Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in these areas is well known, up-to-date information about these woodlands’ diversity is limited and changes in their woody vegetation composition, density, diversity and relative frequency are not monitored over time. This study explored tree diversity and stand stage structure in Nuara Reserved Forest, a typical savanna woodland ecosystem in southeastern Sudan. A total of 638 circular sample plots (1000 m2 for each) were established using a systematic sampling grid method. The distance between plots was 200 m. In each plot, all living trees with diameter at breast height (DBH) ≥5.00 cm were identified and counted, and their DBH values were recorded. From these data, tree composition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species (Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia mellifera) that belong to two families. The dominant species was Acacia seyal. Average tree density was 191 trees/hm2 and the Shannon-Weiner index for trees diversity was 0.204. Overall, young trees comprised 86.30% of the forest. The state of tree richness and density in the study area was low compared to other similar environments in the region and around the world. We recommended adoption of a proper management system that includes monitoring of woody vegetation diversity in this forest, and management actions to enhance tree diversity and sustain ecosystem services to local communities. In addition to care for the dominant Acacia seyal stands, more attention and conservation should be devoted to reestablishing Acacia senegal and Acacia mellifera trees because of their high ecological and economic values for local communities.

中文翻译：

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探索苏丹东南部稀树草原林地的树木多样性和林分结构

苏丹的稀树草原林地拥有丰富的生物多样性，为当地社区提供大量生态系统产品和服务，并维持众多生态功能。尽管金合欢树在这些地区的重要性众所周知，但关于这些林地多样性的最新信息是有限的，并且没有随着时间的推移监测其木本植被组成、密度、多样性和相对频率的变化。本研究探讨了苏丹东南部典型的热带稀树草原林地生态系统 Nuara 保留林的树木多样性和林分阶段结构。使用系统抽样网格方法建立了总共 638 个圆形样地（每个样地 1000 平方米）。地块之间的距离为 200 m。在每个地块中，所有胸高直径（DBH）≥5.00 cm 的活树被识别和计数，并记录它们的 DBH 值。根据这些数据，评估了树木组成、多样性、密度和阶段结构。共有 12,259 棵树木，代表属于两个科的四个物种（Acacia seyal、Balanites aegyptiaca、Acacia Senegal 和 Acacia mellifera）。优势种是金合欢。平均树木密度为 191 棵树/hm2，树木多样性的香农-韦纳指数为 0.204。总体而言，幼树占森林的 86.30%。与该地区和世界各地的其他类似环境相比，研究区域的树木丰富度和密度状态较低。我们建议采用适当的管理系统，包括监测该森林中的木本植被多样性，以及采取管理行动以增强树木多样性并维持对当地社区的生态系统服务。