Description of exposure, sensitivity, and adaptive capacity indicators used to assess urban forest vulnerability and the direction of their assumed relationship with vulnerability, where a positive assumption means an increase in indicator value translates to an increase in vulnerability and a negative assumption means the opposite. Descriptive statistics are given for the 2014 data only, and where denoted by an asterisk (*), data represents the count of occurrences and percent of total measurements for the binary (0/1) indicators.
| Indicator description | Vulnerability assumption | Mean/Count*(standard deviation/percent*) |
|---|---|---|
| Exposure | ||
| Built environment | ||
| Population density (persons/km2) | Positive | 14,834 (±8,146) |
| Built area intensity (%) | Positive | 50.2 (±21.2) |
| Land usez (categorical) | ||
| Site type (categorical) | ||
| Site size (m2 of growing environment) | Negative | 136.7 (±383.4) |
| Type of nearest building (categorical) | ||
| Height of nearest building (storeys) | Negative | 4.1 (±4.5) |
| Distance to nearest building (m) | Negative | 6.7 (±14.2) |
| Distance to street (m) | Negative | 4.1 (±3.0) |
| Width of sidewalk (m) | Positive | 2.7 (±1.9) |
| Width of street (m) | Positive | 11.2 (±6.7) |
| Impervious cover (%) | Positive | 47.3 (±32.1) |
| Light availabilityy (ordinal rank; 0-5) | Negative | 2.7 (±1.1) |
| Conflicts | ||
| Conflict of overhead utilities (0/1)x | Positive | 416 (51.6)* |
| Conflict with sidewalk (0/1) | Positive | 76 (9.4)* |
| Conflict with buildings (0/1) | Positive | 259 (32.1)* |
| Conflict with building foundation (0/1) | Positive | 47 (5.8)* |
| Conflict with other infrastructure (0/1) | Positive | 294 (36.5)* |
| Social stressors | ||
| Poor management (0/1) | Positive | 172 (21.3)* |
| Vandalism (0/1) | Positive | 92 (11.4)* |
| Sensitivity | ||
| Species (categorical) | ||
| DBH class (categorical) | ||
| Tree condition index (Neighbourwoods)w | Positive | 0.30 (±0.17) |
| In-grown tree (0/1)x | Positive | 41 (5.1%)* |
| Adaptive capacity | ||
| Social adaptive capacity | ||
| Median family income ($) | Negative | 54,194 (±11,676) |
| Average dwelling value ($) | Negative | 734,451 (±152,682) |
| Homeownership (%) | Negative | 44.0 (±14.8) |
| Population with a university degree (individuals/10,000 people) | Negative | 4,313 (±1,130) |
| Signs of stewardship (0/1)v | Negative | 162 (20.1)* |
| Environmental adaptive capacity | ||
| Open green space (%) | Negative | 16.7 (±13.4) |
| Existing canopy cover (%) | Negative | 18.0 (±20.3) |
↵z Land-use designation is based on categories described in the i-Tree Eco v. 5.0 manual. Land uses present in Harbord Village include commercial/industrial, institutional, multi-unit residential, park, residential, and vacant.
↵y Light availability was measured using crown light exposure, which is a component of the i-Tree Eco measurement protocol.
↵x 0/1 measurement denotes a binary indicator, where 0 represents absence and 1 represents presence.
↵w An aggregate index that has a maximum value of 1.0 indicating extremely poor tree condition, which is based on the Neighbourwoods assessment protocol (Kenney and Puric-Mladenovic 2001).
↵v Signs of stewardship include direct and obvious actions taken to protect trees or enhance growth (e.g., mulch, bicycle guards, pest protection; Lu et al. 2010). 0/1 measurement denotes a binary indicator, where 0 represents absence and 1 represents presence.