Evaluación de la capacidad de rebrote en Eucalyptus dunnii bajo diferentes tratamientos de cosecha

In Uruguay, Eucalyptus dunnii Maiden is one of the main forest species used in pulp production. Its production system is based on two alternatives: conventional plantation or coppice management. The efficiency of the latter depends on the survival percentage achieved within a given period, which is conditioned by multiple biotic and abiotic factors. Therefore, with the aim of identifying silvicultural practices that optimize vegetative regeneration, the following objectives were proposed: 1) to evaluate the effect of cutting method, cutting height, and the application of chemical products (growth regulator and soil biostimulant), as well as their interactions, on the stump survival percentage of Eucalyptus dunnii at 135 days post-harvest; and 2) to analyze the effect of stump diameter and felling season as predictor variables of said survival. The study was conducted at two forest properties located near Alejandro Gallinal (Florida, Uruguay), named Cruz Roja and Mi Generala. Stump diameter and height were recorded at the time of trial establishment, immediately after harvest, while sprouting was assessed at 135 days post-harvest (4.5 months). Survival as a function of felling time was analyzed using descriptive statistics, while the effect of treatments and factors was evaluated using bootstrapping resampling techniques. Finally, a classical logistic model was used to assess the effect of stump diameter. The trials were analyzed independently due to frost events that affected sprouting, mainly at Mi Generala. Results indicated that the trial installed in February (at Cruz Roja) showed 25.6% higher sprouting than the one installed in March (at Mi Generala). At Cruz Roja, no significant differences were detected among treatments, cutting heights, chemical applications, or stump diameters; only the cutting method showed a significant effect, with higher survival recorded when using a harvester. At Mi Generala, treatments, cutting method, cutting height, and stump diameter all significantly influenced survival, with chainsaw and feller buncher performing notably well, along with higher cutting heights and larger stump diameters. It is concluded that felling season is a determining factor in the coppice regeneration of Eucalyptus dunnii, and its effect can be enhanced through appropriate selection of cutting method and height.