes en la biomasa arbórea a lo largo del turno, lo que permite evaluar las cantidades totales extraídas y devueltas al suelo mediante los restos de corta. Se comprueban los altos valores de extracción anual de nutrientes en eucaliptares y la relativa frugalidad de pino pinaster. Se demuestran las ventajas que desde un punto de vista de la economía de nutrientes tienen los regímenes de claras fuertes en los pinares, así como los negativos efectos que conlleva el habitual aprovechamiento de madera y corteza en todas las especies, y que resulta especialmente relevante en los eucaliptares

Estimación de la biomasa arbórea de Eucalyptus globulus y Pinus pinaster en Galicia

En este trabajo se ha caracterizado la acumulación de biomasa arbórea en masas adultas de Eucalyptus globulus y Pinus pinaster en Galicia. Diferentes intereses industriales, energéticos y ambientales han motivado que en los últimos años el análisis de las distintas posibilidades de aprovechamiento de la biomasa forestal esté adquiriendo un creciente protagonismo, por lo que la cuantificación de la biomasa arbórea de estos sistemas forestales constituye un primer paso fundamental e ineludible. La estimación de la biomasa arbórea se basa en el empleo de un sistema de ecuaciones que relacionan el peso de cada fracción arbórea con variables de árbol sencillas de medir en campo. El ajuste de este sistema de ecuaciones se ha realizado de forma simultánea empleando datos procedentes de un muestreo destructivo de 75 eucaliptos y 125 pinos seleccionados en 12 masas adultas. En las masas de eucalipto, los valores de acumulación de biomasa arbórea variaron entre 142 y 426 Mg ha-1. Estos valores oscilaron entre 203 y 438 Mg ha-1 para las masas de pino. Los porcentajes registrados de biomasa de madera, corteza y copa, con respecto al total de biomasa aérea fueron 82; 7 y 11?% para eucalipto y 68; 11 y 21?% para pino.This study provides information about the above-ground biomass of pure and even-aged stands of Eucalyptus globulus and Pinus pinaster in Galicia. In recent years, there has been considerable interest in evaluating biomass of forest ecosystems due to their importance role as energy and raw materials sources. A total of 75 eucalypt and 125 maritime pine trees were subjectively selected in 12 different stands. The trees were destructively sampled to develop biomass prediction equations of tree components. The estimation of the above-ground biomass was based on a system of equations relating the weight of each tree component with tree and stand variables. All the equations were fitted simultaneously using Seemingly Unrelated regression. The above-ground biomass of eucalypt stands ranged from 142 to 426 Mg ha-1. These values ranged from 203 to 438 Mg ha-1 inmaritime pine stands. The biomass percentages obtained for stem wood, stem bark and crown were 82; 7 and 11?% for eucalypts stands and 68; 11 and 21?% for maritime pine stands

An economic overview of Populus spp. in Short Rotation Coppice systems under Mediterranean conditions: An assessment tool for decision-making

13 Pág. Instituto de Ciencias Forestales (ICIFOR)Poplar Short Rotation Coppices can provide lignocellulosic raw material, promote employment in rural areas, contribute to achieving a low carbon bioeconomy and supply environmental benefits. Nevertheless, the economic feasibility of these plantations is a matter of concern and hampers the expansion of commercial initiatives. In this regard, this work aims to identify the most critical cost factors of poplar plantations under Mediterranean conditions. Data from an extensive network located at 30 different sites were used, in particular, detailed cost data for 2 rotations was available for 6 sites within the network. This study evaluates the critical factors that affect profitability, analysing the influence of the discount rate and biomass price under two productive scenarios derived from the network and evaluated as green biomass yield for the first rotation: Baseline (30.56 Mg ha−1 yr−1) and an Optimum (56.52 Mg ha−1 yr−1). Net Present Value after 12 years (4 rotations of 3 years each), ranges from −1105.54 € ha−1 (Baseline) to 9620.30 € ha−1 (Optimum). According to the findings of this study, profitability of poplar plantations will be achieved by ensuring optimum productivity, through an increase in current market prices (40 € Mg-1) or by valuing the ecosystem services, which are not currently quantified. Sensitivity analyses were performed for the most critical cost factors: land rent (31.88 %), irrigation (16.61 %), and cut-and-chip harvesting (11.87 %), revealing that the influence of the former factor was decisive. Management diagrams that combine the discount rate, yield and biomass price are provided as tools for decision makers.This work has been financially supported by the Spanish Ministry of Economic Affairs and Digital Transformation (MINECO), project RTA2017-00015-C02-01. The experimental PPN and the economic data were partially supported by the PSE-On Cultivos, Decocel, RTA-2011-00006, RTA2014-0007 and the LIGNOCROP project.Peer reviewe

Productivity model and reference diagram for short rotation biomass crops of poplar grown in Mediterranean environments

A Reference Diagram (RD) was constructed for first rotations of the Euroamerican poplar 'I-214' grown as short rotation coppice (SRC). Data from 144 plots, established in eleven sites in Mediterranean environments, were used to develop the model. The density at establishment of the plantations ranged between 6666 and 33,333stoolsha-1, covering the usual densities ranges used in short rotation forestry (SRF). The RD was based on a density-independent mortality model that relates the density of living stools to the average height of dominant shoot and the initial plantation density, and it includes a system of two simultaneously fitted equations relating a) quadratic mean basal diameter of dominant shoots to the average height of dominant shoot and the final density, and b) total above-ground woody dry biomass to quadratic mean basal diameter and final density. The isolines in the RD represented mortality, quadratic mean basal diameter of dominant shoots and total above-ground woody dry biomass at the end of a first rotation of three years. The final yield in terms of biomass ranged from 1 to 85Mgdmha-1. The RD enables rapid and straightforward comparison of different situations, both at planting and at harvesting, and is a useful tool, based on a wide range of empirical data, for management and decision making regarding short rotation poplar crops. © 2014 Elsevier Ltd