The Dallas/Fort Worth, Texas winter urban heat island and variations in low temperature injury to ornamental plants /
Studies were conducted to determine the extent of the winter heat island of the Dallas/Fort Worth, Tex. (DFW) area and how the low temperature variations affect winter damage to ornamental plants. Heat island maps were created using data from the years 1974-1996. The heat island was generally comp...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=727721031&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Studies were conducted to determine the extent of the winter heat island of the Dallas/Fort Worth, Tex. (DFW) area and how the low temperature variations affect winter damage to ornamental plants. Heat island maps were created using data from the years 1974-1996. The heat island was generally composed of hot areas near city centers, a large warm area encompassing the major metropolitan area, and cooler areas to the west and northwest. Single date heat-island intensities were the greatest with temperature differences of up to 12⁰ C. Mean minimum and extreme minimum temperature intensities equaled 4 to 5⁰C. Heat island patterns were not detected using mean winter maximum temperatures. Extreme minimum temperatures were used to recreate hardiness zone maps for DFW. A 1.3⁰C area was added to the USDA number and letter designations to help improve local precision and designated subscript 1 or 2. The first map was created using the same years as the USDA map, 1974-1986. Zone designations and temperature patterns varied only modestly. A second map added the years 1987 to 1996. The metroplex was warmer with hot areas near the city centers of Dallas and Fort Worth. Cooler areas were further west and the temperature gradient steeper with temperature differences exceeding 5⁰C. Winter temperature relationships with plant responses were documented with three species, Asian jasmine [Trachelospermum asiaticum (Siebold & Zucc.) Nakai], Indian hawthorn (Raphiolepis indica (L.) Lindl.), and live oak (Quercus virginiana Mill.) were chosen based on local prevalence and likelihood of cold injury. Plants were graded on a scale of 1 to 6, with 1 being no damage and 6 being complete plant death. Asian jasmine had severe damage in rural areas, whereas only light to no damage occurred in urban sites. Live oak had a range of damage including catastrophic in rural sites, but no damage to urban trees. No difference was found among Indian hawthorn sites. Urban heating may provide protection for many marginally hardy species and allow their use further poleward than would otherwise be expected. |
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| Item Description: | Vita. "Major Subject: Horticulture". |
| Physical Description: | xi, 86 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 79-85). |