Study the impact of Climatic factors in Cupressus sempervirens̛'s ring - width in Misiaf using Dendroclimatology

Abstract

This research aimed to evaluate the relationships between climate factors and rings- width of Cupressus sempervirens. Dendroclimatology techniques were applied to four sample plots that were selected throughout the natural distribution area of Cupressus sempervirens in Misiaf region. Seven old dominant trees were selected from each sample plot and three cores per tree were sampled. Then elementary values of annual growth rings were first standardized to remove the age effect and obtain the growth index.

 Multiple Regression was applied to study the relationship between growth index and both of temperature and precipitation of  Misiaf  meteorological station. The results showed a clear variation in the length of the time-series of Cupressus sempervirens̛'s ring – width among samples. The longest series was the third sample plot, Being 147 years(1872-2018). The length of series in the first sample plot was 103 years(1916-2018).As for the second sample plot, The length of series was 101 years (1918-2018).  The shortest series of ring – width was recorded in the fourth sample plot, With a length of 70  years (1949-2018). Some missing rings were detected in a lot of sample cores (2010), In addition, There are narrow rings in most core's. After standardization the rings – width was averaged  between 0.4 and 2.2.

Response function showed that Precipitation in all of November, December, February, March, May and July were positively correlated with the rings - width. Minimum temperatures of May were positively correlated with the rings – width in the Third sample plot, while Minimum temperatures in November and August correlated negatively in the Fourth sample plot. Minimum temperatures in April were positively correlated to the rings – width, in the Second sample plot.