ABSTRACT - (Litter production and nutrient return in a portion of the secondary Atlantic Forest, at the Biological Reserve of Paranapiacaba, SP). The litter production and nutrient contents have been quantified in an area of Atlantic Forest at the Biological Reserve of Paranapiacaba, in the state of São Paulo, free from the impact of the air pollution from the industrial complex of Cubatão. The objectives of this study were to compare the results obtained here with those of a similar study performed at more and less affected areas of the Reserve and to determine the extension of the air pollution impacts at that region. Thirty litter trays with 0,25 m² were randomly distributed, sampling the litter monthly during one year (Abr/88 to Mar/89). The samples were sorted by leaves, twigs, reproductive parts and miscellaneous, weighed and N, P, K, Ca, Mg and S concentrations were determined. The annual total litter production was 7007 kg.ha-1 (72% of leaves, 22% of twigs, 4% of miscellaneous and 2% of reproductive parts) The litterfall and nutrient fluxes were continuous along the year, without any clear seasonal pattern. Leaves showed higher levels of Ca and Mg while miscellaneous presented more N, P, K and S. The macronutrient return through total litterfall followed the decreasing sequency N>Ca>S>K>Mg>P. Through comparison with results from other studies on tropical forests and on the Paranapiacaba Reserve itself, it is concluded that the part of the forest here studied does not present changes caused by air pollution in this step of nutrient cycling.
Litterfall; nutrient return; Atlantic Forest
