Potencial dendrocronológico de tres especies de Podocarpáceas de la Cordillera de los Andes / Dendrochronological potential of three Podocarpaceae species from the Andean Cordillera

Resumen Introducción: Poco se conoce del potencial dendrocronológico de las Podocarpáceas en el trópico. Objetivo: Explorar el potencial dendrocronológico de tres especies de podocarpáceas: Retrophyllum rospigliosii, Podocarpus oleifolius y Prumnopitys harmsiana. Métodos: De plantaciones no manejadas localizadas en los Andes colombianos, se muestrearon y analizaron 88 árboles: 30 muestras de R. rospigliosii provenientes de secciones transversales, 30 y 28 muestras de P. oleifolius y P. harmsiana, respectivamente, provenientes de núcleos de madera extraídos con barreno de incrementos. Las muestras se procesaron siguiendo las técnicas dendrocronológicas estándar. Resultados: En general, las características anatómicas de los anillos de crecimiento son similares para las tres especies, con una anatomía simple de traqueidas alineadas radialmente por tratarse de coníferas. Dado que la edad conocida de la plantación coincide con el número de anillos se considera una fuerte evidencia de la frecuencia anual de su formación en R. rospigliosii y P. oleifolius, las cuales presentaron buena sincronización (cofechado) con una inter-correlación promedio de 0.55 (r-Pearson). Para P. harmsiana no fue posible concretar series de ancho de anillos de las muestras recolectadas. Las series estandarizadas de R. rospigliosii y P. oleifolius mostraron una relación con los registros instrumentales de precipitación y temperatura, indicando que estas especies pueden ser promisorias para estudios adicionales. Conclusión: La investigación dendrocronología con especies de Podocarpáceas podría realizarse exitosamente con R. rospigliosii y P. oleifolius, pero no con P. harmsiana.

Abstract Introduction: Little is known about the dendrochronological potential of Podocarpaceaes in the tropics. Objective: To explore the dendrochronological potential of three Podocarpaceae species: Retrophyllum rospigliosii, Podocarpus oleifolius, and Prumnopitys harmsiana. Methods: From a non-managed plantation in the Andean cordillera in Colombia, a total of 88 trees were analyzed: 30 samples of cross-sections of R. rospigliosii, and 30 and 28 samples of P. oleifolius and P. harmsiana, respectively, obtained with an increment borer. Samples were processed according to standard dendrochronological methods. Results: The anatomical characteristics of the growth rings of the three species are similar, with a simple conifer anatomy with radially oriented tracheids. Since the known age of the plantation coincides with the number of tree rings this is strong evidence of annual tree-ring frequency of R. rospigliosii and P. oleifolius which also showed a satisfactory cross-dating with an average inter-correlation of 0.55 (r-Pearson). For P. harmsiana, it was not possible to build a tree-ring series from the collected samples. R. rospigliosii and P. oleifolius standardized ring-width chronologies showed a relationship with the instrumental records of rainfall and temperature, indicating these species may be promising further studies. Conclusions: Dendrochronological research with Podocarpaceae species could be carried out successfully with R. rospigliosii and P. oleifolius but not with P. harmsiana.

[Tree species identification of wooden funeral utensil from Qing Dynasty's tombs and its potential of ecological and environmental indicator in Shenyang, Northeast China]. / æ²ˆé˜³æ¸ å¢“æœ¨è´¨è‘¬å ·çš„æ ‘ç§é‰´å®šåŠç”Ÿæ€çŽ¯å¢ƒçš„æŒ‡ç¤ºæ½œåŠ›.

The wood used for funeral utensil in ancient tomb is a kind of valuable materials and important for understanding vegetation, climate and society conditions in the history. Here, we identified the tree species and dated the time of wooden utensils for funeral excavated from tombs in Shuijia Village, Shenyang, using wood anatomy methods and dendrochronological techniques. The results showed that 7 out of the 16 wood samples were identified as Pinus tabuliformis from Pinaceae, 8 were Larix sp. from Pinaceae and most likely Larix olgensis, and the rest one was Acer sp. from Aceraceae. Currently, these tree species are still widely distributed in Liaoning Province, indicating that forest structure (tree species composition) is relatively stable and that the climate at that time was quite similar to that at present. The timbers used for wooden utensils of funeral for civilian tombs had regional biogeographic characteristics and reflected regional social productivity development level in Mukden (now Shenyang) in Qing Dynasty: most of them were native tree species with low cost and high availability; the main timber trees were conifer species, and a few of them were broadleaved trees. These timbers were likely from the forest in Shenyang or mountainous areas in Eastern Liaoning, with Hunhe River waterway being an important transport way for timbers to Shenyang. Some P. tabuliformis and Larix sp. timbers could be cross-dated well, and the growth period of the trees was determined to be 1680s-1770s (early to mid-Qing Dynasty). The variations of tree-ring width of these timbers had good consistency and high climate sensitivity, reflecting the consistency of regional climate and environment. These timbers have the potential to indicate the climate condition of the early to mid-Qing Dynasty.

A field-to-desktop toolchain for X-ray CT densitometry enables tree ring analysis.

BACKGROUND AND AIMS: Disentangling tree growth requires more than ring width data only. Densitometry is considered a valuable proxy, yet laborious wood sample preparation and lack of dedicated software limit the widespread use of density profiling for tree ring analysis. An X-ray computed tomography-based toolchain of tree increment cores is presented, which results in profile data sets suitable for visual exploration as well as density-based pattern matching. METHODS: Two temperate (Quercus petraea, Fagus sylvatica) and one tropical species (Terminalia superba) were used for density profiling using an X-ray computed tomography facility with custom-made sample holders and dedicated processing software. KEY RESULTS: Density-based pattern matching is developed and able to detect anomalies in ring series that can be corrected via interactive software. CONCLUSIONS: A digital workflow allows generation of structure-corrected profiles of large sets of cores in a short time span that provide sufficient intra-annual density information for tree ring analysis. Furthermore, visual exploration of such data sets is of high value. The dated profiles can be used for high-resolution chronologies and also offer opportunities for fast screening of lesser studied tropical tree species.