A dose–response curve of restorative benefits of plant communities: based on visual distances and yellow to green hue range

Abstract

Urban green spaces have positive effects on both physical and mental wellbeing. However, few studies have focused on the trends and thresholds of the effects of different influences on restorative benefits when viewing scenes featuring plant communities. We measured subjective evaluations and objective physiological data from 44 participants who viewed images of plant communities in the yellow to green hue range to compare differences in restorative benefits among plant communities at different visual distances, as well as quantifying the influencing factors involved. The following results were found: (1) Coniferous and multi-layered plant communities were found to provide greater restorative benefits, and the restorative benefits grew with increasing visual distance. (2) Shape and color characteristics were significantly correlated with restorative benefits, but the relationship is not simply linear. (3) The restorative benefits were found to be greatest when crown proportion was 61.23%, trunk proportion ranged from 4.11 to 13.70%, and the value of color index value ranged from 25.44 to 35.56%; the restorative benefits gradually increased when sky proportion exceeded 12.95–13.19%, the fractal dimension exceeded 1.62–1.67, and hue index exceeded 91.64°–95.67°; additionally, the restorative benefits decreased when the saturation index increased. This study provides a scientific basis for the construction and improvement of plant landscapes in urban green spaces.

Keywords

Plant community / Visual distance / Restorative benefits / EEG / Threshold

References

[1] Annerstedt M, Norman J, Boman M, Mattsson L, Grahn P, Währborg P. Finding stress relief in a forest. Ecol Bull, 2010, 53: 33-42

[2] Atkinson J, Campos D. Improving BCI-based emotion recognition by combining EEG feature selection and kernel classifiers. Expert Syst Appl, 2016, 47: 35-41

[3] Bai XY, Yu ZW, Wang BY, Zhang YT, Zhou SQ, Sha XH, Li SH, Yao XH, Geng XL. Quantifying threshold and scale response of urban air and surface temperature to surrounding landscapes under extreme heat. Build Environ, 2024, 247 111029

[4] Balling JD, Falk JH. Development of visual preference for natural environments. Environ Behav, 1982, 14(1): 5-28

[5] Bielinis E, Takayama N, Boiko S, Omelan A, Bielinis L. The effect of winter forest bathing on psychological relaxation of young Polish adults. Urban for Urban Green, 2018, 29: 276-283

[6] Bolliger J, Sprott JC, Mladenoff DJ. Self-organization and complexity in historical landscape patterns. Oikos, 2003, 100(3): 541-553

[7] Bratman GN, Anderson CB, Berman MG, Cochran B, de Vries S, Flanders J, Folke C, Frumkin H, Gross JJ, Hartig T, Kahn PHJr, Kuo M, Lawler JJ, Levin PS, Lindahl T, Meyer-Lindenberg A, Mitchell R, Ouyang Z, Roe J, Scarlett L, Smith JR, van den Bosch M, Wheeler BW, White MP, Zheng H, Daily GC. Nature and mental health: an ecosystem service perspective. Sci Adv, 2019, 5(7): eaax0903

[8] Bringslimark T, Hartig T, Patil GG. Psychological benefits of indoor plants in workplaces: putting experimental results into context. HortScience, 2007, 42(3581-587

[9] Cao YJ, Li YM, Li XY, Wang X, Dai ZY, Duan MJ, Xu R, Zhao ST, Liu XP, Li JL, Xie JF. Relationships between the visual quality and color patterns: study in peri-urban forests dominated by Cotinus coggygria var. cinerea engl. in autumn in Beijing, China. Forests, 2022, 13(12 1996

[10] Chang Y, Mukai N. Color feature based dominant color extraction. IEEE Access, 2022, 10: 93055-93061

[11] Cheng L, Huang J, Jin TH, Chen WD, Li AY, Witlox F. Comparison of station-based and free-floating bikeshare systems as feeder modes to the metro. J Transp Geogr, 2023, 107 103545

[12] Chiang YC, Li DY, Jane HA. Wild or tended nature? The effects of landscape location and vegetation density on physiological and psychological responses. Landsc Urban Plan, 2017, 167: 72-83

[13] Chiang YC, Nasar JL, Ko CC. Influence of visibility and situational threats on forest trail evaluations. Landsc Urban Plan, 2014, 125: 166-173

[14] Deng L, Li X, Luo H, Fu EK, Ma J, Sun LX, Huang Z, Cai SZ, Jia Y. Empirical study of landscape types, landscape elements and landscape components of the urban park promoting physiological and psychological restoration. Urban for Urban Green, 2020, 48 126488

[15] Elsadek M, Liu BY, Lian ZF, Xie JF. The influence of urban roadside trees and their physical environment on stress relief measures: a field experiment in Shanghai. Urban for Urban Green, 2019, 42: 51-60

[16] Fei XH, Zhang YQ, Kong DY, Huang QT, Wang MH, Dong JW. Quantitative model study of the psychological recovery benefit of landscape environment based on eye movement tracking technology. Sustainability, 2023, 15(14): 11250

[17] Frank S, Waters G, Beer R, May P. An analysis of the street tree population of greater Melbourne at the beginning of the 21st century. Arboric Urban for, 2006, 32(4155-163

[18] Fu WJ, Gao F, Zhang X, Dong B, Chen XL, Xu X, Yang ZY, Liu Y. Tree-shrub-grass composite woodland better facilitates emotional recovery in college students emotion better than other plant communities. Front Psychol, 2024, 15: 1285792

[19] Gao XP, Xin JH. Investigation of human's emotional responses on colors. Color Res Appl, 2006, 31(5): 411-417

[20] Gatersleben B, Andrews M. When walking in nature is not restorative—the role of prospect and refuge. Health Place, 2013, 20: 91-101

[21] Giannakakis G, Grigoriadis D, Giannakaki K, Simantiraki O, Roniotis A, Tsiknakis M. Review on psychological stress detection using biosignals. IEEE Trans Affect Comput, 2022, 13(1440-460

[22] Groenewegen PP, van den Berg AE, Maas J, Verheij RA, de Vries S. Is a green residential environment better for health? If so, why?. Ann Assoc Am Geogr, 2012, 102(5): 996-1003

[23] Guan HM, Wei HX, He XY, Ren ZB, An BY. The tree-species-specific effect of forest bathing on perceived anxiety alleviation of young-adults in urban forests. Ann for Res, 2017, 60(2): 327-341

[24] Han KT. A reliable and valid self-rating measure of the restorative quality of natural environments. Landsc Urban Plan, 2003, 64(4): 209-232

[25] Hartig T, Evans GW, Jamner LD, Davis DS, Gärling T. Tracking restoration in natural and urban field settings. J Environ Psychol, 2003, 23(2): 109-123

[26] Hartig T, Korpela KM, Evans GW, Gärling T (1996) Validation of a measure of perceived environmental restorativeness (Göteborg Psychological Reports, 26:7). Department of Psychology, Göteborg University.

[27] Hsieh CH, Yang JY, Huang CW, Chin WCB. The effect of water sound level in virtual reality: a study of restorative benefits in young adults through immersive natural environments. J Environ Psychol, 2023, 88 102012

[28] Hu L, Zhang ZG. EEG signal processing and feature extraction, 2019, Singapore, Springer

[29] Jansson M, Fors H, Lindgren T, Wiström B. Perceived personal safety in relation to urban woodland vegetation—a review. Urban for Urban Green, 2013, 12(2): 127-133

[30] Jiang B, Chang CY, Sullivan WC. A dose of nature: tree cover, stress reduction, and gender differences. Landsc Urban Plan, 2014, 132: 26-36

[31] Jiang B, Li JL, Gong P, Webster C, Schumann G, Liu XM, Suppakittpaisarn P. A generalized relationship between dose of greenness and mental health response. Nat Cities, 2025, 2(8): 739-748

[32] Jiang LK, Kang J. Effect of traffic noise on perceived visual impact of motorway traffic. Landsc Urban Plan, 2016, 150: 50-59

[33] Jiang MY, Hassan A, Chen QB, Liu YG. Effects of different landscape visual stimuli on psychophysiological responses in Chinese students. Indoor Built Environ, 2020, 29(7): 1006-1016

[34] Kang Y, Kim EJ. Differences of restorative effects while viewing urban landscapes and green landscapes. Sustainability, 2019, 11(7): 2129

[35] Kaplan R, Kaplan S, Brown T. Environmental preference: A comparison of four domains of predictors. Environment and behavior, 1989, 21(5509-530

[36] Karmanov D, Hamel R. Assessing the restorative potential of contemporary urban environment(s): beyond the nature versus urban dichotomy. Landsc Urban Plan, 2008, 86(2): 115-125

[37] Knox ECL, Webb OJ, Esliger DW, Biddle SJH, Sherar LB. Using threshold messages to promote physical activity: implications for public perceptions of health effects. The European Journal of Public Health, 2014, 24(2): 195-199

[38] Lanki T, Siponen T, Ojala A, Korpela K, Pennanen A, Tiittanen P, Tsunetsugu Y, Kagawa T, Tyrväinen L. Acute effects of visits to urban green environments on cardiovascular physiology in women: a field experiment. Environ Res, 2017, 159: 176-185

[39] Lee JS, Kim CS, Yim OY, Lee DH (2002) Measurement of area effect by the color panel size. In: 9th Congress of the International Colour Association. Rochester, NY. SPIE, 158. https://doi.org/10.1117/12.464537

[40] Lin W, Chen QB, Zhang XX, Tao JY, Liu ZF, Lyu BY, Li N, Li D, Zeng CC. Effects of different bamboo forest spaces on psychophysiological stress and spatial scale evaluation. Forests, 2020, 11(6): 616

[41] Lin W, Zeng CC, Bao ZY, Jin HX. The therapeutic look up: stress reduction and attention restoration vary according to the sky-leaf-trunk (SLT) ratio in canopy landscapes. Landsc Urban Plan, 2023, 234 104730

[42] Liu QH, Wang XP, Liu JL, An CY, Liu YQ, Fan XL, Hu YS. Physiological and psychological effects of nature experiences in different forests on young people. Forests, 2021, 12(101391

[43] Lohr VI, Pearson-Mims CH. Responses to scenes with spreading, rounded, and conical tree forms. Environ Behav, 2006, 38(5667-688

[44] Long J, Shelhamer E, Darrell T (2015) Fully convolutional networks for semantic segmentation. In: 2015 IEEE conference on computer vision and pattern recognition (CVPR) Boston, MA, USA. IEEE, pp 3431–3440

[45] Lu S, Oh W, Ooka R, Wang LJ. Effects of environmental features in small public urban green spaces on older adults’ mental restoration: evidence from Tokyo. Int J Environ Res Public Health, 2022, 19(9): 5477

[46] Luan HJ (2020) Establishing the downscaling and spatiotemporal scale conversion models of NDVI based on fractal methodology. In Koprowski R (Ed.), Fractal analysis-selected examples (chapter 3). IntechOpen, London, U.K. https://doi.org/10.5772/intechopen.91359

[47] Mangiafico SS. Summary and analysis of extension program evaluation in R. Rutgers Cooperative Extension: New Brunswick, NJ, USA, 2016, 125: 16-22

[48] Masoudinejad S, Hartig T. Window view to the sky as a restorative resource for residents in densely populated cities. Environ Behav, 2020, 52(4401-436

[49] Mousavi Samimi P, Shahhosseini H. Evaluation of resident’s indoor green space preferences in residential complexes based on plants' characteristics. Indoor Built Environ, 2021, 30(6): 859-868

[50] Newsham GR, Cetegen D, Veitch JA, Whitehead L. Comparing lighting quality evaluations of real scenes with those from high dynamic range and conventional images. ACM Trans Appl Percept, 2010, 7(2): 1-26

[51] Nielsen B, Hyldig T, Bidstrup F, González-Alonso J, Christoffersen GRJ. Brain activity and fatigue during prolonged exercise in the heat. Pflügers Arch, 2001, 442(1): 41-48

[52] Nieuwenhuijsen MJ, Dadvand P, Márquez S, Bartoll X, Barboza EP, Cirach M, Borrell C, Zijlema WL. The evaluation of the 3–30-300 green space rule and mental health. Environ Res, 2022, 215 114387

[53] Pedersen EJ, Miller DL, Simpson GL, Ross N. Hierarchical generalized additive models in ecology: an introduction with mgcv. PeerJ, 2019, 7 e6876

[54] Peng ZM, Zhang RY, Dong Y, Liang ZH. A study on the relationship between campus environment and college students’ emotional perception: a case study of Yuelu Mountain National University Science and Technology City. Buildings, 2024, 14(9): 2849

[55] Perez-Valero E, Vaquero-Blasco MA, Lopez-Gordo MA, Morillas C. Quantitative assessment of stress through EEG during a virtual reality stress-relax session. Front Comput Neurosci, 2021, 15 684423

[56] Prüss-Üstün A, Wolf J, Corvalán C, Bos R, Neira M. Preventing disease through healthy environments: a global assessment of the burden of disease from environmental risks, 2016, Geneva, World Health Organization

[57] Robins RK, Hollands MA. The effects of constraining vision and eye movements on whole-body coordination during standing turns. Exp Brain Res, 2017, 235: 3593-3603

[58] Sacchelli S, Grilli G, Capecchi I, Bambi L, Barbierato E, Borghini T. Neuroscience application for the analysis of cultural ecosystem services related to stress relief in forest. Forests, 2020, 11(2190

[59] Sadek ME, Sayaka S, Fujii E, Koriesh E, Moghazy E, El Fatah Y. Human emotional and psycho-physiological responses to plant color stimuli. J Food Agric Environ, 2013, 11: 1584-1591

[60] Sahu A, Priyadarshi A. On the box-counting dimension of graphs of harmonic functions on the Sierpiński gasket. J Math Anal Appl, 2020, 487(2 124036

[61] Shan X, Yang EH, Zhou J, Chang VWC. Human-building interaction under various indoor temperatures through neural-signal electroencephalogram (EEG) methods. Build Environ, 2018, 129: 46-53

[62] Shanahan DF, Fuller RA, Bush R, Lin BB, Gaston KJ. The health benefits of urban nature: how much do we need?. Bioscience, 2015, 65(5476-485

[63] Shu Y, Wu CZ, Zhai YJ. Impacts of landscape type, viewing distance, and permeability on anxiety, depression, and stress. Int J Environ Res Public Health, 2022, 19(16): 9867

[64] Smith AR. Color gamut transform pairs. SIGGRAPH Comput Graph, 1978, 12(312-19

[65] Sonntag-Öström E, Stenlund T, Nordin M, Lundell Y, Ahlgren C, Fjellman-Wiklund A, Järvholm LS, Dolling A. “Nature’s effect on my mind”—patients’ qualitative experiences of a forest-based rehabilitation programme. Urban for Urban Green, 2015, 14(3): 607-614

[66] Sun KX, Li ZF, Zheng SY, Qu HY. Quantifying environmental characteristics on psychophysiological restorative benefits of campus window views. Building and Environment, 2024, 262: 111822

[67] Suppakittpaisarn P, Chang CY, Deal B, Larsen L, Sullivan WC. Does vegetation density and perceptions predict green stormwater infrastructure preference?. Urban for Urban Green, 2020, 55 126842

[68] Ulrich RS, Simons RF, Losito BD, Fiorito E, Miles MA, Zelson M. Stress recovery during exposure to natural and urban environments. J Environ Psychol, 1991, 11(3): 201-230

[69] Van den Berg AE, Joye Y, Koole SL. Why viewing nature is more fascinating and restorative than viewing buildings: a closer look at perceived complexity. Urban for Urban Green, 2016, 20: 397-401

[70] Williams K. Exploring resident preferences for street trees in Melbourne, Australia. Isa, 2002, 28(4161-170

[71] Wu LJ, Dong QD, Luo SX, Li YL, Liu YZ, Li JN, Zhu ZX, He ML, Luo YH, Chen QB. An empirical study of the restoration potential of urban deciduous forest space to youth. Int J Environ Res Public Health, 2022, 19(6): 3453

[72] Wu N, Li P. Analysis on application of green space tree species in Shenyang and suggestions on tree species selection. J Anhui Agric Sci, 2020, 48(12112-116(in Chinese)

[73] Xu JH, Zhong BC. Review on portable EEG technology in educational research. Comput Hum Behav, 2018, 81: 340-349

[74] Xu S, Xu WD, Chen W, He XY, Huang YQ, Wen H. Leaf phenological characters of main tree species in urban forest of Shenyang. PLoS ONE, 2014, 9(6 e99277

[75] Xu WD, He XY, Chen W, Zhang Y, Li HM, Liu CF. Flora and vegetation types in the downtown area of Shenyang. Chin J Appl Ecol, 2003, 14(12): 2095-2102in Chinese

[76] Xu Z, Ma J (2021) Research on the cultural landscape greenway model of water network city—taking Suzhou as an example. In: IOP conference series: earth and environmental science, vol 668, no 1, p 012070. IOP Publishing. https://doi.org/10.1088/1755-1315/668/1/012070

[77] Wood SN. Generalized Additive Models: An Introduction with R, 20172Boca Raton, Florida, CRC Press160194

[78] Yang J, Wang XR, Zhao Y. Leaf color attributes of urban colored-leaf plants. Open Geosci, 2022, 14(1): 1591-1605

[79] Yao XH, Yu ZW, Ma WY, Xiong JQ, Yang GY. Quantifying threshold effects of physiological health benefits in greenspace exposure. Landsc Urban Plan, 2024, 241 104917

[80] Yao Y, Liang ZT, Yuan ZH, Liu PH, Bie YP, Zhang JB, Wang RY, Wang JL, Guan QF. A human–machine adversarial scoring framework for urban perception assessment using street-view images. Int J Geogr Inf Sci, 2019, 33(12): 2363-2384

[81] Yu CP, Lin CM, Tsai MJ, Tsai YC, Chen CY. Effects of short forest bathing program on autonomic nervous system activity and mood states in middle-aged and elderly individuals. Int J Environ Res Public Health, 2017, 14(8): 897

[82] Yu ZW, Yang GY, Lin T, Zhao B, Xu YY, Yao XH, Ma WY, Vejre H, Jiang B. Exposure ecology drives a unified understanding of the nexus of (urban) natural ecosystem, ecological exposure, and health. Ecosyst Health Sustain, 2024, 10: 165

[83] Zhang GC, Wu GW, Yang J. The restorative effects of short-term exposure to nature in immersive virtual environments (IVEs) as evidenced by participants' brain activities. J Environ Manag, 2023, 326 116830

[84] Zhang L, Li X, Li CY, Zhang TY. Research on visual comfort of color environment based on the eye-tracking method in subway space. J Build Eng, 2022, 59 105138

[85] Zhang LW, Dempsey N, Cameron R. Flowers-sunshine for the soul! How does floral colour influence preference, feelings of relaxation and positive up-lift?. Urban for Urban Green, 2023, 79 127795

[86] Zhang LW, Dempsey N, Cameron R. Blossom buddies’—how do flower colour combinations affect emotional response and influence therapeutic landscape design?. Landsc Urban Plan, 2024, 248 105099

[87] Zhang XJ, Chen J, Li QY, Liu JC, Tao JP. Color quantification and evaluation of landscape aesthetic quality for autumn landscape forest based on visual characteristics in subalpine region of western Sichuan, China. Chin J Appl Ecol, 2020, 31(145-54 in Chinese

[88] Zhao JW, Xu WY, Li RJ. Visual preference of trees: the effects of tree attributes and seasons. Urban for Urban Green, 2017, 25: 19-25

[89] Zhao MY, Zhang YT. Exploring the dose-response of landscape preference: a case study in Singapore. Appl Geogr, 2024, 170 103357

[90] Zheng SY, Zhou YZ, Qu HY. Physiological and psychological responses to tended plant communities with varying color characteristics. J for Res, 2024, 35(132

[91] Zhong J, Tu J, Li X, Fu Y, Liu W, Zhang F, Hu S, Wang Q. Variation in vegetation characteristics and landscape patterns of urban forests: implications for ecosystem management under rapid urbanization. J for Res, 2025, 36(11-15

[92] Zuur AF, Ieno EN, Walker NJ, Saveliev AA, Smith GM. Mixed effects models and extensions in ecology with R, 2009, New York, Springer574 574

RIGHTS & PERMISSIONS

The Author(s)