Comparative analysis of wood anatomy of European larch, Norway spruce, and European beech in mixed and monoculture stands under contrasting climatic conditions

Abstract

We present a tree-ring and wood-anatomical study of less widespread European larch (L. decidua) growing in mixed a monoculture stands with the economically important Norway spruce (P. abies) and European beech (F. sylvatica) under identical meteorological conditions in the Czech highlands. Tree responses to drought were assessed by comparing two contrasting periods: Control period (2009–2010) and a Dry period (2017–2018). We analysed tree-ring widths (TRW), early- and latewood widths (EWW/LWW), lumen area (LA), cell wall thickness (CWT), cell density (CD), relative conducting area (RCTA), hydraulically weighted mean cell diameter (D_h), and the potential hydraulic conductivity (K_p). A significant reduction in radial growth (51.8 %) was observed during the Dry period, with spruce and beech showing the greatest decline in monocultures, while larch exhibited mostly non-significant changes. Although TRW did not differ significantly between mixtures and monocultures within species, notable variations emerged at the wood-anatomical level. Tree species generally showed reduced anatomical variability and more stable water conductivity mostly in mixed stands under dry conditions. However, drought impacts were more pronounced in larger trees and denser stands, suggesting that forest structure can amplify vulnerability to water stress. Species-specific drought responses were distinct: larch showed no anatomical changes; spruce exhibited the greatest reduction in latewood lumen area and cell wall thickness; and beech reduced lumen area while increasing cell density, enhancing water transport efficiency under prolonged drought.