The data file (Alnus alnobetula_Wood anatomy.xlsx) contains all raw data, which have been used to create Figures 3-7 in the article. Data are documented in the following article: Gruber A, G Wieser, M Fink, W Oberhuber (2024) Impact of environmental conditions on wood anatomical traits of green alder (Alnus alnobetula) at the alpine treeline. Forests, 15, 24; doi:10.3390/f15010024 Summary Due to land use change, green alder (Alnus alnobetula), formerly restricted to moist slopes, is now expanding to drier south-facing sites at the alpine treeline. To evaluate wood anatomical adaptations, we analyzed vessel characteristics (mean vessel area, MVA; vessel density, VD; and theoretic conductive area, TCA) and axial parenchyma abundance, as well as their distribution in the annual ring at a moist north-facing and a dry south-facing site at the alpine treeline (2150 m asl) on Mt. Patscherkofel (Central European Alps, Austria). Results revealed that lower soil water availability and enhanced evaporative demand did not affect MVA, while VD and TCA were significantly reduced at the dry south-facing site. This suggests that in A. alnobetula, vessel size is a static trait whereas vessel number responds plastic. Harsh environmental conditions at the distributional limit of A. alnobetula led to a near semi-ring-porous distribution of vessels and an accumulation of parenchyma in the late growing season. We conclude that in a warmer and drier climate, physiological stress may set limits to the distribution of A. alnobetula at drought-prone sites at the alpine treeline.

The research was funded by the Austrian Science Fund (FWF), project number P34706-B