In dryland environments where rivers have been modified by water resource developments, the use of environmental water provides a management tool to restore or maintain riparian vegetation conditions. Relevant management actions include watering to promote the recruitment of highly valued woody species. However, for many riparian trees, little is known about the watering regimes needed to achieve successful recruitment. We conducted a glasshouse experiment to investigate the early growth of 5-week old seedlings of two Australian dryland riparian tree species, coolibah (Eucalyptus coolabah) and river red gum (Eucalyptus camaldulensis), in floodplain soil cores to provide insights into their requirements for successful establishment in dryland habitats. Both species exhibited similar growth patterns for their above-ground components. E. coolabah root penetration through soil cores was consistent over the 12-week experiment. In contrast, E. camaldulensis root penetration appeared to be considerably slower during the first 6 weeks, but then became more rapid over the following 6 weeks, with similar rooting depths after 12 weeks observed to those of E. coolabah. These findings suggest that coolibah seedlings are more likely to establish under rapidly drying conditions than river red gum seedlings. Such differences in early growth for these iconic species should be considered when determining the provision of environmental water for their management.

中文翻译：

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两种澳大利亚旱地河岸桉树的幼苗根生长实验为环境浇水提供了新见解

在河流因水资源开发而改变的旱地环境中，环境水的使用提供了恢复或维持河岸植被条件的管理工具。相关管理行动包括浇水以促进高价值木本物种的补充。然而，对于许多河岸树木，对实现成功补充所需的浇水制度知之甚少。我们进行了一项温室试验，以调查两种澳大利亚旱地河岸树种，coolibah ( Eucalyptus coolabah ) 和河红胶 ( Eucalyptus camaldulensis ) 5 周龄幼苗的早期生长情况。)，在洪泛区土壤核心中深入了解它们在旱地栖息地成功建立的要求。这两个物种的地上部分表现出相似的生长模式。在 12 周的实验中，E.coolabah根穿透土壤核心是一致的。相比之下，E. camaldulensis 的根穿透在前 6 周似乎相当缓慢，但在接下来的 6 周内变得更快，12 周后观察到的生根深度与E.coolabah 相似. 这些发现表明，与河红胶树苗相比，库利巴树苗更可能在快速干燥的条件下建立起来。在确定为其管理提供环境水时，应考虑这些标志性物种早期生长的这种差异。