ABOVEGROUND BIOMASS GROWTH AND YIELD OF FIRST ROTATION CUTTING CYCLE OF Acacia AND Eucalyptus SHORT ROTATION DENDROENERGY CROPS

Abstract

ABSTRACT Chile has strong interest in biomass production for the purpose of generating bioenergy to accomplish environmental standards for clean energy production. However, no yield or productivity information is available about forest crop plantations established at high-initial planting densities dedicated to energy production. The objective of the present study was to provide long-term results of short-rotation forest crops research trials, investigating first cutting cycle most promising species biomass production. Plantations of Acacia melanoxylon, Eucalyptus camaldulensis, Eucalyptus globulus, and Eucalyptus nitens were established at initial stockings of 5,000; 7,500 and 10,000 trees ha-1 on marginal sites with important nutritional and hydric limitations in the Biobío Region, Chile. After 48 months, E. camaldulensis reached the highest biomass yield at initial stocking of 7,500 trees ha-1 (22.5 Mg ha-1) on dry land granitic soils, and E. nitens reached 35.2 Mg ha-1 on sandy soils. Initial stockings and biomass yields were directly related, but strongly conditioned by mortality, where greater initial stocking concurred with greater mortality after 4 years. The collar diameter and total height growth was lower at higher stockings.