Growth response of Alnus viridis to application of crushed limestone and amphibolite and forestry potential of the species in harsh acidic mountain sites

An experiment with seedlings of Alnus viridis was established on a clear-felled tract situated on a summit tableland of the Jizerské hory Mts. (central Europe, Czech Republic) at an altitude of 980 m a.s.l. The aims of the experiment were (i) to evaluate the response of A. viridis to the application of a basic mixture containing crushed limestone and amphibolite and (ii) to assess the growth potential of the species in a poor acidic site under climatically harsh conditions. Alnus viridis showed a good growth performance and survival rate, its initial response to fertilization was positive. The height growth and expansion of crowns were slightly but significantly stimulated by the treatment, the survival rate was also increased, though not significantly. The amendment application temporarily increased the foliar Ca and Mg concentrations. The content of foliar P, of the most deficient macroelement, was not improved by the treatment. However, the positive effect of fertilization was short-lasting and unconvincing from the aspect of practical use. In the second half of the reference period the control started to gain on the fertilized variant and as for mean height and crown diameter, both variants got almost equalized eight growing seasons after the treatment.