TY - JOUR
T1 - Quarantining the Sahara desert
T2 - growth and water-use efficiency of Aleppo pine in the Algerian Green Barrier
AU - Choury, Zineb
AU - Shestakova, Tatiana A.
AU - Himrane, Hocine
AU - Touchan, Ramzi
AU - Kherchouche, Dalila
AU - Camarero, J. Julio
AU - Voltas, Jordi
N1 - Publisher Copyright:
© 2016, Springer-Verlag Berlin Heidelberg.
PY - 2017/2/1
Y1 - 2017/2/1
N2 - The Algerian Green Barrier, mainly composed of native and artificial Aleppo pine forests, spreads along the pre-Saharan steppes and is threatened by anthropogenic and natural disturbances, including climate change. We hypothesized that the ecophysiological functioning of this conifer has been substantially modified in reaction to recent warming and drought much beyond the expected effect of CO2 fertilization. Our aim was to characterize the long-term performance (1925–2013) of native Aleppo pines thriving at their southernmost distribution. We used tree-ring width (TRW) and carbon isotope discrimination (Δ13C) to characterize basal area increment (BAI) and intrinsic water-use efficiency (WUEi) at three sites. BAI remained stable or slightly increased over time, with mean values ranging between 4.0 and 6.3 cm2 year−1. Conversely, site-Δ13C decreased from −0.022 to −0.014‰ year−1 along time, which translated into WUEi increases of ca. 39%. This strong physiological reaction indicated that pines were responding simultaneously to rising CO2 and drier conditions, inducing a progressively tighter stomatal control of water losses. However, WUEi increments were essentially unrelated to BAI and did not affect carbon reserves, which suggests a high resilience to climate change. This finding could be due to shifts in growing season towards earlier months in winter–spring, as suggested by temporal changes in climate factors underlying Δ13C and TRW. Our study highlights the substantial plasticity of Aleppo pine, but this species is unlikely to follow a similar pace of ecophysiological adjustments according to unprecedented low Δ13C records and lack of WUEi stimulation observed from 2000 onwards.
AB - The Algerian Green Barrier, mainly composed of native and artificial Aleppo pine forests, spreads along the pre-Saharan steppes and is threatened by anthropogenic and natural disturbances, including climate change. We hypothesized that the ecophysiological functioning of this conifer has been substantially modified in reaction to recent warming and drought much beyond the expected effect of CO2 fertilization. Our aim was to characterize the long-term performance (1925–2013) of native Aleppo pines thriving at their southernmost distribution. We used tree-ring width (TRW) and carbon isotope discrimination (Δ13C) to characterize basal area increment (BAI) and intrinsic water-use efficiency (WUEi) at three sites. BAI remained stable or slightly increased over time, with mean values ranging between 4.0 and 6.3 cm2 year−1. Conversely, site-Δ13C decreased from −0.022 to −0.014‰ year−1 along time, which translated into WUEi increases of ca. 39%. This strong physiological reaction indicated that pines were responding simultaneously to rising CO2 and drier conditions, inducing a progressively tighter stomatal control of water losses. However, WUEi increments were essentially unrelated to BAI and did not affect carbon reserves, which suggests a high resilience to climate change. This finding could be due to shifts in growing season towards earlier months in winter–spring, as suggested by temporal changes in climate factors underlying Δ13C and TRW. Our study highlights the substantial plasticity of Aleppo pine, but this species is unlikely to follow a similar pace of ecophysiological adjustments according to unprecedented low Δ13C records and lack of WUEi stimulation observed from 2000 onwards.
KW - Carbon isotope discrimination
KW - Dendroecology
KW - Forest growth
KW - Maghreb
KW - Pinus halepensis
KW - Water-use efficiency
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U2 - 10.1007/s10342-016-1014-3
DO - 10.1007/s10342-016-1014-3
M3 - Article
AN - SCOPUS:84995799487
SN - 1612-4669
VL - 136
SP - 139
EP - 152
JO - European Journal of Forest Research
JF - European Journal of Forest Research
IS - 1
ER -