Relationship of some exogenous factors to the variability of diameter increment of narrow-leaved ash (Fraxinus angustifolia V a h l) future trees on an ecologically optimal site

The main characteristics of current annual diameter increment of the analys ed narrow-leaved ash (Fraxinus angustifolia Vahl) future trees are variabil ity and oscillations that can be ascribed to a different tree structure and the effect of exogenous factors. The elements that determine the increment potential are readily measurable and visible parameters of tree structure. The significant favourable exogenous meters affecting increment are averag e water level throughout the year, air temperature during the growth season , while rainfall during the period May - June is unfavourable. Marked depre ssions of diameter increment can bd ascribed to the impact of defoliators.