Applying plant hydraulic physiology methods to inform irrigation of maples and oaks grown in oregon nurseries

Authors: KELLER, SADIE - Oregon State University; Scagel, Carolyn; CONTRERAS, RYAN - Oregon State University; NACKLEY, LLOYD - Oregon State University

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/2022
Publication Date: 10/20/2022
Citation: Keller, S., Scagel, C.F., Contreras, R., Nackley, L.L. 2022. Applying plant hydraulic physiology methods to inform irrigation of maples and oaks grown in oregon nurseries. Journal of the American Society for Horticultural Science. 57(9s).
DOI: https://doi.org/10.21273/HORTSCI.57.9S.S1

Interpretive Summary:

Technical Abstract: Ornamental shade trees are one of the most valuable crops grown in Oregon with an annual value of $300 million dollars. Maples and Oaks are two of the most valuable genera of shade trees grown and sold in Oregon. Currently most irrigation decisions for field grown shade trees are based on grower experience and intuition. Few growers use soil moisture sensors and weather stations to inform irrigation. Environmental factors, such as available soil moisture and atmospheric demand, have not been correlated to plant demand and stress tolerance. Therefore, it is impossible to optimize irrigation scheduling because the plant thresholds are unknown. A hydraulic framework is a useful method for understanding plant responses to decreasing water availability. Plant hydraulics is widely used in ecological systems, orchard, and vineyards production systems but has recieved limited attention in nursery production systems. To fill this gap in knowledge we are studying the hydraulic responses of Red Maple (Acer rubrum ‘Franksred’) and Red Oak (Quercus rubra) to increasing xylem tension. These species were selected because they have discrete hydraulic strategies in response to decreasing soil water. Red Maples are an isohydric species that reduces stomatal conductance to maintain a constant stem water potential and Red Oaks are an anisohydric species that maintains constant stomatal conductance and allows stem water potential to decrease. We measured samples from each species at five different tensions. Our results quantify how Red Maple and Red Oak seedlings respond differently to drought-stress like conditions. The two trees had different drought stress responses that indicate a different susceptibility to acute and chronic drought. We are currently evaluating how stem hydraulics thresholds relate to field performance of these species under different irrigation regimes.