Growth of Eucalyptus globulus plantations on red clay soils in the Province of Osorno, 10th Region, Chile

Abstract

Eucalyptus sp. plantations began to be commercially established in 1990 to 2000 in the 10th Region, or “Región de Los Lagos”, Chile, as a result of both a good market and high growth expectations. Further estimations indicated that the growth rates in the Province of Osorno were actually less than those planned, but no measurements were available to back them up. The objective of this work was to measure the volume growth of Eucalyptus globulus plantations established in the western area of the Province of Osorno. The study area was located between 40°S to 41°S and comprised red clay soils that belonged to the Fresia family, specifically the Cudico and Crucero series.
Different plantations, eight years old on average, were measured in areas of at least 5 ha each one, with a total area of 300 ha. These plantations were managed with minimum planting techniques, which meant that they all had to be partially replanted, mainly due to damage caused by frosts during the first two years. A simple random sampling was performed in each plantation with a maximum error of 15% of the basal area. The volume was estimated with a volume function for the species. The annual average increase of E. globulus in the area reached 10 to 12 m3/ha/ year, which was the lowest growth level expected, as a result of the lack of adequate establishment techniques and low temperatures during the winter. However, one particular plantation of the same species established in a propitious place of the same area and with better establishment techniques reached a substantial higher growth of 32 m3/ha/year. The results obtained indicate that in this area, with marginal climatic conditions for the species, very careful site selection is required and that warmer aspects might be preferred. Intensive establishment techniques must also be practiced such as soil cultivation, weed control and fertilization.