330 state. At least 10 minutes elapsed between subsequent pulls on the same root and at least 20 minutes between pulls on roots when moving to the next sampled root. A strong relationship between bending moment and DBH (reported in Beezley et al. 2016) indicates that the trees relaxed between pulls. CONCLUSIONS Efforts to quantify the structural stability of trees are actively being pursued by the arboricultural practi- tioner and research community. Current tree risk assess- ments may not fully consider the long-term responses of trees to mechanical stress, and thus many large amenity trees may have been prematurely felled in hopes of diverting litigious citations and compromis- ing public safety. Mechanical stress is induced within trees during dynamic and static loading events. This loading can cause failure in both aboveground and belowground portions of a tree. Understanding how the load is transferred through the RSTZ, and if the resulting force is evenly dispersed throughout the root zone, can be an important consideration, espe- cially if damage occurs to a specific section of the roots. Understanding how load and resulting strains move from the stem through the RSTZ into the root system and finally into the soil is important for better understanding tree stability. This study demonstrates that DIC can be successfully utilized to map strain in urban tree roots. Researchers can now consider using DIC to investigate how strain moves out from the RSTZ into the structural and smaller roots and poten- tially into the soil. Researchers have noted the importance of under- standing how forces move through trees and finding methods to assess the stability of trees (Dahle et al. 2014). Understanding that loading results in signifi- cantly higher strains on in-line roots, rather than tan- gential roots, has important management implications. Specifically, severing roots in line with the prevailing direction of wind or other loads will lead to reduced tree stability. This finding, however, does not diminish the importance of the tangential sides of the tree and the effects of torsion within the structural root system. Further research is needed to fully understand the implications of loading on tangential root systems. LITERATURE CITED Beezley K, Dahle G, Miesbauer J. 2016. Strain measurement within trees across the root-stem transition zone (RSTZ). ©2020 International Society of Arboriculture Beezley et al: Strain in Roots in Urban Trees Proceedings of the 11th international symposium on environ- mental concerns in rights-of-way management; Halifax, CA, USA. p. 107-114. Beezley K, Dahle G, Miesbauer J, Walker M. 2020. Importance of the root-stem transition zone in the stability of trees. In: Wat- son G, Gilman E, Miesbauer J, Morgenroth J, Scharenbroch B, editors. Landscape below ground IV: proceedings of the fourth international workshop on tree root development in urban soils. Atlanta (GA, USA): International Society of Arboriculture. p. 300-315. Bonnesoeur V, Constant T, Moulia B, Fournier M. 2016. Forest trees filter chronic wind-signals to acclimate to high winds. New Phytologist. 210(3):850-860. Brudi E, van Wassenaer PJ. 2002. Trees and statics: nondestruc- tive failure analysis. In: Coder KD, Smiley ET, editors. Tree structure and mechanics conference proceedings: how trees stand up and fall down. Champaign (IL, USA): International Society of Arboriculture. p. 53-70. Burgert I. 2006. Exploring the micromechanical design of plant cell walls. American Journal of Botany. 93:1391-1401. Coder K. 2008. Storm wind loads and tree damage. Athens (GA, USA): Warnell School of Forestry and Natural Resources, the University of Georgia. WSF&NR08-24. 35 p. Coutts MP. 1983. Root architecture and tree stability. Plant and Soil. 71:171-188. Dahle GA. 2017. Influence of bark on the measurement of mechan- ical strain using digital image correlation. Wood Science and Technology. 51:1469-1477. Dahle GA, Grabosky JC. 2009. Review of literature on the func- tion and allometric relationships of tree stems and branches. Arboriculture & Urban Forestry. 35:311-320. Dahle GA, Grabosky JC. 2010. Variation in modulus of elasticity (E) along Acer platanoides L. (Aceraceae) branches. Urban Forestry & Urban Greening. 9:227-233. Dahle GA, Grabosky JC. 2012. Determining if lateral imbalance exists in first-order branches leading to a potential development of torsional stress. Arboriculture & Urban Forestry. 38(4): 141-145. Dahle GA, Grabosky J, Kane B, Miesbauer J, Peterson W, Telewski FW, Koeser A, Watson GW. 2014. Tree biomechanics: a white paper from the 2010 international meeting and research summit at The Morton Arboretum (Lisle, Illinois, U.S.). Arboriculture & Urban Forestry. 40:309-318. Dahle GA, James KR, Kane B, Grabosky JC, Detter A. 2017. A review of factors that affect the static load-bearing capacity of urban trees. Arboriculture & Urban Forestry. 43(3):89-106. Dupuy L, Fourcaud T, Stokes A. 2005. A numerical investigation into the influence of soil type and root architecture on tree anchorage. Plant and Soil. 278:119-134. Esau K. 1977. Anatomy of seed plants. 2nd Ed. New York (NY, USA): John Wiley & Sons. p. 61-181. Fayle DC. 1983. Differences between stem and root thickening at their junction in red pine. Plant and Soil. 71:161-166. Genet M, Stokes A, Salin F, Mickovski S, Fourcaud T, Dumail J, Beek R. 2005. The influence of cellulose content on tensile strength in tree toots. Plant and Soil. 278:1-9. Gibbs JN, Greig BJW. 1990. Survey of parkland trees after the great storm of October 16, 1987. Arboricultural Journal. 14:321-347.
September 2020
| Title Name |
Pages |
Delete |
Url |
| Empty |
Ai generated response may be inaccurate.
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.
Downloading PDF
Generating your PDF, please wait...
This process might take longer please wait
