172 Kulhavy et al.: Comparison of Tree Condition and Value in Texas, U.S. Table 5. Comparison of center and edge tree condition between the SFASU campus and three city parks. Location Number of trees SFASU Campus Pioneer Park Pecan Park Maroney Park Center (n = 1705) Edge (n = 1630) Center (n = 191) Edge (n = 122) Center (n = 162) Edge (n = 117) Center (n = 160) Edge (n = 95) DISCUSSION Similar tree studies on the SFASU campus have been conducted previously. The initial study in 1971 was based on a portion of the campus and recorded 38 species (Nixon and Mims 1971), 30 species in 1992 (Creech et al. 1994), 37 species in 1994 study (Perkins 1996), and 30 species in 2008. Many of the trees lost or damaged in 1994 were located near new sidewalk construction and utility lines. Also, many of the species reported in 1994 were removed and not replaced. They included the native species Prunus caroliniana (cherry laurel) and the exotic species Ligustrum sp. (privet), Eu- calyptus camaldulensis var. camaldulensis (river red gum), E. ovata (swamp gum), E. robusta (swamp mahogany), E. camldulensis var. obtusa (river red gum), and Prunus mexicana (Mexican plum). For urban forest management, several aspects should be considered, including the desire and needs of the community, the urban forest structure, inven- tory and monitoring, and dialogue among own- ers, managers, and users (Dwyer et al. 2000). Trees dead or in poor condition should be considered for removal and replanting. Developing a management plan for these issues requires adopting an expanded set of goals incorporating environmental processes and conditions at a larger scale than the individual tree. One of the most important tree problems of both SFASU campus and city park trees was trunk decay, progressive deterioration of woody tissue in both living and dead trees (Nicholas and Crawford 2003). Wood decay in a living tree in the middle of a park could result in limb or trunk breakage dur- ing adverse weather. Trees with a low rating of trunk condition have a high rating of insect and disease. As trunk decay increases, as noted by missing bark and evident decay at the base or on the trunk, ©2014 International Society of Arboriculture Average tree condition (SD) 0.77 (0.21) 0.80 (0.18) 0.58 (0.13) 0.62 (0.15) 0.65 (0.14) 0.62 (0.18) 0.75 (0.12) 0.77 (0.13) care must be taken in further analysis of decay. Indicators of decay of branches, the trunk, and the root collar need to be carefully assessed for signs and symptoms of decay and pathogens. Indicators include fungal conks, cavities or openings, and car- penter ant (Camponotus spp.) nests (Luley 2012). Kane et al. (2001) and Kane and Ryan (2004) review strength loss and compare methods between esti- mation of loss as a function of stem hollow per- centage cautioning that deciding on hazardous and non-hazardous trees is complicated, and “Hazard tree assessment is an art as much as it is a science . . . It is better to approach hazard tree assessment as risk management” (Kane et al. 2001). Methods of searching for decay include use of the IML-RESIS- TOGRAPH® branches and calculate strength loss (Johnstone et al. 2007; Johnstone et al. 2010) and the PiCUS® to detect hollow areas of the trunk or Sonic Tomograph for quantification of decay (Gilbert and Smiley 2004). Pokorny (2003) presents urban tree risk assessment incorporating a tree risk man- agement plan (Hauer and Johnson 2003; Pokomy and Albers 2003) including risk inspections; and detection and assessment of hazardous defects in trees (Albers et al. 2003) including decay detec- tion devices benefits and limitations. Therefore, it is important to identify decay in the urban for- est and the care needs to be taken in the evaluation of the trees selected for removal. All defective trees cannot be detected, corrected, or eliminated. Root problems and internal defects are not easily discern- ible and inspections need to be made to determine change in the CTLA rating prompting additional management. Albers et al. (2003) stress seven cat- egories of defects for trees: decayed wood; cracks; root problems; weak branch unions; cankers; poor tree architecture; and dead trees, tops, and branches. P-value of t-test <0.0001 0.038 0.18 0.46 Better condition Edge tree Edge tree N/A N/A
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