The early impact of mixed canopies with Norway spruce, European beech and silver fir on a new forest floor.

The character of pure or mixed forest canopies and their litterfalls contribute to different forest-floor properties. These organic layers and also subjacent topsoil were studied at three study sites covered by mixed treatments such as beech–spruce, beech–fir, spruce–fir and two monospecific beech and spruce treatments. The age of the forest stands ranged from 11 to 15 years when sampled. All study sites were used as meadows when afforested; therefore, the forest floors were new, and the A-horizon topsoil properties were not influenced by older humus inherited from previous forest generations. The mineral soil was likely affected by different levels of former fertilization, which resulted in differences among the study sites. The early-developed forest floors showed differences between the treatments with beech and the others. The topsoil below beech with spruce had more nitrogen, oxidizable carbon and cations of exchangeable hydrogen as well as pH showing more acidic conditions and lower contents and saturation of base cations. Pure beech had more phosphorus. The nutrient pools did not differ among the treatments; significantly more matter was found below the oldest stands on the first afforested site, which also increased nutrient pools. [ABSTRACT FROM AUTHOR]