Kiyomi Morino | The University of Arizona (original) (raw)

Papers by Kiyomi Morino

Tree Physiology, Apr 5, 2021

Tracking wood formation in semiarid regions during the seasonal march of precipitation extremes h... more Tracking wood formation in semiarid regions during the seasonal march of precipitation extremes has two important applications. It can provide (i) insight into the adaptive capacities of trees to drought and (ii) a basis for a richer interpretation of tree-ring data, assisting in a deeper understanding of past and current climate. In the southwestern USA, the anatomical signature of seasonally bimodal precipitation is the 'false ring'-a band of latewood-like cells in the earlywood. These occur when a particularly deep drought during the early growing season ends abruptly with timely, mid-growing season monsoonal rains. Such conditions presented in southern Arizona in 2014, enabling us to explore false-ring formation in ponderosa pine (Pinus ponderosa Lawson and C. Lawson) and Douglas-fir (Pseudotsuga menziesii Mirb. Franco) in mixed-conifer forest at 2573 m above sea level. We ask: what were the cell-by-cell timings and durations in the phases of wood cell development in 2014? How do these seasonal patterns relate to strongly fluctuating environmental conditions during the growing season? We took weekly microcores from March through November from six ponderosa pine and seven Douglas-fir trees at a well-instrumented flux tower site. Thin sections were prepared, and we counted cells in cambial, expansion, cell wall thickening and mature phases. For ponderosa pine trees forming a false ring, the first impact of intensifying seasonal drought was seen in the enlarging phase and then, almost a month later, in cambial activity. In this species, recovery from drought was associated with recovery first in cambial activity, followed by cell enlargement. This timing raised the possibility that cell division may be affected by atmospheric moisture increases before soil recharge. In both species, the last false-ring cells matured during the summer rainy season. Bimodal cambial activity coincident with moisture availability was observed in both species, whether or not they formed a false ring. This deeper knowledge of the precise timing of both developmental and environmental events should help define mechanistic connections among these factors in creating bimodal growth patterns.

Journal of Hydrology, 2012

Summary Streamflow variability on timescales of decades to centuries becomes increasingly importa... more Summary Streamflow variability on timescales of decades to centuries becomes increasingly important as water managers grapple with shortages imposed by increasing demand and limited supply, and possibly exacerbated by climate change. ► Two applications of dendrochronology to the study of flow variability are illustrated for an existing 1244-yr reconstruction of annual flows of the Colorado River at Lees Ferry, Arizona, USA: (1) identification and climatological interpretation of rare flow events, and (2) assessment of vulnerability of water-supply systems to climatic variability. ► Analysis centers on a sustained drought of the mid-1100s characterized by persistent low flows on both the Colorado and Sacramento Rivers. ► Analysis of geopotential height anomalies during modern joint-droughts suggests more than one mode of circulation might accompany joint-drought in the two basins. ► Monte Carlo simulation is used to demonstrate that a drought as severe as that in the 1100s on the Colorado River might be expected about once in every 4–6 centuries by chance alone given the time-series properties of the modern gaged flows. Application of a river-management model suggests a mid-1100s-style drought, were it to occur today, would drop reservoir levels in Lake Mead to dead-pool within a few decades. ► Uncertainty presents challenges to accurately quantifying severe sustained droughts from streamflow reconstructions, especially early in the tree-ring record. ► Corroboration by multiple proxy records is essential. ► Future improvements are likely to require a combination of methodological advancements and expanded basic data.

Tree Physiology

American journal of botany, 2018

$Research paper thumbnail of Carbon and oxygen isotope fractionations in tree rings reveal interactions between cambial phenology and seasonal climate$

Plant, cell & environment, Jan 11, 2018

We developed novel approaches for using the isotope composition of tree-ring subdivisions to stud... more We developed novel approaches for using the isotope composition of tree-ring subdivisions to study seasonal dynamics in tree-climate relations. Across a thirty-year time-series, the δ C and δ O values of the earlywood (EW) cellulose in the annual rings of Pinus ponderosa reflected relatively high intrinsic water-use efficiencies (iWUE) and high evaporative fractionation of O/ O, respectively, compared to the false latewood (FLW), summerwood (SW) and latewood (LW) subdivisions. This result is counter-intuitive, given the spring origins of the EW source water and mid-summer origins of the FLW, SW and LW. Use of the Craig-Gordon (CG) isotope-climate model revealed that the isotope ratios in all of the ring subdivisions are explained by the existence of seasonal lags, lasting several weeks, between the initial formation of tracheids and the production of cellulosic secondary cell-walls during maturation. In contrast to some past studies, modification of the CG model according to convent...

Drought and Water Crises, 2016

Geophysical Research Letters, 2016

Journal of Arid Environments, Jun 1, 2010

Native tree plots have been established in river irrigation districts in the western U.S. to prov... more Native tree plots have been established in river irrigation districts in the western U.S. to provide habitat for threatened and endangered birds. Information is needed on the effective irrigation requirements of the target species. Cottonwood (Populus spp.) and willow (Salix gooddingii) trees were grown for seven years in an outdoor plot in a desert environment in Tucson, Arizona. Plants were allowed to achieve a nearly complete canopy cover over the first four years, then were subjected to three daily summer irrigation schedules of 6.20 mm d À1 ; 8.26 mm d À1 and 15.7 mm d À1. The lowest irrigation rate was sufficient to maintain growth and high leaf area index for cottonwoods over three years, while willows suffered considerable die-back on this rate in years six and seven. These irrigation rates were applied April 15-September 15, but only 0.88 mm d À1 was applied during the dormant period of the year. Expressed as a fraction of reference crop evapotranspiration (ET o), recommended annual water applications plus precipitation (and including some deep drainage) were 0.83 ET o for cottonwood and 1.01 ET o for willow. Current practices tend to over-irrigate restoration plots, and this study can provide guidelines for more efficient water use.

Ecohydrology, Mar 1, 2009

In many places along the lower Colorado River, saltcedar (Tamarix spp) has replaced the native sh... more In many places along the lower Colorado River, saltcedar (Tamarix spp) has replaced the native shrubs and trees, including arrowweed, mesquite, cottonwood and willows. Some have advocated that by removing saltcedar, we could save water and create environments more favourable to these native species. To test these assumptions we compared sap flux measurements of water used by native species in contrast to saltcedar, and compared soil salinity, ground water depth and soil moisture across a gradient of 200-1500 m from the river's edge on a floodplain terrace at Cibola National Wildlife Refuge (CNWR). We found that the fraction of land covered (f c) with vegetation in 2005-2007 was similar to that occupied by native vegetation in 1938 using satellite-derived estimates and reprocessed aerial photographs scaled to comparable spatial resolutions (3-4 m). We converted f c to estimates of leaf area index (LAI) through point sampling and destructive analyses (r 2 D 0Ð82). Saltcedar LAI averaged 2Ð54 with an f c of 0Ð80, and reached a maximum of 3Ð7 with an f c of 0Ð95. The ranges in f c and LAI are similar to those reported for native vegetation elsewhere and from the 1938 photographs over the study site. On-site measurements of water use and soil and aquifer properties confirmed that although saltcedar grows in areas where salinity has increased much better than native shrubs and trees, rates of transpiration are similar. Annual water use over CNWR was about 1Ð15 m year 1 .

Remote Sensing, 2009

We used the Enhanced Vegetation Index (EVI) from MODIS to scale evapotranspiration (ET actual) ov... more We used the Enhanced Vegetation Index (EVI) from MODIS to scale evapotranspiration (ET actual) over agricultural and riparian areas along the Lower Colorado River in the southwestern US. Ground measurements of ET actual by alfalfa, saltcedar, cottonwood and arrowweed were expressed as fraction of potential (reference crop) ET o (ET o F) then regressed against EVI scaled between bare soil (0) and full vegetation cover (1.0) (EVI*). EVI* values were calculated based on maximum and minimum EVI values from a large set of riparian values in a previous study. A satisfactory relationship was found between crop and riparian plant ET o F and EVI*, with an error or uncertainty of about 20% in the mean estimate (mean ET actual = 6.2 mm d −1 , RMSE = 1.2 mm d −1). The equation for ET actual was: ET actual = 1.22 × ET o-BC × EVI*, where ET o-BC is the Blaney Criddle formula for ET o. This single algorithm applies to all the vegetation types in the study, and offers an alternative to ET actual estimates that use crop coefficients set by expert

Water Resources Planning and Management, 2011

... a basin-wide scale, generally over multiple decades, and is used to assess the performance of... more ... a basin-wide scale, generally over multiple decades, and is used to assess the performance of current and alternative operating policies under chan-ging basin ... has been the extension of the long-term record of flows at Lee Ferry back to 762 ad using tree-ring data (Meko et al ...

... and insights. I would also like to thank Ed Glenn for being a reluctant iconoclast. Ed's ... more ... and insights. I would also like to thank Ed Glenn for being a reluctant iconoclast. Ed's ... and angiosperms. In conifers, they are identified by tracheids of reduced radial diameter (Larson 1963, Glerum 1970, Barnett 1976). Initial ...

Plant and Soil, 2013

The original version of this paper should have contained the following statement in the Acknowled... more The original version of this paper should have contained the following statement in the Acknowledgment section: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Journal of Arid Environments, 2010

Hydrological Processes, 2011

Globally, expansion of non-native woody vegetation across floodplains has raised concern of incre... more Globally, expansion of non-native woody vegetation across floodplains has raised concern of increased evapotranspiration (ET) water loss with consequent reduced river flows and groundwater supplies. Water salvage programs, established to meet water supply demands by removing introduced species, show little documented evidence of program effectiveness. We use two case studies in the USA and Australia to illustrate factors that contribute to water salvage feasibility for a given ecological setting. In the USA, saltcedar (Tamarix spp.) has become widespread on western rivers, with water salvage programs attempted over a 50-year period. Some studies document riparian transpiration or ET reduction after saltcedar removal, but detectable increases in river base flow are not conclusively shown. Furthermore, measurements of riparian vegetation ET in natural settings show saltcedar ET overlaps the range measured for native riparian species, thereby constraining the possibility of water salvage by replacing saltcedar with native vegetation. In Australia, introduced willows (Salix spp.) have become widespread in riparian systems in the Murray-Darling Basin. Although large-scale removal projects have been undertaken, no attempts have been made to quantify increases in base flows. Recent studies of ET indicate that willows growing in permanently inundated stream beds have high transpiration rates, indicating water savings could be achieved from removal. In contrast, native Eucalyptus trees and willows growing on stream banks show similar ET rates with no net water salvage from replacing willows with native trees. We conclude that water salvage feasibility is highly dependent on the ecohydrological setting in which the non-native trees occur. We provide an overview of conditions favorable to water salvage.

Ecohydrology, 2008

We measured transpiration by black greasewood (Sarcobatus vermiculatus) (SAVE) and fourwing saltb... more We measured transpiration by black greasewood (Sarcobatus vermiculatus) (SAVE) and fourwing saltbush (Atriplex canescens) (ATCA) over a nitrate-contaminated aquifer in Monument Valley, Arizona, on the Colorado Plateau. Heat balance sap flow sensors were used to ...

Ecohydrology, 2009

Bulletin of the American Meteorological Society, 2014

A synthesis of studies on Colorado River streamflow projections that examines methodological and ... more A synthesis of studies on Colorado River streamflow projections that examines methodological and model differences and their implications for water management.

…, 2009