Tree growth in urban areas is beset by multiple stresses, of which the soil component has imposed severe constraints. In the tropics, the inherently infertile and acidic soils present challenges that demand dedicated solutions. Yet, the key edaphic issues have remained poorly understood and often inadequately evaluated and improved. Where site soil is poor or absent, a soil specification usually prescribes a fabricated soil mix. Unfortunately, these documents frequently include non-essential attributes or exclude essential ones. The specified ranges and thresholds tend to detach from soil science concepts or are irrelevant to local conditions. Some projects would adopt specifications prepared for other local or international sites without modifications to match site requirements. Errors tend to be copied and propagated in different documents. Knowledge transfer from researchers to practitioners can improve the soil specifications to resolve a significant and chronic weakness in urban forestry. Five representative local documents and five from other countries were critically evaluated in detail to distill 21 principal concerns and 20 principles of soil specification design. The knowledge base informed the development of a rationalized and improved soil specification for urban forestry in the tropics. It included the fabricated topsoil mix and fabricated subsoil mix to meet most planting needs, and a dedicated fabricated lightweight mix for planting on rooftops with limited load-bearing capacity. Further explanations justified using local raw materials, soil sampling strategy, soil properties, recommended ranges, and standard laboratory testing methods. Other tropical regions can modify the proposed specification to fit local circumstances and specific landscape needs.

城市地区的树木生长受到多种压力的困扰，其中土壤成分施加了严重的限制。在热带地区，固有的贫瘠和酸性土壤带来了需要专门解决方案的挑战。但是，关键的普及性问题仍然知之甚少，并且往往评估和改进不足。在现场土壤贫瘠或没有土壤的地方，土壤规格通常规定了人造土壤混合物。不幸的是，这些文档经常包含非必要属性或排除必要属性。规定的范围和阈值倾向于脱离土壤科学概念或与当地条件无关。一些项目将采用为其他本地或国际站点准备的规范，而无需进行修改以匹配站点要求。错误往往会在不同的文档中复制和传播。从研究人员到从业人员的知识转移可以改善土壤规格，以解决城市林业中长期存在的重大缺陷。详细评估了五份具有代表性的地方文件和五份来自其他国家的文献，以提炼出21个主要关注点和20个土壤规格设计原则。知识库为热带地区城市林业的合理化和改良土壤规格的开发提供了依据。它包括可满足大多数种植需求的人造表层土混合物和人造地下土混合物，以及专门用于承重能力有限的屋顶种植的人造轻质混合物。使用当地原材料，土壤采样策略，土壤特性，推荐范围和标准实验室测试方法进行进一步解释是合理的。