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.

中文翻译：

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评价来自澳大利亚的多种针叶树种上蓝色强度的树状气候学潜力

摘要。我们评估了来自塔斯马尼亚州和新西兰的八个针叶树种（12个站点）的蓝强度（BI）树年轮参数的树突气候潜力，并以此作为替代木材解剖结构的指标。使用约CA的数据集。每个站点10–15棵树木，我们测量了早木的最大蓝色反射强度（EWB），晚木的最小蓝色反射强度（LWB）以及相关的三角洲蓝色强度（DB）参数，以进行树状年代学分析。没有进行树脂提取，影响了低频趋势。因此，我们仅使用20年立方平滑样条对所有树木年轮和气候数据进行反趋势处理，从而只关注高频信号。与环宽度相比，所有BI参数均表现出较低的相对方差和较弱的信号强度。相关分析和主成分回归实验确定了大多数环宽年表的气候响应较弱且可变。但是，对于大多数站点，尽管信号强度较弱，但EWB数据仍显示了夏季温度下的强校准。还注意到了LWB的显着相关性，但大多数物种的相关关系的迹象与北半球所有针叶树种的报道相反。DB在塔斯马尼亚站点上表现良好，但解释了新西兰的最小温度变化。使用完整的多物种/参数网络，塔斯马尼亚岛和新西兰的夏季温度校准出色，被解释方差在52％到78％之间，并且具有同样可靠的独立验证（效率系数= 0.41至0.77）。塔斯马尼亚州BI重建与木材解剖结构重建的比较表明，这些参数记录了本质上相同的强高频夏季温度信号。尽管取得了这些优异的成绩，但要捕捉潜在的长期尺度气候趋势仍然是一个巨大的挑战。尽管DB，带通和其他信号处理方法可能有助于解决此问题，但结合环密度和定量WA测量的比较分析，还需要进行更多的实验。