ACCUMULATION AND EXPORT OF NUTRIENTS IN HARVESTED WOOD OF <em>VOCHYSIA</em> <em>GUATEMALENSIS</em> IN SMALL-SCALE FOREST PLANTATIONS

Abstract

To enhance knowledge required for better management of tropical forest plantations, aboveground nutrient accumulation in different tree tissues (stem, branches, foliage and total) at different growth stages of Vochysia guatemalensis (white yemeri) was studied. False time series were used from 16 small farmer sites in humid tropical lowlands of Costa Rica. A 17-year-old stand with density of 483 trees ha^-1 and 35 cm diameter at breast height (dbh) accumulated 818 kg ha^-1 N, 686 kg ha^-1 K, 552 kg ha^-1 Ca, 284 kg ha^-1 Mg, 114 kg ha^-1 P, 152 kg ha^-1 S, 11 kg ha^-1 Fe, 101 kg ha^-1 Mn, 0.5 kg ha^-1 Cu, 2 kg ha^-1 Zn, 1 kg ha^-1 B and 1063 kg ha^-1 Al. The expected nutrient export by timber harvest (stem) was 499 kg ha^-1 N, 485 kg ha^-1 K, 314 kg ha^-1 Ca, 188 kg ha^-1 Mg, 46 kg ha^-1 P, 69 kg ha^-1 S, 8 kg ha^-1 Fe, 29 kg ha^-1 Mn, 0.5 kg ha^-1 Cu, 1.4 Zn, 0.6 kg ha^-1 B and 783 kg ha^-1 Al. Aluminium accumulation was higher than other nutrients, confirming that V. guatemalensis is an Al-hyperaccumulator species. Aluminium exported as wood represented between 74–93% of the total accumulated, so large amounts of this element was taken out of the planting site during harvest. Nitrogen and K also had high percentages of accumulation. Thus, the management of this system should pay special attention to the dynamics of these three nutrients.