Drought stress and recovery in green ash (Fraxinus pennsylvanica Marsh.)
| dc.contributor.author | Litus, Gregory, author | |
| dc.contributor.author | Klett, James, advisor | |
| dc.date.accessioned | 2024-03-13T20:12:23Z | |
| dc.date.available | 2024-03-13T20:12:23Z | |
| dc.date.issued | 2009 | |
| dc.description.abstract | Throughout the Front Range of Colorado, municipalities have developed urban forest management plans that focus on preserving the health of landscape trees and promoting an increase in the canopy cover as an offset to carbon dioxide emissions through carbon sequestration. However, drought in recent years has prompted a concerted effort to conserve water used for landscape irrigation. The combined drought and reductions in irrigation have the potentials to increase water stress in shade trees and lessen the amount of carbon sequestered. To assess the effects of drought stress on growth, photosynthesis and long term health of established green ash (Fraxinus pennsylvanica Marsh.), a record dry 2005-2006 winter was exploited so that severe drought stress could be induced. Early season drought reduced spring leaf growth by 25 percent compared to controls. As drought progressed through the growing season, the stressed trees increased intrinsic water use efficiency by controlling stomatal conductance, based on threshold water potentials, while maintaining photosynthesis. After irrigation was applied in late summer, tree water potentials, stomatal conductance and photosynthesis recovered to near pre-drought levels. The decreased photosynthesis contributed to the reduction in tree growth for the season but did not alter total non-structural carbohydrates concentrations or produce a carbohydrate deficit that would dramatically hinder growth in subsequent years. The extended drought stress followed by irrigation did not affect dormancy and cold hardiness was maintained to -50 °C. Potted green ash trees were used to determine the extent of drought stress tolerated by green ash. At a predawn leaf water potential of -5.28 MPa, stomatal conductance and photosynthesis were reduced but still measurable. Established trees exposed to severe drought conditions did not experience predawn leaf water potentials below -3.14 MPa. Considering the range of drought stress tolerated by green ash and the unlikelihood of those conditions occurring in a managed landscape, negative effects of drought stress are minimized as long as late season irrigation can be applied. However, in green ash, the timing of drought stress can permanently restrict growth in any single year and significantly reduce the total carbon sequestered through photosynthesis. | |
| dc.format.medium | born digital | |
| dc.format.medium | doctoral dissertations | |
| dc.identifier | ETDF_Litus_2009_3385162.pdf | |
| dc.identifier.uri | https://hdl.handle.net/10217/237849 | |
| dc.language | English | |
| dc.language.iso | eng | |
| dc.publisher | Colorado State University. Libraries | |
| dc.relation.ispartof | 2000-2019 | |
| dc.rights | Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. | |
| dc.rights.license | Per the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users. | |
| dc.subject | drought stress | |
| dc.subject | green ash | |
| dc.subject | irrigation | |
| dc.subject | photosynthesis | |
| dc.subject | water stress | |
| dc.subject | horticulture | |
| dc.title | Drought stress and recovery in green ash (Fraxinus pennsylvanica Marsh.) | |
| dc.type | Text | |
| dcterms.rights.dpla | This Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). | |
| thesis.degree.discipline | Horticulture and Landscape Architecture | |
| thesis.degree.grantor | Colorado State University | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy (Ph.D.) |
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