Norway spruce (Picea abies/L./Karst.) health status on various forest soil ecological series in Silesian Beskids obtained by grid or selective survey

Abstract

The values of characteristics of forest health status (FHS) depend on design of monitoring plot selection. The aim of the work was to compare the dependence of FHS on various ecological site conditions on research plots with different selection designs. The differences of Norway spruce (Picea abies/L./Karst.) defoliation, discoloration and total damage variance were investigated in the Silesian Beskids (Czech Republic; 297 km2; 304–1067 m a. s.l.) during 1999–2008. FHS results on 187 plots at 400×400 m grid were obtained through routine methods according to EMEP-LRTAP. In addition, forest health status on 18 plots of selective survey design was obtained by estimation of defoliation and crown structure transformation. The comparison of ecological series proportion in individual survey designs was carried out through Mann-Whitney U-test, the comparison of health status feature occurrence in ecological series between different survey designs through analysis of variance. The survey design did not influence ecological series proportion, but influenced FHS feature variance. FHS features on sites of various ecological series have different rate of tree damage in individual survey designs. The selective survey significantly decreased data variance in contrast to low plot frequency.