Health condition of spruce stands in the Orlické hory Mts. in relation to climatic, anthropogenic and stand factors
In stands with the majority of spruce and aged over 70 years, 35 sample plots were laid out (in total 700 trees) in the vicinity of Anenský vrch Hill at altitudes over 800 m above sea level. In the course of the growing season 2005, the following parameters were determined: total defoliation, defoliation of the primary structure, percentage of secondary shoots, presence and extent of yellowing and browning. In 10 selected trees, branches were taken from crowns for morphological analyses and annual length increments of branches and numbers of secondary shoots in the particular years were determined. Total defoliation and the occurrence of yellowing were related to slope orientation and position of the plot towards the ridge. The number of shoots produced in the given year correlated with the level of annual NO<sub>3</sub> deposition. The determined difference in the occurrence of yellowing between limed and unlimed plots cannot be interpreted unambiguously because limed and unlimed plots differ in exposure at the same time. The determined importance of slope orientation for the health condition of a stand shows that under the simultaneous air pollution load climatic factors are a factor deciding on the resulting effect of the synergetic action of stressors on forest stands.