473 research outputs found

    Hazard Rating of Parks Trees and Establishment of Adopt-A-Tree Program, Nacogdoches, Texas

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    The purpose of this project is to inventory parks and recreation trees in the city of Nacogdoches, Texas, using a Trimble Pro XRS GPS unit to establish location; and to construct a geographic information system (GIS) database for forest health that can be updated as forest health conditions change in the future. Tree health data collected will include structure of the main bole and branches; insect and disease pests; life expectancy; and shape of the crown and cultural history. An Adopt-a-Tree program, developed in the Arthur Temple College of Forestry at Stephen F. Austin State University, will be established to document planting and maintenance of the urban forest. Each tree planted will have the person planting the tree, a digital picture and the tree species entered into a GIS database for later retrieval, spatial analysis and visual/map display. The project follows the constructs of landscape ecology for documenting structure, function and change of the urban forest

    Effects of fertilizer and herbicide application on Nantucket pine tip moth infestation (Lep., Tortricidae)

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    A study of fertilizer and herbicide e}ects on Nantucket pine tip moth (NPTM), Rhyacionia frustrana (Comstock) infestations was conducted in loblolly pine (Pinus taeda L) plantations in Nacogdoches Co. Texas from 0877 to 0878. Both fertilizer and herbicide applications had effects on NPTM infestation level, pupal weight and host tree oleoresin production. Nitrogen fertilization increased infestation levels, whereas, phosphorus applications tends to decrease infestation rate. Herbicide treatment had a negative effect on NPTM infestations possibly because of decreased moisture stress and increased tree vigour. This is in contrast to general observations of increased NPTM infestations associated with reducing competing vegetation. Fertilizer application alone did not significantly improve pine growth due to competing vegetation. A combination of fertilizer and herbicide achieved the best growth

    Positional Precision Analysis of Orthomosaics Derived from Drone Captured Aerial Imagery

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    The advancement of drones has revolutionized the production of aerial imagery. Using a drone with its associated flight control and image processing applications, a high resolution orthorectified mosaic from multiple individual aerial images can be produced within just a few hours. However, the positional precision and accuracy of any orthomosaic produced should not be overlooked. In this project, we flew a DJI Phantom drone once a month over a seven-month period over Oak Grove Cemetery in Nacogdoches, Texas, USA resulting in seven orthomosaics of the same location. We identified 30 ground control points (GCPs) based on permanent features in the cemetery and recorded the geographic coordinates of each GCP on each of the seven orthomosaics. Analyzing the cluster of each GCP containing seven coincident positions depicts the positional precision of the orthomosaics. Our analysis is an attempt to answer the fundamental question, “Are we obtaining the same geographic coordinates for the same feature found on every aerial image mosaic captured by a drone over time?” The results showed that the positional precision was higher at the center of the orthomosaic compared to the edge areas. In addition, the positional precision was lower parallel to the direction of the drone flight

    Effects of fertilization and herbicides on growth of young loblolly pine and infestations of Nantucket pine tip moth (Lepidoptera: Tortricidae)

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    A 2-year-old pine plantation was selected to receive treatments of fertilizers and herbicides to evaluate effects on Nantucket pine tip moth infestations and the tree growthparameters of height, diameter and volume increment. Nitrogen and phosphorus fertilizers, and hexazinone and sulfometuron methyl herbicides were used in creating six treatments: (i) control; (ii) phosphorus; (iii) nitrogen and phosphorus; (iv) phosphorus and herbicide; (v) nitrogen, phosphorus and herbicide; and (vi) herbicide. Treatments were applied in 1987 and 1988. In 1987, trees treated with nitrogen, phosphorus and herbicide had significantly greater height, diameter and volume growth than trees not receiving fertilizer treatments, but did not have significantly higher tip moth infestations than control trees. Treatments receiving phosphorus only had much lower tip moth infestation rates than other treatments except nitrogen and phosphorus. In 1988, tip moth infestations were uniformly low, with no differences in treatment effects observed

    Characteristics of bark beetle infestations in East Texas during a period of low southern pine beetle activity

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    The species composition nf southern pine bark beetle infestations was examined in east Texas in 1979, A total of 545 infestations were located in thirteen 18,000 acresurvey blocks. Ips spp, were observed in 98.9 of ihe infestations, with black turpentine beetles, Dendrnclonus lerebrans Olivier, present in 42.4 % ofthe infestations. Southern pine beetles, D. fronlulis Zimmemiann. were only observed in 11 infestations (2.0%), and were less abundant than other bark beetle species in these infestations. Almost 80% of the infestations were associated with a recognizable pre-disposing factor (lightning, fire, etc.). Most Infestations were small (less than six trees), though infestations associated with fire damage typically contained more than five infested trees. In the absence of an identified pre-disposing factor, infestations were frequently located in stands rated as high or moderate hazard for southern pine beetl

    Life in a Pine Cone

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    This exercise focuses on a little-known microhabitat -- the pine cone. A pine cone\u27s primary function is, of course, reproduction ... housing the seeds of the next generation of conifer trees. However, pine cones are also the basis of a food web that provides both resources and living space for a wide variety of small arthropod species. The procedure outlined below is designed to examine this microhabitat and compare its community diversity among different species of conifers and habitats. The exercise is based on a 1985 paper, Life in a Pine Cone, by David L. Kulhavy, Robert S. Baldridge and James W. Bing published in Texas Natural History. The paper is the basis of a Ward\u27s Bulletin of the same title. The procedures have been modified somewhat in cooperation with D. L. Kulhavy for use in this exercise. Students, or teams of students, will collect a standard sample of cones from a species of pine tree in a habitat of their choice, extract the arthropods associated with their cones, and provide numerical and descriptive data in a standard format. To ensure comparability between samples, a sampling protocol will be followed

    Accuracy Assessment on Drone Measured Heights at Different Height Levels

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    The advancement in unmanned aerial system (UAS) technology has made it possible to attain an aerial unit, commonly known as a drone, at an affordable price with increasing precision and accuracy in positioning and photographing. While aerial photography is the most common use of a drone, many of the models available in the market are also capable of measuring height, the height of the drone above ground, or the altitude above the mean sea level. On board a drone, a barometer is used to control the flight height by detecting the atmospheric pressure change; while a GPS receiver is mainly used to determine the horizontal position of the drone. While both barometer and GPS are capable of measuring height, they are based on different algorithms. Our study goal was to assess the accuracy of height measurement by a drone, with different landing procedures and GPS settings

    What\u27s past is prologue : our legacy - our future, 1990 National Interpreters Workshop

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    ... the topics of the papers presented at the 1990 National Interpreters Workshop reflect a dynamic NAI membership. While firmly rooted to principles which have been developed in over a millennium, presenters show a healthy use of past knowledge as prologue to an active, vital present ...https://scholarworks.sfasu.edu/ebooks/1005/thumbnail.jp

    Comparison of modal characteristic of wrapped and winded composite tubes from carbon prepreg

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    Constructions based on long fiber composite frames gaining significant and irreplaceable position through almost all traffic sectors. The aim of this presented work is a study of composite rods made by two ways from pre impregnated fibres. In technical practice, one can find applications of so called “prepregs”, especially for so-called wrapping, which is a gradual helical layering of wide tapes. This is a quite simply method with a good quality of final parts, but the using is limited only for straight shapes. Therefore, a method called winding, which is a simultaneous deposition of larger number of fiber filaments was used to handle the problem for curved shapes and fluently changed cross-sections. Even though this method could expand the using of presaturated fibres, in a real case compared with wrapped parts there is evident imperfect alignment and mutually storing of placed fibers. This could be mainly caused by a significant tortuosity and stickiness of the individual fiber strands. The objective the carried work was to experimentally compare the vibrational - modal behavior of two almost identical rods. One was winded and the second kind was wrapped with the same structure of layers, weight and curing parameters. The results of the two compared tubes, that should be theoretically identical, were significantly different. Another step was compilation of a numerical model and verify its suitability for parts created with the two mentioned production methods. The numerical model was in a good agreement with the empirical obtained from the experiment with wrapped parts. However, the using of this standard model also for winded tube is questionable, because of the significantly differences in founded natural frequencies
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