Tree water relations and climatic variations at the alpine timberline: seasonal changes of sap flux and xylem water potential in Larix decidua Miller, Picea abies (L.) Karst. and Pinus cembra L

• DOI: 10.1051/forest:19980110
• Publication Date: 2007-08-28T08:53:05Z
• Authors: Tommaso Anfodillo; Stefano Rento; Vinicio Carraro; Luca Furlanetto; Carlo Urbinati; Marco Carrer
• Keywords: 0106 biological sciences; [SDV.SA.SF] Life Sciences [q-bio]/Agricultural sciences/Silviculture, forestry; 01 natural sciences

Trees growing at the alpine timberline very seldom undergo severe water stress because of high precipitation during vegetative period.Since trees are adapted to moist con- ditions, moderate deficit may lead a strong reduction in transpiration.Transpiration and xylem potential were measured two individuals each Pinus cembra, Larix decidua Picea abies (2 080 m a.s.l.) north-eastern Italian Alps.From June October 1996 predawn was between -0.29 -1.0 MPa with differences among species.Throughout period L. showed progressive decrease minimum (from -0.45 -1.93 MPa); P. cembra variations more correlated weather conditions minima (-1.2 -1.49MPa, respec- tively) mild drought period.L. mean daily maximum sap flux den- sity (about 3.3 dm 3 -2 h -1 ) while values about 0.9 0.7, respectively.High fluctuations flow observed relation rapid conditions, particularly decidua.Regardless species stomatal sensitivity vapour pressure recorded.The three seem have evolved different avoidance strategies.L. maintained relatively transpiration even periods its uptake capacity.During same an evident flux, suggesting saving behaviour.These responses should be taken into account when considering effects global change on trees. (© Inra/Elsevier, Paris.)water relations / resistance climate warming