In eastern boreal Canada, variability in river discharge is poorly understood at the multi-century scale due to short instrumental records. In recent decades, increased magnitude and frequency of spring floods have raised concerns about the potential effects of climate change on flood risk. Unlike tree-ring width, flood rings have a demonstrated dendrochronological utility for reconstructing high discharge in boreal environments. In this study, twelve chronologies of earlywood vessel cross-sectional area (a new hydrological proxy) and ring width were developed from riparian Fraxinus nigra trees periodically flooded in spring. These chronologies were used as predictors of Harricana River spring discharge, which was reconstructed for the period 1771–2016. The reconstruction captured 69% of the variance over a 102-year calibration period. The reconstruction indicates that the magnitude and frequency of spring high discharge has increased since the end of the Little Ice Age (1850–1870 CE) and since 1950. The change from a multi-decadal frequency in the late 19th century to a decadal and then interannual frequency in the late 20th century is associated with an increase in snow cover over much of central-eastern Canada. The association between the reconstructed spring discharge and spring atmospheric circulation indices NINO3.4, AMO, NAO may also have changed in these periods and further work is needed to assess the stability of these associations. The correlation between reconstructed and instrumental spring discharge at the regional scale, as well as the shared features in reconstructed discharge and other paleorecords from subarctic Québec suggest a common hydrological signal across the study area and for the early 20th to 21st centuries. The unprecedently low and high spring discharge in recent decades compared to the historical natural variability of the last 250 years also suggests that the increase in flood frequency and magnitude originates from climate change.

在加拿大北部的北方地区，由于仪器记录短，在多世纪的尺度上对河流流量的变化了解甚少。近几十年来，春季洪水的数量和频率增加，引起了人们对气候变化对洪水风险的潜在影响的担忧。与树环宽度不同，洪水环在树状年代学上具有实用性，可用于重建北方环境中的高流量。在这项研究中，从河岸水曲柳中获得了十二个早材血管横截面积（一种新的水文代用物）和环宽度的年表。春季树木定期泛滥。这些年表被用作哈里卡纳河春季流量的预报器，该流量在1771年至2016年期间进行了重建。重建在102年的校准期内捕获了69％的方差。重建表明，自小冰期结束（公元1850年至1870年）和1950年以来，春季高流量的幅度和频率增加了。从19世纪后期的多年代际频率到十年年代，然后是20世纪末期的年际频率与加拿大中东部大部分地区的积雪增加有关。重构后的春季排放量与春季大气环流指数NINO3.4，AMO，在这些时期，NAO也可能发生了变化，需要进一步的工作来评估这些协会的稳定性。区域尺度上的重建的和工具的春季排放量之间的相关性，以及重建的排放量和魁北克次大陆其他古记录的共同特征表明，整个研究区域以及20世纪至21世纪初都是一个共同的水文信号。与过去250年的历史自然变化相比，近几十年来前所未有的低和高的春季流量也表明洪水频率和洪水数量的增加是气候变化引起的。以及来自魁北克亚北极的重建流量和其他古记录的共同特征表明，整个研究区域以及20世纪至21世纪初都是一个共同的水文信号。与过去250年的历史自然变化相比，近几十年来前所未有的低和高的春季流量也表明洪水频率和洪水数量的增加是气候变化引起的。以及来自魁北克亚北极的重建流量和其他古记录的共同特征表明，整个研究区域以及20世纪至21世纪初都是一个共同的水文信号。与过去250年的历史自然变化相比，近几十年来前所未有的低和高的春季流量也表明洪水频率和洪水数量的增加是气候变化引起的。