engleski

Stand age as one of the predisposing factors in the decline of pedunculate oak in the stands of the "Spačva" forest basin

Decline of pedunculate oak trees and stands is a phenomena first recorded in Croatia as early as 1909. Since then, vast volume of literature was produced dealing with the problem indicating that the process of oak decline results from the interaction of multiple predisposing, inciting and contributing factors. One of the predisposing factors frequently discussed is the stand age, where older stands, or trees, are more susceptible to dieback. Aim of this contribution is to asses importance of the stand age as one of the predisposing factors in the decline of pedunculate oak in the "Spačva" forest basin. We will quantify incidence of dieback according to stand age in terms of amount of harvested dead oak trees per unit area (m3/ha) and the share of standing volume removed from the stand trough the harvest of dead oak trees (%). We have selected 962 stands of pedunculate oak with total area of 20 671 ha for the analysis. Stand age ranged from 14 up to 120 years, with most of the stands being older than 80 years. Data on stand structure and record of harvested volume per tree species and type of harvest for the period of 11 years (1996-2006) was taken from the Management Plans. Average intensity of decline increased with the increase in stand age, with highest values of 35 m3/ha recorded in the stands of sixth age class. However, the variability of the decline intensity was very pronounced among the stands of the same age class. Thus, it is impossible to arrive at the general conclusion about the role of the stand age in the process of oak decline, because stand age most likely only amplifies negative factors already present in the stand.

Spačva" forest basin; pedunculate oak; decline; stand age

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