Comparison of elevational changes in relationships of blue intensity and ring width index in Picea jezoensis with climatic responses in Laobai Mountain of Jilin, China

In north-western North America, the so-called divergence problem (DP) is expressed in tree ring width (RW) as an unstable temperature signal in recent decades. Maximum latewood density (MXD), from the same region, shows minimal evidence of DP. While MXD is a superior proxy for summer temperatures, there are very few long MXD records from North America. Latewood blue intensity (LWB) measures similar wood properties as MXD, expresses a similar climate response, is much cheaper to generate and thereby could provide the means to profoundly expand the extant network of temperature sensitive tree-ring (TR) chronologies in North America. In this study, LWB is measured from 17 white spruce sites ( Picea glauca) in south-western Yukon to test whether LWB is immune to the temporal calibration instabilities observed in RW. A number of detrending methodologies are examined. The strongest calibration results for both RW and LWB are consistently returned using age-dependent spline (ADS) detrending within the signal-free (SF) framework. RW data calibrate best with June–July maximum temperatures (Tmax), explaining up to 28% variance, but all models fail validation and residual analysis. In comparison, LWB calibrates strongly (explaining 43–51% of May–August Tmax) and validates well. The reconstruction extends to 1337 CE, but uncertainties increase substantially before the early 17th century because of low replication. RW-, MXD- and LWB-based summer temperature reconstructions from the Gulf of Alaska, the Wrangell Mountains and Northern Alaska display good agreement at multi-decadal and higher frequencies, but the Yukon LWB reconstruction appears potentially limited in its expression of centennial-scale variation. While LWB improves dendroclimatic calibration, future work must focus on suitably preserved sub-fossil material to increase replication prior to 1650 CE.

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Tree-ring investigations into changing climatic responses of yellow-cedar, Glacier Bay, Alaska

Canadian Journal of Forest Research ◽

10.1139/x2012-028 ◽

2012 ◽

Vol 42 (4) ◽

pp. 814-819 ◽

Cited By ~ 8

Author(s):

Gregory C. Wiles ◽

Colin R. Mennett ◽

Stephanie K. Jarvis ◽

Rosanne D. D’Arrigo ◽

Nicholas Wiesenberg ◽

...

Keyword(s):

Little Ice Age ◽

Root Zone ◽

Ring Width ◽

High Elevation ◽

Ice Age ◽

Strong Negative Correlation ◽

Glacier Bay ◽

Temperature And Precipitation ◽

Climatic Responses ◽

Response To Temperature

Yellow-cedar ( Callitropsis nootkatensis (D. Don) Örsted ex D.P. Little) is in a century-long decline coinciding with the end of the Little Ice Age (LIA). The leading hypothesis explaining this decline is a decrease in insulating snowpack due to warming and increased susceptibility to damaging frosts in the root zone. A ring-width series from yellow-cedar on Excursion Ridge (260 m a.s.l.) in Glacier Bay National Park and Preserve, Alaska, and another from trees on Pleasant Island (150 m a.s.l.) in the Tongass National Forest in Icy Strait were compared with regional monthly temperature and precipitation data from Sitka, Alaska, to investigate the changing growth response to temperature at these sites. Comparisons with monthly temperatures from 1832 to 1876 during the end of the Little Ice Age show that the high-elevation Excursion Ridge and the low-elevation Pleasant Island sites strongly favored warmer January through July temperatures. Both tree populations have markedly changed their response from a positive to a strong negative correlation with January through July temperatures since 1950. This strong negative response to warming by the yellow-cedar together with a positive relationship with total March and April precipitation suggests that these yellow-cedar sites may be susceptible to decline. Furthermore, these analyses are consistent with the hypothesis that the yellow-cedar decline is linked to decreased snowpack.

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Tree-ring proxies of larch bud moth defoliation: latewood width and blue intensity are more precise than tree-ring width

Tree Physiology ◽

10.1093/treephys/tpy057 ◽

2018 ◽

Vol 38 (8) ◽

pp. 1237-1245 ◽

Cited By ~ 6

Author(s):

Estelle Arbellay ◽

Ingrid Jarvis ◽

Raphaël D Chavardès ◽

Lori D Daniels ◽

Markus Stoffel

Keyword(s):

Tree Ring ◽

Ring Width ◽

Tree Ring Width ◽

Larch Bud Moth ◽

Blue Intensity

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Evaluating the dendroclimatological potential of blue intensity on multiple conifer species from Australasia

10.5194/bg-2021-119 ◽

2021 ◽

Author(s):

Rob Wilson ◽

Kathy Allen ◽

Patrick Baker ◽

Sarah Blake ◽

Gretel Boswijk ◽

...

Keyword(s):

New Zealand ◽

Tree Ring ◽

High Frequency ◽

Ring Width ◽

Signal Strength ◽

Summer Temperature ◽

Weak Signal ◽

Conifer Species ◽

Blue Intensity ◽

Blue Reflectance

Abstract. We evaluate a range of blue intensity (BI) tree-ring parameters in eight conifer species (12 sites) from Tasmania and New Zealand for their dendroclimatic potential, and as surrogate wood anatomical proxies. Using a dataset of ca. 10–15 trees per site, we measured earlywood maximum blue reflectance intensity (EWB), latewood minimum blue reflectance intensity (LWB) and the associated delta blue intensity (DB) parameter for dendrochronological analysis. No resin extraction was performed, impacting low frequency trends. Therefore, we focused only on the high frequency signal by detrending all tree-ring and climate data using a 20-year cubic smoothing spline. All BI parameters express low relative variance and weak signal strength compared to ring-width. Correlation analysis and principal component regression experiments identified a weak and variable climate response for most ring-width chronologies. However, for most sites, the EWB data, despite weak signal strength, expressed strong calibrations with summer temperatures. Significant correlations for LWB were also noted, but the sign of the relationship for most species is opposite to that reported for all conifer species in the Northern Hemisphere. DB performed well for the Tasmanian sites but explained minimal temperature variance in New Zealand. Using the full multi-species/parameter network, excellent summer temperature calibration was identified for both Tasmania and New Zealand ranging from 52 % to 78 % explained variance, with equally robust independent validation (Coefficient of Efficiency = 0.41 to 0.77). Comparison of the Tasmanian BI reconstruction with a wood anatomical reconstruction shows that these parameters record essentially the same strong high frequency summer temperature signal. Despite these excellent results, a substantial challenge exists with the capture of potential secular scale climate trends. Although DB, band-pass and other signal processing methods may help with this issue, substantially more experimentation is needed in conjunction with comparative analysis with ring density and quantitative WA measurements.

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Temperature sensitivity of blue intensity, maximum latewood density, and ring width data of living black spruce trees in the eastern Canadian taiga

Dendrochronologia ◽

10.1016/j.dendro.2020.125771 ◽

2020 ◽

Vol 64 ◽

pp. 125771

Author(s):

Feng Wang ◽

Dominique Arseneault ◽

Étienne Boucher ◽

Gabrielle Galipaud Gloaguen ◽

Anne Deharte ◽

...

Keyword(s):

Temperature Sensitivity ◽

Black Spruce ◽

Ring Width ◽

Intensity Maximum ◽

Maximum Latewood Density ◽

Latewood Density ◽

Blue Intensity

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Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska

Climate of the Past ◽

10.5194/cp-13-1007-2017 ◽

2017 ◽

Vol 13 (8) ◽

pp. 1007-1022 ◽

Cited By ~ 13

Author(s):

Rob Wilson ◽

Rosanne D'Arrigo ◽

Laia Andreu-Hayles ◽

Rose Oelkers ◽

Greg Wiles ◽

...

Keyword(s):

Tree Ring ◽

North Pacific ◽

Ring Width ◽

Gulf Of Alaska ◽

Climate Response ◽

Cool Period ◽

Climate Signal ◽

Latewood Density ◽

Blue Intensity

Abstract. Ring-width (RW) records from the Gulf of Alaska (GOA) have yielded a valuable long-term perspective for North Pacific changes on decadal to longer timescales in prior studies but contain a broad winter to late summer seasonal climate response. Similar to the highly climate-sensitive maximum latewood density (MXD) proxy, the blue intensity (BI) parameter has recently been shown to correlate well with year-to-year warm-season temperatures for a number of sites at northern latitudes. Since BI records are much less labour intensive and expensive to generate than MXD, such data hold great potential value for future tree-ring studies in the GOA and other regions in mid- to high latitudes. Here we explore the potential for improving tree-ring-based reconstructions using combinations of RW- and BI-related parameters (latewood BI and delta BI) from an experimental subset of samples at eight mountain hemlock (Tsuga mertensiana) sites along the GOA. This is the first study for the hemlock genus using BI data. We find that using either inverted latewood BI (LWBinv) or delta BI (DB) can improve the amount of explained temperature variance by > 10 % compared to RW alone, although the optimal target season shrinks to June–September, which may have implications for studying ocean–atmosphere variability in the region. One challenge in building these BI records is that resin extraction did not remove colour differences between the heartwood and sapwood; thus, long term trend biases, expressed as relatively warm temperatures in the 18th century, were noted when using the LWBinv data. Using DB appeared to overcome these trend biases, resulting in a reconstruction expressing 18th–19th century temperatures ca. 0.5 °C cooler than the 20th–21st centuries. This cool period agrees well with previous dendroclimatic studies and the glacial advance record in the region. Continuing BI measurement in the GOA region must focus on sampling and measuring more trees per site (> 20) and compiling more sites to overcome site-specific factors affecting climate response and using subfossil material to extend the record. Although LWBinv captures the inter-annual climate signal more strongly than DB, DB appears to better capture long-term secular trends that agree with other proxy archives in the region. Great care is needed, however, when implementing different detrending options and more experimentation is necessary to assess the utility of DB for different conifer species around the Northern Hemisphere.

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Comparison between Blue Intensity (BI) and Maximum Latewood Density (MXD) tree-ring chronologies from the North American Boreal forests

10.5194/egusphere-egu2020-21137 ◽

2020 ◽

Author(s):

Laia Andreu-Hayles ◽

Rosanne D'Arrigo ◽

Rose Oelkers ◽

Kevin Anchukaitis ◽

Greg Wiles ◽

...

Keyword(s):

High Resolution ◽

North America ◽

Tree Ring ◽

Boreal Forests ◽

Ring Width ◽

Maximum Latewood Density ◽

Latewood Density ◽

Tree Ring Data ◽

Summer Temperatures ◽

Blue Intensity

Tree ring-width (TRW) and Maximum Latewood Density (MXD) series have been largely used to develop high-resolution temperature reconstructions for the Northern Hemisphere. The divergence phenomenon, a weakening of the positive relationship between TRW and summer temperatures, has been observed particularly in northwestern North America chronologies. In contrast, MXD datasets have shown a more stable relationship with summer temperatures, but it is costly and labor-intensive to produce. Recently, methodological advances in image analyses have led to development of a less expensive and labor-intensive MXD proxy known as Blue Intensity (BI). Here, we compare 6 newly developed BI tree-ring chronologies of white spruce (Picea glauca [Moench] Voss) from high-latitude boreal forests in North America (Alaska in USA; Yukon and the Northwestern Territory in Canada), with MXD chronologies developed at the same sites. We assessed the quality of BI in relation to MXD based on mean correlation between trees, chronology reliability based on the Expressed Population Signal (EPS), spectral properties, and the strength and spatial extent of the temperature signal. Individual BI chronologies established significant correlations with summer&#160;temperatures showing a similar&#160;strength and spatial cover than MXD chronologies. Overall, the BI tree-ring data is emerging as a valuable proxy for generating high-resolution temperature spatial reconstructions over northwestern America.

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Evaluating the dendroclimatological potential of blue intensity on multiple conifer species from Tasmania and New Zealand

Biogeosciences ◽

10.5194/bg-18-6393-2021 ◽

2021 ◽

Vol 18 (24) ◽

pp. 6393-6421

Author(s):

Rob Wilson ◽

Kathy Allen ◽

Patrick Baker ◽

Gretel Boswijk ◽

Brendan Buckley ◽

...

Keyword(s):

New Zealand ◽

High Frequency ◽

Ring Width ◽

Principal Component Regression ◽

Principal Component ◽

Signal Strength ◽

Summer Temperature ◽

Weak Signal ◽

Conifer Species ◽

Blue Intensity

Abstract. We evaluate a range of blue intensity (BI) tree-ring parameters in eight conifer species (12 sites) from Tasmania and New Zealand for their dendroclimatic potential, and as surrogate wood anatomical proxies. Using a dataset of ca. 10–15 trees per site, we measured earlywood maximum blue intensity (EWB), latewood minimum blue intensity (LWB), and the associated delta blue intensity (DB) parameter for dendrochronological analysis. No resin extraction was performed, impacting low-frequency trends. Therefore, we focused only on the high-frequency signal by detrending all tree-ring and climate data using a 20-year cubic smoothing spline. All BI parameters express low relative variance and weak signal strength compared to ring width. Correlation analysis and principal component regression experiments identified a weak and variable climate response for most ring-width chronologies. However, for most sites, the EWB data, despite weak signal strength, expressed strong coherence with summer temperatures. Significant correlations for LWB were also noted, but the sign of the relationship for most species is opposite to that reported for all conifer species in the Northern Hemisphere. DB results were mixed but performed better for the Tasmanian sites when combined through principal component regression methods than for New Zealand. Using the full multi-species/parameter network, excellent summer temperature calibration was identified for both Tasmania and New Zealand ranging from 52 % to 78 % explained variance for split periods (1901–1950/1951–1995), with equally robust independent validation (coefficient of efficiency = 0.41 to 0.77). Comparison of the Tasmanian BI reconstruction with a quantitative wood anatomical (QWA) reconstruction shows that these parameters record essentially the same strong high-frequency summer temperature signal. Despite these excellent results, a substantial challenge exists with the capture of potential secular-scale climate trends. Although DB, band-pass, and other signal processing methods may help with this issue, substantially more experimentation is needed in conjunction with comparative analysis with ring density and QWA measurements.

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Blue Intensity for dendroclimatology: The BC blues: A case study from British Columbia, Canada

The Holocene ◽

10.1177/0959683614544051 ◽

2014 ◽

Vol 24 (11) ◽

pp. 1428-1438 ◽

Cited By ~ 33

Author(s):

Rob Wilson ◽

Rohit Rao ◽

Miloš Rydval ◽

Cheryl Wood ◽

Lars-Åke Larsson ◽

...

Keyword(s):

British Columbia ◽

Tree Ring ◽

Large Scale ◽

Ring Width ◽

Frequency Information ◽

Maximum Latewood Density ◽

Latewood Density ◽

Summer Temperatures ◽

Two Parameters ◽

Blue Intensity

Maximum latewood density (MXD) is a strong proxy of summer temperatures. Despite this, there is a paucity of long MXD chronologies in the Northern Hemisphere, which limits large-scale tree-ring-based reconstructions of past temperature which are dominated by ring-width (RW) data – a weaker temperature proxy at inter-annual time-scales. This paucity likely results from the relative expense of measuring MXD and the lack of laboratories with the facilities to measure it. Herein, we test the ability of a relatively new, less expensive, tree-ring parameter, Blue Intensity (BI), to act as a surrogate parameter for MXD. BI was measured on Engelmann spruce samples from British Columbia where MXD had previously been measured to allow direct comparison between the two parameters. Signal strength analyses indicate that 8 MXD series were needed to acquire a robust mean chronology while BI needed 14. Utilising different detrending methods and parameter choices (RW + MXD vs RW + BI), a suite of reconstruction variants was developed. The explained variance from the regression modelling (1901–1995) of May–August maximum temperatures ranged from 52% to 55%. Validation tests over the earlier 1870–1900 period could not statistically distinguish between the different variants, although spectral analysis identified more lower frequency information extant in the MXD-based reconstructions – although this result was sensitive to the detrending method used. Ultimately, despite the MXD-based reconstruction explaining slightly more of the climatic variance, statistically robust reconstructions of past summer temperatures were also derived using BI. These results suggest that there is great potential in utilising BI for dendroclimatology in place of MXD data. However, more experimentation is needed to understand (1) how well BI can capture centennial and lower frequency information and (2) what biases may result from wood discolouration, either from species showing a distinct heartwood/sapwood boundary or from partly decayed sub-fossil samples.

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