Arboriculture & Urban Forestry 45(4): July 2019 Table 1. Sampling location of Scoop & Dump and unamended soil cores. Soil type S&D Site buildinga Plant Science S&D S&D Unamended Unamended Unamended c Mann Library CCC Plant Science Mann Library CCC Planting bed locationb North side West side South side n/a n/a n/a a Site CCC refers to Computing and Communications Center building. b 141 First core locationc West edge South edge East edge 12.2 m North 12.2 m West 7.6 m South Planting bed location refers to its position relative to the building adjacent to site building. The first core location refers to the end of the planting bed where the transect line originates for S&D samples. The first core samples were taken five feet into the bed along the transect. For unamended, the first core location refers to the position at which the unamended samples were extracted relative S&D extracted core. and provide drainage. After the soil cores were col- lected, they were brought to a campus greenhouse and growth chamber for the duration of the experiment. Tree Growth Period The woody evergreen plant Ficus benjamina is used as a street tree in tropical and sub-tropical regions of the world, known for its fast growing, urban- and heat-tolerant characteristics (Vargas-Garzon and Molina-Prieto 2012). Ficus benjamina has been eval- uated for its ecosystem services in the urban forest such as rainfall interception (Guevara-Escobar et al. 2007) and localized cooling (Jimenez 2008). Ficus benjamina ‘Evergreen’ was selected due to its com- mon use as an urban tree and so that this study could be conducted during winter months when northern temperate tree species are dormant (Loh et al. 2003). A 72 cell plug tray of tissue-culture propagated Ficus benjamina ‘Evergreen’ trees were received from Sunshine Horticulture LLC (Apoka, Florida, U.S.A.) on September 23, 2013 and were acclima- tized in the greenhouse for 26 days. Trees were approximately 12 cm (4.7 in) tall, with three to five stems and a root volume of 5 cm3 when they were received. On October 18, 2013, Ficus benjamina ‘Evergreen’ were planted directly into the soil cores in the greenhouse using a metal stake to dig out a planting hole. Disturbed soils were retained on the top of the cores. Resident growing medium was left attached to roots of the tree plugs. After planting, soils were watered until they reached field capacity. Five cores from each of the three sites and two treat- ments were selected at random and thereafter used as the study plants. Study plants were randomly distrib- uted across a greenhouse bench. The greenhouse was heated to maintain a daytime temperature of 26.6°C (80°F) and nighttime temperature of 21.1°C (70°F). Supplemental lighting (Parsource GLXI 1000W Pet- aluma, California, U.S.A.) was used daily from 5am to 10pm EST with a 7-hour night period from planting October 18, 2013 until January 11, 2014. On January 11, the supplemental lighting was adjusted to illumi- nate trees from 6 am to 12 pm. Plants were watered daily between 8:15 to 8:45 am. The study trees received an average of 72.95 μmol s-1 m-2 (+/- SD 30.33) of supplemental greenhouse lighting in addi- tion to daily solar irradiance. Monday–Friday during the plant establishment phase, 150 ppm of N fertilizer was used in applied watering, and clear water was used Saturday and Sunday. The establishment period ended on November 13, 2013 and only clear water was used after this point. The study plants were moved to a growth chamber on January 21, 2014. Lights in the growth chamber were set to 25% corresponding with a 16-hour day providing 5.356 to 7.085 Mol Par/16 hr. On January 29, 2014, light intensity was increased to 100% to reach between 19.41 to 26.9 Mol Par/16 hr. Day tem- peratures were set to 26.6°C (80°F) with the photo- period occurring from 8 pm to 12 pm. Night temperatures were set at 21.1°C (70°F). Humidity was left at ambient levels. On January 28, the soil depth for each container was determined by measuring the difference in height between the top lip of the container and where the soil line started at four evenly spaced locations around the pot. These measurements were used to determine total soil volume and eventually bulk density. The ini- tial growth period ended on February 1, 2014, and all study plants were irrigated until soils were saturated ©2019 International Society of Arboriculture Subsequent core locations 4.5 m intervals, moving East 4.3 m intervals, moving North 3.0 m intervals, moving West 4.5 m intervals, moving East 4.3 m intervals, moving North 3.0 m intervals, moving West
July 2019
| 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
