Regional Variation in Rate of Mass Loss of Pinus sylvestris Needle Litter in Swedish Pine Forests as Influenced by Climate and Litter Quality

The climatic influence on plant litter decomposition has been successfully correlated on a regional level by using estimated actual evapotranspiration (AET) and annual mass loss. This approach was applied to decomposition studies carried out in a transect along Sweden with litter incubated in four different forest types. A unified needle litter was used and among 14 Scots pine sites about 80% of the mass-loss rate could be explained. A simple model was made on the influence of both climate and nutrient concentrations (nitrogen and phosphorus) on mass-loss rate. About 90% of the first-year mass loss could be explained by this approach. As early decomposition stages were studied (<40%) no influence of lignin was observed.