Suitability evaluation of tea trees cultivation based on GIS in Zhejiang Province

A precisely comprehensive regionalization of tea trees cultivation can provide a scientific basis for the optimal distribution of tea industry in Zhejiang. Based on the analysis of the relationships among tea yield, meteorological conditions, topographic conditions, and soil conditions, this study proposed comprehensive regionalization indices including 4 climate factors (the annual mean temperature, the annual accumulated temperature above 10℃, the frequency of extreme low temperature below –13℃ and the mean humidity in 4–10 months), 2 soil factors (soil type, soil texture) and 3 topographic factors(slope, aspect, altitude). Mixed interpolation methods (the trend surface modeling and residual interpolation) were applied to calculate grids of climate factors. Methods of the exponential weighted algorithm were adopted to establish the evaluation model of comprehensive regionalization of the cultivation of tea trees. The distribution of comprehensive evaluation indices was calculated based on GIS. Non-planting areas were extracted from the land-use map, and the comprehensive regionalization of tea tree cultivation was completed and divided into 3 classes including suitable, sub-suitable and unsuitable regions. The results showed that the suitable, sub-suitable and unsuitable regions of tea trees cultivation account for 46.40%, 44.94% and 8.66% respectively. The suitable region was mainly distributed at the altitude of 600-900m in the semi-alpine areas. The sub-suitable region was mainly distributed below the altitude of 600m in plains, hilly and low mountains or between the altitude of 900-1 200 mountains. The unsuitable regions was mainly distributed in the mountainous areas which was higher than the altitude of 1 200 m. Considering the current cultivation of tea, the planting suitability was discussed for each class, which provides a technical support for tree production in Zhejiang.