Climatic Suitability Zoning of Tea Planting in Mainland China

Starting from the national scale and annual level, the potential climate factors are interpolated into 10 km×10 km grid data based on the daily data set of 1903 weather stations from 1961 to 2019 across the country, and a tea plant distribution dataset consisting 1115 records is established. Using the maximum entropy model and GIS technology, the dominant climatic factors affecting tea plant in mainland China are screened according to the contribution percentage and Jackknife method, and the climatic suitability zoning of tea plant is divided into 4 grades: Unsuitable, sub-suitable, suitable and optimum, using the natural break point classification method. The threshold values of dominant climate factors for different division levels are determined and the climate characteristics of tea suitable zones are analyzed. The result shows that the maximum entropy model constructed based on the dominant affecting climatic factors is suitable for climatic suitability zoning of tea plant. The dominant climatic factors affecting the distribution of tea plant are averaged extreme minimum temperature, the frequency of spring frost, annual mean temperature, annual precipitation, and averaged relative humidity from March to September. The zoning results by the model are in good agreement with the distribution of famous tea towns and the location of geographical symbol tea. The changes of areas suitable for tea plant in different periods are also studied, and it shows that the north boundary of the tea plant suitable area for the six decadal periods from 1961 to 2019 is roughly the same, and all regions show a decreasing distribution trend from high latitudes in the east to low latitudes in the west. The areas where the northern boundary moves obviously are mainly in the high-latitude provinces in the east. The decadal variation of the centroid of the overall tea plant suitable area is relatively slight: The suitable areas expand northwards gradually except for the 1960s-1970s and the 1980s-1990s. These results provide a scientific basis for rational planning of tea planting layout and scientific development of tea industry. The zoning method adequately considers climatic conditions of the study area under natural conditions. However, other factors such as land use types, soil conditions, and tea varieties are not fully considered, and the interpolation method does not consider the influence of altitude on meteorological elements, which makes the result of area optimum for tea planting larger than reality.