Montserrat Ribas

University of Barcelona, Barcino, Catalonia, Spain

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Publications (6)11.16 Total impact

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    ABSTRACT: AimClimate change is expected to modify growth trends of forests around the world. However, this modification may vary in strength and intensity across a species' biogeographical range. Here, we study European populations of silver fir (Abies alba) across its southern distribution limits in Spain, Italy and Romania. We hypothesized that growth trends of silver fir will differ across its distribution range, with a marked decline in growth in drought-prone regions near the species' southernmost biogeographical limits.LocationEurope (Spain, Italy, Romania).Methods We collected tree-ring data from at least 1300 silver fir trees located in 111 sites. The dataset was used to assess and model growth trends, quantified as changes in basal area increment, and to determine how growth responds to climate.ResultsWe found contrasting patterns of basal area increments among countries and sites. Populations of silver fir located outside the Mediterranean area (e.g. northern Italy, Romania) have shown a clear increase in growth over the last two decades, whereas most populations in Spain and southern Italy have displayed a marked decline in growth since the 1980s. The growth of silver fir forests at the south-western distribution limit is severely constrained by low spring–summer water availability, whereas growth of silver fir forests in non-Mediterranean areas is limited by cold conditions in late winter to early spring.Main conclusionsClimate warming is distinctly modifying growth patterns and responses to climate in silver fir across most of the species' European distribution area. In south-western Europe the reduction in growth of many populations is related to an observed increase in aridity, whereas in more temperate areas warming is enhancing growth. Our results confirm a decline in the growth of silver fir at its south-western distribution limits as a consequence of climate warming.
    Journal of Biogeography 04/2015; 42(6). DOI:10.1111/jbi.12512 · 4.97 Impact Factor
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    ABSTRACT: Long-term data on radial increment dynamics in Mediterranean species may identify which climatic variables are the main constraints for radial growth and at which temporal scales they act. To this end, we examined stem radial fluctuations in Quercus ilex L., the dominant evergreen oak species in the Western Mediterranean Basin, over a period of 11years (1994–2004) at a coastal site in north-eastern Spain. We used manual band dendrometers to record girth changes in trees on north- and south-facing slopes. Annual increments measured by dendrometers showed good agreement with annual tree-ring width. North-facing trees showed a lower long-term cumulative radial increment than south-facing trees. The seasonal radial increment pattern of Q. ilex was bimodal, being characterized by a greater increase in May and a lesser, more variable increase peak in September. Both phases corresponded to warm and moist climatic conditions, whereas radial increase of stems stopped in winter and occasionally in summer. Considering the whole year, mean maximum air temperature was the main factor positively affecting radial increment of Q. ilex from short- (5days) to- long (30days) time scales, whereas the accumulated precipitation exerted a similar effect at longer (30days) scales, but only on south-facing trees. In summer, all trees were positively correlated with precipitation at long-time scales (30days); however, only stem increment of south-facing trees showed a significant relation to the temperature at short-time scales (10days). We confirmed the dominant role of temperature as the major constraint on radial increment at short time scales, despite most previous studies were mostly biased towards precipitation effects at monthly scales. KeywordsBand dendrometer–Drought–Mediterranean climate–Bimodal growth–Holm oak
    Trees 08/2011; 25(4):637-646. DOI:10.1007/s00468-011-0540-3 · 1.87 Impact Factor
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    ABSTRACT: Wildfires have decimated forests of Pinus nigra in the Mediterranean Basin in recent decades, but little is known about the fire ecology of this native species. We sampled three small relict forest sites on Sierra Turmell, Castellón, Valencia, northeastern Spain, to determine forest structure and past fire events. The forest was characterized by relatively large and old trees (mean 158 year, max 362 year). Fire history was affected by obliteration of some fire scars, but we determined 11 fire dates in the past 172 years. The minimum fire-free interval was 2 years, maximum 57 years. Fire dates were not linked with dry climatic conditions, possibly due to occupational burning by pastoralists. Compared to inventory data averages for P. nigra in northeastern Spain (Catalunya), the old forest at Sierra Turmell supported over twice the basal area and over 2.5 times the biomass, with a comparable advantage in terms of carbon storage. Carbon sequestration, on the other hand, was over six times higher in the younger forests. The relict forest at Sierra Turmell provides evidence of multi-aged forest structure persisting through numerous surface fires over several centuries. This example may be useful for guiding management of younger forests and for ecological restoration of degraded areas.
    Forest Ecology and Management 03/2008; 255(3-4):1234–1242. DOI:10.1016/j.foreco.2007.10.046 · 2.67 Impact Factor
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    ABSTRACT: The influence of climatic factors on tree-ring width and the formation of double rings was studied in Quercus ilex L. growing in a coppice stand left unmanaged for 22 years. Ten trees were felled and discs were taken every 30 cm from bole and dominant branches. Dendrometer bands were installed on 10 nearby trees and the data recorded were used to confirm the accuracy of our tree-ring identification. They were also used to relate the seasonal radial growth pattern to double-ring formation. Double rings were frequent and occurred consistently along the stem. Two types of double rings could be recognized according to their width: type I, with the extra growth band accounting for approximately 50% of the tree ring; and type II, with a narrow extra growth band. Type I double rings were formed when approximately 1/2 of the growing-season precipitation occurred during the second growth period of the season and after the summer drought. Type II double rings occurred when approximately 1/3 of the precipitation in the growing season occurred after the summer drought. The formation of double rings was triggered by rainfall in summer and the extra growth-band width was related to summer and autumn environmental conditions. Double rings in Q. ilex can potentially be used in dendroclimatological studies, as they are formed in response to climatic conditions within the growing season.
    Canadian Journal of Forest Research 10/2007; 37:1915-1923. DOI:10.1139/X07-050 · 1.66 Impact Factor
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    ABSTRACT: Las series de anillos anuales del crecimiento de los árboles proporcionan registros de alta resolución temporal que permiten evaluar cambios ambientales producidos durante los últimos siglos. En este trabajo presentamos la primera red de cronologías establecida en el Parque Nacional de Aigüesrortes (Pirineos)ysu zonaperiférica(42Q35'N, 0005TE) Yanalizamos la variabilidad del crecimiento en grosor de tres especies de árboles. El número total de cronologías establecidas es de 10 para Pinus Imcinafa, cuatro para Abies alba, y una para Pinm sy!vestr¡s, situadas entre los 1.650 y los 2.360 ID s.n.m. Las cronologías más largas son las de P. uncinata, con algunas series de más de 600 años. Del conjunto de todos los árboles muestreados. hemos utilizado 114 árboles de P. 1mcinata y 34 de A. alba para establecer las distribuciones de edades de los árboles. Estas distribuciones muestran algunos de los efectos adversos del clima y de las actividades humanas en el pasado que posiblemente causaron una mayor mortalidad de árboles y una menor regeneración de los bosques. El análisis de componentes principales de la varianza de las 15 cronologías muestra que la varianza en común es alta: un 54% durante el periodo 1850-1994. Esto significa que el crecimiento de las tres especies estudiadas ha estado afectado de manera similar por las condiciones macroclimáticas; no obstante, existen diferencias acusadas entre especies y localidades. Además. hay también diferencias a lo largo del tiempo ya que la varianza en común no se ha mantenido constante: es del 54% de 1850 a 1899, baja a145% de 1900 a 1949, y aumenta hasta a un 63% de 1950 a 1994. Durante los periodos de mayor estrés climático -por ejemplo, desde 1950 hasta la actualidad y coincidiendo con la l1arnada crisis climática del s. XX-la respuesta del crecimiento de las diferentes especies ha sido más sincrónica y la varianza en común es la más alta; este hecho es más acusado en las cronologías de P. uncinata de más altitud, por encima de los 2.050 m s.n.m. Estas cronologías han mostrado ser las más sensibles a las variaciones climáticas y por ello se pueden considerar buenos archivos climáticos regionales durante los periodos de mayor control climático. En el límite altitudinal del bosque en el Tessó de Son, el crecimiento y la regeneración presentan una relación significativa y negativa durante el periodo de 1947 a 1996. Es decir, que determinadas variables climáticas regulan de manera opuesta los dos procesos, aunque otras tienen un efecto en el mismo sentido, por ejemplo, la temperatura de mayo presenta una relaci6n positiva con el crecimiento y la regeneración.
    Ecologia 01/1998; 12:251-283.
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    Montserrat Ribas, Elena Muntán, Emilia Gutiérrez
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    ABSTRACT: Radial growth response of Aleppo pine (Pinus halepensis Mill.) to climatic conditions