GROWTH AND STABILITY OF YOUNG STAND OF SUBSTITUTE TREE SPECIES BLUE SPRUCE IN THE JIZERSKE HORY MTS

Blue spruce was the most commonly used tree species of the substitute tree species forest stands planted after air pollution disaster in the Czech Republic. Research focused on blue spruce forest stand development is very rare. This article aims to assess blue spruce forest stand development in higher locations of the Jizerske hory Mts. from planting to small pole stage. Two blue spruce forest stands at the age of ca 18 years were analyzed. As emerged from the analysis, blue spruce stands in higher mountain locations without tending start to close at the age of ca 15 years, trees growing in the spruce forest vegetation zone have lowered growing potential and predominant trees are susceptible to snow breaks there. Closing stand canopy brings increasing of upper crown height and worsening of health status (defoliation). To increase stability of the young blue spruce forest stands, tending to preserve open crowns should be done.