Abstract
The authors propose a simple observation method to grasp the state of microclimate of suburban area, using the plant indicator. Yellow leaves of gingko that is one of the plant indicators, serve as environmental barometer. We have observed and analyzed the yellow leaves of gingko which was planted in the suburbs of Tokyo. The processes of turn into yellow from green leaves of ginkgo are classified into simple patterns. From the results presented here, we applied the logistic function as a mathematical model of the turn processes into yellow from green leaves of ginkgo. The expression of this model was a well fit with the observed values. Using this mathematical model, we could be classified into the climate of city and the district of microclimate. Furthermore, we analyzed the relation between the heat distribution of buildings and the microclimate around. As a result of the data analysis, it was found that there is the correlation between the heat emission of buildings and process of turning yellow of Ginkgo. Yellow leaves of Ginkgo biloba can become an indicator of small heat island phenomenon.
