Table 5.

Characteristics of Trees in the Urban Forest (T). Second-, third-, and fourth-tier variables relating to (T), one of the five core first-tier factors in the UFSES framework. Abbreviations in the “Other UF frameworks” column correspond to shorthand citation keys for frameworks described in Table 2. Notes for Table 3 through Table 9 appear in Appendix D. UFSES (urban forest social-ecological system); UF (urban forest); DBH (diameter at breast height).

NumberSecond-tier variableThird-a and fourth-tierb variable(s)Description and possible valuesOther UF frameworks
T1Tree taxonomyFamily, genus, species, cultivar; native/nonnative/invasive; seed sourcebTaxonomy influences tree form, size-at-maturity, average growth rate, drought/flood tolerance, nutrient requirements, pest vulnerabilities, climate change vulnerability, etc. (Note 18).SUS, SES1, CC, VULN, MORT
T1-1Tree traitsaTree traits are nested within T1. Tree taxonomy as traits are directly connected to the species/cultivar of a tree.
T1-1aTree typebDeciduous, coniferous, evergreen, fruit trees, palms, etc.
T1-1bStature/expected size-at-maturitybLarge, medium, small, ornamental, etc.
T1-1cTree form/growth habitbExcurrent, decurrent, columnar, etc.
T1-1dDrought or flood tolerancebHow well a tree is expected to be able to withstand periods of low or no rainfall/water or excessive moisture during periods of flooding; connected to tree species and cultivar.
T2At-planting parametersPlanting packaging type/size, nursery of origin, size/age of tree at time of planting, planting season, etc.bLegacy effects of nursery growing conditions impact tree outcomes during the establishment phase, 3 to 5 years post-transplanting, especially; less relevant for larger, mature trees, unless the tree is planted improperly or the planting packaging is left on (Notes 18, 19).SES1, MORT
T3Current tree sizeDBH, caliper, total height of tree, width of crown, proportion of tree in live crown, etc.bImpacts the provision of benefits, likelihood of survival, risk assessment, etc. (Note 18).SES1, VULN, MORT
T4Canopy conditionCrown dieback, crown exposure to light, leaf density, leaf condition such as presence and degree of chlorosis, canopy pest presence, etc.bCanopy condition affects tree health/vigor and the level of urban forest benefits (Note 18).SES1, VULN, MORT
T5Trunk conditionPresence of a root flare, damage to lower trunk, trunk pest presence, etc.bTrunk condition affects tree health/vigor and overall condition; extensive damage to the trunk can be a contributing factor to tree mortality (Note 18).SES1, MORT
T6Overall tree conditionEvidence of other damage to tree, overall good-fair-poor or numeric condition rating, hazard rating, etc.bOverall assessment of condition affects tree health/vigor, vulnerability to pests and diseases, etc. (Note 18).SES1, MORT
T7Tree ageDate of planting, years (or days) since planting, number of growth rings, estimated agebCalculated or estimated age from size or from known planting date or from number of growth rings (Note 18).SES1, MORT
  • a Third-tier variable(s).

  • b Fourth-tier variable(s).