Investigation the affection rate of oak trees to mistletoe, Loranthus europaeus, in forests of Zagross area (A case study of Southern slope of Manesht Mountain in Ilam Province)

To determine extant infected Persian oak forests to parasitic plant, Loranthus europaeus, an area of 700 ha was selected in south of Manesht mountain in north of Ilam province. In order to make an inventory of the healthy as well as infected trees, a two phase sampling procedure with continuous line was applied. First, the oak species ratio was estimated and then the ratio of infected oak trees was determined. Results showed that the total number of trees were 154.47 per ha with 80.2% of them belong to oak species. 25% of oak trees were infected and the rest were healthy. 32.1% of oak trees showed dieback. All of the infected trees by mistletoe showed dieback of branches. It can be concluded that mistletoe activity was affective on dieback of oak trees. This study also showed that the highest rate of mistletoe infection was in mid part of tree crown and the lowest rate was in upper and lower parts.