Hydraulic Water Redistribution by Silver Fir (Abies alba Mill.) Occurring under Severe Soil Drought

Forests

Fengli Yang¹  Heinz Rennenberg¹  NadineK. Ruehr²  Michael Dannenmann²  Romy Rehschuh²  Stephanie Rehschuh²  Paul Töchterle² 

[1] Institut für Forstbotanik und Baumphysiologie, Freiburg University, Georges-Köhler Allee 53/54, 79085 Freiburg, Germany;Institute of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany;

关键词: hydraulic redistribution;    drought;    silver fir;    european beech;    mixed stand;   

DOI  :  10.3390/f11020162

来源: DOAJ

【 摘 要 】

Hydraulic redistribution (HR) of water from wet- to dry-soil zones is suggested as an important process in the resilience of forest ecosystems to drought stress in semiarid and tropical climates. Scenarios of future climate change predict an increase of severe drought conditions in temperate climate regions. This implies the need for adaptations of locally managed forest systems, such as European beech (Fagus sylvatica L.) monocultures, for instance, through the admixing of deep-rooting silver fir (Abies alba Mill.). We designed a stable-isotope-based split-root experiment under controlled conditions to test whether silver fir seedlings could perform HR and therefore reduce drought stress in neighboring beech seedlings. Our results showed that HR by silver fir does occur, but with a delayed onset of three weeks after isotopic labelling with ²H₂O (δ²H ≈ +6000‱), and at low rates. On average, 0.2% of added ²H excess could be recovered via HR. Fir roots released water under dry-soil conditions that caused some European beech seedlings to permanently wilt. On the basis of these results, we concluded that HR by silver fir does occur, but the potential for mitigating drought stress in beech is limited. Admixing silver fir into beech stands as a climate change adaptation strategy needs to be assessed in field studies with sufficient monitoring time.

【 授权许可】

Unknown