Tree-Ring Research is the peer-reviewed journal of the Tree Ring Society. The journal was first published in 1934 under the title Tree-Ring Bulletin. In 2001, the title changed to Tree-Ring Research.

The Tree-Ring Society and the Laboratory of Tree-Ring Research at the University of Arizona partnered with the University Libraries to digitize back issues for improved searching capabilities and long-term preservation. New issues are added on an annual basis, with a rolling wall of five years.


Contact the Editor of Tree-Ring Research at editor@treeringsociety.org.

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  • The Climate Response Of Cedrela Fissilis Annual Ring Width In The Rio Sao Francisco Basin, Brazil

    Pereira, Gabriel De Assis; Maioli Campos Barbosa, Ana Carolina; Arne Torbenson, Max Carl; Stahle, David William; Granato-Souza, Daniela; Dos Santos, Rubens Manoel; Delfino Barbosa, Joao Paulo (Tree-Ring Society, 2018-07)
    The Sao Francisco River basin is one of the most drought-prone regions of Brazil. Seasonally dry tropical forests (SDTF) are widely distributed in the basin and we developed a short chronology of Cedrela fissilis annual ring widths from SDTF fragments based on 89 cores from 44 trees dating from 1961 to 2015. The average correlation among all radii (RBAR) is 0.52. The tree-ring chronology is correlated with wet season precipitation totals, must strongly and consistently near the beginning of the wet season. The spatial pattern of correlation covers most of the southern portion of the Brazilian Drought Polygon and the sub-basins of the two largest tributaries of the Sao Francisco River, in some areas exceeding r = 0.60. The chronology is also correlated with total annual discharge of the Rio Sao Francisco River measured at Barra (r = 0.489; 1961-2015), which is very promising in a country that generates two thirds of its electricity from hydroelectric power plants, particularly if this short chronology can be extended with trees exceeding 150-years old known to still exist in the region.
  • Dendrogeomorphological Evidence Of Flood Frequency Changes And Human Activities (Portaine Basin, Spanish Pyrenees)

    Genova, M.; Diez-Herrero, A.; Furdada, G.; Guinau, M.; Victoriano, A. (Tree-Ring Society, 2018-07)
    The Portaine mountain catchment, containing the Port Aine ski resort (Lleida, Spanish Pyrenees), displays active erosional and depositional phenomena caused by periodic torrential floods. These events present a potential risk and incur significant economic losses. In ungauged remote catchments (like Portaine), trees might be the only paleohydrological source of information regarding past floods. Thus, we estimated the temporal and spatial distribution of torrential floods by dendrogeomorphological techniques to assess whether human impact (land-use changes and infrastructure works) affected their frequency andmagnitude. One-hundred and sixty-six samples from 67 trees belonging to 10 different species were analyzed; past flood events of the last 50 years were identified by dating and relating evidence between them. Moreover, a detailed geomorphological study was performed and the available historical data compiled. Our multi-evidence analysis provides new insight into the occurrence of paleofloods. Changes in flood frequency since 2006, especially from 2008, suggest that the geomorphological equilibrium has been disturbed, coinciding with both major earthworks within the ski resort and intense but not extraordinary rainfall. This conclusion has important implications for land planning and the design of future projects in the mountain watersheds.
  • Tree-Ring Carbon Isotope Records From The Western Oregon Cascade Mountains Primarily Record Summer Maximum Temperatures

    Ratcliff, Christopher J.; Voelker, Steven L.; Nolin, Anne W. (Tree-Ring Society, 2018-07)
    Here we examine climatic influences on inter-annual variation in latewood tree growth (i.e. ring-width indices, RWILW) and stable-carbon isotope discrimination (Delta C-13(LW)) from 1950 to 2013 at two SNOTEL snowpack monitoring sites in the Oregon Cascade Mountains. Douglas-fir and mountain hemlock trees were sampled at the lower and upper elevation sites where annual peak snow water equivalent (SWE) averaged 467 and 1128 mm, respectively. RWILW chronologies were poorly correlated among sites/species (r = 0.23, P = 0.063) and neither exhibited strong correlations with monthly or seasonal climate variables. By contrast, Delta C-13(LW) chronologies were significantly correlated (r = 0.69, P < 0.001) and exhibited stronger climate responses. Multiple regression analyses identified summertime maximum temperature (T-max) and/or vapor pressure deficit (VPD) as the primary drivers of Delta C-13(LW). Secondary influences included summertime precipitation, specific humidity, cloud cover, and SWE from the previous fall and winter. Overall, our findings suggest that Cascade mixed conifer forests will become increasingly drought stressed as rising temperatures cause progressively diminished snowpacks. Moreover, our Delta C-13(LW) records also provide a proof of concept showing strong potential to expand summertime T-max reconstructions to other snowy, montane locations.
  • Determination Of Death Dates Of Coarse Woody Debris Of Multiple Species In The Central Hardwood Region (Indiana, USA)

    Alexander, M. Ross; Rollinson, Christine R.; Moore, David J. P.; Speer, James H.; Rubino, Darrin L. (Tree-Ring Society, 2018-07)
    Coarse woody debris (CWD; i.e. downed limbs and boles) serves numerous ecosystem functions, which vary according to the degree of decay. CWD decay is often described using five categories based on readily observed physical characteristics ranging from freshly fallen (Class I) to advanced decay with little structural integrity (Class V). Though useful in categorizing downed wood in a forest, these categories do not necessarily provide information about time since death or the decay process. Dendrochronology can be used to assign death dates to CWD and begin to provide a temporal description of the decay process. We used standard dendrochronological techniques to determine the death dates of 94 CWD samples from five common hardwood taxa in southern Indiana. Across taxa, the time since death of Class I (1.4 +/- 1.7 years; mean +/- SD; least decayed class) was significantly shorter than Class II (5.2 +/- 3.6 years), which was shorter than the more decayed classes (Class III: 11.5 +/- 4.9, and Class IV: 11.2 +/- 5.6 years). Within this general trend, time since death within a decay class varied greatly among taxa. Combining dendrochronology techniques with visual decay characteristics can improve our understanding of CWD's role and provide a more precise timeline for biomass and nutrient turnover within forested systems.
  • A Machine Learning Approach To Analyzing The Relationship Between Temperatures And Multi-Proxy Tree-Ring Records

    Jevsenak, Jernej; Dzeroski, Saso; Zavadlav, Sasa; Levanic, Tom (Tree-Ring Society, 2018-07)
    Machine learning (ML) is a widely unexplored field in dendroclimatology, but it is a powerful tool that might improve the accuracy of climate reconstructions. In this paper, different ML algorithms are compared to climate reconstruction from tree-ring proxies. The algorithms considered are multiple linear regression (MLR), artificial neural networks (ANN), model trees (MT), bagging of model trees (BMT), and random forests of regression trees (RF). April-May mean temperature at a Quercus robur stand in Slovenia is predicted with mean vessel area (MVA, correlation coefficient with April-May mean temperature, r = 0.70, p < 0.001) and earlywood width (EW, r = -0.28, p < 0.05). Similarly, June-August mean temperature is predicted with stable carbon isotope (delta C-13, r = 0.72, p < 0.001), stable oxygen (delta O-18, r = isotope 0.32, p < 0.05) and tree-ring width (TRW, r = 0.11, p > 0.05 (ns)) chronologies. The predictive performance of ML algorithms was estimated by 3-fold cross-validation repeated 100 times. In both spring and summer temperature models, BMT performed best respectively in 62% and 52% of the 100 repetitions. The second-best method was ANN. Although BMT gave the best validation results, the differences in the models' performances were minor. We therefore recommend always comparing different ML regression techniques and selecting the optimal one for applications in dendroclimatology.
  • Climatic Drivers Of Ponderosa Pine Growth In Central Idaho

    Pettit, Joseph L.; Derose, R. Justin; Long, James N. (Tree-Ring Society, 2018-07)
    Despite the widespread use of ponderosa pine as an important hydroclimate proxy, we actually understand very little about its climate response in the Northern Rockies. Here, we analyze two new ponderosa pine chronologies to investigate how climate influences annual growth. Despite differences in precipitation amount and timing and large elevation differences (1820 m versus 1060 m), ring width at both sites was strongly driven by water availability. The mid-elevation, water-limited site responded well to previous fall precipitation whereas the wetter, high-elevation site responded to growing season precipitation and temperature. When precipitation and temperature were simultaneously accounted for using the standardized precipitation evapotranspiration index, ring-width response between sites converged and appeared nearly identical. Water stress drove the timing of ponderosa pine growth by a combination of factors such as strong water dependence, and determinate growth physiology, as indicated by lag-1 autocorrelation. When analyzing response to single-month climate variables, precipitation from growing-season months dominates. When we examined seasonal variables, climate fromthe previous year became more important. Temporal fidelity of the climatic response at both sites maintained significance across the historical record, although the relationship weakened at the low-elevation site. The collection of new tree-ring data sets such as these for central Idaho improves our understanding of ponderosa pine growth response to climate.
  • Dendroecological Approach To Assessing Carbon Accumulation Dynamics In Two Pinus Species From Northern Mexico

    Pompa-Garcia, Marin; Venegas-Gonzalez, Alejandro; Albiero Junior, Alci; Sigala-Rodriguez, Jose A. (Tree-Ring Society, 2018-07)
    Global climate change will alter forests by shifting species ranges, which has implications for their ecological functions. Annual tree-ring widths andwood density are useful proxies for carbon cycle studies across a range of species. Here, using a dendroecological approach we sought to understand the carbon accumulation rates of two representative pine species growing on contrasting wet (P. arizonica) and dry (P. cembroides) sites and reveal how such species cope with climate variability. Although the rate of carbon gain was not significantly different across sites, we found that variations in carbon accumulation responded differently to specific hydroclimate drivers, site conditions, or to functional features of each species, which are still to be explored. Overall, annual carbon accumulation (C) was less sensitive to climate variability than ring width and wood density. Annual C was more sensitive to rainfall in the cold season (P. arizonica) and to the start of spring (both species). Our species-specific approach provided a suitable basis for modeling projections in the long-term carbon balance in these forests. Using species-specific tree-ring data has the potential to yield better estimations given that tree rings reflect fine spatial and temporal resolution, thereby reducing the uncertainty in forest carbon budgets.
  • Sensitivity Of Three Dominant Tree Species From The Upper Boundary Of Their Forest Type To Climate Change At Changbai Mountain, Northeastern China

    Gao, Lushuang; Zhang, Yun; Wang, Xiaoming; Zhang, Chunyu; Zhao, Yihan; Liu, Lanmei (Tree-Ring Society, 2018-01)
    We quantified the growth dynamics and climatic responses of three tree species that have dominated Changbai Mountain: Korean pine (Pinus koraiensis), Yeddo spruce (Picea jezoensis), and Erman's birch (Betula ermanii). Standardization curves and moving correlations were used to assess growth rate trends and analyze changes in growth-climate relationships of trees at their upper forest boundaries and individual species elevation limits, respectively. Contrasting growth patterns were observed between trees at each upper forest boundary and species-specific upper elevation limits. Korean pines and Yeddo spruces grew faster at their upper forest boundaries than at their individual species limits. A higher growth rate of Erman's birches at their forest upper boundary only occurred before 1960. Relative to the strong effect of temperature on tree growth at individual upper elevation limits, the stable effect of precipitation and changing effect of temperature on tree growth were observed at the upper forest boundaries. Temperature increases have had a significantly negative effect on Korean pine and Erman's birch since 1980, whereas temperature increases were associated with Yeddo spruce growth. This study elucidated the differential growth patterns and temporal changes in climate-growth relationships of these species between their upper forest boundaries and elevation limits.
  • How Do Droughts And Wildfires Alter Seasonal Radial Growth In Mediterranean Aleppo Pine Forests?

    Alfaro-Sanchez, Raquel; Julio Camarero, J.; Sanchez-Salguero, Ral; Trouet, Valerie; de Las Heras, Jorge (Tree-Ring Society, 2018-01)
    Climate models project increasing temperatures, evapotranspiration, and droughts for the Mediterranean Basin, which will trigger more frequent and dangerous fire events. Here, we evaluate the combined effects of drought and wildfire on seasonal tree growth on Aleppo pine stands at the intra-and inter-annual level. Indexed earlywood width (EWI), latewood width (LWI), and latewood proportion (LWPI) series were obtained from unburned and burned stands located at four sites along a precipitation gradient in southeastern Spain. The combined effect of drought in 1994 and 1995 and wildfire in August 1994, negatively impacted seasonal growth in the short term (1994-1999 period) at the site with higher water availability. At the driest site, however, no significant effects were found. We found fewer negative pointer years at the wettest burned stand than at the wettest unburned stand during the post-fire 1994-2012 period, and the opposite pattern was found at the driest site, i.e. more negative pointer years at the driest burned stand than at the driest unburned stand. This result indicates that the drier sites were more sensitive to cumulative impact of drought and wildfire disturbances in the long term, whereas the wetter sites were more sensitive in the short term. Our results demonstrate the seasonal growth plasticity of Aleppo pine to combined disturbances depends on site water availability. This study will help forest managers to implement climate change strategies, such as prescribed fires (controlled low-medium severity fires) to prevent wildfire hazards more efficiently in Aleppo pine stands with high water availability.
  • Climatic Signal In Earlywood And Latewood In Conifer Forests In The Monarch Butterfly Biosphere Reserve, Mexico

    Carlon-Allende, Teodoro; Villanueva-Diaz, Jose; Mendoza, Manuel E.; Perez-Salicrup, Diego R. (Tree-Ring Society, 2018-01)
    Earlywood (EW) and latewood (LW) chronologies can be used to analyze seasonal climatic variation. We constructed and analyzed total ring (RW), EW, and LW ring growth in Abies religiosa and Pinus pseudostrobus trees from the Monarch Butterfly Biosphere Reserve and evaluated their climatic signal (monthly precipitation and mean average, minimum and maximum temperatures) in the growth of tree rings by correlation and response function analyses. Precipitation during October and December of the previous year and during January, February, April, and May of the year of growth had a positive influence in the growth of both P. pseudostrobus and A. religiosa. Mean maximum temperatures had a negative effect on tree growth in both species. Additionally, growth of A. religiosa was more sensitive to variations of mean, minimum, and maximum temperatures in comparison with P. pseudostrobus, and monthly mean minimum temperature was positively correlated with EW and LW series in A. religiosa. We conclude that EW and LW growth of A. religiosa and P. pseudostrobus might be reduced by lower precipitation during the winter-spring season. Consequently, in the eventuality of warmer and drier climate during the latter season as projected by climate change scenarios, growth rates of A. religiosa could become severely affected, negatively impacting the overwintering habitat of the monarch butterfly (Danaus plexippus L.).
  • The First Dendrochronological Dating Of Timber From Tajikistan - Potential For Developing A Millennial Tree-Ring Record

    Opala-Owczarek, Magdalena; Owczarek, Piotr; Rahmonov, Oimahmad; Niedzwiedz, Tadeusz (Tree-Ring Society, 2018-01)
    We are reporting the first dendrochronological dating of timber from Tajikistan. Thirty samples were collected from two old buildings from a village located in the western Pamir-Alay; eight cores were taken from temple. Most of the construction wood was juniper species. The object chronologies cross-dated well with the previously published chronology based on living juniper trees from western PamirAlay. The results of dating revealed that investigated structures are composed of wood coming from several periods. The oldest pieces of wood dated back to the 11th and 12th Centuries. Most timber samples come from the turn of the 17th and 18th Centuries, which were probably the period of intense development of the Artuch village. Besides dating of the wood samples from these historic structures, our investigation provides the opportunity to extend the currently existing regional tree-ring chronology for future climate reconstruction of the Pamir-Alay and High Asia. Dated sequences were assembled into a 1012-year chronology spanning the period 945-2014 C.E. and strengthened the replication of its earliest part (with critical 0.85 EPS value since the beginning of the 13th Century).
  • Ensemble Empirical Mode Decomposition As An Alternative For Tree-Ring Chronology Development

    Guan, Biing T.; Wright, William E.; Cook, Edward R. (Tree-Ring Society, 2018-01)
    Since its establishment, tree-ring analysis has benefitted several scientific fields. Because of its many advantages, dendrochronology is a first choice to reconstruct past environmental variability. Two major concerns about the current tree-ring reconstruction paradigm are the subjective choices of detrending functions and the lack of fidelity to data of chronology generation methods. It is difficult to recover the original tree-ring data once they have been detrended and standardized. In this study, ensemble empirical mode decomposition (EEMD) is introduced as an objective high-fidelity stand-alone approach for developing tree-ring chronologies. Basic concepts of EEMD, recommended steps in developing chronologies, and available public domain programs are discussed. To demonstrate the potentials of EEMD for chronology development, two examples are provided, one for climate and the other for streamflow reconstructions. In both examples, EEMD chronologies show higher correlations with the instrumental data and have more power in their spectra than the ones developed based on the current tree-ring reconstruction approach. General usage concerns and cautions are also addressed.
  • Tree-Ring Research Of Mexican Beech (Fagus Grandifolia Subsp Mexicana) A Relict Tree Endemic To Eastern Mexico

    Chanes Rodriguez-Ramirez, Ernesto; Luna-Vega, Isolda; Rozas, Vicente (Tree-Ring Society, 2018-01)
    Mexican beech (Fagus grandifolia subsp. mexicana) has been classified as an endangered species because of its restricted distribution. The current distribution of Mexican beech, which is considered a Miocene relict, is limited to Tropical Montane Cloud Forests (TMCF) in the mountains of the Sierra Madre Oriental in eastern Mexico. We used dendroclimatic techniques to evaluate the effects of climate variability on the growth of Mexican beech within three forest fragments. The independent chronologies developed for the three sites were 152-178 years long. Cross-sections helped to assess the quality of the crossdating and detect false rings. Over the last 180 years, Mexican beech trees have lower mean radial growth than rates exhibited by other Fagus species. Mexican beech growth appears to be influenced by growing-season temperatures, especially mean maximum temperature. The response appears to be positive at the beginning of the growing season but becomes negative later. These results suggest that the persistence of Fagus-dominated forests in Mexico is dependent on local-scale climatic conditions of the TMCF. Mexican beech forests are associated with micro-climatic conditions that will control the fate of these forests in the face of on-going climate change.
  • Climate Signal In Cork-Ring Chronologies: Case Studies In Southwestern Portugal And Northwestern Algeria

    Ghalem, Amina; Barbosa, Ines; Bouhraoua, Rachid Tarik; Costa, Augusta (Tree-Ring Society, 2018-01)
    In temperate regions, the analysis of climate signals encoded in the wood rings allows assessing tree sensitivity to climate and its potential effects on growth and yield. In Mediterranean regions, the cork oak (Quercus suber L.) has received limited attention for dendrochronological studies because tree rings are faint and cork rings with a clear annual banding have been rather neglected. We analyzed the climatic signal of cork-ring chronologies for AD 1996-2010 from distinct regions in western Algeria [a mountain oak forest called Hafir-Zarieffet] and in southern Portugal [a peneplain wood-pasture called Benavente]. The goal was to evaluate the strength and consistency of climate signal and to assess cork growth sensitivity to climate variables (precipitation and temperature). Our results suggest that cork growth encodes a climatic signal. Trends of cork growth, via correlation analysis, including climate variables (on a monthly and seasonal basis) and Lang's index (on an annual basis) were successfully assessed. Drought-driven cork growth reduction is a threshold function of a P-T ratio, and with expected increase in the drought occurrence under changing climate, cork growth is likely to be similarly affected in both regions.
  • Dendrochronological Reconstruction Of Environmental History Of Fagus Grandifolia Subsp Mexicana In Mexico

    Beatriz Ortiz-Quijano, Adriana; Cuevas-Cardona, Consuelo; Villanueva-Diaz, Jose; Lopez-Mata, Lauro; Sanchez-Gonzalez, Arturo (Tree-Ring Society, 2018-01)
    Growth-ring analysis is a valuable source of information for reconstructing environmental history. In this study, ring-width series of a sample of Fagus grandifolia subsp. mexicana were used to identify the main events that have affected populations of this species. Core samples were extracted in three representative beech forests in Mexico. These are forests where F. grandifolia subsp. mexicana dominates the canopy. A total of 3355 years of growth rings were measured and three ring-width chronologies were generated. Average annual ring widths were similar between the three sites and ranged from 0.98 to 1.08 mm. A pattern of multiple suppressions and releases was observed, mainly associated with local events, but with a slight climatic influence. Correlations between the ring-width index and climate variables were not statistically significant, with the exception of a seasonal January-June precipitation pattern (1982-2001). There has not been a large-scale disturbance of natural or human origin in the beech forests of the state of Hidalgo in the past 150 years, except in El Gosco, where anthropogenic disturbances have increased in the past decade.
  • Growth-Ring Boundary Anatomy And Dendrochronological Potential In A Moist Tropical Forest In Northeastern Bangladesh

    Islam, Mahmuda; Rahman, Mizanur; Braeuning, Achim (Tree-Ring Society, 2018-01)
    We present the microscopic analysis of growth-ring boundary anatomy of 27 tree species from a moist tropical forest in Bangladesh and evaluate their dendrochronological potential. We observed high inter-species variability in the anatomical features that define growth-ring boundaries. Marginal parenchyma, fibre zones, and thick-walled latewood fibres were identified as the dominant anatomical features delineating growth-ring boundaries. The evaluation of growth-ring boundary distinctness in thin-sections and scanned images revealed that 25 out of 27 studied species (93%) showed distinct to fairly distinct growth-ring boundaries. Cluster analysis of wood anatomical features was used to select an additional 5 species for further investigation. Ring-width series of these species crossdated well within the same tree. Between trees crossdating was also successful in all 5 species. The Gleichlaufigkeit (GLK; i.e. the proportion of agreement/disagreement of inter-annual growth tendencies among the trees) varied among species between 0.55 and 0.71. A strong synchronization of tree-ring series between trees suggests that growth rings are annual and influenced by common environmental factors. The derived tree-ring series, estimated tree ages, and growth trajectories underline the high potential of our study area for answering a variety of climatological, ecological and archaeological questions by applying den-drochronology. This study will therefore provide a new endeavor in tropical dendrochronology of South Asian moist tropical forests.
  • South American Dendroecological Fieldweek 2016: Exploring Dendrochronological Research In Northern Patagonia

    Amoroso, Mariano M.; Speer, James H.; Daniels, Lori D.; Villalba, Ricardo; Cook, Edward; Stahle, David; Srur, Ana; Tardif, Jacques; Conciatori, France; Aciar, Eugenia; et al. (Tree-Ring Society, 2018-01)
    The South American Dendroecological Fieldweek (SADEF) associated with the Third American Dendrochronology Conference was held in El Bolson, Argentina, in March 2016. The main objective of the SADEF was to teach the basics of dendrochronology while applying specific knowledge to selected research questions. The course included participants and instructors from six different countries. This report describes activities of the course and briefly summarizes exploratory group projects. The Introductory Group developed an Austrocedrus chilensis chronology from 1629-2015 and documented a persistent decline in growth since 1977 which supports the fact that the current severe drought is the most severe in the 386-year record. Based on regional A. chilensis chronologies from 32. to 39. S Latitude, the Stream Flow Reconstruction Group developed a regional 525 year-long reconstruction from Rio Chubut and found the most severe drought episodes from 1490 to the present occurred from 1680-1705, 18131828, 1900-1920, 1993-2002, and from 2011 to the present. The Drought Reconstruction Group used A. chilensis annual tree-ring width chronologies to develop preliminary spatial field reconstructions of the Palmer Drought Severity Index spanning the Central Andes region. The reconstructions explain up to 81% of the 1907-1975 PDSI variance, indicating this tree species is powerful for informing on historical drought especially in very arid domains. The Dendroecology Group documented three spreading fires since the 1850s with a 12-year return interval but lack of fire for the last 94 years; they also documented a persistent decline in their chronologies in recent years, dating back to 1965.
  • Keith R. Briffa 1952-2017 In Memoriam

    Hughes, Malcolm K.; Cook, Edward R.; Osborn, Timothy J.; Melvin, Thomas M. (Tree-Ring Society, 2018-01)
  • Millennium-Long Tree-Ring Chronology Reveals Megadroughts on the Southeastern Tibetan Plateau

    Nie, C.-Y.; Zhang, Q.-B.; Lyu, L. (Tree-Ring Society, 2017-01)
    Millennium-aged trees are rare in natural forests. Here we present an 1184-year-long tree-ring width chronology from living juniper trees in the Biru area on the southeastern Tibetan Plateau. Growth-climate response analysis shows that the Biru chronology is significantly and positively correlated with late-spring (May-June) Standardized Precipitation Evaporation Index (SPEI) (r = 0.67, n = 53, p < 0.01). The tree-ring chronology explains 44.5% of the total variance of SPEI during the period AD 81957-2010. Reconstruction of May-June SPEI shows that there was a two-century-long megadrought during the late 13th to late 15th Centuries, and a seven-decade-long megadrought during AD 1630s to 1690s. Comparisons with other moisture records in the region suggest that the two-century megadrought identified in our reconstruction might be a widespread phenomenon most likely reflecting a stage of reduced Southwest Asian Summer Monsoon. Our results provide new evidence on the megadrought events on the Tibetan Plateau for the last millennium. © 2017 by The Tree-Ring Society.
  • Assessing the Potential of Pinyon Pine for Climate Reconstructions in Eastern California

    Wilding, T.; Woodhouse, C. (Tree-Ring Society, 2017-01)
    This paper documents a pilot study investigating the potential use of pinyon pine (Pinus monophylla Torr. & Frem) growing in the White Mountains of eastern California for climate reconstructions. The single-leaf pinyon pine from this study exhibit a significant and stable relationship with annual (August-July) precipitation over the instrumental record (r = 0.69). This relationship is stronger than that of the lower forest border bristlecone pine (Pinus longaeva) growing nearby. Spatially, the climate-growth relationship remains strong beyond this localized region, extending over Southern California. Although pinyon pine is not as long lived as the bristlecone pine, these results indicate that the strength of the climate-growth relationship makes this species valuable in developing climate reconstructions in the future. Additionally, the presence of persistent remnant wood at all sampling sites offers an opportunity to extend pinyon records further back in time. Furthermore, the close proximity of pinyon pine to bristlecone pine at these sites presents the possibility of developing multi-species reconstructions using both species. © 2017 by The Tree-Ring Society.

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