Age structure of european ash (fraxinus excelsior l.) Forests in the left-bank forest-steppe of Ukraine

Abstract

The age structure of European ash stands in the forest fund of ten forest enterprises from Sumy, Kharkiv and Poltava regions was analyzed considering forest site conditions, stand origin, site index and ash proportion in the forest composition. The average age of ash stands is 68 years for the Left-Bank Forest-Steppe. On average from 46.1 % to 81.6% of European ash stands survive up to the V age class. The average age of ash stands is the highest in the forest-steppe part of Sumy Region in D2 and D3, in Kharkiv Region in D1, and in Poltava Region in C2 and C3. The average age is the highest (75 years) in artificial seed stands in Kharkiv Region, in natural seed (86 years) and vegetative (77 years) origin in Sumy Region. The survival of pure and almost pure ash stands is the highest in Kharkiv Region and the lowest in Poltava Region. In the legislatively adopted maturity age (VIII age class) survival of European ash with its proportion of 80–100 % is 26.5 %, 13.1 % and 3.2 % in Kharkiv, Sumy and Poltava Regions respectively. Correction of the main felling age in forests that are possible for exploitation is suggested considering the possible loss of timber quality as a result of forest damage by different causes.