Categories of biophysical and human factors associated with mortality based on forty-one papers that provided sufficient information about mortality factors or mechanisms. Within each major category (biophysical or human), factors are listed in order of the frequency with which they appear in the mortality studies reviewed. Studies marked with an (*) used statistical analysis to quantitatively examine factors (see Appendix Table 3), while unmarked studies examined factors qualitatively (e.g., case studies or surveys of residents). Studies marked with a (‡) examined trees affected by a natural disturbance.
| Factor | Number of studies | Citations |
|---|---|---|
| Biophysical factors | ||
| Taxa (e.g., genus, species, cultivar) | 15 | Nowak 1986*; Miller and Miller 1991*; Hauer et al. 1993‡; Duryea et al. 1996*; Duryea 1997‡; Nowak et al. 2004*; Duryea et al. 2007*‡; Lu et al. 2010*; Jack-Scott 2012*; Lawrence et al. 2012*; Koeser et al. 2013*; Lima et al. 2013*; Koeser et al. 2014*; Roman et al. 2015; Boukili et al. 2017* |
| Size/age | 13 | Nowak 1986*; Polanin 1991*; Hauer et al. 1993; Duryea et al. 1996*‡; Nowak et al. 2004*; Duryea et al. 2007*‡; Jack-Scott et al. 2013*; Koeser et al. 2013*; Lima et al. 2013*; Roman et al. 2014a*; Roman et al. 2014b*; Ko et al. 2015a*; Morgenroth et al. 2017* |
| Site characteristics (e.g., planting space, site type, tree density) | 12 | Jim 2005*; Duryea et al. 2007*‡; Lu et al. 2010*; Staudhammer et al. 2011*; Lawrence et al. 2012; Koeser et al. 2013*; Lima et al. 2013*; Roman et al. 2014a*; Roman et al. 2014b*; Ko et al. 2015a*; Roman et al. 2015; Vogt et al. 2015a* |
| Condition/vigor/health | 6 | Nowak 1986*; Hickman et al. 1995*; Nowak et al. 2004*; Koeser et al. 2013*; Roman et al. 2014a*; Roman et al. 2015 |
| Planting season | 4 | Miller and Miller 1991*; Roman et al. 2014b*; Ko et al. 2015a*; Vogt et al. 2015a* |
| Nursery (e.g., source, stock, type, size) | 3 | Koeser et al. 2014*; Roman et al. 2015; Vogt et al. 2015* |
| Human factors | ||
| Stewardship, maintenance, vandalism | 15 | Sklar and Ames 1985; Nowak 1986*; Gilbertson and Bradshaw 1985; Struve et al. 1995; Duryea et al. 1996*‡; Sullivan 2005; Boyce 2010*; Lu et al. 2010*; Jack-Scott et al. 2013*; Koeser et al. 2014*; Richardson and Shackleton 2014; Roman et al. 2014b*; Ko et al. 2015a*; Roman et al. 2015; Vogt et al. 2015a* |
| Socioeconomic measures | 8 | Gilbertson and Bradshaw 1985; Nowak et al. 1990*; Lu et al. 2010*; Jack-Scott et al. 2013*; Lima et al. 2013*; Roman et al. 2014b*; Ko et al. 2015a*; Vogt et al. 2015a* |
| Land use | 6 | Nowak et al. 1990*; Nowak et al. 2004*; Jim 2005*; Lu et al. 2010*; Lawrence et al. 2012*; Steenberg et al. 2017* |
| Construction and redevelopment activity | 6 | Nowak 1986*; Miller and Miller 1991*; Hauer 1994*; Koeser et al. 2013*; Steenberg et al. 2017*; Morgenroth et al. 2017* |
| Infrastructure conflict (e.g., overhead utilities, sidewalks, transportation) | 5 | Nowak et al. 1990*; Nowak et al. 2004*; Lu et al. 2010*; Jack-Scott 2012*; van Doorn & McPherson 2018* |
| Landscaping norms and behavior | 2 | Kirkpatrick et al. 2013; Conway 2016 |