Forest tillage experiments regularly use long-term evaluations of large plots creating temporal and/or spatial correlations among observations. Not modeling these correlations could compromise treatment comparisons. The aim of this study was to evaluate the effect of modeling spatio-temporal (ST) variability in forest tillage experiments. We used different strategies that incorporate spatial and/or temporal correlations in the evaluation of tillage intensity effect in initial Eucalyptus growth as well as evaluate the effect of intraplot mortality and competition dynamics. Three tillage intensities in two contrasting soil conditions were compared for tree height and wood volume. Additionally, we compared the use of three individual growth curves for plant height to evaluate the time needed to reach 2 m in height (T_2m). We modeled the spatial correlation of T_2m using mixed models. In both sites, ST models were superior for plant height and wood volume per hectare, whereas for individual-tree wood volume, temporal models were superior. Pit planting always had a lower performance than disk harrowing and subsoiler, which behaved similarly. The competition dynamics within the plot because of tree mortality was affected by treatments and site. Modeling ST variability is key to improving treatment comparisons in forest experiments.

中文翻译：

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桉树早期生长的森林耕作试验时空模型和竞争动力学。

森林耕作实验经常使用对大块土地的长期评估，从而在观测结果之间建立时间和/或空间相关性。不对这些相关性建模可能会损害治疗比较。这项研究的目的是评估在森林耕作试验中模拟时空（ST）变异性的影响。我们在初始桉树耕作耕作强度影响评估中采用了包含空间和/或时间相关性的不同策略增长以及评估团内死亡率和竞争动态的影响。比较了两种相反土壤条件下三种耕作强度的树高和木材体积。此外，我们比较了使用三个单独的生长曲线作为植物高度来评估达到2 m高度（T _2m）所需的时间。我们模拟了T _2m的空间相关性使用混合模型。在这两个地点，ST模型在株高和每公顷木材量方面都比较好，而在单树木材量方面，时间模型更好。坑式种植总是比圆盘耙和深耕机表现差。由于树的死亡率，该地块内的竞争动态受到处理和场地的影响。对ST变异性进行建模是改善森林实验中的处理比较的关键。