Drought and irrigation affect transpiration rate and morning tree water status of a mature European beech (Fagus sylvatica L.) forest in Central Europe

Abstract

Severity and frequency of recurrent droughts is likely to be amplified by recent climate changes and may adversely affect large areas of temperate forests. This study addresses the ecophysiological responses of a mature beech forest in Central Europe (Slovakia, 450 m a.s.l.) exposed to drought during the growing seasons of 2012–2014. Sap flow and stem circumference changes of European beech (Fagus sylvatica L.) were measured in two contrasting treatments (drought vs. irrigation). Limited water availability reflected in the morning tree water status (morning stem contraction, ΔW) significantly reduced transpiration. Trees stressed by drought in the years 2012 and 2013 showed remarkably lower values of morning ΔW than those in the irrigated group. This suggests (a) lower water potential of the stem‐conducting tissues and (b) increased use of internally stored water to maintain daily transpiration. Additionally, morning ΔW showed a close relationship with soil water potential, particularly in the nonirrigated trees. Potential evapotranspiration (PET) explained less variability in the transpiration of the control stand than that of the irrigated stand. The use of a simple analysis of covariance model comprising morning ΔW and PET interaction significantly increased the explained variability in transpiration in the control stand. Morning ΔW of mature beech trees seems to be a useful and easily obtainable non‐invasive bioindicator of their ability to reduce and regulate transpiration in relation to atmospheric evaporative demands in response to drought.

Sap flow and growth response of Norway spruce under long-term partial rainfall exclusion at low altitude

“…Nevertheless, PE treatment reduced its Q rates sooner than PC under decreasing SWP, probably due to the long-term priming effect of reduced water availability ( Tombesi et al., 2018 ). In general, Q and transpiration rates are driven by ambient atmospheric conditions (VPD, GR, T air ), creating evaporation demand ( Cruiziat et al., 2002 ; Nalevanková et al., 2018 ). However, high VPD accelerates sap flow, particularly under sufficient soil water content ( Matejka et al., 2009 ; Flo et al., 2021 ).…”

Comprehensive Response of Daily Transpiration from Armeniaca sibirica Plantations to Meteorological and Soil Moisture/Temperature Conditions on the Semi-Arid Loess Plateau, China

“…[15,16], management measures, and environmental factors (atmospheric temperature, precipitation, soil moisture, soil temperature, etc.) [17]. For plantations with simple structures, environmental factors can be divided into two types based on differences in the influencing mechanisms [18].…”

Impact of Environmental Conditions and Seasonality on Ecosystem Transpiration and Evapotranspiration Partitioning (T/ET Ratio) of Pure European Beech Forest

“…Drought induces a reduction of T in plants due to increasing water potential which leads to stomatal closure, which contributes to a lower T/ET ratio [47]. Oppositely, mature European beech has been characterized as a strongly anisohydric species, keeping its stomata open for a longer period under drought conditions [48,49]. Anisohydric behaviour would then promote maintenance of high T/ET values even under increasing aridity.…”