TY - JOUR
T1 - Ecohydrology of urban trees under passive and active irrigation in a semiarid city
AU - Luketich, Anthony M.
AU - Papuga, Shirley A.
AU - Crimmins, Michael A.
N1 - Funding Information:
SP received funding from NSF CNH award 1518376. https://www.nsf.gov/ awardsearch/showAward?AWD_ID=1518376. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We would like to thank Phil Guertin and Tom Meixner for their guidance throughout this research. Additionally, we thank Yoga Korgaonkar, Neha Gupta, Jack Anderson, Emily Bell, and Liliana Gomez for field and computational assistance. Finally, we thank the staff at Watershed Management Group and University of Arizona Residence Life for providing assistance and the necessary space to conduct this research.
Publisher Copyright:
© 2019 Luketich et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2019/11/1
Y1 - 2019/11/1
N2 - The infiltration of stormwater runoff for use by urban trees is a major co-benefit of green infrastructure for desert cities with limited water resources. However, the effects of this passive irrigation versus regular, controlled moisture inputs, or active irrigation, is largely unquantified. We monitored the ecohydrology of urban mesquite trees (Prosopis spp.) under these contrasting irrigation regimes in semiarid Tucson, AZ. Measurements included soil moisture, sap velocity, canopy greenness, and leaf-area index. We expected both irrigation types to provide additional deep (>20 cm) soil moisture compared to natural conditions, and that trees would depend on this deep moisture for transpiration and phenological activity. Results show that active irrigation supported higher soil moisture throughout the study than passive irrigation. Passive irrigation only provided additional deep moisture when green infrastructure features received impervious runoff from a city street. Sap velocity and greenness were similar under both irrigation types, outside of isolated periods of time. These differences occurred during the extremely wet summer 2017 when passively irrigated trees exhibited a greenness peak, and the dry conditions of spring when actively irrigated trees had higher sap flow and relative greenness. Finally, it was not determined that deep soil moisture had a stronger relationship with mesquite productivity than shallow moisture, but both relationships were stronger in the spring, before summer rains. This study aims to contribute empirical observations of green infrastructure performance for urban watershed management.
AB - The infiltration of stormwater runoff for use by urban trees is a major co-benefit of green infrastructure for desert cities with limited water resources. However, the effects of this passive irrigation versus regular, controlled moisture inputs, or active irrigation, is largely unquantified. We monitored the ecohydrology of urban mesquite trees (Prosopis spp.) under these contrasting irrigation regimes in semiarid Tucson, AZ. Measurements included soil moisture, sap velocity, canopy greenness, and leaf-area index. We expected both irrigation types to provide additional deep (>20 cm) soil moisture compared to natural conditions, and that trees would depend on this deep moisture for transpiration and phenological activity. Results show that active irrigation supported higher soil moisture throughout the study than passive irrigation. Passive irrigation only provided additional deep moisture when green infrastructure features received impervious runoff from a city street. Sap velocity and greenness were similar under both irrigation types, outside of isolated periods of time. These differences occurred during the extremely wet summer 2017 when passively irrigated trees exhibited a greenness peak, and the dry conditions of spring when actively irrigated trees had higher sap flow and relative greenness. Finally, it was not determined that deep soil moisture had a stronger relationship with mesquite productivity than shallow moisture, but both relationships were stronger in the spring, before summer rains. This study aims to contribute empirical observations of green infrastructure performance for urban watershed management.
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U2 - 10.1371/journal.pone.0224804
DO - 10.1371/journal.pone.0224804
M3 - Article
C2 - 31703086
AN - SCOPUS:85074719794
SN - 1932-6203
VL - 14
JO - PloS one
JF - PloS one
IS - 11
M1 - e0224804
ER -