ARBORICULTURE ARBORICULTU & CONTENTS URBAN FORESTRY Volume 41, Issue 5, September 2015 Formerly the Journal of Arboriculture, 1975 – 2005 (Volumes 1 – 31) ® www.isa-arbor.com Ivan André Alvarez, Bruna Cristina Gallo, Edlene Aparecida Monteiro Garçon, and Osvaldo Tadatomo Oshiro Street Tree Inventory of Campinas, Brazil: An Instrument for Urban Forestry Management and Planning .............................................................................................................................233 ® Abstract. Campinas Metropolitan Region is the third richest city in Brazil. This study assesses the urban street trees of Campi- nas based on data from a survey performed using satellite images in the year 2011. All public domain trees in the street sys- tem were counted and separated into trees, shrubs, palm trees, and seedlings. The density of trees was obtained using the images census and expressed as trees per linear kilometer for the perimeter of the block. The number of trees per linear kilometer was grouped into nine classes of different densities for data validation. The final number of trees was estimated based on the valida- tion’s results. The Gini coefficient shows that the number of trees per person is very irregular in city neighborhoods (i.e., Campinas has a fairer income distribution than street trees distribution). There is a lower density of trees in the downtown area, due to the high concentration of population, and in more peripheral neighborhoods, due to the lack of design planning. The results obtained here may be used to support a new setting of local priorities for planting actions aimed at urban forestry management. Key Words. Brazil; Campinas; Census; Density; Geoprocessing; Gini Coefficient; Remote Sensing; Street Trees; Urban Ecology; Urban Forest. G.M. Moore and C.M. Ryder The Use of Ground-Penetrating Radar to Locate Tree Roots .......................................................245 Abstract. Until recently the only way to investigate tree root architecture and distribution involved the physical removal of soil. However, in the past decade, ground-penetrating radar (GPR), which has been used in many other industries for about 30 years, has been used to study tree roots. GPR is relatively new to Australia and the aim of this research was to assess its spatial accuracy and ability to detect tree roots. Three experiments were conducted using a 900 MHz GPR device (Tree Radar®). The first experiment tested the ability of GPR to detect roots of sizes 10 mm, 20 mm, and 40 mm in diameter at depths of 200 mm, 400 mm, and 800 mm, while the second experiment tested its capacity to resolve two roots placed close together. Roots of 20–30 mm in diameter were placed in pairs at 20 mm, 40 mm, and 80 mm apart at depths of 200 mm, 400 mm, and 800 mm. The final experiment used GPR to analyze the in situ root system of a small Pistacia chinensis (Chinese pistachio) aſter which the root system was excavated using an AirSpade® and counts of root numbers were undertaken and compared with the predicted results. GPR detected and discriminated tree roots accurately at 200 mm depth, but as the depth increased to 400 mm and then to 800 mm, the lev- els of error increased, probably due to the choice of antenna available for the experiments, leading to the presence of phantom roots in some results and the misdetection of true roots in others. Confounding of the signal with unexpected interference or inadequate signal processing was most likely the cause. In the final experiment, GPR missed many small roots in the trenches close to the tree and appeared to detect multiple roots as one. In the outer trenches, GPR predicted 52 roots in total but excavation revealed only one in these disturbed urban soils. Key Words. Discriminating Roots; Ground-Penetrating Radar; Root Architecture; Root Detection; Tree Radar; Tree Roots. Edward F. Gilman, Maria Paz, and Chris Harchick Container and Landscape Planting Depth and Root Ball Shaving Affects Magnolia grandiflora Root Architecture and Landscape Performance .........................................................................260 Abstract. Plants were grown in a 2 × 2 factorial combination of planting depth in nursery containers and at a landscape installation to study effects on root architecture, growth, and mechanical stability of Magnolia grandiflora L. Planting depth into containers or landscape soil had no impact on bending stress to tilt trunks 40 months aſter landscape planting, and impacted neither trunk diameter nor tree height growth 68 months later. Trees planted 128 mm deep into 170 L containers had more circling roots at landscape planting and 68 months later than trees planted shallow in containers. Root pruning at landscape planting reduced the container imprint rating on the root system to one-third of that absent root pruning with only a 4 mm reduction in trunk diameter growth over 68 months. Improvement in root architecture from root pruning likely outweighs the rarely encountered downside of slightly less anchorage in an extreme weather event simulated by winching trunks. Trees planted 5 cm above grade were slightly—but significantly—less stable in landscape than trees planted deeper (10 cm below grade). Root pruning at planting to remove roots on root ball periphery appeared to improve root architecture while only slightly impacting growth and anchorage. Key Words. Anchorage; Bending Stress; Circling Roots; Magnolia grandiflora; Nursery Containers; Planting; Root Pruning. ©2015 | International Society of Arboriculture | ISSN:1935-5297
September 2015
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