New research informs design of thermally comfortable parks of the future. Key is to include a broad variety of microclimates sunny, shaded and half-shaded places.
Published in 'Urban Forestry & Urban Greening', volume 21, January 2017, p.134-145.
Authors: W. Klemm, B. van Hove, S. Lenzholzer, H. Kramer.
This study investigated human behaviour in parks in order to develop spatially explicit design guidelines considering future climate conditions in moderate climates. Fieldwork was carried out in two parks (in Utrecht and Wageningen, the Netherlands) during summer and tropical days (Ta max > 25 °C and > 30 °C, respectively), the latter representing future climate conditions. Behavioural responses (park attendance, spatio-temporal user patterns) and thermal perception of resting park visitors were studied through unobtrusive observations (N = 11337) and surveys (N = 317). Outcomes were related to air temperature (Ta) of meteorological reference stations and spatial data on the vegetation structures of the parks.
Observational data show that daily park attendance decreased with rising Ta max. Survey results indicate that resting park visitors perceived a high level of thermal comfort during all investigated days. Park visitors chose resting locations predominantly based on solar exposure conditions (sun, half shade, shade). Those solar exposure preferences were significantly related to Ta: with increased Ta the number of park visitors in the shade increased and decreased in the sun (p < 0.001) with a tipping point of 26 °C. These results indicate that parks in moderate climates may guarantee a high level of thermal comfort, even on tropical days, if a variety of solar exposure conditions is guaranteed. A ratio of 40% sun, 20% half shade and 40% shade in parks was derived from spatio-temporal user patterns, which appear to accommodate preferences of resting park visitors under summer and tropical thermal conditions and on various daytimes. These results and a spatial typology of tree configurations for microclimatic variety provide direction for designing future parks: they need to offer a wide range of sun-exposed, half shaded and shaded places to accommodate for different user needs and future climate conditions.