Tree growth and water-use in hyper-arid Acacia occurs during the hottest and driest season

Show simple item record Winters, Gidon Ochuodho, Dennis O. Cohen, Shabtai Bogner, Christina Ragowloski, Gideon Paudel, Indira Klein, Tamir 2018-11-15T05:58:49Z 2018-11-15T05:58:49Z 2018
dc.identifier.issn 1432-1939
dc.description.abstract Drought-induced tree mortality has been recently increasing and is expected to increase further under warming climate. Conversely, tree species that survive under arid conditions might provide vital information on successful drought resistance strategies. Although Acacia(Vachellia) species dominate many of the globe’s deserts, little is known about their growth dynamics and water-use in situ. Stem diameter dynamics, leaf phenology, and sap flow were monitored during 3 consecutive years in five Acacia raddiana trees and five Acacia tortilistrees in the Arid Arava Valley, southern Israel (annual precipitation 20–70 mm, restricted to October–May). We hypothesized that stem growth and other tree activities are synchronized with, and limited to single rainfall or flashflood events. Unexpectedly, cambial growth of both Acacia species was arrested during the wet season, and occurred during most of the dry season, coinciding with maximum daily temperatures as high as 45 °C and vapor pressure deficit of up to 9 kPa. Summer growth was correlated with peak sap flow in June, with almost year-round activity and foliage cover. To the best of our knowledge, these are the harshest drought conditions ever documented permitting cambial growth. These findings point to the possibility that summer cambial growth in Acacia under hyper-arid conditions relies on concurrent leaf gas exchange, which is in turn permitted by access to deep soil water. Soil water can support low-density tree populations despite heat and drought, as long as recharge is kept above a minimum threshold en_US
dc.language.iso en en_US
dc.publisher Springer-Verlag GmbH Germany en_US
dc.subject Acacia raddiana en_US
dc.subject Acacia tortilis en_US
dc.subject Leaf Phenology en_US
dc.subject Sap Flow en_US
dc.subject Desert en_US
dc.subject Global warming en_US
dc.subject Tree drought resistance en_US
dc.subject Arava en_US
dc.title Tree growth and water-use in hyper-arid Acacia occurs during the hottest and driest season en_US
dc.type Article en_US

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