Impacts of climate change on apple tree cultivation areas in Iran

Climate change is the most important challenge for human advance in the future. The horticultural sector is sensitive and vulnerable to climate change. In the present study, to reveal the climate change of the future period on the apple tree cultivation areas in Iran, the simulated data from the HadGEM2-ES coupled model output from the CMIP5 model series under RCP8.5 and RCP4.5 scenarios as cynical and optimistic scenarios. The results showed that the increase of air temperature under the conditions of climate change is a serious stress for the deciduous trees in cold regions of Iran because it will reduce the regions for cultivating trees like apples. Climate change and changes in temperature patterns will cause changes in agroclimatic indexes associated with fruit trees. Typically, the minimum and maximum temperature of the apple tree growth period during the baseline will change according to the pessimistic scenario from 11.6 and 27.3 degrees C to 16.7 and 33.4 degrees C in the 2090s. Changes in the temperature indices and agroclimatic indices are higher than the vulnerability threshold for apple trees, showing the effect of climate change on fruit trees. In the upcoming period, the suitable area for apple tree cultivation in Iran will reach 29,073,448ha. In fact, 46.7% of apple tree cultivation areas will be lost. Under the climate change conditions, the cultivation of apple trees in Iran will be extended to higher regions. An increase in air temperature will threaten deciduous trees in the cold regions of Iran.