Abstract Stand structure can have a considerable influence on forest growth and productivity. A stand’s response to factors like temperature, precipitation, vapor pressure deficit and different soil characteristics may result not only from the mean change in tree responses (e.g. growth decrease or increase), but may also depend on how individual tree responses vary in relation to their size and how they cope with competition. There may be a large growth imbalance among trees as a function of their size, which is referred to as growth dominance. That is, a change in a factor may have different impacts on stand growth depending on stand structure and how growth is distributed. Thus, using an experimental platform spanning tropical Brazil, we explored the relationship between growth dominance and stand growth, and whether this relationship changes across a wide climatic gradient, represented by soil water deficit. We found a predominance of negative growth dominance during the early phase of stand development which increased until dominance became positive, after about 30 months, and kept increasing afterwards. Increasing soil water deficit slowed the increase in growth dominance throughout time. The intensification of growth dominance (either positive or negative) was associated with decreasing stand growth. Increasing soil water deficit decreased the negative effect of growth dominance on increment in absolute terms, but we showed that, at the end of a 5-year rotation, increasing growth dominance at a site with more intense water deficit led to a greater growth loss in relative terms than at a site with milder water deficit. For example, the estimated difference in increment between a stand with a low growth dominance of 0.05 and a stand with a high growth dominance of 0.20 at the end of a 60–month rotation at a site with an accumulated water deficit of −200 mm was about 28 m3 ha−1 year−1, which is equivalent to a 39% decrease in relative terms. This same GDC difference under a water stress of −4000 mm resulted in a decrease in increment of approximately 18 m3 ha−1 year−1, or 48% in relative terms.

中文翻译：

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探索巴西整个大陆环境梯度桉树单克隆人工林林分生长、结构和生长优势之间的关系

摘要 林分结构对森林生长和生产力有相当大的影响。林分对温度、降水、蒸气压不足和不同土壤特征等因素的响应可能不仅源于树木响应的平均变化（例如生长减少或增加），而且还可能取决于个体树木的响应如何相对于它们的变化而变化。规模以及他们如何应对竞争。作为树木大小的函数，树木之间可能存在很大的生长不平衡，这被称为生长优势。也就是说，一个因素的变化可能对林分生长产生不同的影响，这取决于林分结构和生长分布。因此，使用跨越热带巴西的实验平台，我们探索了生长优势与林分生长之间的关系，以及这种关系是否在广泛的气候梯度上发生变化，以土壤水分亏缺为代表。我们发现在林分发展的早期阶段，负生长优势占优势，这种优势一直在增加，直到优势变为正，大约 30 个月后，然后继续增加。随着时间的推移，土壤水分亏缺的增加减缓了生长优势的增加。生长优势的加强（正的或负的）与林分生长的下降有关。增加土壤水分亏缺减少了生长优势对增量的绝对影响，但我们表明，在 5 年轮换结束时，在水分亏缺更严重的地点增加生长优势导致更大的生长损失相对而言，与缺水程度较轻的地点相比。例如，在累积水分亏缺为 -200 毫米的地点，在 60 个月轮换结束时，0.05 的低生长优势林分和 0.20 高生长优势林分之间的估计增量差异约为 28 立方米ha-1 年-1，这相当于相对减少 39%。在 -4000 mm 的水分压力下，相同的 GDC 差异导致大约 18 m3 ha-1 year-1 的增量减少，或相对而言 48%。