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Understanding the impact of thinning on holm oak water-use through simultaneous and continuous monitoring of twig water potential, transpiration and soil moisture

XV World Forestry Congress, 2-6 May 2022

Year of publication 2022

Place of publication Rome, Italy ;

Pages 9p.

Author Blanco Cano, L., Del Campo García, A. D., González-Sanchis, M., et al.

Publisher FAO ;

Product type Article

Synopsis (short abstract) Adaptive silviculture in semiarid climates must focus on enhancing eco-physiogical traits that provide functional advantages to water scarcity. Intraspecific plasticity in such traits is especially important to correctly address silvicultural prescriptions. Studying changes in avoidance (tightly closure of stomata when water potential drops, or atmospheric demand rises) or tolerance (weak stomatal control of transpiration) mechanisms to water stress after forest treatments could improve the understanding of their eco-physiological impact to cope with increasing aridity in forests. Water potential (Ψ), transpiration (T) and other ecohydrological variables are important in this sense and can be simultaneously assessed, although measuring Ψ in forests with traditional pressure chamber is cumbersome and not continuous in time. The aim of this work is to use continuous measures of Ψ, T and soil moisture (SM) to test the ecohydrological behavior of oaks 10 years after thinning. This study was carried out in a holm oak forest in southwestern Spain, where one plot was thinned 10 years ago, and another plot was a control (without treatment). Three trees in each plot were continuously (every hour) monitored for Ψ, T and soil moisture (SM) besides meteorological variables. The continuous measurement of Ψ was obtained by using psychrometers and validated with pressure chamber. Our results show that the average Ψ of the thinned trees, -0.487 ± 0.639 MPa, reflects a more favorable water status than that of the control plot, -0.604 ± 0.698 MPa, despite the lower tree-water use in the latter plot. Also, it was observed a more positive relationship between T and Ψ in the control than in thinning plot. On the other hand, the relationship between Ψ and SM was not affected by the treatment. In addition to this physiological benefit, it could be an advantage against climate change, since by favoring these flows, the trees' CO2 uptake will increase. Keywords: Adaptive and integrated management, Monitoring and data collection, Sustainable forest management, Knowledge management, Climate change. ID: 3623177

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