2026-08-25 カナダ・ブリティッシュコロンビア大学(UBC)
＜関連情報＞
- https://news.ubc.ca/2026/08/new-tool-helps-cities-plant-trees-where-theyre-needed-most/
- https://www.sciencedirect.com/science/article/pii/S1618866725003267
樹冠から快適性へ：半乾燥都市における住宅地の景観選択が熱力学に与える影響 From canopy to comfort: The impact of residential landscape choices on thermal dynamics in a semi-arid city
Aubrey Benson, Bianca N.I. Eskelson, Travis Warziniack, Melissa R. McHale
Urban Forestry & Urban Greening Available online: 5 August 2025
DOI:https://doi.org/10.1016/j.ufug.2025.128992
Highlights
- Linear relationship: ∼1°C drop in mean radiant temperature per 10 % increase in yard canopy cover.
- Xeriscapes show ∼1.5°C warmer morning air temperature than grass lawns.
- Afternoon yard temperatures show no consistent pattern by cardinal orientation.
Abstract
Extreme summertime heat, intensified by climate change and urbanization, is the leading weather-related cause of mortality in the USA. Cities are increasingly turning to urban forests for heat mitigation, yet the complex relationship between urban ecosystem structure and cooling remains largely uninterrogated, leaving land managers uncertain about how to optimize ecosystem services and minimize disservices. This study examined hyper-local cooling mechanisms in residential landscapes in a semi-arid Colorado, USA city, using data from thirty-two front yards varying by cardinal orientation, ground cover (grass lawns vs. xeriscapes), and canopy cover (0–100 %). Using a mobile biometeorology unit, we measured mean radiant temperature, air temperature, and actual vapor pressure. We found a linear decrease in mean radiant temperature of approximately 1 °C for every 10 % increase in canopy cover at the sub-parcel scale. Xeriscapes were approximately 1.5 °C warmer in morning air temperature than grass lawns. Cardinal orientation effects were inconclusive, questioning the common assumption that trees provide the greatest cooling benefits on the west side of buildings. Findings emphasize the need for context-specific land management recommendations and offer a foundation for further research on how urban structure shapes microclimates at human-relevant scales.
