Few spring paleoclimate records are available for boreal Canada and given the warming of spring temperatures in recent decades and its impact on snowmelt and hydrological processes, the search for spring climate proxies is receiving increasing attention. Tree-ring anatomical features and intra-annual widths were used to reconstruct regional mean March-April-May temperature from 1770 to 2016 in eastern boreal Canada. Nested principal component regressions calibrated on 116 years of gridded ...

In eastern boreal Canada, in the absence of long gauge records, changes in tree-ring anatomy of periodically flooded trees have allowed reconstruction of spring floods in natural rivers. This study analyzes the effect of regulation on the flood rings (FR) occurrence and on ring widths in Fraxinus nigra trees growing at 5 sites distributed along the Driftwood River floodplain to determine if a flood reconstruction using FR could be done in regulated rivers. Driftwood River was regulated by ...

We report on research to develop quantitative, annually resolved, multi-century, tree-ring reconstructions of streamflow for 12 interstate river systems in eight states (Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, and Virginia) in the South Atlantic Gulf Basin (AGB) of the southeastern United States.We used a nested principal components regression method to develop annually resolved tree-ring reconstructions of warm-season (March-October streamflo...

Over the past 10 years, X-ray Computed Tomography (CT) has been increasingly applied to dendrochronological research. This technique provides 3D images of the internal structure of objects, allowing non-invasive access to tree rings in cultural heritage objects that are often inaccessible from the outside. Here, we will present the state-of-the-art of tomographic X-ray imaging for the application to dendrochronology. We will give a comprehensive overview of how X-ray computed tomography is...

Forty years ago Dr. Tom Yanosky, a research botanist with the US Geological Survey, reported that ash trees growing along the Potomac River contained rings with abnormal wood anatomy caused by flood damage. Dr. Yanosky recommended these rings — which he dubbed “flood rings” — could be used to estimate the date, seasonal timing, and (most importantly) peak stage of past floods. Since that discovery, flood rings have been identified for forested river systems in eastern France, central Canad...

The objective of this study is to verify if stable isotopes (C, O) and growth series retrieved from black spruce trees (Picea mariana) growing on boreal lakeshores (riparians trees) show similar variations to those growing away from the shores (non-riparian trees). In NE Canada, riparian trees are particularly interesting because they eventually become lake subfossils, which form the main archives of hydro-climate conditions. However, the extent to which those riparian trees, growing in ol...

The assessment of pre-instrumental climate variability during the Common Era (CE) has been a key element of IPCC reports and was recently emphasized by showing a single temperature reconstruction as the first figure in the 2021 Summary for Policymakers (SPM). This reconstruction is derived from dozens of proxy records including tree-rings, corals, ice cores and sediments, and displays the course of global temperatures over the past 2000 years. Show casing a single study for paleoclimate co...

Tree-ring records have been used extensively to reconstruct past streamflow variability.  Annually resolved estimates for several centuries prior to observations, and in some cases millennia, have been produced from dendroclimatic proxies.  However, despite an often strong hydroclimatic signal embedded in the rings, some factors limit the skill of such reconstructions, including human interference with the hydrological cycle.  We examine the relationship between local output...

Trees exhibit different growth rates and timings of wood formation. However, the factors explaining these differences remain undetermined, making samplings and estimations of the growth dynamics a complicated task based on technical rather than statistical reasons. We collected weekly wood microcores in 159 balsam firs (Abies balsamea (L.) Mill.) from April to October 2018. We tested spatial autocorrelation, tree size, and cell production rates as explanatory variables of xylem phenology, ...

In mixed forests, diffuse-porous and ring-porous species represent two distinct functional groups undergoing similar environmental variations, but allegedly displaying different growth responses due to their anatomical features. We hypothesized that in sympatric species, functional groups-specific carbon allocation strategies result in different relationships between wood traits and canopy architecture, mirroring contrasting sensitivity to drought.We selected 2 diffuse-porous species (...