Optimization of Biomass Production in Eucalyptus Globulus Plantations. — A Case Study

Eucalyptus globulus Labill. was introduced in Portugal in the middle of the last century (Pimentel 1884) and has been widely planted for pulpwood production for the last thirty years. The eucalypt stands are tended according to the principles of intensive silviculture in a coppiced system with short rotations (7–14 years) and are usually maintained for four rotations. The productivity of E. globulus is high and reaches, in unfertilized plantations, 24 to 30 t ha-1 year-1 at 10 years of age (Fabiao 1986). Productivity is, however, strongly influenced by the availability of soil water and mineral nutrients. E. globulus is reported to have a good potential for high production under improved conditions of water and nutrition (cf. Cromer et al. 1975, 1981). This was clearly demonstrated by data from four contiguous plots, each 1000 m2 in size, situated along a gentle slope at Quinta do Furadouro, Obidos, Portugal. The standing biomass varied, at the age of 15 years, from 100 t ha-1 in the plot at the top of the slope to 350 t ha-1 in the more fertile soils of the valley (M. Tome and L. Leal, unpublished).