Climate forecast in Giulan province using tree chronology and time series analysis by Box-Jenkins method

Global warming and climate change are very important issues of the last century, which have been considered by scientists in various fields of science. The Hyrcanian forest is one of the oldest and most historic habitats of the world's deciduous trees. Beech trees are one of the valuable industrial species with a lifespan of 200 to 300 years. The science of tree chronology can show past weather events. The diameter of the annual growth rings of the trees forms a time series. With this method, a time series of 202 (1816-2017) years was obtained from the diameter of the growth rings of beech trees.Researchers are always thinking about the future. This study uses time series of growth rings of forest beech trees and analyzes it.And the use of modeling based on the Box-Jenkins method with emphasis on ARIMA models were examined. The results showed, Time series with ARIMA model (1,1,1) had the best fit, at the 95% level, it is significant and the trend forecast has a negative and decreasing slope. Climatic factor of annual precipitation in the regional station and neighboring stations with a decreasing and negative trend The average minimum, middle and maximum average temperatures are increasing. Climate change is reducing growth for Hyrcanian forest trees. It was registered as the second natural heritage of Iran in UNESCO. It will pose a threat to plant and animal communities.