108 Lu et al: Modeling the Shading Effect of Vancouver’s Urban Tree Canopy current shading impact on heat mitigation (Wong et al. 2010). Thirdly, current results were expressed in solar irradiance (e.g., kWh). Given the reduced solar exposure, it would also be beneficial to estimate the potential outdoor and indoor temperature differences by utilizing microclimate models. Lastly, the newest ALS acquired by the City of Vancouver during peak summer conditions (currently unreleased at the time of this project) can also improve the accuracy of can- opy cover density measures and include smaller trees and tree species information that was previously omitted (the True Positive rate of ALS crown detec- tion is 76.6%, Matasci et al. 2018). CONCLUSION Urban canopy, when implemented appropriately, can become an effective shading agent for the built envi- ronment, in particular for streets and building façades. This work integrated remotely sensed ALS point clouds with a Radiance daylight simulation engine (Honey- bee) to simulate the potential shading impact of urban canopies on Vancouver’s streets, building roofs, and façades. The results indicated that street surfaces received the most solar irradiance reduction compared to roofs and façades. Neighborhoods with less density and lower-rise buildings were shaded noticeably better than areas with higher density. Among Vancouver’s 22 local neighborhoods, Kitsilano and West End demonstrated a promising sign where both building density/height and canopy shading can be relatively high at the same time. This work not only generated a detailed citywide simulation on existing shading con- ditions for over 200,000 trees in Vancouver but also offered useful insights to planners and builders for implementing innovative urban green infrastructures such as green roofs and vertical greeneries. One key future research direction is that one should evaluate how a changing climate will impact the health of existing and/or future urban trees as well as the need for cooler streets and internal environments in extreme hot summer days. LITERATURE CITED Akbari H, Davis S, Dorsano S, Huang J, Winnett S. 1992. Cooling our communities: A guidebook on tree planting and light-colored surfacing. Washington (DC, USA): US Environmental Pro- tection Agency. 264 p. Akbari H, Taha H. 1992. The impact of trees and white surfaces on residential heating and cooling energy use in four Canadian cities. Energy. 17(2):141-149. https://doi.org/10.1016/0360 -5442(92)90063-6 ©2022 International Society of Arboriculture Aksamija A. 2018. Methods for integrating parametric design with building performance analysis. EAAE/ARCC International 2018 Conference; 2018 May 16–18; Philadelphia, PA, USA. ARCC Conference Repository. https://www.arcc-journal.org/ index.php/repository/article/view/459 Alexandri E, Jones P. 2008. Temperature decreases in an urban canyon due to green walls and green roofs in diverse climates. Building and Environment. 43(4):480-493. https://doi.org/10 .1016/j.buildenv.2006.10.055 Aminipouri M, Rayner D, Lindberg F, Thorsson S, Knudby AJ, Zickfeld K, Middel A, Krayenhoff ES. 2019. Urban tree planting to maintain outdoor thermal comfort under climate change: The case of Vancouver’s local climate zones. Build- ing and Environment. 158:226-236. https://doi.org/10.1016/j .buildenv.2019.05.022 BC Assessment. 2021. Check your property with assessment search and compare it to others. [Accessed 2019 December 20]. https://www.bcassessment.ca BC Hydro. 2018. Cold comfort: The rising use (and cost) of air conditioning in B.C. Vancouver (BC, Canada): BC Hydro Power Smart. BCH18-712. https://www.bchydro.com/content/ dam/BCHydro/customer-portal/documents/news-and-features/ air-conditioning-report-july-2018.pdf Berry R, Livesley SJ, Aye L. 2013. Tree canopy shade impacts on solar irradiance received by building walls and their surface temperature. Building and Environment. 69:91-100. https:// doi.org/10.1016/j.buildenv.2013.07.009 Bowler DE, Buyung-Ali L, Knight TM, Pullin AS. 2010. Urban greening to cool towns and cities: A systematic review of the empirical evidence. Landscape and Urban Planning. 97(3): 147-155. https://doi.org/10.1016/j.landurbplan.2010.05.006 Chance CM, Coops NC, Plowright AA, Tooke TR, Christen A, Aven N. 2016. Invasive shrub mapping in an urban environ- ment from hyperspectral and LiDAR-derived attributes. Frontiers in Plant Science. 7:1528. https://doi.org/10.3389/ fpls.2016.01528 City of Vancouver Open Data Portal. 2013. LiDAR 2013. [Accessed 2021 May 27]. https://opendata.vancouver.ca/ explore/dataset/lidar-2013/information Czekajlo A, Coops NC, Wulder MA, Hermosilla T, Lu Y, White JC, van den Bosch M. 2020. The urban greenness score: A satellite-based metric for multi-decadal characterization of urban land dynamics. International Journal of Applied Earth Observation and Geoinformation. 93:102210. https://doi.org/ 10.1016/j.jag.2020.102210 EnergyPlus. 2016. Weather data for simulation. Washington (DC, USA): US Department of Energy Building Technologies Office, National Renewable Energy Laboratory. [Accessed 2021 May 27]. https://energyplus.net/weather/simulation Environment and Climate Change Canada. 2021. Temperature— Monthly data for Vancouver. Vancouver (BC, Canada): Envi- ronment and Climate Change Canada. [Accessed 2021 May 27]. https://vancouver.weatherstats.ca/charts/temperature-monthly .html Erlwein S, Pauleit S. 2021. Trade-offs between urban green space and densification: Balancing outdoor thermal comfort, mobil- ity, and housing demand. Urban Planning. 6(1):5-19. https:// doi.org/10.17645/up.v6i1.3481
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