在全球暖化及都市熱島日趨嚴重的情況下，廣植喬木不僅可以為都市降溫，其廣大冠層的遮蔽性也能夠提高人體熱舒適度。然而，回顧與喬木遮蔭程度相關的文獻及政策時發現，鮮少透過葉面積指數（Leaf Area Index，LAI）討論喬木對都市空間降溫的效益，或是提出兼具遮蔭與通風的種植建議。另外，發現臺灣目前缺乏對喬木遮蔭程度的評估方法與資料庫，對城市的綠覆率規範也缺乏思考立體綠化以及綠化降溫的概念。
本研究透過實測臺灣喬木的LAI建置喬木遮蔭程度檢索表，發展LAI簡易評估方法，並分析LAI與天空可視率（Sky View Factor，SVF）的關係。驗證確定喬木遮蔭微氣候實測數據與ENVI-met模擬結果之後，進行大量模擬以探討喬木遮蔭程度對人體熱舒適度的影響，提出兼具遮蔭降溫及通風散熱之設計建議。最終，建立綠色容積率（Green Plot Ratio，GPR）、喬木遮蔭率（Arbor Shading Ratio，ASR）以及基地綠化降溫評估公式（Greenery Cooling Capability，GCC）三項評估工具，分別可以評估基地的綠化量、遮蔭品質以及綠化降溫效益。
研究結果發現，高LAI的喬木可以為都市帶來良好的遮蔭降溫效果。隨著喬木的LAI從0.5-6.0，可以降低Tmrt 11.0-27.0°C ，PET 1.0-8.0°C。但需要留意種植LAI 4.0以上的喬木會對都市及人行風場造成屏蔽效應，使都市風場的風速降低1.0-1.5m/s，人行風場的風速降低0.5-1.0m/s。不過，根據模擬結果發現，當其以株距8米以上的方式種植時，就可以緩解風速降低的現象，使其同時具有遮蔭降溫及通風散熱的效果。
透過收集臺北市、臺中市以及高雄市綠覆率的檢討報告試算GPR及ASR，除了示範評估工具的使用方法同時也進行差異性分析。分析結果顯示：臺中市的綠化及遮蔭品質最佳，高雄市的GPR高於臺北市，但因為其綠化形式大部分是使用灌木及草皮，因此，ASR低於臺北市。最終，在計算GCC時發現，GPR及基地綠化體感降溫值（△SG-PET）之間存在良好的相關性。當GPR2.0時可以降低SG-PET 2.2°C，GPR3.0時則可以降低3.8°C，而當GPR高達4.0時，可以降低5.4°C。
欲實際落實基地高綠化量以創造更多都市綠化遮蔭及降溫的空間，需要透過政府及相關單位訂定相關政策規範。本研究的研究成果目前已經初步導入臺灣綠建築評估手冊-社區類以及臺北市新建建築物綠化實施規則中，望藉此可以緩解都市高溫問題並且增加城市綠化量之目標。

In response to global warming and worsening urban heat islands, extensive tree planting enhances human thermal comfort through shading. However, relevant literature and policies on tree shading lack comprehensive discussions on the impact of trees on urban cooling and design recommendations based on the Leaf Area Index (LAI). Additionally, Taiwan lacks assessment methods for evaluating tree shading levels, while urban green coverage regulations overlook three-dimensional greening.
This study addresses these gaps by establishing a shading index table and LAI assessment method through field measurements of common trees in Taiwan. It investigates the relationship between LAI and Sky View Factor (SVF). Through microclimate measurements and verification with ENVI-met simulation, this study explores the impact of trees on human thermal comfort, offering pertinent design recommendations. Ultimately, this study developed two assessment tools, Green Plot Ratio (GPR) and Greenery Cooling Capability (GCC), to evaluate greening quantity and cooling benefits.
The findings reveal that high LAI trees effectively provide shading and cooling in urban areas. For LAI ranging from 0.5 to 6.0, the PET can be reduced by 1.0 to 6.5°C. However, LAI exceeding 4.0 may decrease environmental wind speed by 1.0 to 1.5 m/s, but this effect can be mitigated by maintaining a planting distance of 6 to 8 meters. Notably, a strong relationship between GPR and △PET on-site (△SG-PET) was observed, with a GPR of 2.0 resulting in a 2.2°C in △SG-PET, and a GPR of 3.0 achieving a reduction of 3.2°C.

西文文獻
1. Armson, D., Asrafur Rahman, M., & Roland Ennos, A. (2013). A Comparison of the Shading Effectiveness of Five Different Street Tree Species in Manchester, UK. Arboriculture & Urban Forestry, 39(4), 157–164. https://doi.org/10.48044/jauf.2013.021
2. Aleksandra K. & Jeremy C. (2010). Adaptation to climate change using green and blue infrastructure - A database of case studies. The University of Manchester. https://orca.cardiff.ac.uk/id/eprint/64906/1/Database_Final_no_hyperlinks.pdf
3. Almeida, D.R.A.d., Stark, S. C., Shao, G., Schietti, J., Nelson, B. W., Silva, C. A., Gorgens, E. B., Valbuena, R., Papa, D.d.A. & Brancalion, P. H. S. (2019). Optimizing the Remote Detection of Tropical Rainforest Structure with Airborne Lidar: Leaf Area Profile Sensitivity to Pulse Density and Spatial Sampling. Remote Sensing. 11, 92, doi:10.3390/rs11010092
4. Andrew Speak, Leonardo Montagnani, Camilla Wellstein & Stefan Zerbe (2020). The influence of tree traits on urban ground surface shade cooling. Landscape and Urban Planning. 197. 103748. https://doi.org/10.1016/j.landurbplan.2020.103748.
5. Asef, S. M., Tolba, O. & Fahmy, A. (2020). THE EFFECT OF LEAF AREA INDEX AND LEAF AREA DENSITY ON URBAN MICROCLIMATE. Journal of Engineering and Applied Science. 67(2). 427-446.
6. Brown, R. D. & Gillespie, T. J. (1995). Microclimate Landscape Design: Creating Thermal Comfort and Energy Efficiency (1st ed.) . USA: John Wiley & Sons.
7. Broadhead, J. S., Muxworthy, A. R., Ong, C. K. & Black, C. K. (2003). Comparison of methods for determining leaf area in tree rows. Agricultural and Forest Meteorology, 115(3-4), 151-161. https://doi.org/10.1016/S0168-1923(02)00212-5
8. Chicco, D., Warrens, M. J., & Jurman, G. (2021). The coefficient of determination R-squared is more informative than SMAPE, MAE, MAPE, MSE and RMSE in regression analysis evaluation. PeerJ. Computer science, 7, e623. https://doi.org/10.7717/peerj-cs.623
9. Daranee Jareemit & Manat Srivanit. (2022). A Comparative Study of Cooling Performance and Thermal Comfort under Street Market Shades and Tree Canopies in Tropical Savanna Climate. Sustainability, 14(8), 4653. https://doi.org/10.3390/su14084653
10. De Abreu-Harbich, L. V., Labaki, L. C. & Matzarakis, A. (2015). Effect of tree planting design and tree species on human thermal comfort in the tropics, Landscape and Urban Planning, 138, 99-109. http://dx.doi.org/10.1016/j.landurbplan.2015.02.008
11. Dissegna, M.A., Yin, T., Wu, H., Lauret, N., Wei, S., Gastellu-Etchegorry, J.-P. & Grêt-Regamey. A. (2021). Modeling Mean Radiant Temperature Distribution in Urban Landscapes Using DART. Remote Sensing. 13(8), 1443. https://doi.org/10.3390/rs13081443
12. Dong, N., Luo M., Liu, Z., Sun, J. Y., Wu, K. L. & Lin, H. (2022). The roles of leaf area index and albedo in vegetation induced temperature changes across China using modelling and observations. Climate Dynamics, 58, 2557-2573.10.1007/s00382-021-06028-9
13. Fahmy, M., El-Hady, H. & Mahdy, M. M. (2016). LAI and Albedo Measurements Based Methodology for Numerical Simulation of Urban Tree's Microclimate: A Case Study in Egypt. International Journal of Scientific & Engineering Research, 7(9), 790-797.
14. Forest for All NYC. NYC Urban Forest Agenda. Retrieved from : https://forestforall.nyc/nyc-urban-forest-agenda/ (May. 06, 2024)
15. Iñigo A., Juan Ángel Acero, Leire G. & Eduardo Rojí (2021). Tree layout methodology for shading pedestrian zones: Thermal comfort study in Bilbao (Northern Iberian Peninsula). Sustainable Cities and Society, 72, 102996, ISSN 2210-6707, https://doi.org/10.1016/j.scs.2021.102996.
16. Konarska, J., Lindberg, F., Larsson, A., Thorsson, S. & Holmer, B. (2013). Transmissivity of solar radiation through crowns of single urban trees—application for outdoor thermal comfort modelling. Theoretical And Applied Climatology. 117, 363–376 10.1007/s00704-013-1000-3
17. Knerl, A., Anthony, B., Serra, S., & Musacchi, S. (2018). Optimization of Leaf Area Estimation in a High-Density Apple Orchard Using Hemispherical Photography. HortScience horts, 53(6), 799-804. https://doi.org/10.21273/HORTSCI12969-18
18. Kamoske, A. G., Dahlin, K. M., Stark, S. C. & Serbin, S. P. (2019). Leaf area density from airborne LiDAR: Comparing sensors and resolutions in a temperate broadleaf forest ecosystem. Forest Ecology and Management, 433, 364-375. 10.1016/j.foreco.2018.11.017
19. Lalic, B., & Mihailovic, D. T. (2004). An Empirical Relation Describing Leaf-Area Density inside the Forest for Environmental Modeling. Journal of Applied Meteorology, 43(4), 641-645. https://doi.org/10.1175/1520-0450(2004)043<0641:AERDLD>2.0.CO;2
20. Larsen, D. (2020). Maximum crown width to diameter relationships. available from : http://oak.snr.missouri.edu/silviculture/mosilviculture/maxcw.html.
21. Lin, T. P., & Matzarakis, A. (2008). Tourism climate and thermal comfort in Sun Moon Lake, Taiwan. International journal of biometeorology, 52(4), 281–290. https://doi.org/10.1007/s00484-007-0122-7
22. Lin, B., & Lin, Y. (2010). Cooling Effect of Shade Trees with Different Characteristics in a Subtropical Urban Park. HortScience horts, 45(1), 83-86. https://doi.org/10.21273/HORTSCI.45.1.83
23. Urban Redevelopment Authority. (2017). Landscaping for Urban Spaces and High-Rises (LUSH) Programme: LUSH 3.0. Singapore.
24. Urban Redevelopment Authority. Landscaping for Urban Spaces and High-Rises (LUSH). Retrieved from : https://www.ura.gov.sg/Corporate/Guidelines/Development-Control/Non-Residential/SR/Greenery (May. 06, 2024)
25. Lin, Z. S., Guldmann, J. M., Liu, Z. X. & Zhao, L. H. (2018). Influence of Trees on the Outdoor Thermal Environment in Subropical Areas: An Experimental Study in Guang Zhou, China. Sustainable Cities and Society, 42, 482-497. 10.1016/j.scs.2018.07.025
26. Lin, Z. S., Guldmann, J. M., Liu, Z. X., Zhao, L. I., Wang, J. S., Pan, X. L. & Zhao, D. F. (2020). Predicting the influence of subtropical trees on urban wind through wind tunnel tests and numerical simulations. Sustainable Cities and Society, 57(4). https://doi.org/10.1016/j.scs.2020.102116.
27. Springer Nature Pte Ltd. (2022). Outdoor Thermal Comfort in Urban Environment: Assessments and Applications in Urban Planning and Design. Singapore: Lau, K. L., Tan, Z., Morakinyo, E. & Ren, C. https://doi.org/10.1007/978-981-16-5245-5
28. Li, L., Zou, Z., Zhou, T., Zhou, X., & Li, Q. (2022). Simulation and Analysis of Influencing Factors of Pavement Thermal Environments in Guangzhou. Sustainability. 14(12). https://doi.org/10.3390/su14127251
29. Lim H. W., Jo S. M. & Park S. K. (2022). Analysis of Thermal Environment Modification Effects of Street Trees Depending on Planting Types and Street Directions in Summertime Using ENVI-Met Simulation. J Korean Inst Landsc Archit, 50(2),1-22. https://doi.org/10.9715/KILA.2022.50.2.001
30. Li, W., Wu, J., Xu, W., Zhong, Y. & Wang, Z. (2022). How Thermal Perceptual Schema Mediates Landscape Quality Evaluation and Activity Willingness. Int. J. Environ. Res. Public Health, 19, 13681. https://doi.org/10.3390/ijerph192013681
31. Matzarakis A., Rutz F. & Mayer H. (2007). Modelling Radiation fluxes in simple and complex environments- Application of the RayMan model. Int J Biometeorol. 51:323–334
32. Meteorological Institute. Rayman. Retrieved from : https://www.urbanclimate.net/rayman/index.htm (May. 06, 2024)
33. METER Group. The researcher's complete guide to Leaf Area Index (LAI). Retrieved from : https://metergroup.com/education-guides/the-researchers-complete-guide-to-leaf-area-index-lai/ (May. 06, 2024)
34. Mohr, M., Jayawardena, W., Arnqvist, J. & Bergström, H. (2014, March). Wind energy estimation over forest canopies using WRF mesoscale model. EWEA 2014 : Barcelona, Spain: Europe’s Premier Wind Energy Event. Presented at the European Wind Energy Association, EWEA 2014, Barcelona, Spain. Retrieved from : https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-241263.
35. Morakinyo, E. & Lam, Y. F. (2016). Simulation study on the impact of tree-configuration, planting pattern and wind condition on street-canyon's micro-climate and thermal comfort. Building and Environment, 103, 262-275. 10.1016/j.buildenv.2016.04.025
36. M M Fadhlurrahman & N Nasrullah (2020). Study of Thermal Comfort under The Shade of Varied Tree Canopy Form and Distance from The Stem. IOP Conference Series: Earth and Environmental Science, 501. 012048. 10.1088/1755-1315/501/1/012048
37. Melnikov, V. R., Christopoulos, G. I., Krzhizhanovskaya, V. V., Lees, M. H., & Sloot, P. M. A. (2022). Behavioural thermal regulation explains pedestrian path choices in hot urban environments. Scientific reports, 12(1), 2441. https://doi.org/10.1038/s41598-022-06383-5
38. Melnikov, V. R., Krzhizhanovskaya, V. V., Lees, M. H., Sloot, P. M. A. (2020). The impact of pace of life on pedestrian heat stress: A computational modelling approach. Environmental Research, 186. https://doi.org/10.1016/j.envres.2020.109397
39. Meili, N., Manoli, G., Burlando, P., Carmeliet, J., Chow, W. T. L., Coutts, A. M., Roth, M., Velasco, E., Vivoni, E. R. & Fatichi, S. (2021). Tree effects on urban microclimate: Diurnal, seasonal, and climatic temperature differences explained by separating radiation, evapotranspiration, and roughness effects. Urban Forestry & Urban Greening, 58. https://doi.org/10.1016/j.ufug.2020.126970
40. Ossola, A., G. Darrel Jenerette, McGrath, A., Chow, W., Hughes, L. & R. Leishman, M. (2021). Small vegetated patches greatly reduce urban surface temperature during a summer heatwave in Adelaide, Australia, Landscape and Urban Planning, 209. https://doi.org/10.1016/j.landurbplan.2021.104046
41. Pomeroy J. W., Gray D. M. , Hedström N. R. & Janowich J. R. (2002, June). Physically Based Estimation of Seasonal Snow Accumulation in the Boreal Forest. 59th Eastern Snow Conference, Stowe, Vermont USA.
42. Peeters, A., Shashua-Bar, L., Meir, S., Shmulevich, R. R., Caspi, Y., Weyl, M., Motzafi-Haller, W. & Angel, N. (2020). A decision support tool for calculating effective shading in urban streets. Urban Climate, 34. https://doi.org/10.1016/j.uclim.2020.100672
43. Rasmus, S., Gustafsson, D., Koivusalo, H., Laurén, A., Grelle, A., Kauppinen, O. K., Lagnvall, O., Lindroth, A., Rasmus, K., Svensson, M. & Weslien, P. (2012). Estimation of winter leaf area index and sky view fraction for snow modelling in boreal coniferous forests: Consequences on snow mass and energy balance. Hydrological Processes, 27(20), 2876-2891. 10.1002/hyp.9432
44. Ratnayake, Chanodi & Perera, Narein & Emmanuel, R. (2022). Street Tree Planting Patterns to Modify the Sky View Factor for Outdoor Thermal Comfort Enhancement. FARU Journal. 9. 1. 10.4038/faruj.v9i2.167.
45. Jo, Sangman & Park, Sookuk. (2023). Shading Effect of Single Trees on the Human Thermal Sensation During Summer: A Case Study in Jeju, Republic of Korea. Available at SSRN: https://ssrn.com/abstract=4605269 or http://dx.doi.org/10.2139/ssrn.4605269
46. Samain S., Maryam K., Rouzbeh N., Joshua P. & Joshua B. (2021). Effects of Different Urban-Vegetation Morphology on the Canopy-level Thermal Comfort and the Cooling Benefits of Shade Trees: Case-study in Philadelphia. Sustainable Cities and Society, 66, 102684, ISSN 2210-6707, https://doi.org/10.1016/j.scs.2020.102684.
47. Senlin Zheng, Jean-Michel Guldmannb, Zhixin L. & Lihua Z. (2018). Influence of trees on the outdoor thermal environment in subtropical areas: T An experimental study in Guangzhou, China. Sustainable Cities and Society, 42, 482-497, https://doi.org/10.1016/j.scs.2018.07.025
48. Shahidan, M. F., Shariff, M. K. M., Jones, P., Salleh, E. & Abdullah, A. M. (2010). A comparison of Mesua ferrea L. and Hura crepitans L. for shade creation and radiation modification in improving thermal comfort. Landscape and Urban Planning, 97(3),168-181, 10.1016/j.landurbplan.2010.05.008
49. Shata, R. O., Mahmoud, A. H. & Fahmy, M. (2021). Correlating the Sky View Factor with the Pedestrian Thermal Environment in a Hot Arid University Campus Plaza. Sustainability, 13(2), 468. 10.3390/su13020468
50. Senate Department for Urban Mobility, Transport, Climate Action and the Environment, BAF – Biotope area factor, https://www.berlin.de/sen/uvk/en/nature-and-green/landscape-planning/baf-biotope-area-factor/. (Accessed 13 January 2024)
51. Teshnehdel, S., Akbari, H., Giuseppe, E. D. & Brown, R. D. (2020). Effect of tree cover and tree species on microclimate and pedestrian comfort in a residential district in Iran, Building and Environment, 178, 106899, 10.1016/j.buildenv.2020.106899
52. Toronto Cancer Prevention Coalition. (2010). Shade Guidelines. Canada.
53. Verseghy, D.L., McFarlane, N.A. & Lazare, M. (1993). Class—A Canadian land surface scheme for GCMS, II. Vegetation model and coupled runs. International Journal Climatology, 13(4), 347-370. https://doi.org/10.1002/joc.3370130402
54. Wong, N. H., Kwang Tan, A. Y., Chen, Y., Sekar, K., Tan, P. Y., Chan, D., Chiang, K. & Wong, N. C. (2010). Thermal evaluation of vertical greenery systems for building walls, Building and Environment, 45(3), 663-672. 10.1016/j.buildenv.2009.08.005
55. Wagner, J., Wildmann, N. & Gerz, T. (2019). Improving boundary layer flow simulations over complex terrain by applying a forest parameterization in WRF. Wind Energy Science Discussions, 10.5194/wes-2019-77
56. Wei, S. S., Yin, T. G., Dissegna, M. A., Whittle, A. J., OW, G. L. F., Yusof, M. L. M., Lauret, N. & Gastellu-Etchegorry, J. P. (2020). An assessment study of three indirect methods for estimating leaf area density and leaf area index of individual trees. Agricultural and Forest Meteorology. 292-293. 10.1016/j.agrformet.2020.108101
57. Wang, J., Guo, W., Wang, C. L., Yao, Y. F., Kou, K., Xian, D. Q. & Zhang, Y. T. (2021). Tree crown geometry and its performances on human thermal comfort adjustment. Journal of Urban Management, 10(1), 16-26. https://doi.org/10.1016/j.jum.2021.02.001
58. WOHA. Retrieved from : https://woha.net/project/sky-green-taichung/ (May. 06, 2024)
59. Works Branch Development Bureau Government Secretariat. (2012.06). Site Coverage of Greenery for Government Building Projects. Hong Kong.
60. Zhang, J. & Gou, Z. H. (2021).Tree crowns and their associated summertime microclimatic adjustment and thermal comfort improvement in urban parks in a subtropical city of China. Urban Forestry & Urban Greening, 59, 126912. https://doi.org/10.1016/j.ufug.2020.126912
61. Zhuang, Q. R. & Lu, Z. M. (2021). Optimization of Roof Greening Spatial Planning to Cool Down the Summer of the City, Sustainable Cities and Society, 74. 10.1016/j.scs.2021.103221

中文文獻
1. 應政華（2012）。葉面積指數對室外微氣候影響之調查研究（博碩士論文）。檢自：https://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22100NUUM0222002%22.&searchmode=basic
2. 董孟杰（2015）。都市綠園道戶外熱舒適評估之研究-以台中市為例（博碩士論文）。檢自：https://www.airitilibrary.com/Article/Detail/U0001-1208201515304000
3. 侯彥宇（2018）。於台灣中低海拔森林檢驗葉面積指數間接量測法的測量表現（博碩士論文）。檢自：https://www.airitilibrary.com/Article/Detail/U0021-G060443008S
4. 何明錦與黃國倉（2013）。臺灣建築能源模擬解析用逐時標準氣象資料TMY3之建置與研究。內政部建築研究所。
5. 農委會林務局（2017）。臺灣原生植物於園藝、景觀應用樹種名錄。臺灣。
6. 農業部林業及自然保育署。原來你最美林務局推106種園藝及景觀用臺灣森林植物。檢自：https://www.forest.gov.tw/0000013/0065373 （2024年5月）
7. 臺北市工務局公園路燈工程管理處。園藝小學堂 行道樹相關。檢自：https://pkl.gov.taipei/Content_List.aspx?n=CA83546177382B1C （2024年5月）
8. 臺北市工務局公園路燈工程管理處。臺北市公園、綠地、廣場及行道樹不再種植樹種種類。檢自：https://pkl.gov.taipei/cp.aspx?n=7400D752A0FBE09F （2024年5月）
9. 臺北市法規查詢系統。臺北市樹木移植作業規範。附錄三、樹木根系與挖掘根球部判定詳圖。檢自：https://www.laws.taipei.gov.tw/Law/LawSearch/LawInformation?sysNumber=P06H2007（2024年5月）
10. 內政部建築研究所。綠建築評估手冊-基本型（2023年版）。臺灣。
11. 臺北市政府（2016）。臺北市新建建築物綠化實施規則。臺灣。
12. 臺中市政府（2021）。臺中市鼓勵宜居建築設施設置及回饋辦法。臺灣
13. 臺中市政府（2022）。致力打造宜居城市！ 中市宜居建築3週年成果展今登場。檢自：https://www.taichung.gov.tw/2080258/post （2024年5月）
14. 高雄市政府（2023）。高雄市高雄厝設計及鼓勵回饋辦法。臺灣。
15. 高雄市政府工務局建築管理處。2019 高雄厝成果專輯-高雄厝 3.0 幸福建築計畫。檢自：https://build.kcg.gov.tw/index.aspx?au_id=41&sub_id=244&id=180369（2024年5月）
16. 內政部建築研究所。綠建築評估手冊-社區類（2019年版）。臺灣。
17. 中華人民共和國香港特別行政區政府發展局 - 綠化、園境及樹木管理組。檢自：https://www.greening.gov.hk/tc/home/index.html（2024年5月）
18. 林子平（2021）。都市的夏天為什麼愈來愈熱?:圖解都市熱島現象與退燒策略。臺北市：商周。
19. 李岳蓉（2024）。都市綠化之可及性評估及熱輻射降溫模式探討。國立成功大學建築學系，臺南市。
20. 天下雜誌。台北在悶燒！五大熱風險區都在哪？檢自：https://www.cw.com.tw/graphics/taipei-heat/（2024年5月）
21. 科協儀器股份有限公司。手持式葉面積指數測量儀 LaiPen。檢自：https://www.kohsieh.com.tw/ver4/newfile_357.htm（2024年5月）

日文文獻
1. 東京都環境局（2021年3月）。綠化計画の手引き書。日本。
2. 京都府（2004年4月）。緑化計画の手引き書。日本。