title: Does mixing of beech (Fagus sylvatica) and spruce (Picea abies) litter hasten decomposition?
abstract: OBJECTIVE
  It is of practical relevance to know how much beech must be admixed to pure spruce stands in order to increase litter decomposition and associated nutrient cycling, since the formation of thick organic layers is commonly ascribed to the recalcitrance of spruce needles. We addressed the impact of tree species mixture within forest stands and within litter on mass loss and nutritional release from litter.
  
  
  METHODS
  Litter decomposition was measured in three adjacent stands of pure spruce (Picea abies), mixed beech-spruce and pure beech (Fagus sylvatica) on a nutrient-rich site and a nutrient-poor site over a 2-year period using litterbags which were filled with five different mixtures of beech and spruce litter.
  
  
  RESULTS
  Mass loss of beech litter was not higher than mass loss of spruce litter. Decay was primarily affected by tree species composition of the incubation stand and was faster in (mixed) beech forests stands than in spruce forests, while the influence of litter species and their mixtures on decay rates was small. Net transfers of nutrients between the two litter species (direct effects) in the mixed bags were minimal, since initial beech and spruce litter did not have different litter quality. However, in a few cases indirect effects (e.g., changing decomposer abundance and activity) caused non-additive patterns for the totals within the mixed bags, hastening decomposition within the first year.
  
  
  CONCLUSIONS
  Greater accumulation of litter in spruce compared to beech stands is not a consequence of the inherent recalcitrance of needles. Adverse environmental conditions in spruce stands retard decomposition. Indirect effects on decomposition caused by stand mixture are not mimicked by litter mixtures within mesh bags.
authors.affiliation: Department of Forest- and Soil Sciences, Institute of Forest Ecology, University of Natural Resources and Live Sciences (BOKU), Peter Jordan-Straße 82, 1190 Vienna, Austria.
authors.forename: Torsten W
authors.initials: TW
authors.lastname: Berger
authors.affiliation: Department of Forest- and Soil Sciences, Institute of Forest Ecology, University of Natural Resources and Live Sciences (BOKU), Peter Jordan-Straße 82, 1190 Vienna, Austria.
authors.forename: Pétra
authors.initials: P
authors.lastname: Berger
keywords: Decomposition; Fagus sylvatica; Litter quality; Litterbag; Mixing effects; Picea abies
references.citation: Oecologia. 2010 Feb;162(2):479-89
references.pmid: 19756760
references.citation: Oecologia. 2010 Dec;164(4):1083-94
references.pmid: 20596729
references.citation: Plant Soil. 2012;358(1-2):349-369
references.pmid: 25834285