Changes in climate suitability for oil-tea (C. oleifera Abel) production in China under historical and future climate conditions

Defining climate suitability zones accurately can provide supporting information for locating regions for crops with a long period of return on investment such as oil-tea (C. oleifera). The objective of this study was to evaluate changes in suitability for a typical oil-tea species (Abel) under climate change conditions in China. Based on correlation analysis, annual mean temperature, mean temperature in July, annual rainfall, and annual sunshine hours were identified as the factors impacting production suitability. A modified bioclimatic method was verified using extensively collected crop occurrence data. Changes in climate suitability under two different historical periods (1961–1990, 1991–2020) and under two future climate change periods (2021–2050, 2051–2100) using 28 General Circulation Models (GCMs) under Representative Concentration Pathway (RCP) 4.5 and 8.5 emission scenarios were then investigated. Results showed that: (1) The modified method well described the main climatic features of the actual production regions; 96.3% of the dominant production regions and 92.4% of the main production regions were located in the regions classified as most suitable and suitable; (2) Historical climate change has caused the northern and southern production boundaries to move northward by 130 and 70 km, respectively, and the east-central part of the study region has degraded to the suitable classification; (3) Under RCP 4.5, the regional pattern of suitability did not change much, while under RCP 8.5, the area of the most suitable region was reduced by up to 66%; (4) Suitability varied greatly between different GCMs, especially under RCP 8.5. Our results showed that historical climate change had negative impacts in some of the most suitable regions, and that future climate change will have negative impacts on more regions. To maintain future healthy development of production, significant efforts should be devoted to breeding heat and drought-resistant varieties and to improving management practices.