Climatic Signals in δ<sup>13</sup>C and δ<sup>18</sup>O of Tree-rings from White Spruce in the Mackenzie Delta Region, Northern Canada

Porter, Trevor J.; Pisaric, Michael F. J.; Kokelj, Steven V.; Edwards, Thomas W. D.

doi:10.1657/1938-4246-41.4.497

Cited by 62 publications

(53 citation statements)

References 58 publications

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“…Even so, the EPS obtained here is low compared to results for different species from other isotope studies in which 4-6 trees have often been sufficient to produce EPS scores > 0.85 (e.g. Robertson 1997a, b;McCarroll and Pawellek 2001;Porter et al 2009). The most likely reason for this is considered to be a combination of the sensitivity of young trees to micro-scale endogenous influences and the difficulties of processing kauri wood to α-cellulose (Brookman and Whittaker 2012;Brookman 2014).…”

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confidence: 81%

Raised in the wild south: a dendrochronological and dendrochemical profile of a far-southern stand of kauri (Agathis australis) on the Taieri Plain, Otago

Brookman

Steward

Palmer

et al. 2014

N.Z. j. of For. Sci.

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Background: Kauri (Agathis australis (D.Don) Lindl.) is endemic to New Zealand and is the southernmost species of the tropical genus Agathis. Methods:The growth history of the second southern-most known stand of New Zealand kauri is documented. This stand is located at Wairongoa Springs near Dunedin, approximately 8°of latitude south of the modern natural range of the species. This stand was established in the 1950s and now approximates a natural 'ricker' stand of juvenile kauri. Sample plot measurements of height and diameter growth taken in 2009 were compared to published 1986 data from the same stand, and were used for modelling self-thinning dynamics. An investigation was also undertaken using ring-widths from cores obtained by increment boring to generate a 52-year dendrochronological record that shows a strong common pattern of long-term and inter-annual changes in growth. Carbon isotope analysis of annual rings from 1983-2009 revealed corresponding multi-decadal chemical trends. Segmented linear regression was used to compare the ring-width record with existing kauri growth and self-thinning models.Results: Growth of kauri at Wairongoa Springs was fast, was comparable to other plantations of kauri without silvicultural tending, and was generally faster than that of natural stands. The growth of the stand can be considered as occurring in two apparent phases. The first was a 26-year period of relatively constant rapid growth with ring-widths averaging 3.5 mm while the second phase showed a steady decline in annual growth thought to be indicative of self-thinning due to increasing competition. This ring-width decline was matched by a gradual decline in the ratio of carbon isotope 13 C to 12 C.Conclusions: Ring-width measurements and carbon isotope determinations compared with forestry-based modelling of self-thinning in kauri suggest that this stand is undergoing self-thinning much sooner than other kauri stands. This result highlights other possible influences beyond simple biomass accumulation triggering the onset of self-thinning. The growth rate of the plantation is comparable to others from the North Island, demonstrating that kauri can be grown, albeit in sheltered sites, throughout the length of New Zealand.

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confidence: 81%

Raised in the wild south: a dendrochronological and dendrochemical profile of a far-southern stand of kauri (Agathis australis) on the Taieri Plain, Otago

Brookman

Steward

Palmer

et al. 2014

N.Z. j. of For. Sci.

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“…Previous studies of tree ring records from central Canada (Case and Macdonald, 1995;Sauchyn and Beaudoin, 1998;Sauchyn and Skinner, 2001), Yellowknife and the Mackenzie delta area (Pisaric et al, 2007Porter et al, 2009) going as far back as 1505 can be used to infer precipitations and assess the variability of freshwater inputs from the Mackenzie River. Reconstruction of August-July annual precipitations in two regions of the western Canadian Prairies (western Saskatchewan) indicate that the period 1850-1900 was characterised by drought or low-precipitation episodes lasting several years, the most severe occurring between ∼ 1860-1875 (Case and Macdonald, 1995), 1880-1900(Sauchyn and Beaudoin, 1998, Sauchyn and Skinner, 2001, and 1842-1877 in the Eastern Rocky Mountains (St George et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns

et al. 2012

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Abstract. Dinoflagellate cyst (dinocyst) assemblages have been widely used over the Arctic Ocean to reconstruct seasurface parameters on a quantitative basis. Such reconstructions provide insights into the role of anthropogenic vs natural forcings in the actual climatic trend. Here, we present the palynological analysis of a dated 36 cm-long core collected from the Mackenzie Trough in the Canadian Beaufort Sea. Dinocyst assemblages were used to quantitatively reconstruct the evolution of sea-surface conditions (temperature, salinity, sea ice) and freshwater palynomorphs fluxes were used as local paleo-river discharge indicators over the last ∼ 150 yr. Dinocyst assemblages are dominated by autotrophic taxa (68 to 96 %). Cyst of Pentapharsodinium dalei is the dominant species throughout most of the core, except at the top where the assemblages are dominated by Operculodinium centrocarpum. Quantitative reconstructions of sea-surface parameters display a series of relatively warm, lower sea ice and saline episodes in surface waters, alternately with relatively cool and low salinity episodes. Variations of dinocyst fluxes and reconstructed sea-surface conditions may be closely linked to large scale atmospheric circulation patterns such as the Pacific Decadal Oscillation (PDO) and to a lesser degree, the Arctic Oscillation (AO). Positive phases of the PDO correspond to increases of dinocyst fluxes, warmer and saltier surface waters, which we associate with upwelling events of warm and relatively saline water from Pacific origin. Freshwater palynomorph fluxes increased in three phases from AD 1857 until reaching maximum values in AD 1991, suggesting that the Mackenzie River discharge followed the same trend when its discharge peaked between AD 1989 and AD 1992. The PDO mode seems to dominate the climatic variations at multi-annual to decadal timescales in the western Canadian Arctic and Beaufort Sea areas.

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“…So precipitation at the sampling site can greatly differ from those recorded at the relatively distant weather stations due to the fragmentary nature and dynamics of the cloud systems. Porter et al (2009), Saurer et al (2004 and Warren et al (2001) also observed weak relationships between precipitation and carbon isotopes. They suggested that δ 13 C values are not sensitive to differences in precipitation in non-arid areas where moisture is not the main limiting factor.…”

Section: Carbon Isotopic Ratiosmentioning

confidence: 95%

Assessing tree-ring carbon and oxygen stable isotopes for climate reconstruction in the Canadian northeastern boreal forest

Bégin

Gingras

Savard

et al. 2015

Palaeogeography, Palaeoclimatology, Palaeoecology

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Climatic Signals in δ¹³C and δ¹⁸O of Tree-rings from White Spruce in the Mackenzie Delta Region, Northern Canada

Cited by 62 publications

References 58 publications

Raised in the wild south: a dendrochronological and dendrochemical profile of a far-southern stand of kauri (Agathis australis) on the Taieri Plain, Otago

Raised in the wild south: a dendrochronological and dendrochemical profile of a far-southern stand of kauri (Agathis australis) on the Taieri Plain, Otago

Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns

Assessing tree-ring carbon and oxygen stable isotopes for climate reconstruction in the Canadian northeastern boreal forest

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Climatic Signals in δ13C and δ18O of Tree-rings from White Spruce in the Mackenzie Delta Region, Northern Canada

Cited by 62 publications

References 58 publications

Raised in the wild south: a dendrochronological and dendrochemical profile of a far-southern stand of kauri (Agathis australis) on the Taieri Plain, Otago

Raised in the wild south: a dendrochronological and dendrochemical profile of a far-southern stand of kauri (Agathis australis) on the Taieri Plain, Otago

Quantitative reconstruction of sea-surface conditions over the last 150 yr in the Beaufort Sea based on dinoflagellate cyst assemblages: the role of large-scale atmospheric circulation patterns

Assessing tree-ring carbon and oxygen stable isotopes for climate reconstruction in the Canadian northeastern boreal forest

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Climatic Signals in δ¹³C and δ¹⁸O of Tree-rings from White Spruce in the Mackenzie Delta Region, Northern Canada