Tree planting indices and their effects on summer park thermal environment: A case study of a subtropical satellite city, China

Abstract

Urban residents are suffering from serious thermal stress resulting from urban heat island and global warming. Investigators have explored several methods to address this issue. Vegetation, especially trees, were found to play a vital part in urban environments. It produces a cooling effect by reducing temperature and radiation levels. To find thermal performances of trees in detail, this study physically measured two urban parks during August 2019 in a satellite city of China regarding their thermal environments relevant to tree planting indices. There were three planting indices used, sky view factor, leaf area index and enclosure area. Through associating them with thermal indicators by linear regression, all of the indices were confirmed to have significant thermal effects. Every 0.1 increase in sky view factor resulted in an increase of 1°C air temperature, 0.16 m/s air velocity, 40 W/m2 solar radiation level and 1.6°C mean radiant temperature. Same effects were found in nearly 0.4 leaf area index decrease and approximately 20 m2 enclosure area increase. These results provide very optimistic directions for future urban forestry planning and landscaping.

The tree cooling pond effect and its influential factors: A pilot study in Gold Coast, Australia

“…Table 1. Detailed components and functions of the instrument (Testo 480 [33]). A and C was defined as D (D AC ), which was calculated through several parameters, including tree crown size (diameter, TCD), tree height (H), and sunlight angle (θ) (Fig.…”

“…Previous studies have confirmed that the cooling effects of trees were correlated with the crown size (i.e., the tree crown size, TCD [43]) and LAI [33]. They needed to be considered.…”

Multi-objective optimization of energy, thermal and visual comfort for dormitory buildings in the cold climate of China

“…33 Three important parameters of green roofs were selected, that is, plant height, leaf area index (LAI) and soil thickness considering their impact on the energy performance. 34,35…”

An investigation of the influence of the morphological indexes of trees on the outdoor microclimate at high altitude in summer

“…Many scholars have studied the factors that improve the urban microclimate. As an important part of the urban life system, trees play an important role in increasing humidity and cooling and improving urban comfort (Guo et al, 2022). Compared with shrubs, arbors can not only regulate the microclimate through canopy shading and leaf transpiration, but also create a…”

“…In February 2022, Working Group II (AR6 WGII IPCC) of the Intergovernmental Panel on Climate Change (IPCC) released the sixth assessment report "Climate Change 2022: Impacts, Adaptation and Vulnerability" (IPCC, 2022), which states that the effects of high temperatures and floods caused by global climate change result in human-induced diseases or premature deaths or lead to changes in the spatial and temporal distribution of vectors, environmental pollution, infectious diseases, and even psychological stress or mental illness (Huang and Liu, 2022).Many scholars have studied the factors that improve the urban microclimate. As an important part of the urban life system, trees play an important role in increasing humidity and cooling and improving urban comfort (Guo et al, 2022). Compared with shrubs, arbors can not only regulate the microclimate through canopy shading and leaf transpiration, but also create a…”