John Du Vall Hay
Departamento de Ecologia, Universidade de Brasilia, Brasilia, DF, 70910-900, Brazil
Arundo donax L. (giant cane) is a fast-growing tall grass that has been used as an energy crop in several countries around the world. It is considered to be one of the world’s most invasive species due to its capacity to occupy space in different plant communities. Although there have been many studies of biomass production in A. donax, there is only one previous study on its allometric growth. The objective of this study was to compare allometric growth of A. donax collected in different locations within the Federal District of Brazil. At each site a minimum of 10 and a maximum of 20 stems were collected ranging from 0.22 to 7.04 m in height and 0.001 to 1.29 kg in dry weight. Other measurements made in the field were basal diameter (mm), diameter at 1 m (mm), number of nodes, and number of green leaves. If lateral sprouts were present, their number was counted. All individuals were regrowth from a previously cut clump, but the time since cutting was unknown. As in previous allometric studies of A. donax, the general equation for these data was a power function and height (R2 = 0.9043) was a better predictor of biomass than basal diameter (R2 = 0.6605). Although the fit of this general equation for the entire data set was excellent, when each collection was analyzed separately, the results showed that allometric growth at different sites was different as was allometric growth at the same site when data were collected in different seasons.