Small rodents as the cause of decrease in young narrow-leaved ash tree growth (Fraxinus angustifolia V a h l)

The paper deals with the results of a six-year investigation on the influence of small rodents in the process of recovery (sanation process) and renovation of pedunculate oak forest stands (Genisto elatae-Quercetum roboris caricetosum brizoides H t. 1938.) by narrow-leaved ash seedling plants (Fraxinus angustifolia V a h l). In the Spring of 1996, damage by small rodents in the form of bites of various intensity on a sample of 2580 two-year old narrow-leaved ash seedling plants was recorded in the lower parts of the stalk of 2197 seedling plants (85.16%). According to the intensity of the damage, the plants were divided into three categories. In December 2000, the increment of 31 trees was analysed. Having analysed the variance of diameter (F = 117.14; df = 2; p < 0.0001) and height (F = 128.41; df = 2; p < 0.0001) of trees, significant difference between damage categories was established. Scheffe's post-hoc test showed statistically significant difference between damage categories, annual radial growth and their interaction.