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Changes in mean earlywood vessel areas in mature Quercus macrocarpa were analyzed to determine possible sources of bias in paleoflood records derived from anatomical tree-ring signatures. Tree-ring cores were collected at intervals along the vertical axis of four Q. macrocarpa in a flood-prone stand near the Red River in Manitoba. The WinCELL PRO image analysis system was used to measure mean vessel areas in each annual ring. Most cores displayed a pronounced juvenile increase in mean vessel area before stabilizing between 40 and 60 years. The lowest samples from several trees contain rings with anomalously small mean vessel areas that are coincident with high-magnitude Red River floods in 1950 and 1997. The anatomical response of Q. macrocarpa appears to be conditional on the relative timing of earlywood development and flooding. Flood signatures are most strongly developed near the tree base and become less evident up the trunk. Most signatures disappear between one and three meters in height. Differences in flood response between trees are likely caused by internal differences rather than hydrological or topographic factors. Paleoflood studies based on samples obtained exclusively at breast height may miss some anatomical flood signatures and underestimate flood frequency relative to earlier intervals.

A 345-year (AD 1656-2000) ring-width chronology of common yew (Taxus baccata L.) from the western Himalaya has been prepared. This provides the first record of a well crossdated ring-width chronology of yew from the Himalayan region, India. The mean temperature of the premonsoon (March-June) season has an indirect relationship with tree growth. The yew chronology is also significantly correlated with an Abies pindrow chronology prepared from the same stand as well as A. spectabilis from the treeline zone of an adjacent site. Such a significant relationship indicates the good potential of yew for dendroclimatic studies in the Himalayan region.

Dendrochronologists traditionally report the grit size on abrasive papers used to prepare surfaces for tree-ring analysis, but significant differences exist in the measured particle size ranges defined by the different systems (e.g. FEPA, ANSI, ISO, JIS, etc.) used worldwide. The systems themselves are also subject to change and discontinuation. We propose that dendrochronologists report (1) the standard used to manufacture the grit (e.g. ANSI in the U.S.), (2) the grade within the standard (e.g. 400-grit), and (3) the SI equivalent measurements of mean or included-range grit-size dimensions (e.g. 20.6-23.6 μm). For example, rather than reporting our use of 60-grit or 400-grit, we would instead report ANSI 60-grit (250- 297 μm) and ANSI 400-grit (20.6-23.6 μm) sandpaper. Adopting SI equivalents will help standardize our methods by providing concise, replicable information about surface preparation, considered by many the most crucial step for helping to define clear ring boundaries and to ensure successful crossdating.

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When trembling aspen (Populus tremuloides Michx.) from northern Minnesota, USA, were sampled in 2000, the impact on annual radial growth of a 1951-1954 outbreak of forest tent caterpillar (Malacosoma disstria [Hbn.]) was found to be just as strong and clear as it was when estimated from samples taken in 1955. During those 45 intervening years, at least three tent caterpillar outbreaks occurred, yet the statistical distribution of ring-width profiles did not change. This suggests that survivorship bias is not a major impediment to the use of aspen ring widths for inferring the magnitude of past tent caterpillar outbreaks.

Within the framework of landscape and settlement archaeology, archaeological tree-ring data may contain information on the interrelation between humans, climate and environment. This study uses data collected through the systematic analysis and dendrochronological dating of timber from prehistoric lakeshore and bog sites in southwestern Germany spanning 2000 to 500 BC (i.e. Bronze and Early Iron Age). Crossdating various tree species associated with different ecosystems permits exploration of two areas: woodland development and human impact based principally on species determination from wood anatomy and dendrotypological analysis of a large sample series, and archaeological tree-ring data from a paleoecological and paleoclimatological perspective.

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No description available.