عنوان مقاله [English]
The biological reserve of Biota orientalis with 195 hectare, which was located 23 km far from south of Fazelabad Gorgan, were studied. The dominant species of this area is Platycladus orientalis which is natural and native in the north part of Iran in Fazelabad. Observations showed that many stands of Platycladus orientalis had sever physiological weakness. Most of trees had shriveled. T. Ephebea. Results showed that the range of dryness in different diameters and ages were different and also with increasing density of lichen, growth of trees decreased salient.