Yellow-cedar blue intensity tree-ring chronologies as records of climate in Juneau, Alaska, USA

This is the first study to generate and analyze the climate signal in blue intensity (BI) tree-ring chronologies from Alaska yellow-cedar (Callitropsis nootkatensis (D. Don) Oerst. ex D.P. Little). The latewood BI chronology shows a much stronger temperature sensitivity than ring width and can thus provide information on past climate. The well-replicated BI chronology exhibits a positive January–August mean maximum temperature signal for 1900–1975, after which it loses temperature sensitivity following the 1976–1977 shift in northeastern Pacific climate. The positive temperature response appears to recover and remains strong for the most recent decades, but the coming years will continue to test this observation. This temporary loss of temperature sensitivity from about 1976 to 1999 is not evident in ring width or in a change in forest health but is consistent with prior work linking cedar decline to warming. A confounding factor is the uncertain influence of a shift in color variation from the heartwood–sapwood boundary. Future expansion of the yellow-cedar BI network and further investigation of the influence of the heartwood–sapwood transitions in the BI signal will lead to a better understanding of the utility of this species as a climate proxy.

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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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Different Wood Anatomical and Growth Responses in European Beech (Fagus sylvatica L.) at Three Forest Sites in Slovenia

Frontiers in Plant Science ◽

10.3389/fpls.2021.669229 ◽

2021 ◽

Vol 12 ◽

Author(s):

Domen Arnič ◽

Jožica Gričar ◽

Jernej Jevšenak ◽

Gregor Božič ◽

Georg von Arx ◽

...

Keyword(s):

Tree Ring ◽

Climatic Factors ◽

Ring Width ◽

European Beech ◽

Growing Season ◽

Climatic Conditions ◽

Maximum Temperature ◽

Tree Ring Width ◽

Vessel Area ◽

Temperature And Precipitation

European beech (Fagus sylvatica L.) adapts to local growing conditions to enhance its performance. In response to variations in climatic conditions, beech trees adjust leaf phenology, cambial phenology, and wood formation patterns, which result in different tree-ring widths (TRWs) and wood anatomy. Chronologies of tree ring width and vessel features [i.e., mean vessel area (MVA), vessel density (VD), and relative conductive area (RCTA)] were produced for the 1960–2016 period for three sites that differ in climatic regimes and spring leaf phenology (two early- and one late-flushing populations). These data were used to investigate long-term relationships between climatic conditions and anatomical features of four quarters of tree-rings at annual and intra-annual scales. In addition, we investigated how TRW and vessel features adjust in response to extreme weather events (i.e., summer drought). We found significant differences in TRW, VD, and RCTA among the selected sites. Precipitation and maximum temperature before and during the growing season were the most important climatic factors affecting TRW and vessel characteristics. We confirmed differences in climate-growth relationships between the selected sites, late flushing beech population at Idrija showing the least pronounced response to climate. MVA was the only vessel trait that showed no relationship with TRW or other vessel features. The relationship between MVA and climatic factors evaluated at intra-annual scale indicated that vessel area in the first quarter of tree-ring were mainly influenced by climatic conditions in the previous growing season, while vessel area in the second to fourth quarters of tree ring width was mainly influenced by maximum temperature and precipitation in the current growing season. When comparing wet and dry years, beech from all sites showed a similar response, with reduced TRW and changes in intra-annual variation in vessel area. Our findings suggest that changes in temperature and precipitation regimes as predicted by most climate change scenarios will affect tree-ring increments and wood structure in beech, yet the response between sites or populations may differ.

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Improved dendroclimatic calibration using blue intensity in the southern Yukon

The Holocene ◽

10.1177/0959683619862037 ◽

2019 ◽

Vol 29 (11) ◽

pp. 1817-1830 ◽

Cited By ~ 4

Author(s):

R Wilson ◽

K Anchukaitis ◽

L Andreu-Hayles ◽

E Cook ◽

R D’Arrigo ◽

...

Keyword(s):

North America ◽

Tree Ring ◽

Picea Glauca ◽

Ring Width ◽

Gulf Of Alaska ◽

Wood Properties ◽

Temperature Sensitive ◽

Latewood Density ◽

June July ◽

Blue Intensity

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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Independent Aridity and Drought Pieces of Evidence Based on Meteorological Data and Tree Ring Data in Southeast Banat, Vojvodina, Serbia

Atmosphere ◽

10.3390/atmos10100586 ◽

2019 ◽

Vol 10 (10) ◽

pp. 586 ◽

Cited By ~ 1

Author(s):

Milivoj B. Gavrilov ◽

Wenling An ◽

Chenxi Xu ◽

Milica G. Radaković ◽

Qingzhen Hao ◽

...

Keyword(s):

Tree Ring ◽

Air Temperature ◽

Meteorological Data ◽

Ring Width ◽

Surface Air Temperature ◽

Aridity Index ◽

Precipitation Trend ◽

Positive Temperature ◽

Tree Ring Width ◽

Tree Ring Data

In this study, aridity data and tree ring data were collected in Northern Serbia, in Southeast (SE) Banat, a subregion within Vojvodina, and Vojvodina at large. They were each investigated independently. The De Martonne Aridity Index and the Forestry Aridity Index are derived from examining the relationship between precipitation and surface air temperature data sets sourced from seven meteorological stations in SE Banat, and from 10 meteorological stations located in Vojvodina as a whole. Vojvodina is a large territory and used as the control area, for the period 1949–2017. The Palmer Drought Severity Index was derived for the period 1927–2016, for both SE Banat and the totality of Vojvodina. The results of the Tree Ring Width Index were obtained from samples collected in or around the villages of Vlajkovac and Šušara, both located in SE Banat, for the period 1927–2017. These tree ring records were compared with three previous aridity and drought indices, and the meteorological data on the surface air temperature and the precipitation, with the objective being to evaluate the response of tree growth to climate dynamics in the SE Banat subregion. It was noted that the significant positive temperature trends recorded in both areas were too insufficient to trigger any trends in aridity or the Tree Ring Width Index, as neither displayed any change. Instead, it appears that these climatic parameters only changed in response to the precipitation trend, which remained unchanged during the investigated period, rather than in response to the temperature trend. It appears that the forest vegetation in the investigated areas was not affected significantly by climate change in response to the dominant temperature increase.

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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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Tree vitality and forest health: any better indicators?

10.5194/egusphere-egu21-15377 ◽

2021 ◽

Author(s):

Paolo Cherubini ◽

Giovanna Battipaglia ◽

John L. Innes

Keyword(s):

Stable Isotopes ◽

Tree Ring ◽

Forest Health ◽

Ring Width ◽

Sampling Bias ◽

Stress Factors ◽

Tree Vitality ◽

The Past ◽

Physiological Processes ◽

The Impact

Forest health, although not yet unanimously defined, has been monitored in the past forty years assessing tree vitality, trying to estimate tree photosynthesis rates and productivity. Used in monitoring forest decline in Central Europe since the 1980s, crown foliage transparency has been commonly believed to be the best indicator of tree condition in relation to air pollution, although annual variations appear more closely related to water stress. Although crown transparency is not a good indicator of tree photosynthesis rates, defoliation is still one of the most used indicators of tree vitality. Tree rings have been often used as indicators of past productivity. However, long-term tree-growth trends are difficult to interpret because of sampling bias, and ring-width patterns do not provide any information about tree physiological processes.&#160;In the past two decades, tree-ring carbon and oxygen stable isotopes have been used &#160;to reconstruct the impact of past climatic events, such as drought. They have proven to be useful tools for retrospectively understanding physiological processes and tree response to &#160;stress factors.&#160;Tree-ring stable isotopes integrate crown transpiration rates and photosynthesis rates and may enhance our understanding of tree vitality. They are promising indicators of tree vitality. We call for the use of tree-ring stable isotopes in future monitoring programmes.

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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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Exploring the climate signal in tree-ring density of Clanwilliam cedar, South Africa

10.5194/egusphere-egu2020-20692 ◽

2020 ◽

Author(s):

Valerie Trouet ◽

Tom De Mil ◽

Matthew Meko ◽

Jan Van den Bulcke

Keyword(s):

South Africa ◽

Tree Ring ◽

Southern Africa ◽

Ring Width ◽

Future Climate Change ◽

Spring Precipitation ◽

Climate Signal ◽

Climatic Signal ◽

X Ray Computed ◽

Instrumental Records

High-resolution annual precipitation and temperature proxies are largely lacking in Southern Africa, partly due to the scarcely available tree species that are suitable for dendrochronology. Clanwilliam cedar (Widdringtonia cedarbergensis) from Cape Province, South Africa, is a long-lived conifer with distinct tree rings and thus a strong dendroclimatic potential. However, the climatic signal in its tree-ring width (TRW) is weak and other tree-ring parameters such as density need to be explored to extract climatic information from this proxy. Here we investigate the climatic signal of density parameters in 17 Clanwilliam cedar samples (9 trees) collected in 1978 (Dunwiddie & LaMarche, 1980). We use a non-destructive X-ray Computed Tomography facility to develop minimum density (MIND) and maximum density (MXD) chronologies from 1900 until 1977. EPS for both density series exceeded 0.85. For the period 1930-1977 (reliable instrumental records), MIND correlates negatively with early-growing season precipitation (Oct-Nov), whereas MXD correlates negatively with end-of-season (March) temperature. The spatial correlation between MIND and spring precipitation spans the winter rainfall zone of South Africa. Clanwilliam cedar can live to be 356 years old and the current TRW chronology extends to 1564 CE. Full-length density chronologies for this long-lived species could provide a precipitation reconstruction for southern Africa, a region where historical climate observations are limited and where societal vulnerability to future climate change is high.References:Dunwiddie, P. W., & LaMarche, V. C. (1980). A climatically responsive tree-ring record from Widdringtonia cedarbergensis, Cape Province, South Africa. Nature, 286(5775), 796&#8211;797.

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