Biomass and nutrient accumulation in a planted E. globulus (Labill.) fertilizer trial

Abstract

The above ground biomass of Eucalyptus globulus was estimated four times during 9.5 years in a plantation treated with four levels of fertilizer. A linear relationship between biomass components and tree basal area was appropriate up to 4 years of age but the allometric relationship was more suitable in subsequent years. A biomass of 3 kg m-2 took 9. 5 years to accumulate in unfertilized plots compared with 4 years in heavily fertilized plots. Net primary production reached 1, 5 kg m-2 year-1 in the heavily fertilized plots between 6 and 9.5 years of age. Nitrogen accumulation in heavily fertilized plots reached a peak of 2.6 g m-2 year-1 before 2 years of age compared with a plateau of 0.8 g m-2 year-1 in unfertilized plots. Maximum accumulation of phosphorus in heavily fertilized and unfertilized trees was 0.25 and 0.10 g m-2 year-1 respectively. The effect of fertilizer on nutrient accumulation disappeared during the period from 6 to 9.5 years.