Response of Quercus pyrenaica (melojo oak) to soil water deficit: a case study in Spain

Abstract

In the present study, carried out from 2004 to 2006, leaf and stem water potential and stem water content were measured in Quercus pyrenaica Willd. individuals in an experimental forested catchment located in Central Western Spain under Mediterranean subhumid conditions. These indicators of tree water status were compared with soil moisture contents measured in the same area from 0 to 1 m depth and from 0 to 2.5 m depth during the last year of the study. The objectives were to clarify the seasonal and year-to-year variations in tree water status, to examine applicability of stem water content as useful water stress indicator and to discuss how deep soil water and root uptake contribute to survival during the long dry summer. Seasonal variations in the tree variables measured revealed a typical pattern, with maximum values at the end of spring followed by a progressive decline during the summer drought in response to the decrease in soil water content (almost exhausted at 0-100 cm depth). The relatively high values and the non-signiWcant variation in predawn leaf water potentials (except for 2005, which was exceptionally dry) indicate that no clear water stress situations occurred. This may be explained in terms of a progressive absorption of water from the deeper layers. The results also suggest that the stem water content is a more sensitive indicator of long-term water limitation than the other variables measured.

Canopy transpiration of a semi arid Pinus canariensis forest at a treeline ecotone in two hydrologically contrasting years

“…There is evidence that in semi arid environments the ability to tap water from deeper ground layers determines the treesí water status when the top soil moisture is exhausted (David et al, 2007;Dawson, 1994;Hernández-Santana et al, 2008;Villar-Salvador et al, 1997). The high E c rates observed during the dry summer of 2009 (Fig.…”

Evaluating the effect of drier and warmer conditions on water use by Quercus pyrenaica

“…Despite the relatively high annual rainfall of the study area (1000 mm), it was observed that during the summer soil moisture decreased considerably due to the Mediterranean climate conditions and elevated tree water use (Herná ndez-Santana et al, 2008a). A preliminary analysis of climate trends has shown that over the last 55 years rainfall has decreased at this site by 18%, more markedly during the summer season (26% from June to September).…”

“…From a previous study (Herná ndez-Santana et al, 2008a) it is known that this plot is representative of the experimental forested catchment. Altitude ranges between 1140 and 1450 m with a SW-NE orientation.…”

Investigation of Factors Controlling the Regional-Scale Distribution of Dried Soil Layers Under Forestland on the Loess Plateau, China

“…DSL characteristics and dynamic properties depend on many interrelated links among climate, soil, terrain, and vegetation (Hernández-Santana et al 2008;Li et al 2002;Vörösmarty and Moore 1991). However, the measurement of DSL indices in the field is expensive, time-consuming, and technically difficult.…”