Lack of management, land-use changes, poor site conditions and drought contribute to the decline of old pollarded oaks

In Europe, people have managed forests and woodlands for centuries. Old pollarded oaks reflect historical legacies, and their conservation is threatened by the abandonment of this traditional forest use. However, site conditions (topography, soil features, land cover, and historical use) and warming...

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Detalles Bibliográficos
Autores: Colangelo, Michele, Valeriano, Cristina, González de Andrés, Ester, Pizarro Gavilán, Manuel, Murria, Enrique, Camarero, Jesús Julio
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2024
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/378545
Acceso en línea:http://hdl.handle.net/10261/378545
https://api.elsevier.com/content/abstract/scopus_id/85196360468
Access Level:acceso abierto
Palabra clave:Dendrochronology
Dendroecology
Pollard
Quercus subpyrenaica
Descripción
Sumario:In Europe, people have managed forests and woodlands for centuries. Old pollarded oaks reflect historical legacies, and their conservation is threatened by the abandonment of this traditional forest use. However, site conditions (topography, soil features, land cover, and historical use) and warming-triggered drought stress also contribute to their growth decline, particularly in seasonally dry regions. We investigated two stands of pollarded Mediterranean oaks (Quercus subpyrenaica), where pollarding was abandoned in the 1950s, showing contrasting land cover and tree sizes in north-eastern Spain. Changes in land cover, soil characteristics (texture, pH, and nutrient concentrations), climate conditions, and tree-ring data (basal area increment −BAI−, and ring-width indices) were analysed. The Artosilla site, showing the smallest trees, presented the lowest long-term growth rates (period 1730−2022, mean BAI = 19.7 cm2 yr−1) as compared with the Aineto site with bigger oaks (mean BAI = 32.9 cm2 yr−1). Old trees were found in both sites with ages ranging 293−311 years. The less fertile soils in Artosilla, where pine plantations diminish canopy thermal amplitude, may contribute to the long-term growth decline observed there. Moreover, more major growth suppressions were found in this site, particularly in the 1940s, which suggest a more intensive historical use. Aineto showed a stronger BAI decline since the 1950s, which could be a response to increasingly warmer and drier summer conditions. In contrast, growth in Artosilla is decoupling from soil and atmospheric drought suggesting chronic growth stagnation. Poor site conditions (steeper slope, less fertile soils, intensive historical use) contributed to the decline of pollarded oaks. Active management is required to preserve these unique old, monumental trees.