Table of Contents Bixia Chen and Yuei Nakama On the Establishment of Feng Shui Villages from the Perspective of Old Fukugi Trees in Okinawa, Japan .......................................................................................................................... 19 Abstract. A Feng Shui village landscape features Fukugi (Garcinia subelliptica) tree lines surrounding every house and orderly laid out roads. Such a green landscape, which is assumed to be planned or reformed during the modern Ryukyuan period around 300 years ago, is well preserved in Okinawa Island, Japan, and its nearby isolated islands. But it is still a mystery to the historians when and how these Fukugi trees were planted. In order to clarify the development process of the house-embracing Fukugi trees, all Fukugi trees that were assumed to be older than 100 years in Bise, Tonaki, Imadomari, and Aguni Island were measured. It was found that huge Fukugi trees older than 200 years, cluster around the core area kami-asagi or haisyo inside the village. Both the kami-asagi and haisyo are sacred places where guardian gods were summoned in order to hold ceremonies and rituals. The oldest trees were approximately 300, 268, 294, 296, and 281 years in Bise, Tonaki, Imadomari, Yae (East & West), and Hama in Aguni Island, respectively. These old trees might have been planted prior to the period from 1737 to 1750, when Sai On was a member of the Sanshikan, during which Fukugi trees were planned and recommended. While Fukugi trees might have been planted as windbreaks around the houses prior to the Sai On period, however, the current house-embracing Fukugi tree landscape came into being during the Sai On period based on Feng Shui concepts. Key Words: Feng Shui Village; Fukugi; Garcinia subelliptica; Isolated Islands; Old Trees; Sacred Sites. Jason C. Grabosky and Nenad Gucunski A Method for Simulation of Upward Root Growth Pressure in Compacted Sand .......................... 27 Abstract. In order to model the impacts of tree root growth under pavement as a layered design, the behavior of the components need to be defined or assumed. Since the behavior of materials and the design of pavement sections work on the presumption of loading from the pavement surface downward, it is reasonable to check engineering behavior assumptions with a testing method for controlled loading upward from a growing perennial root. A root simulation was developed to inflate with water to known input pressure. Sand displace- ment in response to increasing input pressure was tracked over several sand density-moisture level pairings. Load cells tracked the trans- lation of sand displacement to load at a simulated pavement surface to develop data plots of a line-load spreading wider with increasing distance between root and pavement. The results from the laboratory experiments were compared to the results from numerical simulations using finite elements to develop better understanding of the mechanisms of load generation due to the root growth. Sand was mod- eled as a Mohr-Coulomb type material for that purpose. The numerical results are qualitatively in agreement with the experimental results. Key Words. Compaction; Pavement; Root. Jason C. Grabosky, E. Thomas Smiley, and Gregory A. Dahle Research Note: Observed Symmetry and Force of Plantanus × acerifolia (Ait.) Willd. Roots Occurring Between Foam Layers Under Pavement ......................................................................... 35 Abstract. Root damage to infrastructure is common in the urban environment. Many problems could be avoided if more were known about tree root growth patterns and the forces involved. This study looks at the growth symmetry and forces from four roots to aid in the development of a computer model. Two primary roots, each from two trees, that were growing between two foam layers under pave- ment for 10 years were harvested and sectioned to measure radial growth symmetry to assist in the development of a computer simulation of root growth under pavement. The indentations in the foam created by the root growth were replicated using a universal loading press to estimate the radial growth pressure. Root growth was offset upward when close to the tree trunk, but shiſted to a downward offset within 1 m from the trunk. Load penetration testing of the foam suggested a minimal load of 0.35–0.40 MPa to replicate the foam deformation. Key Words. Infrastructure Damage; Root Diameter Growth; Root Pressure; Sidewalk Liſting. ©2011 | International Society of Arboriculture | ISSN:1935-5297
January 2011
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