Summary of future planting scenario rules, including mortality rates, rates of replacement and additional trees, species lists and mixes, as well as the general placement of additional trees. “Aged-out trees” refers to trees removed between baseline and future scenarios. “Replacement trees” are new trees provided to future scenarios in place of aged-out trees. “Additional trees” are new trees that are provided to the future models to achieve scenario and location-based tree counts. CA (climate-adapted); L (large); M (medium); m (metre); S (small); SE (southeast); SW (southwest).
| Attribute | Location | S1 2050: Existing policy | S2 2050: Existing policy + CA trees | S3 2050: Target building shading | S4 2050: Maximize tree canopy |
|---|---|---|---|---|---|
| Mortality rate (annual)a | Street | 2.6% | 2.1% | 1.6% | |
| Park/civic | 2.2% | 1.7% | 1.2% | ||
| Private | 4.6% | 4.1% | 3.6% | ||
| Replacement tree rate | 1:1 ratio of replacement to aged-out trees; 2:1 ratio of replacement to aged-out trees for small trees on developed parcels | ||||
| Additional tree rate | Street | 150% of area-based planting rate (City of Vancouver and Vancouver Park Board 2018) Same as S1-3 for regular parks; maximized canopy cover for partially forested parks | Doubled the planting rate of S1-3 | ||
| Park/civic | Same as S1-3 for regular parks; maximized canopy cover for partially forested parks | ||||
| Private | 80% parcels with ≥ 1 tree; developed parcels followed city bylawb | 100% parcels with ≥ 2 trees; same as S1-3 for developed parcels | |||
| Species list | All | City of Vancouver tree list (City of Vancouver 2011) | Metro Vancouver CA tree list (Diamond Head Consulting 2019) | Same as S2 and S3; 2nd rows of select species for blue-green streetsc | |
| Species mix | All | 30% per family, 20% per genus, 10% per speciesd | |||
| Tree size proportions | Street | 21% L, 37% M, 42% S (about the same as baseline 2020) | Same as S1-3; 42% L, 58% M for blue-green streets | ||
| Park/civic | 45% L, 50% M, 5% S | Same as S1-3; 50% L, 50% M for partially forested parks | |||
| Private | 2% L, 48% M, 50% S | 2% L, 54% M, 44% S | |||
| General placement of additional trees | Street | Prioritized streets with low existing tree cover (i.e., < 6 trees per 100 m) or adjacent to the parcel with school (civic land use) | Filled gaps on streets; added 2nd tree rows for blue-green streets; prioritized streets with < 8 trees per 100 m | ||
| Park/civic | Ring of trees around parcel boundary | Ring of trees around parcel boundary; groups of > 5 trees | Same as S2-3; infilled for partially forested parks | ||
| Private | Randomly distributed | At least 1 new deciduous tree placed at SW corner of principal building | At least 2 new deciduous trees placed at SW and SE corners of principal building | ||
| Spacing requirements | Street | 11 m for L, 10 m for M, 9.5 m for S | Same as S1-3; 10 m for L, 9.5 m for M, 9 m for S in same row for blue-green streets | ||
| Park/civic | 1.5 m from buildings; no planting on sport fields; 4 m spacing and closer to the center (away from streets) for conifers | ||||
| Private | 1.5 m from buildings; 2.5 m from any other tree | ||||
↵a S1 mortality rates were based on the higher median annual mortality rates per planting location as reported in Hilbert et al. (2018). For S2-3, we deducted 0.5% from S1 mortality rates to reflect the policy changes that would provide better tree planting and tree care. For S4, another 0.5% was deducted (1% deduction from S1) per planting location to show maximum level of tree planting and tree care.
↵b Protection of Trees Bylaw 9958 (City of Vancouver 2010): the current requirements on the number of trees per site is specified in Schedule C of the Protection of Trees Bylaw by the City of Vancouver. A higher number of trees are required for a larger site, and the minimum requirement is 2 trees per site (for sites that are no larger than 365 m2). Trees were applied as per bylaw up to allowable space.
↵c Blue-green streets include trees and other green infrastructure designed to manage water cycles (e.g., water quality and flood risk management), enhance access to urban green space, and provide other ecosystem services, such as heat mitigation and air quality improvement (City of Vancouver 2023a).
↵d Based on the ‘10-20-30’ rule for tree diversity presented by Santamour (1990).