Seven spruce species on a mountain site - performance, foliar nutrients, and forest floor properties in stands 20 years old.
Norway spruce is often considered to have a negative impact on a site, yet it is native to many mountain regions of Europe. The relative influence of Norway spruce on site properties has frequently been compared with that of both broadleaved and other coniferous tree species. In our study, growth, as well as needle, forest floor, and topsoil chemistry were compared between Norway spruce and introduced spruce species (white, black, red, Serbian, Sitka, and blue spruce), all growing on the same, formerly polluted mountain site. There were few differences in needle nutrient status between the introduced spruce species and native Norway spruce. The chemistry of forest floor horizons beneath some of the non-native species showed less acidity and better conditions of the soil sorption complex. There were no significant differences in the nutrient pools, indicating that the influence of the various spruce species on the site was comparable. Given the small differences observed in the various nutritional characteristics, it appears that, under the conditions of the study site, the alternative spruces had substituted for the role of Norway spruce before its recovery in the 2000s. The six spruces grew quite consistently during 2001-2012, while the mean height of Norway spruce shifted from the lowest 176 cm (2001) to one of the tallest. At 710 cm (2012), its height had become comparable with that of Sitka. The poorest performing were black spruce (due to bark beetle attack) and blue spruce (due to bud blight infestation and decline).