Arboriculture & Urban Forestry 33(2): March 2007 155 leaves before they are shed late in the fall, often aggravated by wind. Nor was any indication of invasiveness reported, although there were grassy areas adjacent to some of the plots where seedlings could grow. CONCLUSIONS Figure 1. Heights (m) of cultivars 3 to 12 years after planting. Ar = Aristocrat; CS = Cleveland Select; Rd = Red- spire; AB = Autumn Blaze. and 6 m (16.5 to 19.8 ft). Cleveland Pride®, Valiant®, and ‘Whitehouse’ were as narrow as ‘Cleveland Select’ until the 9th year but afterward spread out much more. Trunk diameters at a height of 1.35 m (4.5 ft) varied con- siderably among communities. Aristocrat™ had the largest trunk diameters, but trunks of all cultivars were sturdy enough to provide good support. The foliage and branches of all but one of the cultivars remained healthy throughout the 12 years as indicated by ratings above 4.0. The one minor exception was the foliage of ‘Whitehouse’ at both locations where it was planted. An- thracnose or fireblight were suspected causes of injuries to leaves but were not verified. Fireblight can be serious in southern states (Fare et al. 1991) but was not a problem in this study. Two undesirable characteristics of Callery pears that have been reported elsewhere did not affect the trees in the per- formance tests. No breakage or tearing out of branches was reported, although it is known that severe damage to branches and trunks can occur when heavy snow or ice accumulates on All of the Callery pear cultivars that were evaluated for 12 years performed well as street trees, although the likelihood of breakage by storms in the future could cause some to be less desirable than others. Some were distinctive in height or crown spread. ‘Autumn Blaze’ was somewhat shorter than others, and ‘Cleveland Select’ was narrower. The latter, also known as ‘Chanticleer’ pear, was selected as the 2005 Urban Tree of the Year by the Society of Municipal Arborists (2004). All of the Callery pears were still growing in height at the 12th year, and most of them were already interfering with utility wires, so none of the tested cultivars should be planted below overhead wires. Acknowledgments. Financial support for the Municipal Tree Res- toration Program was provided by Allegheny Energy, Asplundh Tree Expert Co., Baltimore Gas&Electric, Bartlett Tree Expert Co., Duquesne Light, Environmental Consultants Inc., FirstEnergy Corp., Hazlett Tree Service, PECO Energy Company, PPL Electric Utilities, and UGI Utilities. Service foresters of the Pennsylvania Bureau of Forestry and extension urban foresters of Penn State University assisted with the measurements. LITERATURE CITED Fare, D.C., C.H. Gilliam, and H.G. Ponder. 1991. Fireblight susceptibility, growth and other characteristics in orna- mental pears in Alabama. Journal of Arboriculture 17: 257–260. Gerhold, H.D. 2000. Callery pear cultivars tested as street trees: Second report. Journal of Arboriculture 26:55–59. Gerhold, H.D., and H.L. McElroy. 1994. Callery pear culti- vars tested as street trees: Initial results. Journal of Arbo- riculture 20:259–261. Haserodt, H., and T.D. Sydnor. 1983. Growth habits of five cultivars of Pyrus calleryana. Journal of Arboriculture 9: 160–163. Kuser, J.E., G. Robinson, and N. Polarin. 2001. Four-year evaluation of five cultivars of Pyrus calleryana. Journal of Arboriculture 27:88–91. Society of Municipal Arborists. 2004. 2005 urban tree of the year, ‘Chanticleer’ pear. City Trees 40:34–38. Figure 2. Crown widths (m) of cultivars 6 to 12 years after planting. Ar = Aristocrat; CS = Cleveland Select; Rd = red- spire; AB = Autumn Blaze; CP = Cleveland Pride; Va = Valiant; Wh = Whitehouse. Henry D. Gerhold Professor of Forest Genetics School of Forest Resources Penn State University 333 Forest Resources Building University Park, PA 16801, U.S.
[email protected] ©2007 International Society of Arboriculture
March 2007
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