Geographia Polonica (2012) vol. 85, iss. 2
What Determines Forest Litter Decomposition? Global Trends And Local Variance
Global patterns in forest leaf litter decomposition has been studied for decades. The result has been the formulation ofa range of models relating organic matter decay rate to climatic and litter-specific factors. It is now commonly acceptedthat the prime factor determining the litter decomposition rate on a global scale, is actual evapotranspiration (AET).However, this main effect can be seriously modified by the chemical composition of organic matter itself, resulting in largevariance at local scales. Among leaf litter components, the lignin concentration, content of water-soluble compounds,concentration of nitrogen and some other nutrients have been indicated by different authors as the major determinantsof litter decomposition rate. Unfortunately, our understanding of the factors regulating the decomposition is still far fromsatisfactory as indicated by the failure of existing models to predict properly litter decay rate in many cases. These includeespecially ecosystems from outside the temperate climate, such as boreal and wet tropical forests. The existing modelsstill cannot explain the large differences in litter decomposition rates between species, even within reasonably wellstudiedtemperate forests. My article presents several reasons for the problem of finding satisfactory litter decompositionmodels. The most important reason is the bias in studies towards temperate ecosystems, high inter-correlations betweenchemical characteristics of litter and soil, and the lack of properly designed studies on very broad geographic scales.
, Department of Ecosystem Ecology, Institute of Environmental Biology, Jagiellonian University, Ingardena 6, 30-060 Krakow, Poland.