Water relations in tree physiology: where to from here?

Area of Science:

• Plant physiology
• Forest ecology
• Hydrology

Background:

• Over 50 years of research in tree water relations.
• Assessing the maturity of the field using Kuhn's paradigm concept.
• Established understanding of physical processes in transpiration.

Purpose of the Study:

• Review the maturity of tree water relations research.
• Evaluate current understanding of water transport and storage in trees.
• Identify knowledge gaps and future research directions.

Main Methods:

• Literature review of 50 years of research.
• Analysis of physical processes in transpiration and stomatal conductance.
• Assessment of hydraulic pathways, cavitation, and water storage.

Main Results:

• Tree water relations is a mature field with well-tested concepts.
• Significant advances in understanding stomatal responses and hydraulic pathways.
• Models can now scale transpiration and predict drought responses.

Conclusions:

• The field is mature, with few anomalies, and models are well-accepted.
• Research is refining existing concepts and filling knowledge gaps.
• Focus is shifting to climatic thresholds for tree mortality, emphasizing hydraulic failure and stomatal sensitivity.