Abstract

GARCIA, María A.; RAMOS, S.O.  and  ALEJANDRO, J.D.. Growth response of two genetic materials of Eucalyptus to different height and time of pruning. RIA. Rev. investig. agropecu. [online]. 2024, vol.50, n.1, pp.14-20. ISSN 1669-2314.

We conducted four experiments to evaluate the effects of different heights and times of pruning on the growth of Eucalyptus grandis and E. grandis x E. camaldulensis GC INTA 8 in Concordia (Entre Ríos, Argentina). During winter, two experiments were carried out on 20 months old stands and, during spring, two more experiments were carried out on 24 months old stands. Each experiment consisted of two treatments assigned under a completely randomized design with four replicates of 300 m2 plots: T1= pruning to 2.5 m; T2= pruning to 4.5 m. Diameter at breast height (DBH) and total height were measured before pruning and after 12 months to calculate height and DBH growth in the first year following pruning. We used GLM and GLMM to modeling growth. Then, we compared the mean values of height and DBH growth ofT1 with T2 using Fisher’s LSD test. Finally, we calculated the resulting remaining crown (RC) after pruning treatments. After winter pruning, we found no significant differences in the growth of the two genetic materials. On the contrary, after spring pruning, the DBH growth of E. grandis was significantly lower (p=0.001) in T2 (3.4 cm) than in T1 (3.9 cm), while the height growth of GC INTA 8 was significantly lower (p=0.011) in T2 (3.2 m) than in T1 (3.5 m). According to the results, winter pruning of Eucalyptus genetic materials does not affect their growth in the first year, regardless of the height of pruning. However, spring pruning can affect DBH or height growth, depending on the variety. The extremely dry conditions during the development of these experiments may have affected growth responses differently. Further studies should focus on growth responses to pruning under normal climate conditions and other factors that may also affect growth.

Keywords : eucalyptus; hybrid clone; silvicultural practice.

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