ARBORICULTURE ARBORICULTU & CONTENTS URBAN FORESTRY Volume 35, Issue 3, May 2009 Formerly the Journal of Arboriculture, 1975 – 2005 (Volumes 1 – 31) www.isa-arbor.com Daniel K. Struve, Francesco Ferrini, Alessio Fini, and Laura Pennati Relative Growth and Water Use of Seedlings from Three Italian Quercus Species .......................113 Abstract. A species’ water use characteristics and growth habits are important to urban foresters. Seedlings from three species (and two sources)—Quercus cerris L., Q. pubescens Willd., and Q. robur L.—were container-grown and subjected to a three day water use trial under nonlimiting soil moisture conditions. Water use varied among species and between sources within a species. Larger seedlings used more water than smaller seedlings; Q. robur seedlings were the tallest, 70.5 cm (27.8 in), and had the greatest water use seedling, 73.4 g (2.5 oz) water, while Q. pubescens and Q. cerris seedlings were shorter, 46 and 45 cm (18.1 and 17.7 in), and averaged 47.5 and 44.9 g (1.68 and 1.58 oz) water, respectively. Quercus pubescens seedlings had the highest water use cm-2 (0.111 g); Q. cerris seedlings had the highest height-adjusted water use (1.4 g water cm-1 leaf area height). There were significant differences in water use between sources within species. Principal component analysis, using 20 variables, showed that seedlings of Q. robur and Q. pubescens sources clustered while seedlings of the two Q. cerris sources were separate from each other and the Q. robur and Q. pubescens sources. The clustering reflected the proportionally greater distribution of dry weight to shoot growth and correspondingly less to root growth of the Q. robur and Q. pubescens seedlings, than that for Q. cerris seedlings. The results are related to the species’ relative value to nursery producers and to the potential value to urban forest managers and the potential for cultivar development. Key Words. Drought Resistance; Dry Weight Partitioning; Seedling Growth; Water Use. Michael R. Kuhns and Douglas K. Reiter Tree Care and Topping Beliefs, Knowledge, and Practices in Six Western U.S. Cities ................. 122 Abstract. A survey of households was conducted in six cities in the interior western United States to determine homeowners’ knowledge of tree biology and tree care and their knowledge and practice of topping. Tree biology and tree care knowledge was low, depending on the specific subject, and few respondents had any formal training in tree care. Respondents’ topping knowledge was moderate to poor if they had topped trees before, regardless of whether they received a topping-related educational brochure. Those who had not previously topped trees were fairly knowledgeable and the brochure increased knowledge in some cases. Topping was fairly commonly practiced, even by those who cared about trees, and oſten was done for safety and to improve tree appearance and tree health. Amongst those who had topped trees, the survey explored who performed the topping, why it was done, and their satisfaction with the practice. Examples of ways the tree care industry and others may be contributing to misunderstanding, such as inconsistent practices, are discussed. Recommendations are made for changing knowledge and attitudes about tree care as well. Key Words. Planting; Pruning; Topping; Tree Care; Urban Forestry. Raul I. Cabrera Revisiting the Salinity Tolerance of Crapemyrtles (Lagerstroemia spp.) ...................................... 129 Abstract. The crapemyrtle (Lagerstroemia L.) is one of the most popular flowering trees in the U.S. and abroad. L. indica culti- vars have dominated urban and landscape settings until their recent displacement by modern interspecific L. indica × L. fauriei Kohene hybrids. This study evaluated the salt tolerance of an older L. indica cultivar, ‘Pink Lace,’ and the hybrids ‘Natchez’ and ‘Basham’s Party Pink.’ While the growth of these three cultivars was significantly and negatively affected by increasing NaCl salinity (0 to 24 mM) in the irrigation water, the shoot to root ratio (S/R) and aesthetic parameters (chlorophyll con- tent and salt burn ratings) of ‘Pink Lace’ was the most affected. This cultivar showed the most responsive relationships between salt burn ratings and sodium (Na) and chloride (Cl) accumulation in leaf tissues. ‘Basham’s Party Pink’ was rated as the most salt tolerant, with relatively steady S/R, chlorophyll contents and salt burn rating across all salinities, and its leaf tissues had the lowest accumulation of Na and Cl. Results from this study also support the hypothesis that geographical and eco- logical origins of the parent Lagerstroemia species and selections largely influences the relative salinity tolerance of the cultivars. Key Words. Irrigation; Salinity Tolerance; Water Quality. ©2009 | International Society of Arboriculture | ISSN:1935-5297
May 2009
Title Name |
Pages |
Delete |
Url |
Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait