Relationship among soil parameters, tree nutrition and site index of Pinus radiata D. Don in Asturias, NW Spain

Abstract

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.

Stand and environmental data from Pinus halepensis Mill. and Pinus sylvestris L. plantations in Spain

“…The knowledge about the relationships between environmental factors and stand data in forest plantations can help forest managers to achieve both protective and productive goals for these plantations and are useful for the understanding of the ecosystem functioning (Bueis et al 2016(Bueis et al , 2017. Environmental parameters including climatic, topographic and soil (physical, chemical and biochemical) parameters have proved useful for estimating forest productivity (Aertsen et al 2012;Afif-Khouri et al 2010;Bravo-Oviedo and Montero 2005;Bravo and Montero 2001;Bueis et al 2016Bueis et al , 2017Corona et al 1998;Hagglund and Lundmark 1977;Nieppola and Carleton 1991;Pietrzykowski et al 2015;Romanya and Vallejo 2004;Sanchez-Rodriguez et al 2002;Sharma et al 2012). Forest productivity is usually estimated through stand parameters such as the dominant height (the height of the 100 thickest trees per hectare) at a reference age, because it is strongly correlated to wood production (Skovsgaard and Vanclay 2008).…”

Growth and yield models in Spain: Historical overview, Contemporary Examples and perspectives

“…However, these data are not always available, for example in young stands where crown differentiation is not apparent. In such situations, site index is usually related to climate or soil variables in a linear fashion Romanyà and Vallejo, 2004;Afif-Khouri et al, 2010;Álvarez-Álvarez et al, 2011) or by discriminant rules Bravo-Oviedo and Montero, 2005).…”