ARBORICULTURE ARBORICULTU & CONTENTS URBAN FORESTRY Volume 36, Issue 4, July 2010 Formerly the Journal of Arboriculture, 1975 – 2005 (Volumes 1 – 31) www.isa-arbor.com Susan D. Day, P. Eric Wiseman, Sarah B. Dickinson, and J. Roger Harris Contemporary Concepts of Root System Architecture of Urban Trees ........................................ 149 Abstract. Knowledge of the extent and distribution of tree root systems is essential for managing trees in the built environment. Despite recent advances in root detection tools, published research on tree root architecture in urban settings has been limited and only par- tially synthesized. Root growth patterns of urban trees may differ considerably from similar species in forested or agricultural environ- ments. This paper reviews literature documenting tree root growth in urban settings as well as literature addressing root architecture in nonurban settings that may contribute to present understanding of tree roots in built environments. Although tree species may have the genetic potential for generating deep root systems (>2 m), rooting depth in urban situations is frequently restricted by impenetrable or inhospitable soil layers or by underground infrastructure. Lateral root extent is likewise subject to restriction by dense soils under hardscape or by absence of irrigation in dry areas. By combining results of numerous studies, the authors of this paper estimated the radius of an unrestricted root system initially increases at a rate of approximately 38 to 1, compared to trunk diameter; however, this ratio likely considerably declines as trees mature. Roots are often irregularly distributed around the tree and may be influenced by car- dinal direction, terrain, tree lean, or obstacles in the built environment. Buttress roots, tap roots, and other root types are also discussed. Key Words. Root Depth; Root Extent; Root Restriction; Urban Forestry; Woody Plants. Chris Sargent, Michael Raupp, Dick Bean, and Alan J. Sawyer Dispersal of Emerald Ash Borer within an Intensively Managed Quarantine Zone ...................... 160 Abstract. Emerald ash borer (EAB) (Agrilus planipennis) is one of the most destructive insect pests of urban trees in the United States. The objective of the current study was to determine the rate of spread of EAB in a quarantine zone where aggressive interven- tion tactics such as tree destruction occurred. Historical records were examined from the Maryland Department of Agriculture for the years 2003, 2006, 2007, and 2008, to determine the rate of spread of EAB in Maryland, U.S., within the quarantine zone. Despite attempts at eradication and public education, EAB persisted, and the leading edge of beetles moved away from the central infestation point at an average annual rate of 1 km per year and a maximum annual rate of 1.37 km per year between 2003 and 2008. This paper dis- cusses the relative merits and limitations of this quarantine and eradication program and makes suggestions for future management of EAB. Key Words. Agrilus planipennis; dispersal; emerald ash borer; eradication; quarantine; rate of spread. Rebecca Tirado-Corbalá and Brian K. Slater Soil Compaction Effects on the Establishment of Three Tropical Tree Species ............................ 164 Abstract. Tree seedlings planted in containers along sidewalks in urban environments show restricted growth and development over time. This is the result of limited soil volume and soil compaction that hampers nutrient availability and water movement. Using tree species commonly used in urban forestry in Puerto Rico, this study was conducted to determine their growth response when planted in compacted soils. Seedlings of three ornamental tropical tree species, trumpet bush [Tecoma stans (L.) Juss. ex Kunth], bottle brush [Callistemon citrinus (Curtis) Skeels], and pink trumpet (Tabebuia rosea dc.) were transplanted into pots of sandy clay loam or clay soils at three levels of compaction: control (no compaction), 1.2 g/cm3 and 1.4 g/cm3 eter, leaf number and color, foliar area, and root, shoot, and leaf dry weights were measured on two plants every two months for six months. All species exhibited better growth in sandy clay loam at 1.2 g/cm3 ratio. When planted in clay at 1.4 g/cm3 Urban Soils. bulk density, respectively. Plant height, shoot diam- ; after six months, all species showed a reduced root-shoot , all trumpet bush seedlings died within two months. No leaf color differences were observed between species at different compaction levels. Bottle brush showed less growth suppression by increasing compaction level in both soils. Key Words. Callistemon citrinus; Root Growth; Root-Shoot Ratio; Tabebuia rosea; Tecoma stans; Tree Establishment; Urban Forestry; ©2010 | International Society of Arboriculture | ISSN:1935-5297
July 2010
| 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
