Fast-growth plantation forestry is relatively new in many Southeast Asian countries, and there is a clear need for monitoring and assessment of plantation forest soils in this region. In this study, we used miniature plots to estimate and explain site productivity for three widely planted hardwood tree species: Acacia mangium, Falcataria moluccana and Eucalyptus pellita. Miniature plots investigate forest productivity by carrying out very small-scale, short-term experimental studies and treating the results as analogous to what would occur in an operational-scale forest stand over a normal rotation. Miniature plots were established in three separate compartments of a tropical forest plantation in southeastern Sabah, Malaysia. Plots included the three species of interest, each with a fertilised and unfertilised subplot. Assessments were made of site and soil factors including soil profile properties and laboratory analysis of soil carbon, nitrogen, phosphorus (total and available) and pH. Tree growth was measured for nine months to estimate site productivity. Results suggest the need for research focusing on the role of soil carbon, carbon:nitrogen ratio, available phosphate and possibly soil pH in tropical plantation productivity, as well as the potential for large increases in productivity with high rates of fertiliser. In addition, there were differences in the fertiliser response between species, suggesting that F. moluccana in particular might respond more strongly than A. mangium to high application rates of fertiliser. The results also suggest that miniature plots have considerable potential for monitoring and investigating site productivity in fast-growth tree plantations in Southeast Asia.

快速增长的人工林在许多东南亚国家相对较新，显然需要对该地区的人工林土壤进行监测和评估。在这项研究中，我们使用微型地块来估计和解释三种广泛种植的硬木树种的场地生产力：金合欢、Falcataria moluccana和Eucalyptus pellita. 微型地块通过进行非常小规模的短期实验研究并将结果视为与正常轮作中的操作规模林分中发生的情况类似，来调查森林生产力。在马来西亚沙巴东南部热带森林种植园的三个独立隔间中建立了微型地块。地块包括三个感兴趣的物种，每个物种都有一个受精和未受精的子地块。对场地和土壤因素进行了评估，包括土壤剖面特性和土壤碳、氮、磷（总和可用）和 pH 值的实验室分析。对树木生长进行了九个月的测量，以估计现场生产力。结果表明需要重点研究土壤碳、碳氮比、可用磷酸盐和热带种植园生产力中可能的土壤 pH 值，以及在高施肥率下生产力大幅提高的潜力。此外，物种之间的肥料反应存在差异，表明特别是F. moluccana可能比A. mangium对高施肥率的反应更强烈。结果还表明，微型地块在监测和调查东南亚快速生长的树木种植园的现场生产力方面具有相当大的潜力。