Abstract Many microdensitometric techniques are available for deriving maximum latewood density (MXD), which is the state-of-the-art proxy parameter for local to hemispheric-scale temperature reconstructions of the last millennium. Techniques based on X-ray radiation and visible light reflection, such as “blue intensity” (BI), integrate both the density/composition and the dimensions of the cell walls to derive microdensitometric data. In contrast, the dendroanatomical technique relies only on the dimensions of the cell walls. It is therefore possible to isolate cell wall variables by subtracting data derived using the dendroanatomical technique from data derived using X-ray and BI-based techniques. In this study, we explore differences in well-replicated data from parallel X-ray, BI, and dendroanatomical measurements of temperature-sensitive Pinus sylvestris trees from northern Finland. We aim to determine whether cell wall density is critical to the success of X-ray-based MXD, and whether the BI-based parameter counterpart, here termed MXBI, contains useful information about the composition of the cell wall (specifically the lignin). Our results indicate that cell wall density and cell wall BI have no relevant influence on MXD and MXBI measurements. Even in years with severely reduced lignification, identified as so-called “blue rings”, dendroanatomical MXD (aMXD) measurements do not deviate significantly from their MXD or MXBI counterparts. Moreover, derived chronologies of cell wall density and cell wall BI contain no significant climate signals when correlated with local climate. Maximum latewood density of conifers can thus be obtained without bias using the dendroanatomical technique. Because lignin content appears to play a negligible role for cell wall BI, the cell wall BI likely presents the biggest challenge when producing unbiased MXBI data. This is because BI data is notorious for cell wall color distortion across the heartwood and sapwood, and between living wood and dead wood, and may therefore distort the otherwise strong link with wood density on multidecadal scales.

中文翻译：

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细胞壁尺寸至高无上：细胞壁组成与苏格兰松中晚材密度/蓝色强度的温度信号无关

摘要 许多显微密度计技术可用于推导最大晚材密度 (MXD)，这是上一千年局部到半球尺度温度重建的最新代理参数。基于 X 射线辐射和可见光反射的技术，例如“蓝色强度”（BI），整合了细胞壁的密度/组成和尺寸，以得出微密度数据。相比之下，树状解剖技术仅依赖于细胞壁的尺寸。因此，可以通过从使用 X 射线和基于 BI 的技术获得的数据中减去使用树状解剖技术获得的数据来分离细胞壁变量。在这项研究中，我们探索了来自平行 X 射线、BI、芬兰北部对温度敏感的樟子松树的树体解剖学测量。我们的目标是确定细胞壁密度是否对基于 X 射线的 MXD 的成功至关重要，以及基于 BI 的参数对应物（此处称为 MXBI）是否包含有关细胞壁组成（特别是木质素）的有用信息。我们的结果表明细胞壁密度和细胞壁 BI 对 MXD 和 MXBI 测量没有相关影响。即使在木质化严重降低的年份，即所谓的“蓝环”，树状解剖学 MXD (aMXD) 测量值与 MXD 或 MXBI 测量值也没有显着差异。此外，当与当地气候相关时，细胞壁密度和细胞壁 BI 的派生年表不包含显着的气候信号。因此，使用树状解剖技术可以无偏差地获得针叶树的最大晚材密度。由于木质素含量对细胞壁 BI 的作用似乎可以忽略不计，因此在生成无偏 MXBI 数据时，细胞壁 BI 可能是最大的挑战。这是因为 BI 数据因心材和边材以及活材和死材之间的细胞壁颜色失真而臭名昭著，因此可能会扭曲与木材密度在几十年尺度上的强关联。