GROWTH-RATES AND MORTALITY PATTERNS OF TROPICAL LOWLAND TREE SPECIES AND THE RELATING TO FOREST STRUCTURE IN AMAZONIAN ECUADOR

Growth in diameter and the relationship between age and size are analysed for 22 tree species in Amazonian Ecuador using growth simulation by a stochastic technique that projects the diameter-age relationships of a species. Maximum diameter growth rates varied from 1.2 mm y-1 (Grias neuberthii) to 20.0 mm y-1 (Cecropia sciadophylla). Minimum growth rates ranged from almost zero in Neea divaricata to 2.4 mm y-1 in Mollia lepidota. Median growth rates ranged between c. 0.5 mm y-1 (Grias neuberthii, Neea divaricata) and 11.6 mm y-1 (Cecropia sciadophylla). The maximum simulated life-span spent between a DBH of 10 cm and the largest DBH of a species varied from 54 y (Cecropia sciadophylla) to 529 y (Neea divaricata). Fast growing species and species that potentially can grow old showed a convex survivorship curve, whereas slower growing species and species that do not grow very old showed sigmoid, linear and convex survivorship curves. The species were grouped according to their DBH-height relationship and according to their maximum age, maximum growth rate, and maximum DBH. The groups probably reflect different light requirements. A negative correlation was found between maximum age and mortality rate. Growth rates vary within species, thus the largest tree is not necessarily the oldest.