Ecological study ofBetula pendulastands in Hyrcanian forests, North Iran

Abstract

This study was carried out in the rocky forests of Dodangeh, south of Sari, an area extended as a narrow strip from east to west in the heights of Hyrcanian forests, with the area of ca 2,000 ha and the altitude of 2,500-2,950 m a.s.l. Regarding vegetation history, Dodangeh is a refuge for Betula pendula Roth. This species together with Corylus avellana L. are the first ones formed a plant community in Hyrcanian region since the glaciation of the Tertiary period and gradual retrogression of conifers. A number of 181 plant species belonging to 52 families were identified through sampling of 20 relevés of the size 400 m 2 . Out of these, 17% were endemic of Hyrcanian and Irano-Turanian regions including four species viz. Aconitum iranshahrii Renz., Cortusa mathioli subsp. iranica, Delphinium elbursense var. elbursense and Doronicum wendelboii which could be found nowhere else in the world. Querco macrantherae-Betuletum pendulae association is recorded in the Hyrcanian and Euro-Siberian regions for the first time. Chorological studies of Querco macrantherae-Betuletum pendulae showed that the elements of Irano-Turanian, Euro-Siberian and Hyrcanian regions are more than those of the other existing vegetational regions in the area. Dynamic processes of this association and its restoration were also considered in the study.

Vegetation–environment relationships in the alderwood communities of Caspian lowlands, N. Iran (toward an ecological classification)

“…Acidic situation in group V is responsible for decrease in soil mineralization and then increase the C/N ratio especially in the lower soil depth. Although a low C/N ratio has been recorded in an acidic Hyrcanian forest soil (Ejtehadi et al, 2004), we found that C/N ratios were decreased with an increase in soil pH (Fig. 5) being consistent with findings by Schuster and Diekmann (2005).…”

Flora and vegetation of rocky outcrops/cliffs near the Hyrcanian forest timberline in the Mazandaran mountains, northern Iran

“…Irano–Turanian and Mediterranean). This is consistent with previous studies showing that the upper areas of the Hyrcanian forest benefits much from plants of Euro–Siberian origin (Zohary , Akhani , Ejtehadi et al , Jafari and Akhani , Akhani et al ). Nevertheless, there is a consistent penetration of Irano–Turanian elements into neighboring rocky habitats of the Hyrcanian area (Akhani and Ziegler , Jafari and Akhani ).…”

“…However, the most important differences between the two preceding vegetation units are the rocky habitats and the high occurrence of Fagus orientalis in the former. Despite the dominance of Carpinus orientalis communities on rocky outcrops and cliffs of many parts of western, central and eastern parts of lowlands and mountain areas of the Hyrcanian area (Dorostkar and Noirfalise , Akhani and Ziegler , Jafari and Akhani ), the Betula pendula remnant community occurs locally on more or less inaccessible cliffs of the study area and in some rocky forests of Dodangeh, Sari (Ejtehadi et al ). This vegetation type is generally species poor and accompanied by Quercus macranthera, Johereniopsis seseloides, Saxifraga iranica, Asplenium trichomanes and Alchemilla cf.…”

“…Many mountain ridges running in a predominantly east–west direction constitute tall vertical cliffs that intensify the accumulation of clouds and humidity in the upper mountain timberline and forest/steppe ecotone zones (cf. Akhani , Ejtehadi et al , Naqinezhad et al ). The high accumulation of long‐lasting fog at these altitudes are favorable for establishing woodland communities which are floristically different from the neighboring forest areas (Zare et al , Naqinezhad et al ).…”

“…Other woody species accompanying this species are Quercus macranthera, Sorbus aucuparia, Carpinus orientalis, Acer hyrcanum and Rhamnus cathartica . A climax woodland community of these species, Querco macrantherae‐Betuletum pendulae has been described from some parts of the Hyrcanian highlands (Ejtehadi et al ).…”