(Re)Designing Urban Parks to Maximize Urban Heat Island Mitigation by Natural Means

Abstract

Urban trees play a key role in mitigating urban heat by cooling the local environment. However, the cooling benefit that trees can provide is influenced by differences in species traits and site-specific environmental conditions. Fifteen dominant urban tree species in parks from Mexico City were selected considering physiological traits (i.e., transpiration and stomatal conductance) and aesthetic and morphological characteristics. Species’ physiological performance was measured to explore the potential of trees to reduce urban heat load. Data were collected over a 4-week period in the months of April and May 2020, the warmest and driest months of the year in Mexico City. We used the Thermal UrbaN Environment Energy (TUNEE) balance model to calculate the cooling benefit of each species and the number of individuals necessary to reduce local air temperature. The highest midday transpiration was registered for Liquidambar styraciflua L. (0.0357 g m−2 s−1) and the lowest for Buddleja cordata H.B.K (0.0089 g m−2 s−1), representing an energy consumption and cooling potential of 87.13 and 21.69 J m−2 s−1, respectively. Similarly, the highest stomatal conductance was recorded for L. styraciflua., whereas the lowest was recorded for B. cordata. Based on the species transpiration rates and aesthetic characteristics, we developed a proposal and outline for a 50 × 50 m urban park (i.e., park community) consisting of six species with 19 individuals, and according to the TUNEE model, the proposed arrangement can reduce air temperature up to 5.3 °C. Our results can help urban planners to (re)design urban parks to mitigate urban heat while increasing urban tree diversity in parks.

The Thermal Effect of Various Local Park Settings: A Simulation-Based Case Study of Sunshine Coast, Australia

“…Regardless of the local park settings, all the parks reduced the urban heat intensity by 0.78 • C-1.34 • C on average during the day and reduced the peak temperature by 2 • C-3.6 • C. This emphasises the importance of increasing the number of parks within the built environment as an effective strategy to mitigate UHIs, and this also aligns with the studies by Gago, Roldan, Pacheco-Torres and Ordóñez [5], Sun, et al [63], Shao and Kim [64]. It also emphasises the importance of evaluating local park design and vegetation typologies to reach the maximum cooling effect, results that align with the findings of both Yao, et al [65], Barradas, et al [66]. Regardless of the local park settings, once the temperature drops, there will be a delay in the effect of that drop due to the hot air trapped in the vegetation canopy and the high temperature of the vegetation's leaves, as demonstrated by Gago, Roldan, Pacheco-Torres and Ordóñez [5].…”

Studi Kenyamanan termal dan konsentrasi CO2 pada kamar anak ber-pendingin udara masa Pandemi Covid-19

“…The effect of heat on occupants can be quantified by an index known as the heat index (HI) (Suparta et al 2017). The level of heatrelated discomfort can be classified based on temperature and relative humidity and their impact on health issues (Barradas et al 2022, López-Pérez et al 2019, Gopalakrishnan et al 2021. The levels of heat discomfort can be classified into four categories: caution, extreme caution, danger, and extreme danger.…”

Who removes seeds in a heavily urbanized area?

“…Urban green infrastructure design is usually planned from an economic perspective, exploring social, and spatial attributes [8,9]. However, can also be directed to achieve specific goals, such as ecosystem services that are processes through which ecosystems and species support and enrich human life [10].…”