| Popis: |
An estimate has been made of the quantities of nutrients in trees, shrubs, litter and soil at a jarrah forest site near Dwellingup, Western Australia. This shows that the nutrient status is lower than most Australian eucalypt forest ecosystems, particularly with respect to the soil. The concentrations of elements in leaves and bark have been found to vary with location in the trees. This may be important in future sampling for studies of tree nutrition. Calculations based on timber harvested from the entire area of prime jarrah forest since the 1830's indicate that the average removal of nutrients has been small. However, where harvesting has been more intensive or land use activities have removed much of the biomass, the available nutrient store may have been substantially depleted. For example, removal of 100 t ha−1 of logs containing 84 kg N, 3 kg P, 75 kg K, 16 kg S, 52 kg Ca, 28 kg Mg, 2 kg Mn, 0.2 kg Cu and 0.2 kg Zn is substantial when compared with the 13 kg P, 55 kg K and 28 kg S in readily extractable forms in the soils. |
