Urban forests increase spontaneous activity and improve emotional state of white mice

Empirical studies on the effects of urban forests on human health are needed to rationalize the construction of health-care urban forests. Our study investigated the effect of urban forests on the physical activity and emotional state of white mice and major environmental factors influencing the mice to provide a scientific basis for the rational construction and use of urban forests. We measured spontaneous behavior, body weight (BW), and fecal production in white mice after their entry in three urban forest habitats (foothill, valley, and ridge) during successive 6-day experiments, and monitored major environmental factors (negative air ions (NAIs), O2 content (OC), and microclimate). Compared with indoor control mice, in mice exposed to forest environments: 1) total distance travelled (TDT), distance travelled in central area (DTCA), number of times entering central area (NTECA), and time spent in central area (TSCA) significantly increased (TDT, 31.73–118.56%; DTCA, 52.9–105.8%; NTECA, 75.09–118.93%; TSCA, 59.46–112.54%); 2) the diurnal BW gain increased by 3.9–6.8-fold; 3) the number of fecal grains (NFG) significantly decreased (by 20.47–34.49%); and 4) TDT, DTCA, NTECA, TSCA, and BW were positively correlated with NAIs, air temperature (AT), and relative humidity (RH) and were negatively correlated with OC. Furthermore, NFG was significantly positively correlated with OC but significantly negatively correlated with NAIs, AT, RH, and WS. Our findings indicate that the aforementioned environmental factors in urban forests can enhance the physical activity and emotional state of white mice.