Impact of mega-drought on tree radial oak growth Nothofagus obliqua (Mirb.) Oerst. (Roble), Chile

Abstract

In order to evaluate the impact of the decline in rainfall between 2007 and 2012 in Central Chile on the northern forests of Nothofagus obliqua, a total of 223 growth plugs were measured in 51 isolated trees and 172 growing in competition. Local annual precipitation data were used to compare the growths of the normal period (2001-2006) with those of the dry period (2007-2012). The current annual growth in radius to normal diameter and its sensitivity were contrasted, showing that both isolated and competing trees showed an evident deterioration in their growth rates. A 34.8 % deficit in precipitation translates into a 17.6 % and 28.8 % decrease in current annual growth in isolated and competing trees, respectively. In the dry period, compared to the previous period, isolated trees showed a less sensitive growth (0.364) than that of competing trees (0.384). It was also established that the precipitation evaluated in a moving average of previous years to the year in evaluation is able to explain, through a linear model, up to 57.3 % of the total variability of the radial growth in isolated trees, using an average window of 6 years and 41.7 % in trees that compete with a window of 3 years.

Keywords

• Árboles aislados
• competencia
• crecimiento radial
• precipitación.