Application of forest inventories to assess the forest developmental stages on plots dedicated to long-term vegetation studies

Abstract

The possibility to distinguish changes in vegetation related to the dynamics of the forest stand and / or the regimes of forest management from directional or random changes would allow for more precise recognition, and counteracting the effects of global threats. However, in most cases, records for particular periods of vegetation surveys do not contain data allowing assessment of the forest stand dynamic. In this work, we provided the forest developmental stages assessment method using variables recorded on the sampling plots designed for vegetation surveys, supplemented by variables from forest inventories conducted in managed European beech forests from the Carpathian Mountains. Three distinct forest stages were distinguished. Based upon distribution of variables, specific for individual stages, we classified them as growing (G), optimum (O), and terminal (T) stage. The characteristics of these stages were similar to those for old-growth forests European beech forests. Our results demonstrated a simple, clear and repeatable method of using forest inventories and data from traditional vegetation surveys, useful in the assessment of managed forest stands for long term study purposes. It was possible based on 10 variables, among which the most decisive seems to be stocking, tree regeneration and mean tree DBH and height. As each of the distinguished stages were characterised by a separate herb layer species composition, the method allows for better identification of the impact of cyclical changes in the structure of the stand from the directional causes of long-term changes in forest herbaceous vegetation. Although our method gave a very realistic division and characterisation of the developmental stages, due to the bias of vegetation researchers (who more often conducted research in the optimum stage of the forest), does not allow for the correct quantification of the proportion of developmental stages in the forest.