It is well established that national retail chains impact small, single location retail businesses in terms of revenue generation, retail structure, retail type diversity, and location. This study examines the retail structure and diversity of five retail districts in the City of Denton, Texas. The analysis focuses on one central business district (CBD), one traditional retail strip center (University Drive, also known as US HWY 380), one special retail district (Fry Street District), one traditional enclosed shopping mall and associated development (Golden Triangle Mall), and one power retail center (Denton Crossing). The empirical foundation for the investigation is a historical business database covering years 1997 to 2010, obtained from Info Group's Reference USA. This Reference USA database includes location, industry, and status (single versus chain location) information for each business. Retail diversity and evenness were measured for each of the five retail districts using the Simpson's Diversity Index and the Simpsons Measure of Evenness, leading to specification of the differences that exist in retail structure and diversity among the districts. Golden Triangle Mall and Denton Crossing were primarily chain location in composition while Fry Street District, the CBD, and University Drive were primarily single location in composition. Across all years, …

Elemental carbon (EC), a product of incomplete combustion of fossil fuels and biomass, contributes to climate warming and poor air quality. In urban areas, diesel fuel trucks are the main source of EC emissions from mobile sources. After emission, EC is deposited to receptor surfaces via two main pathways: precipitation (wet deposition) and directly as particles (dry deposition). Urban trees may play an important role in removing EC from the atmosphere by intercepting and delivering it directly to the soil. The goal of this research was to quantify the magnitude of EC retention in leaf waxes (in-wax EC) and EC fluxes to the soil via leaf litterfall in the City of Denton, Texas. Denton is a rapidly growing urban location in the Dallas-Fort Worth metropolitan area. A foliar extraction technique was used to determine EC retention in leaf waxes. Foliar samples were collected monthly, from April through July, from pairs of Quercus stellata (post oak, n=10) and Quercus virginiana (live oak, n = 10) trees. Samples were rinsed with water and chloroform in a two-step process to determine EC retained in leaf waxes. A Sunset OC/EC aerosol analyzer was utilized to analyze the EC content of extracts filtered onto quartz-fiber …

Rainfall interception is one mechanism by which tree canopies can reduce surface runoff in urban areas. The objectives of this research were to: 1) quantify rainfall interception by urban tree canopies, and 2) determine the influence of vegetation and microenvironmental factors on rainfall interception rates. In the city of Denton, Texas, 30 mature post oak (Quercus stellata) and blackjack oak (Quercus marilandica) trees were selected for study. Trees were assigned to one of three categories: clusters of trees on greenspace (CG), isolated trees on greenspace (IG), and isolated trees surrounded by pavement (IP). Throughfall (the volume of water that travels through the canopy and reaches the soil surface) collectors were placed beneath these trees and rainfall collectors were placed in nearby open areas. Throughfall and rainfall were collected daily from 19 March to 4 July. Interception was calculated as the difference between throughfall and gross rainfall. Over the study period, there were 27 days with measurable rainfall; daily rainfall ranged from 1-51 mm. Over the sampling period, rainfall interception for individual trees ranged from -10% to 49%, indicating high spatial variability in interception. Percent interception was highest for the CG treatment (22.7 ± 3.8 SE), intermediate for IG (27.4 ± …

This study implemented a GIS-based analysis of local climate zones (LCZ) in Denton, TX with data sets from 2009, 2011, 2015, and 2016. The LCZ scheme enables evaluation of distinct regions' thermal characteristics with greater granularity than conventional urban-rural dichotomies. Further, the GIS-based approach to LCZ mapping allows use of high-resolution lidar data, the availability of which for the study area enabled estimation of geometric and surface cover parameters: height of roughness elements, sky-view factor, and building surface fraction. Pervious surface fraction was estimated from National Landcover Database impervious imagery. A regular grid was used to estimate per-cell mean values for each parameter, and with a decision-making algorithm (if/then statements) two maps were produced (2011 and 2015) and six LCZ identified in each: LCZ 6 (open low-rise), LCZ 8 (large low-rise), LCZ 9 (sparsely built), LCZ A (dense trees), LCZ B (scattered trees), and LCZ C (bush/scrub). Post-processing was carried out to ensure identified zones met the spatial minimum for qualification as LCZ. Landsat Collection 2 Level 2 surface temperature products from various seasons of 2011 and 2015 were acquired to examine LCZ thermal differentiability, and preliminary surface urban heat island intensity values were estimated. Particular attention was afforded to …