Investigation on relationship between tree rings of Cupressus sempervirens l. var. horizantalis and climatic variables

During 2008, a severe deluge in Sari caused huge damages and Cupressus sempervirens l. var. horizantalis trees in botany garden of Natural Sciences College were also fallen by the overflow. To perform the study the fallen trees disks and cores of standing trees were prepared. Using Lintab Measurement Table, the width of each growth ring per year and their average were calculated. The raw data related to rings growth were standardized by method of ARSTAN and index average of growth rings was recorded. To study the relationship between climatic variables and C. sempervirens rings growth, data of Babolsar and Tajan synoptic stations were found. The observation results of fallen trees in flat sites showed that C. sempervirens is not resistant against deluge and in the places which ground water table is raised; C. sempervirens is not suggested for planting. Numerical results also indicated that the mean growth ring is about 3.62 mm per year. Taking into account the bark width, the average of trunk diameter after 40 years was about 30 cm. Temperature increase during the Past years had caused the trend of growth width to reduce. Also the relation of index average of growth with rainfall showed that precipitation is an effective factor on C. sempervirens growth and as a result, the average of rainfall in April had a positive and significance effect on C. sempervirens growth (R= 0.61 and P<0.01).