The Need and Means To Update Chronologies In A Dynamic Environment

Larson, Evan R.; Allen, Sara; Flinner, Nicholas L.; Labarge, Steven G.; Wilding, Thomas

doi:10.3959/1536-1098-69.1.21

Cited by 8 publications

(8 citation statements)

References 14 publications

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“…Thus, more than three quarters of the ITRDB chronologies do not extend beyond the year 2000 [ 4 ]. This and the lack of spatial representativity could have negative consequences for paleoclimatic investigations, in addition to precluding the integration of tree-ring width data with the increasingly available data from instrumental weather stations, remote sensing, national forest inventories, and other in situ measurements of forest growth [ 4 , 19 ]. Moreover, tree-ring data are mostly distributed in North America and Europe, focusing on marginal growing environments selected to maximize the climatic signal, and the selective sampling of the biggest trees within populations (with the aim of producing long chronologies) often leads to bias in archived datasets.…”

Section: Introductionmentioning

confidence: 99%

Extracting coherent tree-ring climatic signals across spatial scales from extensive forest inventory data

et al. 2017

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Increasing access to extensively replicated and broadly distributed tree-ring collections has led to a greater use of these large data sets to investigate climate forcing on tree growth. However, the number of chronologies added to large accessible databases is declining and few are updated, while chronologies are often sparsely distributed and are more representative of marginal growing environments. On the other hand, National Forest Inventories (NFI), although poorly replicated at the plot level as compared to classic dendrochronological sampling, contain a large amount of tree-ring data with high spatial density designed to be spatially representative of the forest cover. We propose an a posteriori approach to validating tree-ring measurements and dating, selecting individual tree-ring width time series, and building average chronologies at various spatial scales based on an extensive collection of ring width measurements of nearly 94,000 black spruce trees distributed over a wide area and collected as part of the NFI in the province of Quebec, Canada. Our results show that reliable signals may be derived at various spatial scales (from 37 to 583,000 km2) from NFI increment core samples. Signals from independently built chronologies are spatially coherent with each other and well-correlated with independent reference chronologies built at the stand level. We thus conclude that tree-ring data from NFIs provide an extraordinary opportunity to strengthen the spatial and temporal coverage of tree-ring data and to improve coordination with other contemporary measurements of forest growth to provide a better understanding of tree growth-climate relationships over broad spatial scales.

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Section: Introductionmentioning

confidence: 99%

Extracting coherent tree-ring climatic signals across spatial scales from extensive forest inventory data

et al. 2017

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“…Due to changes in the density of the tree-ring network of the ITRDB and the use of a large radius (450 km) to reconstruct drought for the LBDA, soil moisture variability at small or local scales is potentially absent in areas that are underrepresented in the tree-ring network. Further, many of the chronologies that are available on the ITRDB were collected in the 1980s and have not been updated (Larson et al 2013;Zhao et al,2019).…”

Section: Introductionmentioning

confidence: 99%

“…Changes in the drought signal recorded by tree rings have been established only recently (Larson et al, 2013;Maxwell et al, 2015Maxwell et al, , 2016Maxwell et al, , 2019Helcoski et al, 2019), making an investigation of its causes essential to ensuring the interpretability of tree-ring-based hydroclimate reconstructions. Of these recent studies, Maxwell et al (2016) provided the first documentation of an apparent deteriorating relationship between radial tree growth and summer soil moisture that is not accompanied by an increase in signal strength during another season.…”

Section: Introductionmentioning

confidence: 99%

Sampling density and date influence spatial representation of tree ring reconstructions

Maxwell

Harley

Matheus

et al. 2020

Preprint

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Abstract. Our understanding of the natural variability of hydroclimate before the instrumental period (ca. 1900 in the United States; US) is largely dependent on tree-ring-based reconstructions. Large-scale soil moisture reconstructions from a network of tree-ring chronologies have greatly improved our understanding of the spatial and temporal variability in hydroclimate conditions, particularly extremes of both drought and pluvial (wet) events. However, certain regions within these large-scale reconstructions in the US have a sparse network of tree-ring chronologies. Further, several chronologies were collected in the 1980s and 1990s, thus our understanding of the sensitivity of radial growth to soil moisture in the US is based on a period that experienced multiple extremely severe droughts and neglects the impacts of recent, rapid global change. In this study, we expanded the tree-ring network of the Ohio River Valley in the US, a region with sparse coverage. We used a total of 72 chronologies across 15 species to examine how increasing the density of the tree-ring network influences the representation of reconstructing the Palmer Meteorological Drought Index (PMDI). Further, we tested how the sampling date influenced the reconstruction models by creating reconstructions that ended in the year 1980 and compared them to reconstructions ending in 2010 from the same chronologies. We found that increasing the density of the tree-ring network resulted in reconstructed values that better matched the spatial variability of instrumentally recorded droughts and to a lesser extent, pluvials. By sampling tree in 2010 compared to 1980, the sensitivity of tree rings to PMDI decreased in the southern portion of our region where severe drought conditions have been absent over recent decades. We emphasize the need of building a high-density tree-ring network to better represent the spatial variability of past droughts and pluvials. Further, chronologies on the International Tree-Ring Data Bank need updating regularly to better understand how the sensitivity of tree rings to climate may vary through time.

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“…The negative consequences of this decline in data availability for palaeoclimatological research and the need to regularly update existing chronologies have already been noted 7 . Here, we emphasize that the low coverage of tree-ring data from diverse geographic and climatic space over the past decade is limiting opportunities to integrate the global tree-ring network with newer observation platforms.…”

mentioning

confidence: 99%

“…However, EO records are still problematically short-term when the aim is to study the full range of ecosystem variability, especially in the context of long-term climate change. If sufficient spatiotemporal coverage can be achieved and maintained 7 , tree-ring records offer opportunities to contextualize EO data by reflecting climate-or disturbanceinduced tree-growth anomalies over decades to centuries. Further opportunities emerge from integration of tree rings with (1) canopy variability observed from of tree growth through sub-annual tree-ring studies 6 .…”

mentioning

confidence: 99%