Application of the Minimum Blue-Intensity Technique To A Southern-Hemisphere Conifer

Brookhouse, Matthew; Graham, Rochelle

doi:10.3959/1536-1098-72.02.103

Cited by 13 publications

(29 citation statements)

References 18 publications

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“…Finally, Blake et al (2020) explored the climate signal in BI parameters measured from silver pine (Manoao colensoi) samples growing on New Zealand's South Island and found strong significant relationships between both earlywood and latewood BI parameters and summer temperatures. Although the sign (positive) of the earlywood BI relationship with temperature agreed with results detailed in other studies (Björklund et al, 2017;Buckley et al, 2018), the latewood relationship was inverse to that detailed for Northern Hemisphere conifers (Briffa et al, 2002) and observed by Brookhouse and Graham (2016). This difference in latewood response begs the intriguing question as to whether some Southern Hemisphere conifers may have evolved differently from their Northern Hemisphere counterparts, resulting in a different anatomical and physiological response to climate.…”

Section: Introductionsupporting

confidence: 86%

“…Although a spring-early summer temperature signal is extant in Northern Hemisphere conifer minimum density data from temperature limited sites (Björklund et al, 2017), correlations are generally not as strong as the earlywood results detailed by Buckley et al (2018). In the Southern Hemisphere, Brookhouse and Graham (2016) measured latewood BI from Errinundra plum-pine (Podocarpus lawrencei) samples taken from the Australian Alps and identified a strong inverse (r = −0.79) relationship with August-April maximum temperatures, suggesting substantial potential for this species if long-lived specimens could be found. Finally, Blake et al (2020) explored the climate signal in BI parameters measured from silver pine (Manoao colensoi) samples growing on New Zealand's South Island and found strong significant relationships between both earlywood and latewood BI parameters and summer temperatures.…”

Section: Introductionmentioning

confidence: 95%

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

et al. 2021

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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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Section: Introductionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 95%

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

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Finally, Blake et al 90 (2020) recently explored the climate signal in BI parameters measured from Silver pine (Manoao colensoi) samples growing on the New Zealand's South Island and found strong significant relationships between both earlywood and latewood BI parameters and summer temperatures. Although the sign (positive) of the earlywood BI relationship with temperature agreed with results detailed in other studies (Björklund et al 2017;Buckley et al 2018), the latewood relationship was inverse to that detailed for Northern Hemisphere conifers (Briffa et al 2002) and observed by Brookhouse and Graham (2016). This 95 difference in latewood response begs the intriguing question as to whether some Southern Hemisphere conifers may have evolved differently to their Northern Hemisphere counterparts, resulting in a different anatomical and physiological response to climate.…”

supporting

confidence: 86%

“…Although a 85 spring/early summer temperature signal is extant in Northern Hemisphere conifer minimum density data (Björklund et al 2017), correlations are generally not as strong as the earlywood results detailed by Buckley et al (2018). In the Southern Hemisphere, Brookhouse and Graham (2016) measured latewood BI from Errinundra plum-pine (Podocarpus lawrencei) samples taken from the Australian Alps and identified a strong inverse (r = -0.79) relationship with August-April maximum temperatures, suggesting substantial potential for this species if long-lived specimens could be found. Finally, Blake et al 90 (2020) recently explored the climate signal in BI parameters measured from Silver pine (Manoao colensoi) samples growing on the New Zealand's South Island and found strong significant relationships between both earlywood and latewood BI parameters and summer temperatures.…”

mentioning

confidence: 95%

See 1 more Smart Citation

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

Wilson¹,

Allen²,

Baker³

et al. 2021

Preprint

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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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Blue intensity of Swiss stone pine as a high-frequency temperature proxy in the Alps

et al. 2023

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Tree rings are widely used for climatic reconstructions and for improving our understanding of ongoing climate change in high-altitude sensitive areas. X-ray maximum latewood density is a very powerful parameter to reconstruct past climatic variations, especially if compared to tree-ring width, but this method is neither inexpensive nor timesaving. However, blue intensity (BI) has resulted in an excellent maximum wood density surrogate that measures the intensity of reflected light from latewood in the blue spectra. This methodology is still considered a prototype parameter, and more data are needed for validation of the method. We present the first BI values coming from Swiss stone pine (Pinus cembra L.) collected on the southern margin of the Alps. Analyses were performed by testing different solvents and polishing techniques, as well as different CooRecorder pixel percentage settings. The results demonstrate that solvents and software parameters have little influence on the final chronologies. Dendroclimatic analyses demonstrate that Swiss stone pine BI can be a useful tool to extract at least the high-frequency variations in July–August temperatures with a correlation coefficient of up to 0.6 (over the 1800–2017 time period). The immunity of Swiss stone pine to insect defoliator outbreaks further enhances the reliability of the BI values of this species in reconstructing past high-frequency temperature variations in high-altitude sensitive areas.

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Application of the Minimum Blue-Intensity Technique To A Southern-Hemisphere Conifer

Cited by 13 publications

References 18 publications

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

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

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

Blue intensity of Swiss stone pine as a high-frequency temperature proxy in the Alps

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