Temperate continental-monsoon transitional zones are sensitive to variations in the global hydrological climate, and the long-term patterns of hydrological variability in this zone should be explored urgently. In this study, based on the tree-ring width of Platycladus orientalis, we reconstructed the annual runoff sequence during 1666–2016 (351 years) on Wula Mountain, which lies within the low-latitude temperate continental-monsoon transitional zone. Our reconstruction model is stable and reliable because our reconstruction results overlap well with the arid and flood years and periods found in local historical records. Our analysis results show that over the last four centuries, the annual runoff in the low-latitude transitional zone is characterized by an overall decrease, with heightened fluctuations. Specifically, in the 18th century, wet and extremely wet years appeared frequently, while continuous wet periods grew progressively shorter. Later, this area experienced a mean-flow period of approximately 100 years ending in the 1930 s, when progressively longer dry periods began to occur. In the last 30 years, this area has suffered from its longest dry period in 351 years. Regarding runoff variability, over two centuries in the temperate continental-monsoon transitional zone, high-latitude areas had more wet periods with significant variation in large-scale periodicities; the majority of the zone had simultaneous variation in wetting and drying and a significant drying trend in the first half of the 20th century. High- and low-latitude areas had long and slowly changing arid periods, while mid-latitude areas had short and quickly changing arid periods. This study enriches the understanding of the dendrohydrology of the low and middle latitudes of the temperate continental-monsoon transition zone, analyzes the runoff variations throughout the transition zone area, and helps reconstruct the long-term historical runoff sequence over four centuries in the transitional zone.

温带大陆-季风过渡带对全球水文气候的变化敏感，应紧急探索该区域的水文变异性的长期模式。在这项研究中，基于侧柏的树轮宽度，我们在低纬度温带大陆-季风过渡带内的乌拉山上重建了1666-2016年（351年）的年度径流序列。我们的重建模型稳定可靠，因为我们的重建结果与当地历史记录中发现的干旱和洪水年份和时期有很好的重叠。我们的分析结果表明，在过去四个世纪中，低纬度过渡带的年径流量总体上呈下降趋势，且波动较大。具体来说，在18世纪，经常出现潮湿和极端潮湿的年份，而连续潮湿的时期逐渐缩短。后来，该地区经历了大约100年的平均流量期，该平均流量期于1930年代结束，之后逐渐出现了更长的干旱期。在过去的30年中，该地区遭受了351年最长的干旱期。关于径流的变异性，在温带大陆-季风过渡带的两个多世纪中，高纬度地区的湿润期较多，而大尺度周期性变化很大。在20世纪上半叶，该地区的大部分地区湿润和干燥同时发生变化，并且出现了明显的干燥趋势。高纬度地区和低纬度地区的干旱时期长而缓慢地变化，而中纬度地区的干旱期则短而迅速地变化。这项研究丰富了对温带大陆-季风过渡带中低纬地区树状水文学的理解，分析了整个过渡带地区的径流变化，