The Study of some of Ecological Characteristics ofWych elm (Ulmus glabra Huds.) in Nav-Asalem Guilan Forests, Iran

Wych elm (Ulmus glabra Huds.) is one of the most important species in Northern Forests of Iran that due to illegal logging and Dutch elm disease its presence in the forest ecosystems is in danger of being eliminated. The correct management of forests needs to identify the ecological characteristics of trees. In this research, some of ecological characteristics of Wych elm trees were studied in 215 hectare, 800 to 1400 meters from sea level, in Asalem Nav forest area in the north of Iran. After field inspection, all Wych elm trees whose diameter at breast height (DBH) were greater than 10 cm were identified and their quality and quantity characters were measured. Inaddition, physiographical characteristics of sites were recorded. For studying trees diversity and species importance, the value of each wych elm tree was taken as center of sampling plots (round shaped and 1000 m2 area) and DBH was measured. Soil sampling followed the spatial pattern of wych elms. The results showed that density of wych elms in the study area was 0.32 stem per hectare and averages of height and DBH were 18.8 m and 48.5 cm. Respectively Frequency, quality and quantity of wych elms in the northern aspects were 800 to 950 m from sea level, 25 to 50% of slopes respectively, the foots and sandy loam soils were more and better in quality than other sites. With increasing height from sea level, frequency of wych elms decreased in northern slopes, but increased in southern slopes. Natural sites of wych elms have fertile soils. With regard to the little density of wych elms in the stands of study area, special silvicultural activity is necessary to conservation, reconstruction and development of this species.