Nicole K Davi

William Paterson University · Department of Environmental Science

The distributions of forest, ice and snow in the Hengduan Mountains of China have undergone significant changes due to ongoing climatic warming. To better understand the spatiotemporal pattern of temperature changes in the Hengduan Mountains, we used tree-ring cores collected from multiple individuals of Larix speciosa Cheng et Law at five sites to...

Climate change is increasing the intensity and frequency of extreme heat events. Ecological responses to extreme heat will depend on vegetation physiology and thermal tolerance. Here we report that Larix sibirica, a foundation species across boreal Eurasia, is vulnerable to extreme heat at its southern range margin due to its low thermal tolerance...

Two large volcanic eruptions contributed to extreme cold temperatures during the early 1800s, one of the coldest phases of the Little Ice Age. While impacts from the massive 1815 Tambora eruption in Indonesia are relatively well-documented, much less is known regarding an unidentified volcanic event around 1809. Here, we describe the spatial extent...

Recent climate extremes in Mongolia have ignited a renewed interest in understanding past climate variability over centennial and longer time scales across north-central Asia. Tree ring-width records have been extensively studied in Mongolia as proxies for climate reconstruction, however, the climate and environmental signals of tree-ring stable is...

Linked to major volcanic eruptions around 536 and 540 CE, the onset of the Late Antique Little Ice Age has been described as the coldest period of the past two millennia. The exact timing and spatial extent of this exceptional cold phase are, however, still under debate because of the limited resolution and geographical distribution of the availabl...

Mass livestock mortality events during severe winters, a phenomenon that Mongolians call dzud, cause the country significant socioeconomic problems. Dzud is an example of a compound event, meaning that multiple climatic and social drivers contribute to the risk of occurrence. Existing studies argue that the frequency and intensity of dzud events ar...

Mid-to-high latitudes of Asia and its adjacent Arctic area are some of the most sensitive regions to climate warming in Eurasia, but spatio-temporal temperature variation over this region is still limited by a lack of long-term temperature records. Here, June-July temperature reconstructions are developed from a Larix sibirica composite chronology...

Vaccines are critical for curtailing the COVID-19 pandemic and may represent an important tool for return to “normalcy” on college campuses in the Fall of 2021. The purpose of this study was to investigate the extent of vaccination coverage and intention to vaccinate among college students. College students (N = 457) enrolled in the Spring 2021 sem...

Mass livestock mortality events during severe winters, a phenomenon that Mongolians call dzud, cause the country significant socioeconomic problems. Dzud is an example of a compound event, meaning that multiple climatic and social drivers contribute to the risk of occurrence. Existing studies argue that the frequency and intensity of dzud are risin...

Warming in Central Asia has been accelerating over the past three decades and is expected to intensify through the end of this century. Here, we develop a summer temperature reconstruction for western Mongolia spanning eight centuries (1269–2004 C.E.) using delta blue intensity measurements from annual rings of Siberian larch. A significant cooling...

Scientists rely heavily on tree-ring records to better understand climate variability of the past millennium. Tree rings can also be utilized to give students a window into paleoclimate research, the methods scientists use, and the importance of scientific findings. Here, we present five online labs that introduce undergraduate students to the fiel...

Objective: The COVID-19 pandemic has been a period of upheaval for college students. The objective of this study was to assess the factors associated with the increased levels of mental health burden among a sample of undergraduate college students in Northern New Jersey, the region of the U.S. severely impacted by the outbreak of COVID-19. Metho...

X‐ray microdensitometry on annually resolved tree‐ring samples has gained an exceptional position in last‐millennium paleoclimatology through the maximum latewood density (MXD) parameter, but also increasingly through other density parameters. For 50 years, X‐ray based measurement techniques have been the de facto standard. However, studies report...

INTRODUCTION Many aspects of dendrochronology are accessible to undergraduate students. Conceptually, tree rings are both visual and intuitive. Trees are part of the everyday experience of most students, and even non-experts can start to see patterns of climate variability through time just by looking at a cross-section of a tree. Many tree-ring sc...

In north-western North America, the so-called divergence problem (DP) is expressed in tree ring width (RW) as an unstable temperature signal in recent decades. Maximum latewood density (MXD), from the same region, shows minimal evidence of DP. While MXD is a superior proxy for summer temperatures, there are very few long MXD records from North Amer...

The original version of this Article contained an error in the Data Availability section, which incorrectly read ‘All data will be freely available via https://www.ams.ethz.ch/research.html.’ The correct version states ‘http://www.ams.ethz.ch/research/published-data.html’ in place of ‘https://www.ams.ethz.ch/research.html’. This has been corrected...

Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the 14C content in 484 individual tree rings formed in the periods 770...

We developed Blue Intensity (BI) measurements from the crossdated ring sequences of Fokienia hodginsii (of the family Cupressaceae) from central Vietnam. BI has been utilized primarily as an indirect proxy measurement of latewood (LW) density of conifers (i.e., LWBI) from high latitude, temperature-limited boreal forests. As such, BI closely approx...

Some of the oldest and most important trees used for dendroclimatic reconstructions develop strip-bark morphology, in which only a portion of the stem contains living tissue. Yet the ecophysiological factors initiating strip bark and the potential effect of cambial dieback on annual ring widths and tree-ring estimates of past climate remain poorly...

Understanding past and recent climate and atmospheric circulation variability is vital for regions that are affected by climate extremes. In mid-latitude Asia, however, the synoptic climatology is complex and not yet fully understood. The aim of this study was to investigate dominant synoptic-scale circulation patterns during the summer season usin...

Ring-width (RW) records from the Gulf of Alaska (GOA) have yielded a valuable long-term perspective for North Pacific changes on decadal to longer timescales in prior studies but contain a broad winter to late summer seasonal climate response. Similar to the highly climate-sensitive maximum latewood density (MXD) proxy, the blue intensity (BI) para...

Volcanic eruptions have global climate impacts, but their effect on the hydrologic cycle is poorly understood. We use a modified version of superposed epoch analysis, an eruption year list collated from multiple datasets, and seasonal paleoclimate reconstructions (soil moisture, precipitation, geopotential heights, and temperature) to investigate v...

Climate in the Gulf of Alaska (GOA) reflects large-scale ocean-atmosphere variability of the North Pacific climate system. Ring-width (RW) records from the GOA have yielded a valuable long-term perspective for North Pacific changes on decadal to longer time scales in prior studies, but express a broad winter to late summer seasonal response. Simila...

Climate field reconstructions from networks of tree-ring proxy data can be used to characterize regional-scale climate changes, reveal spatial anomaly patterns associated with atmospheric circulation changes, radiative forcing, and large-scale modes of ocean-atmosphere variability, and provide spatiotemporal targets for climate model comparison and...

The eruption of Samalas in Indonesia in 1257 ranks among the largest sulfur-rich eruptions of the Common Era with sulfur deposition in ice cores reaching twice the volume of the Tambora eruption in 1815. Sedimentological analyses of deposits confirm the exceptional size of the event, which had both an eruption magnitude and a volcanic explosivity i...

We present a well-verified precipitation reconstruction (r = 0.612, p < 0.01), spanning 1741 to 1998, for a relatively humid monsoon region from southern Northeast China and the northern Korean peninsula, based on tree rings from Chinese pine and Korean pine. We then investigate the variability of the reconstruction, and identify the leading rainfa...

In a warming world, water scarcity is one of the main concerns for sustainable development and human well-being in inner Asia. Due to the lack of instrumental streamflow records, the natural variability of the water supply from inner Asian rivers is not well understood from a long-term perspective. Here, we have reconstructed the streamflow of Uppe...

Tree-ring chronologies are widely used to reconstruct high-to low-frequency variations in growing season temperatures over centuries to millennia. The relevance of these timeseries in large-scale climate reconstructions is often determined by the strength of their correlation against instrumental temperature data. However, this single criterion ign...

Large-scale millennial length Northern Hemisphere (NH) temperature reconstructions have been pro- gressively improved over the last 20 years as new datasets have been developed. This paper, and its companion (Part II, Anchukaitis et al. in prep), details the latest tree-ring (TR) based NH land air temperature reconstruction from a temporal and spat...

Robert MacFarlane writes “There is no lone tree language, but a forest of tree languages.” In About Trees, Katie Holten (and contributors) invites us to enter some of these forests. She has created a Tree Alphabet and used it to translate a compendium of well known, loved, lost and new writing. She takes readers on a journey from ‘primeval atoms’...

Recent incidences of mass livestock mortality, known as dzud, have called into question the sustainability of pastoral nomadic herding, the cornerstone of Mongolian culture. A total of 20 million head of livestock perished in the mortality events of 2000–2002, and 2009–2010. To mitigate the effects of such events on the lives of herders, internatio...

While paleoclimatic studies have extended our understanding of North Pacific climate variability, these have been almost exclusively based on proxies from western North America. We present a tree-ring reconstruction of June to September coastal air temperatures for Nemuro, northeastern Japan for the past four centuries. It explains 36% of the varia...

Hydroclimate variations since 1300 in central and monsoonal Asia and their interplay on interannual and interdecadal timescales are investigated using the tree-ring based Palmer Drought Severity Index (PDSI) reconstructions. Both the interannual and interdecadal variations in both regions are closely to the Pacific Decadal Oscillation (PDO). On int...

There is a need to understand the long-term variability Asian-Pacific Oscillation (APO) due to its close linkages with large-scale ocean–atmosphere anomalies. The first principal component (PC) of a network of 130 temperature proxies covering East Asia and the northeastern Pacific Ocean was employed to reconstruct the instrumental APO index from 50...

A top priority in climate research is obtaining broad-extent and long-term data to support analyses of historical patterns and trends, and for model development and evaluation. Along with directly measured climate data from the present and recent past, it is important to obtain estimates of long past climate variations spanning multiple centuries a...

Traditional detrending methods assign equal mean value to all tree-ring series for chronology developments, despite that the mean annual growth changes in different time periods. We find that the strength of a tree-ring model can be improved by giving more weights to tree-ring series that have a stronger climate signal and less weight to series tha...

Spatial reconstructions of drought for central High Asia based on a tree-ring network are presented. Drought patterns for central High Asia are classified into western and eastern modes of variability. Tree-ring based reconstructions of the Palmer drought severity index (PDSI) are presented for both the western central High Asia drought mode (1587–...

The availability of the first tree-ring based drought reconstructions for the entire central and eastern Asia (CEA) allowed comprehensive investigation of its spatiotemporal hydroclimate features for the past seven centuries. Drought variability of ten factors in the context of Asian monsoon and westerlies was analyzed. The Angkor drought (the 1350...

This paper presents a spatially and temporally improved reconstruction of mean summer (June–August) temperature derived from tree-ring width data of Dahurian larch (Larix gmelinii Rupr.) from the northern Great Xing'an Mountains, Northeast China. Three new chronologies were added to the original 2011 reconstruction, and the reconstruction extended...

A 183-year record of total precipitation from September to current July was reconstructed using tree rings from Chinese pine (Pinus tabulaeformis) to explore regional moisture variations in northwestern Liaoning province. The reconstruction accounts for 35.4% of the total variance of the instrumental precipitation from 1957 to 2010. The reconstruct...

Key Points Significantly spatially and temporally improved streamflow reconstruction Greater variability captured then in the original reconstruction Drought conditions seen over the past decade may be return to normal conditions

The Kongtong Mountain area is a marginal area of the Asian summer monsoon and is sensitive to monsoon dynamics. The sensitivity highlights the need to establishing long-term climate records there and evaluating links with the Asian monsoon. Using “signal-free” methods, we developed a tree-ring chronology based 52 ring-width series from 23 Pinus tab...

a b s t r a c t In its continuing move toward resource independence, Mongolia has recently entered a new agricul-tural era. Large crop fields and center-pivot irrigation have been established in the last 10 years across Mongolia's "Breadbasket": the Bulgan, Selenge and Tov aimags of northcentral Mongolia. Since meteo-rological records are typically...

The Kongtong Mountain area is a marginal area of the Asian summer monsoon and is sensitive to monsoon dynamics. The sensitivity highlights the need to establishing long-term climate records there and evaluating links with the Asian monsoon. Using "signal-free" methods, we developed a tree-ring chronology based 52 ring-width series from 23 Pinus tab...

To understand how urban tree growth has responded to the accelerating expansion in population and urbanization, an understanding of the tree-climate–urban ecosystem relationship is necessary. To this end, a metropolitan, suburban, and rural forest stand in and near Shenyang; and a rural forest stand in Weichang, were sampled in southern Northeast C...

May–September temperatures were reconstructed for the past 250 yr based on Dahurian larch Larix gmelinii Rupr. growing in permafrost region of Northeast China. The reconstruction accounts for 39.3% of the actual temperature variance over the period 1958–2008. The reconstruction captured 3 relatively cold periods in 1847–1852, 1861–1866 and 1935–194...

Previous tree ring based hydrologic studies in Mongolia have been regional in scale. Here, we present a large-scale summer drought reconstruction for Mongolia that reveals the main summer moisture patterns of the past. This reconstruction is based on a network of tree ring chronologies that span the country. The resulting drought model explains 61%...

Spatial reconstructions of drought for central High Asia based on a tree-ring network are presented. Drought patterns for central High Asia are classified into western and eastern modes of variability. Tree-ring based reconstructions of the Palmer drought severity index (PDSI) are presented for both the western central High Asia drought mode (1587–...

A great impediment of Asian monsoon (AM) climate studies is the general lack of long-term observations of large-scale monsoon variability. Here we present a well-verified reconstruction of temporal changes in the dominant summer moisture pattern over China and Mongolia (CM), based on a network of tree-ring chronologies (1600-1991). The reconstructi...

We present a Palmer Drought Severity Index reconstruction (r=0.61, P<0.01) from 1440 to 2007 for the southeastern Tibetan Plateau, based on tree rings of the forest fir (Abies forrestii). Persistent decadal dry intervals were found in the 1440s–1460s, 1560s–1580s, 1700s, 1770s, 1810s, 1860s and 1980s, and the extreme wet epochs were the 1480s–1490s...

Tree-ring records can provide longer, high-resolution records of climate variability in remote regions such as western Mongolia, where recorded data are extremely limited. Here, we use three absolutely dated tree-ring-width chronologies to reconstruct the Palmer Drought Severity Index (PDSI) for a grid point in western Mongolia (48.75°N, 88.75°W)....

The Asian monsoon system can be studied using a complementary proxy/simulation approach which evaluates climate models using estimates of past precipitation and temperature, and which subsequently applies the best understanding of the physics of the climate system as captured in general circulation models to evaluate the broad-scale dynamics behind...

We are reporting the first dendrochronological dating in Mongolia; the building history of two temples in the Mandal Monastery, Central Bayankhongor Province. Twenty core samples were collected from the Mandal East Temple and 25 disks from Mandal School Temple. All species of sampled woods were larch (Larix sibirica). The chronologies of two buildi...

Central Asian drought has had drastic impacts on vast regions over recent years. Longer records and insight into temporal drought patterns could aid greatly in anticipating extreme events and agrarian plan-ning. Mongolia is representative of the central Asian region, and tree-ring resources are used herein to extend the climate record and test for...

1] The first verifiable reconstruction of spring (April – July) precipitation is presented for Crimea, Ukraine. It is derived from Crimean pine (Pinus hamata) ring-width data spanning A.D. 1620– 2002. The reconstruction accounts for 37% of the variance in observed precipitation over 1896 – 1988. Most droughts recorded in Crimean historical document...

1] A few tree ring studies indicate recent growth declines at northern latitudes. The precise causes are not well understood. Here we identify a temperature threshold for decline in a tree ring record from a well-established temperature-sensitive site at elevational tree line in northwestern Canada. The positive ring width/temperature relationship...

1] We investigate the physiological effects of the elongation of the growing season and the increase in summer greenness on northern hemisphere forests by examining the relationship between NDVI and tree rings. These variables are correlated during June and July only. These results suggest that NDVI proxies the physiological status of trees and tha...

high-resolution proxies to extend the climate record in the Wrangell Mountain region of Alaska. We developed a warm-season (July–September) temperature reconstruction that spans A.D. 1593–1992 based on the first eigenvector from principal component analysis of six maximum latewood density (MXD) chronologies. The climate/tree-growth model accounts f...

Variations in both width and density of annual rings from a network of tree chronologies were used to develop high-resolution proxies to extend the climate record in the Wrangell Mountain region of Alaska. We developed a warm-season (July–September) temperature reconstruction that spans A.D. 1593–1992 based on the first eigenvector from principal c...

Several tree species in Crimea can reach ages of 1000 years or more (Crimea..., 1999), including Taxus baccata L., Arbutus andrachne L., Quercus pubescens Willd, Quercus petraea (Mattuschka) Liebl., Quercus robur L., Juniperus excelsa M.B., and Pistacia mutica Fisch.et Mey. In September 2002, we collected samples from several long-lived tree sites...

The late Holocene history of eolian activity in a parabolic dune complex in the northern Chugach Mountains, Alaska, is reconstructed using 80 tree-ring dates and 5 radiocarbon ages. A radiocarbon age on detrital organics shows mobilization of sands about cal yr A.D. 1260. General forest growth over the dune field area indicates that this active int...

Four intervals of late Holocene glacier advance are recognized from study of nine valley glaciers in the Wrangell and westernmost St. Elias Mountains of Alaska. The oldest glacial advance is recognized at the Nabesna and Barnard Glaciers where five radiocarbon ages suggest advance as early as 2700 cal. (calibrated) yr B.P. Two additional radiocarbo...

The Maunder Minimum interval (from the mid-1600s-early 1700s) is believed to have been one of the coldest periods of the past thousand years in the Northern Hemisphere. A maximum latewood density temperature reconstruction for the Wrangell Mountains, southern Alaska (1593-1992) provides information on regional temperature change during the Maunder...

We present a warm season (April–September) temperature reconstructionfor Asahikawa, north central Hokkaido, Japan for AD 1557–1990. The reconstruction, which accounts for 34% of the temperature variancefrom 1925–1990, is based on maximum latewood density data from Saghalinspruce (Picea glehnii) growing at timberline (1340–1390 m) at MountAsahidake,...