Growth response following green crown pruning in plantation-grown Eucalyptus pilularis and Eucalyptus cloeziana

Abstract

Pruning of live branches is performed to enhance wood quality in plantation trees. Stem, branch and wood properties may be altered following pruning from below, but the extent and duration of such effects are unknown for many plantation Eucalyptus species. The effect of 0%, 20%, 50%, and 70% green crown length removal on growth and wood quality was examined in 3.5-year-old plantation-grown Eucalyptus pilularis Sm. (blackbutt) and Eucalyptus cloeziana F. Muell. (Gympie messmate) trees on two subtropical sites in eastern Australia. Growth increment of the stem at breast height was not affected by 20% crown removal. However, stem increment at breast height was reduced for up to 8 months with 50% crown removal and up to 12 months with 70% crown removal. Pruning had no impact on height growth. However, the height of trees pruned to 70%, relative to the height of the surrounding unpruned trees, was temporarily reduced 12 months after pruning in both species. Stem form, stem taper, wood density, and residual branch growth above the pruned zone were unaffected by pruning. Owing to the fast vertical crown expansion, trees were able to rapidly compensate for leaf area removal without long-term reductions in stem growth. The implications for management operations utilizing pruning as a means of enhancing timber quality are discussed.

Changes in Whole-Tree Water Use Following Live-Crown Pruning in Young Plantation-Grown Eucalyptus pilularis and Eucalyptus cloeziana

“…However, given the rapid recovery of transpiration rates, determining the best time to prune these fast-growing eucalypts in order to achieve the maximum drought-buffering effect requires further study. The minor and insignificant reduction in diameter growth is consistent with other pruning studies on E. pilularis and E. cloeziana that removed the lower 50% of the live-crown length [30]. Pruning also had no significant effect on the above-ground biomass growth of the largest 200 trees ha −1 of E. nitens trees, 2-3 years after pruning [31].…”

Potential gains through selecting for resistance in spotted gum to Quambalaria pitereka

“…If pruning is required, then the cost of this action increases with increasing branch size and frequency, with wounds taking longer to overgrow on larger branches (Smith et al 2006). In addition to this, larger branch knots result in greater levels of degrade in the final product (Alcorn et al 2008). The frequency of ramicorns was also reduced when susceptibility to Q. pitereka was low.…”

Pruning of Eucalyptus grandis x Eucalyptus urophylla planted at low density in Southeastern Brazil

“…Brendenkamp et al, 1983;Pinkard and Beadle, 2000;Monte et al, 2009). A general consensus is that 40 to 50% of the lower green crown can be removed without affecting tree growth (Pinkard and Beadle, 1998;Alcorn et al, 2008;Forrester et al, 2010). The results found in this study indicated a stronger response of growth loss following pruning than usual, with mean stand attributes suffering reduction with the removal of 40% of lower green crown onwards.…”