Impact of some environmental factors on regeneration status of Juniperus excelsa subsp. polycarpus in Hezar Masjed Mountains (Layen Region) of Iran

In order to investigate the effect of environmental factors, including slope gradient, aspect and elevation on regeneration of Juniperus excelsa subsp. polycarpus, some Juniper stands were selected at Hezar Masjed Mountains, north of Khorasan Razavi province, north-east of Iran. Maps of slope gradient, aspect, elevation and landform were used and combined together to develop homogenious polygons of land units. The sampling was made, using stratification method and three sample plots, each 1000 m2. The plots were then laid out on the land units. To study the physico-chemical properties, one soil sample was made from subsoil, at each plot. The soil data were analyzed, using the Principle Component Analysis (PCA). Some parameters, including number of Juniper seedlings and their total height, collar diameter, health and vitality status were measured. The results showed that the elevation has significant effect on number of the seedlings, collar diameter and total height of the seedlings and proportion of health classes. Slope gradient showed significant effect on number of the seedlings per plot. The geographic aspect showed significant relation only with the proportion of moderate healthy seedlings. The impact of land form on Juniper seedlings was not significant. The Principle Component Analysis (PCA) output showed that phosphorus, clay, silt, EC and CaCo3 are the most important factors influencing regeneration of Juniperus excelsa subsp. polycarpus.