Effect of climatic factors, temperature and precipitation, on radial growth patterns of beech and oak in of central Alborz Mountains altitudes

Trees respond to environmental and climatic changes during their biological life. Tree rings study is one way to discover these responses called dendrochronology. The most effective climatic factors which affect tree rings are temperature and precipitation. Present study aimed at investigating the influence of temperature and precipitation on annual growth of oriental beach (Fagus orientalis Lipsky) and oak (Querscus castaneifolia C.A. Mey), which clearly illustrate climatic factors on their tree rings. Trees were selected in three altitudes (450, 900 and 1380 a.s.l), from forest part 2 of Neka and Haft Khal in central Alborz mountains of Iran. Core samples were extracted from two sides of trees with an increment borer. Growth rings widths were measured by using LINTAB6 table with accuracy of 0.1 mm. The measurement results were analyzed using time series analysis software TSAPWin. Results showed that growth pattern of oak and beech in three altitudes were not similar. Altitudes affect mean growth of these species significantly. In each altitude, oak and beech have shown different responses to temperature and annual precipitation. These differences could be depending on species’ nature. In response to climatic factors, oak was more sensitive than beech. In high altitude, previous growth season temperature of affect oak chronology negatively while had positive effect on mid and low altitudes. In all altitudes, oak positively affected by precipitation of June (of current growth year). Beech of high altitude showed positive correlation with March and summer precipitation. However, no significand correlation was detected in beech in low altitude