TY - JOUR
T1 - Sap flow of three co-occurring Mediterranean woody species under varying atmospheric and soil water conditions
AU - Martínez-Vilalta, Jordi
AU - Mangirón, Marta
AU - Ogaya, Romà
AU - Sauret, Miquel
AU - Serrano, Lydia
AU - Peñuelas, Josep
AU - Piñol, Josep
PY - 2003/1/1
Y1 - 2003/1/1
N2 - We studied the seasonal patterns of water use in three woody species co-occurring in a holm oak forest in northeastern Spain. The three species studied, Quercus ilex L., Phillyrea latifolia L. and Arbutus unedo L., constitute more than 99% of the total basal area of the forest. The study period included the dry seasons of 1999 and 2000. Water use was estimated with Granier-type sap flux sensors. Standard meteorological variables, soil water content and leaf water potentials were also monitored. All monitored individuals reduced leaf-related sap flow (Q1) during the summer, concurrent with an increase in soil moisture deficit (SMD). Despite similar maximum Q1 between species, the decline in Q1 with increasing SMD was species-dependent. The average reduction in Q1 between early summer and the peak of the drought was 74% for A. unedo (n = 3), 58% for P. latifolia (n = 3) and 87% for Q. ilex (n = 1). The relationship between canopy stomatal conductance (Gs) and vapor pressure deficit (D) changed during the course of the drought, with progressively lower G s for any given D. Summertime reductions of Q1 and G s were associated with between-species differences in vulnerability to xylem embolism, and with the corresponding degree of native embolism (lowest in P. latifolia and highest in Q. ilex). Our results, combined with previous studies in the same area, outlined differences among the species studied in manner of responding to water shortage, with P. latifolia able to maintain water transport at much lower water potentials than the other two species. In an accompanying experiment, A. unedo responded to an experimental reduction in water availability by reducing Q1 during the summer. This species also modified its water use between years according to the different seasonal patterns of precipitation. These results are discussed in relation to the possible impacts that climate change will have on Q. ilex-dominated forests.
AB - We studied the seasonal patterns of water use in three woody species co-occurring in a holm oak forest in northeastern Spain. The three species studied, Quercus ilex L., Phillyrea latifolia L. and Arbutus unedo L., constitute more than 99% of the total basal area of the forest. The study period included the dry seasons of 1999 and 2000. Water use was estimated with Granier-type sap flux sensors. Standard meteorological variables, soil water content and leaf water potentials were also monitored. All monitored individuals reduced leaf-related sap flow (Q1) during the summer, concurrent with an increase in soil moisture deficit (SMD). Despite similar maximum Q1 between species, the decline in Q1 with increasing SMD was species-dependent. The average reduction in Q1 between early summer and the peak of the drought was 74% for A. unedo (n = 3), 58% for P. latifolia (n = 3) and 87% for Q. ilex (n = 1). The relationship between canopy stomatal conductance (Gs) and vapor pressure deficit (D) changed during the course of the drought, with progressively lower G s for any given D. Summertime reductions of Q1 and G s were associated with between-species differences in vulnerability to xylem embolism, and with the corresponding degree of native embolism (lowest in P. latifolia and highest in Q. ilex). Our results, combined with previous studies in the same area, outlined differences among the species studied in manner of responding to water shortage, with P. latifolia able to maintain water transport at much lower water potentials than the other two species. In an accompanying experiment, A. unedo responded to an experimental reduction in water availability by reducing Q1 during the summer. This species also modified its water use between years according to the different seasonal patterns of precipitation. These results are discussed in relation to the possible impacts that climate change will have on Q. ilex-dominated forests.
KW - Arbutus unedo
KW - Drought
KW - Phillyrea latifolia
KW - Quercus ilex
KW - Sap flux
KW - Water use
U2 - 10.1093/treephys/23.11.747
DO - 10.1093/treephys/23.11.747
M3 - Article
VL - 23
SP - 747
EP - 758
IS - 11
ER -
