Vegetation-environment relationship in the birch (Betula pendula Roth.) site in the mountainous riparian forests of Marmisho valley

Marmisho valley, located in the north-western Iran, encompasses high species diversity and a unique habitat for birch stands (Betula pendula Roth.). This study was carried out to investigate the vegetation-environment relationship in this area and also to determine the most important environmental factors affecting species distribution with emphasis on the birch species distribution. 30 sample plots were implemented using a random sampling method with a grid size of 200 × 100 m. At each sampling point, 400 m2 and 100 m2 were set up respectively for recording the cover-abundance of woody species and herbaceous species. Also at the center, a soil sample was taken from 0-30 cm depth of mineral soil. As a result, 251 taxa were observed in Marmisho valley. The results of cluster analysis illustrated that sampling plots were respectively divided into three and five ecological groups based on woody and herbaceous species composition, in which significant differences between different ecological groups were approved by MRPP analysis. In addition, DCA indicated that soil texture and soil pH had the most influence on the distribution of ecological groups in the region. Marmisho valley encompasses high level of plant diversity. Therefore, we need urgent forest management strategies such as protective plan to conserve the region.