Transpiration Rate of Scots Pine Trees on Very Oligotrophic Soils of Normal Moisture in Relation to Different Meteorological Condition

Abstract

Continuous monitoring of the tree ring formation and transpiration throughout the year is crucial for understanding the tree reaction to changes in meteorology, and evaluating its adaptiveness to recent environmental changes. Data were collected from four Pinus sylvestris L. trees which sapflow was measured by the heat wave propagation method using SFM1 sensors (ICT International, Australia) and annual tree stem increment by electronic dendrometer DRL26. Investigation was performed in middle age pine stand on very oligotrophic soil. Meteorological data revealed that 2019 was the year of drought. In this year pine transpiration rate and volume increment were the lowest. However, water was used most efficiently, which means that pines needed less water to produce 1 cm 3 of wood. 2020 was characterized as a year of recovery of moisture regime, when during vegetation precipitation increased up to long term value and the mean air temperature was the lowest. Annaul volume increment of pine trees in this year was the biggest, transpiration rate the highest, but WUE was the smallest, indicating that pine used more water to produce 1 cm 3 of wood. Obtained data on WUE during different growing season revealed that Scots pine trees are well adapted to recent meteorological condition. Increase in tree diameter reduced values of Scots pine WUE, what means that bigger pine trees used significantly less water to produce 1 cm 3 of wood.