Monitoring the spring phenological stages in a spruce monoculture in the Drahanská vrchovina upland in 2005–2011

摘要

The paper evaluates the onset and duration of spring vegetation phenological stages in a spruce monoculture of the third age class in relation to changing parameters of the environment in the region of the Drahanská vrchovina Upland. Temperature requirements of Norway spruce necessary for the onset particular phenological stages were evaluated on the basis of sums of effective temperatures 5 supo/supC. The period of 2005–2011 is processed in relation to long-term monitoring since 1991. Based on results obtained, there is considerable variability owing to changing climatic conditions in the onset of spring phenological stages in the course of monitored years. In recent years, the earlier onset of spring phenological stages occurs and their duration gets shorter. This phenomenon is caused by higher air temperatures in spring months. The statistical processing of results obtained demonstrated the high dependence of the onset of particular phenological stages on the temperature of air and soil. Particular factors affecting budbreak and foliation cannot be detached and thus, it is necessary to be evaluated as a complex of influences. Long-term phenological studies of forest trees can serve as the bioindicator of climatic changes.