As a long master tree -ring chronology for the region around the Aegean approaches completion, timbers from monuments and archaeological sites as far as 2,000 km apart, and as far back as 7000 BC, are being dated. The patterns used in this dating are characterized by signature years, in which trees at the majority of the sites have smaller or broader rings than in the previous year. We show that the signature years are consistently associated with specific, persistent, circulation anomalies that control the access of precipitation- bearing systems to the region in springtime. This explains the feasibility of dating wooden objects from widely dispersed sites, and opens the possibility of reconstructing aspects of the climate in which the wood grew.

Archaeological tree-ring samples provide environmental, chronological, and behavioral information about past human use of the landscape. Such information, however, can only be fully exploited if sample pro- veniences and beam attributes are completely documented. This paper discusses implications of the sample proveniences, beam attributes, and dates from McKean Pueblito, an eighteenth century Navajo site in northwestern New Mexico, USA. Although the date distribution suggests at least three different interpretations of the site construction history, the contextual data indicate that the site was built in AD 1708 and remodeled in 1713. Areal contextual and tree-ring data from McKean Pueblito and other sites in the area are used to discuss larger scale Navajo behavioral and demographic adaptations to the changing physical and social environments of eighteenth century New Mexico. These examples illustrate how sample context at various spatial scales can significantly enhance interpretations of tree-ring data.

Many studies use the temporal record of dendrochronologically-dated fire scars to document properties of fire regimes before human interference (e.g. fire suppression, logging, and agriculture) became pervasive. Such reconstructions provide vital information that can be used by land management agencies when designing and implementing fire management policies, and are especially useful for justifying the reintroduction of fire to areas where fire has long been excluded by humans. Tree-ring based fire history studies produce large quantities of data that require efficient tools for compilation, organization, and analysis. In this paper, I describe the development and use of FHX2, software comprised of individual modules designed specifically for (1) entering and archiving of fire history data, (2) creating graphs that display both temporal and spatial features of the site fire history, (3) conducting statistical analyses on fire intervals and seasonality, and (4) performing superposed epoch analysis to analyze climate /wildfire interactions. Although designed to analyze fire history, the software can be used to analyze any set of events recorded in the tree- ring record, such as growth suppressions and releases, floods, and insect outbreaks.

No description available.

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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No description available.

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.