A 280-year old white oak chronology was developed for south-central Virginia to verify the timber harvesting and construction dates of a cabin located on the Reynolds Homestead Research Center. A plaque on the cabin stated that the logs were harvested in 1814. However, the outer rings of the logs dated to 1875 and 1876. From the land-use history of the area, the cabin was most likely constructed to house tenant farmers after the Civil War. Most of the periods of below average growth identified in the 280-year chronology were related to drought events. Correlations between the radial growth of the white oak with temperature and precipitation data from a local weather station were examined. Precipitation had more influence on radial growth than temperature, and significant correlations (p = 0.05) existed between radial growth and precipitation from the previous September, the current April, and the current June.

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.

A new collection of tree-ring chronologies developed from trees and remnant material located in the western and central Great Plains makes an important contribution to the spatial coverage of the US tree- ring chronology network. Samples from 24 sites were collected from the west-central Great Plains, and to date, ten chronologies have been produced. When correlated with a set of 47 single-station PDSI records, the chronologies display relationships with regional spring and summer drought. The reconstruction of spring PDSI for eastern Colorado generated in this study suggests that the inclusion of Great Plains trees can improve the quality of Great Plains drought reconstructions. The eastern Colorado drought reconstruction explains 62% of the variance in the instrumental record and extends to 1552. This reconstruction provides information about the regional character of major droughts over the past four and a half centuries. Major eastern Colorado droughts include events in the 1580s, 1630s, 1660s, 1730s, and the 1930s. The late 16th century drought, noted as an especially severe drought in the southwestern US, appears in this reconstruction as only slightly more severe than other major droughts in this region.

Six mean ring-width tree-ring chronologies were constructed for living Scots pine (Pious sylvestris L.), growing near the species' upper and northern limits in the area between the Ob River and the subpolar Ural Mountains in Russia. All ring-width series were standardized by fitting cubic smoothing splines and chronologies were constructed as biweight robust means. The six chronologies ranged from 181 to 276 years in length. Response function analysis showed all chronologies to have negative responses to winter precipitation. Most chronologies also showed positive, but relatively low responses to temperatures of the current and previous summer. Total October-May precipitation was reconstructed back to A.D. 1843 using the lagged and unlagged chronologies as candidate predictors. In addition to reflecting an unstable and time-varying growth-climate link, moderate verification results may partly be due to problems with short verification periods. The reconstruction contains almost equal amounts of high-frequency (<8 years) and low-frequency ( >8 years) variations, among them a significant 30-year variation. The precipitation signal may add an important aspect to reconstructing paleoclimatic fluctuations in the northern hemisphere. Continuing work with the Scots pine from this area depends on improving the quality of a precipitation reconstruction and finding older living and subfossil wood.

The Giant Sequoia played several crucial roles in the founding of the modern science of tree-ring dating. These included at least two central theoretical constructs and at least two minor ones; however, historical studies of dendrochronology are actively continuing and this list is expected to expand. Second only to the importance of the ponderosa pine (Pinus ponderosa) in the earliest days of the infant science, the Giant Sequoia (Sequoiadendron giganteum) was at the very center of the establishment of the discipline of dendrochronology. How the sequoia came to be used by A.E. Douglass, and what vital information and how it provided such information is the topic here.

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.

Fifty-three ring-width chronologies have been developed from open-grown, low-elevation stands of Pseudotsuga menziesii (Douglas-fir) and Pinar ponderosa (ponderosa pine) in the southern Canadian Cordillera. These chronologies will be used to develop precipitation reconstructions for the region. The sites are unevenly distributed across the interior valleys from east of the Coast Ranges to the Canadian Rockies and from the Canada-U.S. border to the northern limits of both species. The chronologies range from 123-691 years (mean = 383 years) and, on average, have a strong within-chronology common signal (Expressed Population Signal > 0.85) with as few as eight trees. A Rotated Principal Components Analysis (RPCA) identified three regions within which annual ring-width chronologies covary similarly. A preliminary assessment of regional chronologies and patterns of extreme narrow and wide marker rings demonstrates that common growth variations exist in the chronology network that are probably precipitation related. Both the RPCA and marker ring analyses suggest distinctive regional patterns of growth on both interannual and longer timescales that vary through time and are possibly linked to persistent large scale climatic anomalies.

Our objective was to document the effect of fire-history sampling on the mortality of mature ponderosa pine trees in Oregon. We examined 138 trees from which fire-scarred partial cross sections had been removed five to six years earlier, and 386 similarly sized, unsampled neighbor trees, from 78 plots distributed over about 5,000 ha. Mortality was low for both groups. Although mortality was significantly higher for the sectioned trees than their neighbors (8% versus 1 %), removing a partial section did not appear to increase a tree's susceptibility to death from factors such as wind or insect activity. Specifically, the few sectioned stems that broke did so well above sampling height. Most sectioned trees (79 %) had evidence of insect activity in 1994/95, while only an additional 5% had such evidence in 2000. Mortality among sectioned trees in this study was low probably because we removed relatively small sections, averaging 7 cm thick and 8% of the tree's cross-sectional area, from large trees of a species with effective, resin-based defenses against insects and pathogens. Sampling live ponderosa pine trees appears to be a non-lethal method of obtaining information on past fire regimes in this region because it only infrequently led to their death in the early years after sampling.

Dendrochronological analysis of fire scars requires tree survival of fire exposure. Trees survive fire exposure by: (1) avoidance of injury through constitutive protection and (2) induced defense. Induced defenses include (a) compartmentalization processes that resist the spread of injury and infection and (b) closure processes that restore the continuity of the vascular cambium after fire injury. Induced defenses are non-specific and are similar for fire and mechanical injury. Dissection of central hardwood species in a prescribed fire treatment area in southeastern Ohio provided an opportunity to place features seen in dendrochronological samples into their biological context. Terms for these features are proposed and further discussion is solicited.