Impact of Physiographic Factors on Growth of Alder : (Alnus Subcordata C. A. Meyer) In North Forest of Iran

In new era of technology and development which accompany with water and air pollution, global warming, climate chaos and deforestation, pay attention the native species in different geographical zone can be help to preservation of ecosystems and sustainable development. The Alder (Alnus subcordata C. A. Meyer) is a rare species sturdy and fast-growing belonging to the birch family (Betulaceae) and native to temperate area in North forests of Iran. As genus of Alder, the trees establish symbiosis with the nitrogen-fixing Actinobacteria. These bacteria convert atmospheric nitrogen into soil-soluble nitrates, which can be utilized by plants and favorably enhances the soil fertility. The fallen alder leaves make very rich compost, especially through mineralization of nitrogen leached from litter. The physiographic variables such as elevations, aspects and slopes had positive and negative significant relationship emerged as the effective factor on Alder growth. In worldwide there are many academic resources about Alder species except Alnus subcordata. In this book we attempt to explain the natural and plantation Alder stands and analyze the physiographic factors on growth of the trees.