This study investigated the composition, age-and size-structure, and tree-ring relationships for an old-growth, warm-temperate, mixed-evergreen forest at the University of Tokyo Chiba Forest, Japan. A total of 32 tree species were recorded, which was dominated by Abies firma and Quercus acuta. Tsuga sieboldii dominated the recruitment after 1850, followed by Abies firma. After 1920, many individuals of Castanopsis, Cinnamomum, Cleyera and Quercus became established. The temporal pattern of conifer recruitment did not correspond to the record of strong wind events. Basal area increment in Abies firma and Castanopsis sieboldii trees increased throughout their lives, a trend not seen in the ring width index. Mean annual temperature was below the 100-year mean between 1920 and 1940 and 1960-1980, but increased rather abruptly after 1980. Mean annual precipitation decreased after 1960. Tree-ring releases are very common at the study forest, which are indicative of frequent small to moderate-sized disturbances. At least one release was recorded in every decade from 1890 to the present day, which is likely the primary causal factor promoting tree growth and recruitment. Our results suggest that early logging activities coupled with natural disturbances had a great influence on the developmental process and current structure of the study stand and that tree growth is varying in a manner consistent with forest dynamics. © 2017 by The Tree-Ring Society.

Pinus edulis is one of the most ubiquitous tree species in the US Southwest. It accounts for over a fifth of the total number of trees in New Mexico alone. Its prevalence and relatively long-lived nature makes it an ideal candidate for dendroclimatological studies of the North American Monsoon. The problem occurs with delineating the boundary of the earlywood and latewood for sub-annual reconstructions. In this study, we present a novel method ("the resin duct method") for delineating the latewood boundary using resin ducts of P. edulis from three sites in New Mexico. The climate sensitivity of partial ring widths of P. edulis is then explored and compared to co-occurring Pinus ponderosa, which has a clear latewood boundary. The method of using resin ducts for delineating latewood in P. edulis resulted in a statistically significant relationship when compared to the latewood widths of co-occurring P. ponderosa. Although we found a similar climate response of P. edulis when compared to P. ponderosa, P. edulis latewood was a poor predictor of North American Monsoon precipitation unlike P. ponderosa. However, P. edulis earlywood has a statistically significant correlation with cool-season precipitation, making it useful for cool-season climate reconstructions in the Southwest. © 2017 by The Tree-Ring Society.

We reconstruct pandora moth (Coloradia pandora Blake) outbreaks and climate from a 1572-year (435-2006 CE) ponderosa pine (Pinus ponderosa Dougl. ex Laws.) chronology from a lava flow in central Oregon. We took samples from 128 living trees and remnant logs and crossdated the samples using skeleton plots and COFECHA for quality control. After cutting out and removing those time periods from the chronology during which insects become the main limiting factor to growth, we examine the response of tree rings to climate. Evidence of species longevity (up to 877 years), presence of periodic pandora moth defoliations (13 total), and a significant relationship with the Palmer Drought Severity Index were observed (R2 = 0.34, p < 0.001). Suppressions related to pandora moth outbreaks were recorded back to 618 CE, with a mean return interval of 104 years. Previous-fall to current-spring PDSI was reconstructed over 1376 years (630-2006 CE), where the most prolonged drought periods were 1136-1166 CE and the Dust Bowl 1924-1941. Our research documents longevity of ponderosa pine, resilience in the presence of multiple disturbances, and demonstrates a technique to separate insect outbreak signals from climate reconstructions in long chronologies while embracing the entire signal available in tree rings. © 2017 by The Tree-Ring Society.

During May 2013, the Bear Paw State Natural Area near Boone, North Carolina acquired an 11.5 ha tract of land and two log cabins from David Wray of Blowing Rock, North Carolina. Work was soon underway to determine the historical nature of these two buildings and to evaluate them for consideration for the National Register of Historic Places. A historic structure report, completed as a collaboration between Appalachian State University and the North Carolina Division of Parks and Recreation, was unable to discover much about the history of the two log cabins except that they were both likely moved to their current location in the early 20th Century. To determine when the cabins were built, we extracted core samples from logs in both cabins and compared the tree-ring patterns to region-wide, precisely-dated reference chronologies. We dated the tulip poplar tree-ring chronology from the Big Cabin to the period 1675-1859. Cutting dates on several of the logs revealed tree harvest likely occurred between fall 1859 and spring 1860. Some logs had outermost rings that dated to 1857 and 1858. Still, these logs may have been harvested a few years earlier, or some of the outer rings may have been lost during construction or sampling. We were unable to absolutely date an 81-year long American chestnut chronology from the Small Cabin. Our results confirmed that the Big Cabin was an Antebellum Period structure (pre-American Civil War) and therefore has potential historical significance. Because we still cannot tie this cabin to a historical figure or a historical event, the cabin cannot be nominated yet for inclusion in the National Register of Historic Places, but the identification of an original construction date for the cabin may contribute to further assessment for inclusion on a local or national register. In the meantime, we intend to use this cabin in annual summer workshops for undergraduate students taking courses at Appalachian State University so that more students can be exposed to the hands-on nature of scientific inquiry and can learn the value of dendrochronology for understanding human and environmental history. © 2017 by The Tree-Ring Society.

Minimum blue-intensity (BI) appears to be a viable source of proxy-temperature data, but is yet to be applied to a Southern-Hemisphere species. Here, we apply the BI technique to Podocarpus lawrencei, a conifer endemic to the Australian Alps. We develop sample-preparation protocols and examine the climate sensitivity of resulting tree-ring width (TRW) and BI chronologies. We found that extractable resins were removed from P. lawrencei samples after 28 hours of Soxhlet extraction and a highly-significant negative correlation (r =-0.79, p<0.0001) exists between the resulting BI chronology and growing season (August-April) temperature maxima. The climate sensitivity of our BI data, combined with an apparent teleconnection with a previously-reported dataset, suggests that an unparalleled opportunity exists to develop a powerful proxy for growing-season temperatures in southeast Australia. © 2016 by The Tree-Ring Society.

The Wabash and Erie Canal system was an important transportation network in the early 1800s prior to the dominance of trains and later automotive transportation. In this work, timbers from Culvert 151 were examined, after they were exhumed during construction of Hwy 641 on the south side of Terre Haute, Indiana. Cross-sections were taken from each of 22 beams and allowed to air dry to determine the stability of the timbers. We examined the wood to determine the genera or species of each sample that was used in this construction project and developed a floating chronology from our white oak group samples. The mix of species present included 11 beams of American beech (Fagus grandifolia), five white oak group (Quercus subgenus Lepidobalanus), and one each of American elm (Ulmus americana), winged elm (Ulmus alata), sugar maple (Acer saccharum), shagbark hickory (Carya ovata), white ash (Fraxinus americana), and black walnut (Juglans nigra). This suggests that the timbers were cut from the available trees in a certain size class without much regard for wood properties. The oak trees were an average of 186 years in age and the floating chronology dated to AD 1827. We also compared our chronology to 16 other oak chronologies in the region using an Inverse Distance Weighting (IDW) algorithm in ArcGIS to determine the most likely provenance of the samples. Our oak chronology correlates the strongest to archaeological samples from southeastern Indiana in Jefferson County along the Ohio River. It is possible that the timbers were cut near Madison Indiana, shipped down the Ohio River and up the Wabash River prior to incorporation in Culvert 151 on the Wabash and Erie Canal. © 2016 by The Tree-Ring Society.

The relationship between earlywood width (EW) and latewood width (LW) is investigated using 197 tree-ring collections representing several tree species from across the North American continent. Chronologies of LW have limited paleoclimate value when they have low variance or very high correlation with EW from the same site. The correlation of LW and EW can be removed by taking the residuals from linear regression to provide a chronology of discrete latewood growth free from the carryover effects of prior EW (the so-called adjusted latewood chronology, LWa). The correlation between EW and LW, along with LWa variance, varies dramatically across North America. The lowest correlations between EW and LW chronologies can be found in Pseudotsuga menziesii in the summer monsoon region of northwestern Mexico. Low correlations between EW and LW chronologies are also noted for Pinus echinata and Quercus stellata in the south-central United States. Q. stellata also displays the highest LWa variance among any species in the dataset. For three conifer species, correlations between EW and LW appear to increase with the biological age of the tree. An age-related decline in LWa variance was also detected for Douglas-fir, bald cypress and ponderosa pine older than 200 years. These results imply that heavy sampling to produce "age-stratified" chronologies based on trees ≤ 200 years in age throughout the record may produce the best quality LW chronologies with the highest variance and most discrete growth signal independent from EW. © 2016 by The Tree-Ring Society.

We reconstructed August-May precipitation from AD 1765 to 2010 for the eastern part of the Hexi Corridor, northwest China, using tree rings of Picea crassifolia. The precipitation reconstruction explains 44.1% of the actual precipitation variance during the common period of 1951-2010. The precipitation reconstruction is representative of precipitation conditions over a large area of the Hexi Corridor. Multi-taper spectral analysis reveals the existence of significant variability with periods of 9.3, 6.7, 3.1, and 2.6 years. Comparison between the precipitation reconstruction of the eastern part of the Hexi Corridor and other nearby precipitation/drought reconstructions shows high coherency in the timing of dry/wet episodes on annual to decadal scale. The divergences existing between the reconstructions may reflect the influence of different geographic features in Gansu and differences in seasonality of the various precipitation/drought reconstructions. © 2016 by The Tree-Ring Society.