Does post-fire forest management increase tree growth and cone production in Pinus halepensis?

Abstract

Sapling densities may greatly increase in Pinus halepensis forest stands after fire. This study examines the effects of different post-fire silvicultural treatments on Aleppo pine forests at sites of different quality in Spain: dry (good) (Yeste, Albacete) and semiarid (worse) (Calasparra, Murcia) by monitoring permanent plots from 1999 to 2001. Changes occurring as a consequence of thinning (to a constant density of 1600 trees/ha), full scrubbing and pruning (to one-half to total height) practices were examined measuring diameter and total height of the trees in a 2-year interval. The growth (except on relative diameter increment) of Aleppo pine from Yeste was greater than from Calasparra, probably as a result of its better site quality. Thinning in the good quality site, and thinning plus scrubbing, in the worse quality one, were the treatments that most improved pine growth. Pruning, in contrast should not be carried out in any site, at least under the conditions of this study. The different response in total growth between plots for the same treatment was caused by differences in initial characteristics of the plots: micro-site quality (dominant height by plot) was important in the good quality site, whereas initial density (saplings/ha) was important in the worse quality one. Regarding fructification, treatments that included thinning plus scrubbing improved, 22 months later, the probability of cone production by a factor of 2.07 in relation to control.