Litterfall production and nutrient return to the forest floor in Scots pine and Norway spruce stands in Finland

The main objective of this study was to determine the importance of nutrient return in litterfall (LF) to forest nutrient cycling. Therefore, we investigated the quality and quantity of LF in relation to the above-ground tree biomass (AGT) and determined the turnover rates. The study was carried out on seven Norway spruce (Picea abies) and six Scots pine (Pinus sylvestris) plots. LF was sampled during 1996-2003, and AGT in 2005-2006. The studied nutrients were N, Ca, K, Mg, P, S, Mn, Zn, Fe. Overall, the results indicated that there are quality, quantity and spatial differences in LF and AGT compartments. In general, both concentrations and mass of LF and AGT were higher on the spruce plots; 2% of the AGT biomass returned to the forest floor as LF on the plots. Magnesium turnover rate was higher on the spruce plots. The turnover rates of other nutrients were slightly higher on the pine plots, indicating faster nutrient cycling via LF. More litter needles (kg ha -1 ) ended up on the forest floor in relation to living needles on the spruce plots.