124 self-assessed urban tree knowledge (χ2 = 4.105; P = 0.392) or in the number of tree-related workshops attended (t = -0.369; P = 0.712). However, respondents significantly differed from non- respondents in the importance of trees to them (78.9% high or very high importance versus 60.3%, respectively; χ2 = 15.021; P = 0.005) and in the proportion who had topped a tree (37% had topped versus 62% of nonrespondents; χ2 = 20.568; P < 0.001). In topping-related knowledge and attitudes, respondents were significantly more likely than nonrespondents to correctly respond to the statements: “Topping benefits a tree by letting in more light” (Disagree was the correct answer; χ2 P = 0.008), and “Topping decreases tree health” (Agree; χ2 = 7.052, = 6.795, P = 0.009), but were not significantly different in their response to “Fast growth after topping is a sign of good health” (χ2 ly more likely than nonrespondents to Disagree that “Topping improves a tree’s appearance” (χ2 = 3.369, P = 0.066). Finally, respondents were significant- = 5.302, P = 0.021), and to Agree that “Topping is destructive, and should not be done” (χ2 = 3.514, P = 0.019). Note that only respondents who did not receive a brochure were used in these topping statement com- parisons because those who were phoned did not receive the bro- chure, which also included negative information about topping. These differences between respondents and nonrespon- dents should be taken into account when considering the applicability of the findings to the overall population of those six cities. In particular, it appears that respondents are much less likely to have topped trees than the general pub- lic in these cities, a point that seems particularly relevant to this paper’s discussion of topping knowledge and practice. Tree and Tree Care Knowledge Responses to the seven statements about tree fertilization, plant- ing, roots, and pruning (agreement or disagreement with the seven tree/tree care statements listed in the methods) are sum- marized in Figure 1. Among the seven statements, “do not know” responses ranged from 15 to 33%. One statement was answered correctly by the majority of respondents – 80% knew that tree roots need oxygen to survive (Figure 1). Most respon- dents were incorrect in their answers to the other six statements. The greatest misconception had to do with fertilization termi- nology – 92% of respondents incorrectly believed that fertilizing trees “feeds” them (Figure 1). This response was understandable, since professionals often refer to fertilization as “feeding” and Kuhns and Reiter: Tree Care and Topping Beliefs have so since the 1920s (Struve 2002). A Google internet search for the terms “tree feeding” performed by the authors in August 2008 yielded many commercial mentions of fertilization as feed- ing, and the second highest hit was a noncommercial 2004 news release from Kansas State University Research and Extension (Ward 2004) titled “Tree-feeding time a dormant matter,” which used the terms “feeding” and “meal” in describing fertilization. In another statement related to fertilization, 61% of respon- dents incorrectly agreed that fertilization is usually needed to keep trees healthy (Figure 1). Researchers, arborists, and urban foresters certainly disagree about whether fertilization is need- ed for tree health (Struve 2002; Ferrini and Baietto 2006). The American National Standards Institute (ANSI) A300 tree fer- tilization standard states that the reason for fertilization should be “to supply nutrients determined to be deficient to achieve a clearly defined plant management objective” (ANSI 2004). How- ever, what constitutes an acceptable plant management objec- tive or a deficiency is not defined. This ambiguity, coupled with marketing of routine fertilization by some businesses (based on timing rather than a measured deficiency), might explain confusion amongst both professionals and nonprofessionals. A majority of respondents were also incorrect about root depth, with 41% correctly agreeing that most tree roots are fairly shallow (Figure 1). The International Society of Arboriculture’s “Trees Are Good” public outreach program makes progress to- ward countering this misconception with an educational mes- sage that emphasizes the shallowness of tree root systems and the futility of deep root fertilization (ISA 2007). Belief in deep roots was perhaps reflected in the incorrect belief by a majority of respondents (53%) that trees should be planted deeper than they were grown in the nursery (Figure 1). Some confusion may be due to the prevalence of deep root collars in nursery stock, but recent research on the effects of these problems and efforts to correct them during production may help end this confusion and clarify the message that root collars need to be at or near the soil surface (Watson and Hewitt 2006; Arnold et al. 2007). Less than a majority of respondents (43%) correctly agreed that root ball packing materials should be removed when trees are transplanted (Figure 1). It seems that most arboricultural pro- fessionals would agree that twine tied around trunks and con- tainers should be removed. Yet disagreement remains amongst professionals about removal of wire baskets and burlap. The au- thors of the survey have encountered retail nurseries that void their warranty if packing materials are removed. Appleton and Floyd (2004) showed a clear consensus amongst researchers that most wire baskets should be removed or heavily altered at planting time. She also noted, however, that some growers were recommending that baskets be left in place. Burlap removal recommendations range from remove-none to remove-all, with little research to back-up those recommendations (Kuhns 1997). Finally, almost three-quarters (73%) of respondents agreed Figure 1. Percentage of respondents correctly answering ques- tions on tree and tree care (correctly agreeing or disagreeing with statements) (T = True, F = False). ©2009 International Society of Arboriculture that large-growing trees can be kept smaller by pruning without harm (a response judged as incorrect) (Figure 1). Uncertainty was high however, as more checked Do Not Know for this state- ment than for any other (33%). Once again, there also appears to be considerable disagreement amongst professionals with these ideas or at least with the terminology (Harris 1994; Ryan 1994). These results match well with respondents’ self-assessed ratings of their knowledge about urban trees and their care, which was rated fairly low with 56% of respondents rating
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