Influence of Irrigation, Soil and Weeding on Performance of Mediterranean Cypress Seedling in Nursery

Mediterranean cypress, an evergreen softwood species, is well-known as Cupressus sempervirens L. var. horizontalis Mill. (Gord). It is an indigenous species of Mediterranean Europe and western Asia, including, Cyprus, Crete, Turkey, Syria, Saudi Arabia, Caucasian and Iran, resembling the Mediterranean climate (Sabeti, 2004). It is belonged to warming period and interglacial climate. Plant structure has a lot of the Mediterranean elements (Sagheb-Talebi et al., 2003). In Iran among the fifth-fold native coniferous trees (Juniperus communis, J. Sabina, J. polycarpus, Biota orientalis) it plays a unique role in restoration of deforested area of the Mediterranean zones (Rezaei, 1992); and the most important natural habitats of this species are found in northern regions and in special bio-geographical stations, as well as in warm valleys subjected to the southern winds (Mossadegh, 1996). The best developed Mediterranean cypress forests are found in the Chalous valley, and then, in the valley of Sefid-Roud (Roudbar). As small and isolated areas, it distributes in other parts of the country, particularly in west and south, in provinces of Lorestan, Sistan, Fars, Khozestan and Kohkilouye-Booyerahmad (Zare, 2002). Some scientists believe that the Mediterranean and semi-Mediterranean climates occurred in some parts of Iran are the major reason for distribution of this tree. The components of the flora of these forests include many Mediterranean elements (Asadolahi, 1991). Although some conifers show better performance in more fertile beds (substrate or medium) but Mediterranean cypress does not care the nutritional quality of soil and is able to survive in poor and dry habitats. It is a resistant tree to hard conditions and in some parts of northern Iran particularly in Marzan-Abad, Roudbar and Manjil it exists on low nutrient, superficial and calcareous soils. It has been known as a low nutrient demanding species; its strong root system makes it able to easily establish on steep slope, rock and cliff. It tolerates well high dry; on rich soil it grows fast and on moist soil the root system forms shallow (Bolandian, 1999). Since 1980, in dry slopes and semi-arid zones of northern Iran, more than 20.000 ha, have been afforested with this species. This is while that the increased destruction of Hyrcanean forests and the need for development of afforestation and green space in some capable regions have been given rise to producing its seedlings in forest nurseries. In 1996 the seedling production in communal nurseries was 96 million, with majority of this species. In