The gum exudation of Elaeagnus angustifolia is affected by various factors. The observation results show that the gum exudation is related to the physiological activity of Elaeagnus angustifolia, which strongly depends on moisture conditions. Gum productivity of Elaeagnus angustifolia is higher in the forests with good moisture conditions than that in the forests with arid environment. The descending order of gum productivity of moisture conditions is humid, semi-humid and arid forests. Air temperature plays an active role in activating and improving the physiological activity of Elaeagnus angustifolia, and the gum productivity of Elaeagnus angustifolia is significantly increased with the increase of air temperature. The maximum gum productivity of Elaeagnus angustifolia occur during the period from May to July. Wound shape and number affect the gum productivity, gum productivity is increased with the increase of wound number, the effects of wounds are different from the different wound shapes, and the mechanical damages and insect pests damages are the main causes resulting in the tree's wounds. Gum productivity of Elaeagnus angustifolia is directly related to the physiological activity and age of Elaeagnus angustifolia. Gum productivity of the mature trees of about 25 years is the highest and it is significantly higher than that of the 17-year-old middle-aged trees and the 41-year-old overmature trees. The overmature trees are easy to suffer from pest's damage and have higher gum productivity than that of middle-aged trees.
