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dc.contributor.authorFarrell, Robert Williamen_US
dc.date.accessioned2014-03-14T20:36:25Z
dc.date.available2014-03-14T20:36:25Z
dc.date.issued2003-03-25en_US
dc.identifier.otheretd-05122003-124617en_US
dc.identifier.urihttp://hdl.handle.net/10919/32619
dc.description.abstractCrotches were cut out of red maple (Acer rubrum), callery pear (Pyrus calleryana), and sawtooth oak (Quercus acutissima) trees (2.5â -7â d.b.h.) and then pulled apart in an engineering testing machine to identify physical parameters correlated with crotch strength. Parameters measured included the diameter of the branch and of the trunk above and below the crotch, angle of the branch and branch bark ridge, and the length of the crotch and the branch bark ridge. The force required to break each sample was used to calculate breaking strength based on the formula for bending stress. Each parameter was tested for correlation with crotch strength within the individual species and for the three species combined. The ratio of branch diameter over crotch width had the highest correlation coefficient for crotch strength. Branch angle was also correlated with crotch strength but not as highly as the ratio of the diameters. V-shaped crotches (those with included bark) were significantly weaker than U-shaped crotches for all species. The ratio of the two stem diameters greatly influenced the manner in which the crotches broke. In crotches where the branch diameter was 2/3 the size of the trunk or smaller, the crotch broke by being pulled directly out of the trunk. Crotches with branches more than 2/3 the diameter of the trunk broke when the trunk split longitudinally and had significantly lower strength values. These results indicate that increased crotch strength results from a small branch diameter relative to that of the trunk.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartFarrellthesis0610.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectincluded barken_US
dc.subjecttree failureen_US
dc.subjectbranch failureen_US
dc.subjectcrotch strengthen_US
dc.subjectpruningen_US
dc.titleStructural Features Related to Tree Crotch Strengthen_US
dc.typeThesisen_US
dc.contributor.departmentForestryen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineForestryen_US
dc.contributor.committeechairZedaker, Shepard M.en_US
dc.contributor.committeememberSmith, David Williamen_US
dc.contributor.committeememberLoferski, Joseph R.en_US
dc.contributor.committeememberKane, Brian P.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05122003-124617/en_US
dc.date.sdate2003-05-12en_US
dc.date.rdate2003-06-11
dc.date.adate2003-06-11en_US


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