Assessment of radial growth of Cupressus sempervirense var. horizontalis trees by use of dendrochronology knowledge in its native site (Case study: Gorgan Ali Abad Catool)

Trees having long living are able to reflex long effects of climatic conditions on their spread of tree ring width. So, this research we tried to analyse the impact of climatic variables (rainfall & temperature) on radial growth in Ali Abad Catool, Gorgan. For this reason between 23 (Cupressus sempervirense var. horizontalis) trees increment cores in diameter of beast height (DBH) using an increment borer were extracted. The width of annual rings of samples after making ready by use of measuring table, with LINTAB6 program and correctness 0.01 mm was measured. The cross-date and adjustment were done between samples, and maximum and minimum amount of GLK between samples, 0.75 and 59.2 were obtained. Average amount of tree ring width has been standardized and index of (Cupressus sempervirens var. horizontalis) has been calculated. Length of chronology that is got 244 years has been determined. The relationship between growth and climate was figured using action response function. That minimum February’s temperature in the last growth season is most important factor of electable climate on growth of (Cupressus sempervirens var horizontalis). The analysis of pointer years showed that minimum chronological distance of eventual event of climatic arid phenomenon is one year and maximum six years in the region. This research was figured consistently the growth limiting factor isn’t raining in the low heights but the temperature also reveals its role in low heights. Although the necessity of more study on other species can proves or disprove the results.