Spatiotemporal Variability in Tree Growth in the Central Pyrenees: Climatic and Site Influences

Abstract

To understand how tree growth has responded to recent climate warming, an understanding of the tree-climate-site complex is necessary. To achieve this, radial growth variability among 204 trees established before 1850 was studied in relation to both climatic and site factors. Seventeen forest stands were sampled in the Spanish Central Pyrenees. Three species were studied: Pinus uncinata, Abies alba, and Pinus sylvestris. For each tree, a ring-width residual chronology was built. All trees cross-dated well, indicating a common influence of the regional climate. For the 1952-1993 period, the radial growth of all species, especially P. uncinata, was positively correlated with warm Novembers during the year before ring formation and warm Mays of the year the annual ring formed. Differences in species-stand elevation modulated the growth-climate associations. Radial growth in P. uncinata at high elevation sites was reduced when May temperatures were colder and May precipitation more abundant. In the 20th century, two contrasting periods in radial growth were observed: one (1900-1949) with low frequency of narrow and wide rings, low mean annual sensitivity, and low common growth variation; and another (1950-1994) with the reverse characteristics. The increased variability in radial growth since the 1950s was observed for all species and sites, which suggests a climatic cause. The low shared variance among tree chronologies during the first half of the 20th century may result from a ''relaxation'' of the elevation gradient, allowing local site conditions to dominate macroclimatic influence. These temporal trends may be related to the recently reported increase of climatic variability and warmer conditions. This study emphasizes the need to carefully assess the relationships between radial growth and site conditions along ecological gradients to improve dendroclimatic reconstructions.

Summer rainfall variability in European Mediterranean mountains from the sixteenth to the twentieth century reconstructed from tree rings

“…This increase is consistent with that observed by Manrique and Fernández-Cancio (2000), Tardif et al (2003), Camarero and Gutiérrez (2004), Andreu et al (2007) and Macias et al (2006) in the Pyrenees and by Ceballos et al (2004) and Galán et al (1999) on Spain's Central Plateau. We believe that the value of the present paper lies in the first combination of the six sites studied in two composite chronologies and in the joint analysis thereof in order to obtain regional chronologies that can be useful for understanding past climate in southwestern Europe.…”

“…Both species are located in this peninsula at the edge of their phytogeographical range (Fernández et al 1996;Génova and Fernández 1999;Génova 2000). Here, the summer water deficit contrasts with the temperature limitation observed by other authors at higher latitudes in Europe, where summertime water availability does not constitute a limiting factor (Grace and Norton 1990;Rolland and Schueller 1994;Guerrero et al 1998;Kirchhefer 2001;Tardif et al 2003;Koprowski et al 2012). The specific objectives involved (a) recognizing the most relevant modes of temporal variability in the summer precipitation reconstruction in order to better understand the main periodicity characterizing summer precipitation variability, (b) assessing changes in variability during the last century compared to the previous ones, (c) comparing this reconstruction with previous tree ring precipitation records on the Iberian Peninsula and (d) establishing the spatial representativeness of the reconstructed precipitation patterns on the Iberian Peninsula.…”

Black pine (Pinus nigra Arn.) growth divergence along a latitudinal gradient in Western Mediterranean mountains

“…Mean sensitivity (MS) measures the relative difference from one tree-ring to the next and thus the year to year variation, first order autocorrelation coefficients (AC) reflects how previous year growth influences current year growth, and mean interseries correlation (Rbar) measures the between-tree signal (Fritts, 1976). We also analyzed the variation of our chronologies and the change of the importance of climatic influence on growth (Tardif et al, 2003) by calculating their MS using a 40-y time window lagged 5 y. The average (MS x ) and standard deviation (SD x ) of the mean sensitivity of all chronologies were calculated to show general trends.…”

Physiognomic and chemical characters in wood as palaeoclimate proxies

“…Although growth rings in essence appear to be a rich archive of palaeoclimatic information, careful evaluation of the material for study is paramount to ensure that the climate signal is not being confused with expressions of variation which in turn would affect wood growth and growth ring characters (see Creber and Chaloner 1984;Briffa et al 1998;Tardif et al 2003). Problems arise from restricted biotic (including genetic) and abiotic effects often surpassing the climate effect.…”