Search

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 rainfall patterns and regional dryness and wetness modes during the latest 2.5 centuries. This reconstruction shows that three persistent dry decades occurred during the 1840s, 1910s and 1850s and the three wettest decades occurred during the 1770s, 1820s and 1930s. The five years with lowest rainfall were 1759, 1917, 1841, 1747 and 1839, and 1770, 1938, 1819, 1941 and 1822 were the five years with highest rainfall, respectively. As indicated by the spatial correlation patterns, the reconstruction also exhibits regional characteristics. The variation of reconstructed rainfall significantly corresponds to East Asian monsoon. [ABSTRACT FROM AUTHOR]

The southern part of northeast China has experienced a marked warming and drying climate. We provide dendrochronological evidence for atmospheric CO fertilization and the impacts of warming on Chinese pine ( Pinus tabulaeformis) growth. The results of this study show that increased temperature has a negative effect on pine growth during a major part of the growing season and a weakly positive effects on growth during the remaining portion of the year. The monthly temperatures explain ca. 20 % of the total variance in the annual radial growth of Chinese pine from 1901 to 2009. An increase of approximately 3-5 °C is the maximum that Chinese pine can tolerate in this region with an annual rainfall of 500-700 mm. Our results suggest a that there is a proportional response to warming only up to a maximum of 1 °C warming, and indicate the complexitiesof succession in forest ecosystems in terms of adaptation and evolution in local pine populations under a rapid warming condition. In addition, increasing atmospheric CO concentrations have a positive effect on tree growth. This effect can be detected with conventional dendrochronological methods. [ABSTRACT FROM AUTHOR]

Abstract: 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 back to AD 1715. The reconstruction was generated using a simple linear regression method, verified by independent meteorological data, and accounts for 47.0% of the actual temperature variance during the common period (1957–2008). The reconstruction captures decadal and century-scale regional temperature variability, such as cold decades (1940s, 1930s, 1790s, 1950s and 1850s), warm decades (2000s, 1870s, 1750s, 1980s and 1840s), a cold half-century (ca. 1750–1799), and a warm half-century (ca. 1900–1949). It also reveals slightly higher frequency of cold years (20.4%) than warm years (18.0%), and a recent warming trend. Compared to the original 2011 reconstruction, this reconstruction has lower inter-annual temperature variability, high explained variance and high representativeness of regional climate. The reconstruction also correlates with the East Asian Monsoon and the Pacific Ocean signals, and indicates the feasibility of using tree rings from high latitude Northeast China to reconstruct summer temperature in permafrost forest environments. [Copyright &y& Elsevier]

Abstract: We present a precipitation reconstruction for the ecotone of Hulunbei''er steppe and Great Xing''an Mountain forest region, Inner Mongolia, based on tree rings of Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) scattered in regional sandy dune forests. The ring-width chronology shows most significant correlation with precipitation from prior August to current June. Based on this relationship, a precipitation reconstruction (1806–2007A.D.) was developed. The reconstruction was verified with independent data, and accounts for 39.7% of the actual precipitation variance during their common period (1953–2007). The reconstruction shows a relatively wet early half of the 19th century, a reversal from generally dry conditions during the late-19th century to generally wet conditions during the early 20th century, and a drying trend in general since the mid-20th century. The driest decades are found in 1856–1865 and 1889–1898, and the wettest decades occurred in 1944–1953 and 1826–1835, respectively. Multi-decadal (≥56.8year) and inter-annual (2.3, 4.6, 4.8, 4.9, 5.7–6.0, 9.0 and 9.1year) cycles are also detected in our reconstruction. Our precipitation reconstruction is significantly correlated with the East Asian Monsoon and Pacific Ocean signals, such as the El Niño-Southern Oscillation and Pacific Decadal Oscillation. [Copyright &y& Elsevier]

Abstract: For drought and flood forecasting, it is critical that we understand regional rainfall patterns as well as their potential underlying forcings, particularly in urban regions with greater long-term anthropogenic influences compared to rural areas. To achieve this, three Chinese pine (Pinus tabulaeformis) tree-ring width chronologies were developed from the metropolitan, suburban, and rural sites near Shenyang city of Northeast China and used to study regional dryness and wetness variability in the past 232yr. January–May precipitation (1771–2002) was successfully reconstructed from the tree-rings, although urban factors caused a slightly reduced response of the tree-rings to precipitation. Our reconstruction captures certain local rainfall variability and dryness/wetness signals, such as three unusually dry decades (1920s, 1850s and 1960s), an unusually dry half-century (1850–1899) and some significant cycles (2–8yr and ~20yr) associated with them. It also reveals a relatively equal number of dry/wet events (38.79% wet years versus 35.78% dry years) and a recent drying trend. Our study also indicates the feasibility of using urban tree-rings to reconstruct dry/wet patterns in city environments. [Copyright &y& Elsevier]

Forests provide irreplaceable ecosystem services for human society and prevent environmental degradation but climate change has substantially undermined these fundamental functions. It is therefore important to examine the responses and adaptation of different tree species to climate warming. Here, we investigated how climate warming has affected tree growth patterns and growth-climate responses of a conifer (Pinus tabuliformis) and two broad-leaved species (Populus davidiana and Betula platyphylla) in a temperate semi-arid region in the northern China. Our results showed that P. tabuliformis had a similar regional growth pattern and two broad-leaved species shared an interspecific growth similarity at the same site. Broad-leaved trees had a higher recovery and resilience to drought than the conifer while conifers were more resistant to drought compared to broad-leaved trees, indicating a faster drought-response of broad-leaved species than that of conifers. The warming climate has hindered the tree growth by exacerbating water-deficit, and in particular, water availability has become the limiting factor for the growth of pines in the area. Trees coped with the water-deficit by taking advantage of non-growing season water to compensate the water source for tree growth. The study not only revealed the differences of growth-climate responses between species but also highlighted the necessity to consider species-specific adaptation to climate warming and diversify forest management strategies. Highlights: The conifers and broad-leaved trees had divergent growth patterns and growth-climate response in temperate semi-arid China. Trees coped with the warming-drying climate by taking advantage of non-growing season water. The warming climate had a discriminatory effect on conifers and broad-leaved trees in temperate semi-arid regions. [ABSTRACT FROM AUTHOR]

The frequency, intensity, and duration of extreme droughts, with devastating impacts on tree growth and survival, have increased with climate change over the past decades. Assessing growth resistance and resilience to drought is a crucial prerequisite for understanding the responses of forest functioning to drought events. However, the responses of growth resistance and resilience to extreme droughts with different durations across different climatic zones remain unclear. Here, we investigated the spatiotemporal patterns in growth resistance and resilience in response to extreme droughts with different durations during 1901–2015, relying on tree‐ring chronologies from 2389 forest stands over the mid‐ and high‐latitudinal Northern Hemisphere, species‐specific plant functional traits, and diverse climatic factors. The findings revealed that growth resistance and resilience under 1‐year droughts were higher in humid regions than in arid regions. Significant higher growth resistance was observed under 2‐year droughts than under 1‐year droughts in both arid and humid regions, while growth resilience did not show a significant difference. Temporally, tree growth became less resistant and resilient to 1‐year droughts in 1980–2015 than in 1901–1979 in both arid and humid regions. As drought duration lengthened, the predominant impacts of climatic factors on growth resistance and resilience weakened and instead foliar economic traits, plant hydraulic traits, and soil properties became much more important in both climatic regions; in addition, such trends were also observed temporally. Finally, we found that most of the Earth system models (ESMs) used in this study overestimated growth resistance and underestimated growth resilience under both 1‐year and 2‐year droughts. A comprehensive ecophysiological understanding of tree growth responses to longer and intensified drought events is urgently needed, and a specific emphasis should be placed on improving the performance of ESMs. [ABSTRACT FROM AUTHOR]

Abstract The Earth has experienced an unequivocal warming, with the warmest period of the past 150 years occurring in the last three decades. Korean pine (Pinus koraiensis), a key tree species in northeast Asia, is predicted to be particularly vulnerable to climate change. Here, we use dendrochronological methods to test whether the observed growth decline of Korean pine in northeast China is related to climate warming and whether climate-growth responses varied with age. A total of 628 cores from 401 trees across 16 sites were sampled over the entire distribution area of Korean pine in China. Samples were divided into three age classes: younger (50–130 years), middle (131–210 years), and older trees (>210 years), and measured by the ring-width index and basal area increment (BAI). Results showed a significant decline in BAI in most sites coinciding with an increase of temperature in the growing season and a decrease in precipitation since the 1980s. Meanwhile, we found that temperature-induced growth decline was significantly related to tree age. The BAI of younger trees decreased significantly and sharply (0.44 cm2 year−1, P < 0.0001), while old trees either decreased slightly or stabilized (0.04 cm2 year−1, P = 0.33). Tree growth in the southernmost locations was more likely to decline, what was most likely a result of forest-stand age. The age-related growth decline induced by climate warming might be explained by tree species traits, differences in growth rates between age classes and their relation to stress, changes in root system, competition/stand structure or physiological mechanisms. Our results might also predict that early stand process-thinning is exacerbated by warming and drying. This research informs that the age effect of growth response to rising temperature should be considered in forest management under climate change, and particularly models of future carbon cycle patterns and forest dynamics. Graphical abstract Unlabelled Image Highlights • Young Korean pine, but not older trees, showed a growth decline in response to climate warming. • Trees in the southern region are more likely to decline, depending on age. • Drought caused by climate warming is the main cause of young tree decline. [ABSTRACT FROM AUTHOR]

ABSTRACT Possible future climate change can be projected by general circulation models ( GCMs), and the future geographic distribution of global climate zones can be projected based on these GCM simulations. In this study, the performance of 33 GCMs in simulating the distribution of global climate zones was evaluated using Kappa values. The results show that certain models are more skillful than other models in simulating the present distribution of global climate zones. The ensemble mean of all the GCMs showed worse performance than some individual models in simulating the present distribution of climate zones. The ensemble mean based on the three GCMs that showed superior performance achieved the optimum results in simulating the future distribution of climate zones. Based on the simulations of the ensemble mean of these three GCMs, the distributions of global climate zones in the future were projected for three scenarios (Representative Concentration Pathways, RCP) ( RCP2.6, RCP4.5, and RCP8.5). The climate types in the temperate zone were susceptible to climate changes under the three scenarios. The shift in the distribution of climate zones was mainly caused by the joint variations of temperature and precipitation among different climate zones. [ABSTRACT FROM AUTHOR]

A method was developed, based on Bayesian model averaging (BMA), to reconstruct regional mean temperature. Different from the arithmetic mean, which gives equal weight to each chronology, BMA weights the chronologies according to their contributions to the actual temperature variances. Thus, BMA holds advantages in integrating chronologies to reconstruct the regional mean temperature. The regional mean temperature for the Yunnan-Guizhou Plateau was reconstructed for the past four centuries (1628-2005) using BMA, which performed better than the simple arithmetic mean. The reconstruction explained 41.33% of total observed temperature variances during the period of 1961-2005. The warmest decade was found to be 1840-50 and the coldest 1810-20 prior to the instrumental period. The reconstructed temperature showed a high correlation ( r > 0.7, p < 0.001) with gridded observed temperatures in most grid cells of the Yunnan-Guizhou Plateau, suggesting that the regional temperature changes were captured well by the reconstruction. [ABSTRACT FROM AUTHOR]

• The intra-annual response rhythm of P. sylvestris exist at its southern limits. • The effects of temperature and precipitation on growth were anti-phase. • Temperature dominated the intra-annual growth-climate response rhythm. • A high water demand for rapid earlywood growth caused the spring response shift. • The response shift in autumn was related to the heat demand for cambium activity. Warming climate has posed a pressing threat on boreal forests and an improved understanding of the intra-annual pattern of climatic influences on the tree growth can help interpret the response of boreal forest to climate change. Here, we systematically examined the growth-climate relationship, cambium phenology, and xylem cell dynamics of Pinus sylvestris (PS) to disentangle its intra-annual growth rhythm to external drivers and internal physiological process at its southern distribution limits across Eurasia. We showed the intra-annual rhythm of PS to temperature and precipitation is anti-phase and synchronous at its southern limits. Temperature had both promoting and inhibiting effects on PS growth over growing season where the growth-temperature response gradually changed from positive in winter-early spring to negative in late spring-summer, and then returned to positive in autumn. Precipitation enhanced PS growth in late spring-summer. Temperature dominated the intra-annual growth-climate response rhythm, and the response shifted to negative when temperature reached 13.72 °C in spring-summer and shifted to positive when temperature reached 17.41 °C in summer-autumn in Shenyang, respectively. A high water demand for the rapid earlywood cell formation in spring-summer and heat requirement for cambial cell division in summer-autumn caused the shifts in growth-temperature response, respectively. Climatic warming advances and prolongs the time of summer water availability that limits PS growth at its southern distribution limits and thus warming climate may pose a greater threat to the southern population of PS. [Display omitted] [ABSTRACT FROM AUTHOR]

Boreal forests are facing profound changes in their growth environment, including warming‐induced water deficits, extended growing seasons, accelerated snowmelt, and permafrost thaw. The influence of warming on trees varies regionally, but in most boreal forests studied to date, tree growth has been found to be negatively affected by increasing temperatures. Here, we used a network of Pinus sylvestris tree‐ring collections spanning a wide climate gradient the southern end of the boreal forest in Asia to assess their response to climate change for the period 1958–2014. Contrary to findings in other boreal regions, we found that previously negative effects of temperature on tree growth turned positive in the northern portion of the study network after the onset of rapid warming. Trees in the drier portion did not show this reversal in their climatic response during the period of rapid warming. Abundant water availability during the growing season, particularly in the early to mid‐growing season (May–July), is key to the reversal of tree sensitivity to climate. Advancement in the onset of growth appears to allow trees to take advantage of snowmelt water, such that tree growth increases with increasing temperatures during the rapidly warming period. The region's monsoonal climate delivers limited precipitation during the early growing season, and thus snowmelt likely covers the water deficit so trees are less stressed from the onset of earlier growth. Our results indicate that the growth response of P. sylvestris to increasing temperatures strongly related to increased early season water availability. Hence, boreal forests with sufficient water available during crucial parts of the growing season might be more able to withstand or even increase growth during periods of rising temperatures. We suspect that other regions of the boreal forest may be affected by similar dynamics. [ABSTRACT FROM AUTHOR]

Abstract Forests are sensitive to climate change at high altitude and high latitude. Dahurian larch (Larix gmelinii Rupr.) has experienced an unprecedented forest retreat northward during the last century. Whether the response of growth to climate has dissimilar patterns at different altitudes, and what the "altitudinal trends" of forest development will be in the future, remains unclear. We dendroclimatically investigated the impacts of climate change on the growth of larch forests along an altitudinal gradient. In total, 721 trees from 25 forest stands, representing an altitudinal range from 400 to 950 m a.s.l. in the Great Xing'an Mountains, northeast China, were sampled and used to develop tree-ring width chronologies. The results suggest that warming caused a decline in larch growth at low altitude, while tree growth increased at high altitude. The growth–climate relationships indicate that October–February temperatures were positively correlated with larch growth at low- and high-altitude sites, but negatively correlated at medium-altitude sites (ca. 600–700 m a.s.l.). April–May (early spring) temperatures and October–January precipitation had positive effects on growth in general (ca. 75% of all sites). The effects of summer temperature/precipitation on larch growth at high-altitude sites were opposite to that at low-altitude sites. This change of response from significantly positive/negative correlation to significantly negative/positive correlation occurred gradually along the altitudinal gradient. The relationships varied significantly with altitude both in the case of temperature (R 2 = 0.425, P < 0.001) and precipitation (R 2 = 0.613, P < 0.001). The shift in response of larch forest to changes in summer temperature and precipitation occurred in the areas with a mean annual temperature of ca. −4 °C and ca. −5 °C, respectively; larch growth at temperatures lower or higher than these thresholds was limited by temperature and precipitation, respectively. Graphical abstract Unlabelled Image Highlights • The larch growth decline at low altitude and increase at high altitude. • Effects of summer temperature/precipitation on growth at high altitude was opposite to that at low altitude. • The response shift threshold of larch to temperature and precipitation of ca. –4 °C and ca. –5 °C, respectively. • The larch radial growth changed from the temperature limit at high altitude to the drought limit at low altitude. [ABSTRACT FROM AUTHOR]

To extend the historical temperature record in the permafrost region of Northeast China, we reconstruct the regional ground surface temperature (GST) for the past four centuries based on a network of Dahurian larch (Larix gmelinii Rupr.) tree-ring width chronologies. Seven standard tree-ring chronologies, which correlate well with each other, are averaged to create a regional mean chronology. GST is the major limiting factor for tree growth in this region. The optimum range of GSTs is from 30 May to 26 August (summer GST), identified by combining the days on which tree growth was strongly influenced by the daily GST data. The summer GST was significantly correlated with the regional mean chronology (r = 0.704, p < 0.001) over the common period 1971-2008 and was reconstructed for the period 1587-2008. The reconstructed GST accounts for 49.4% of the actual variance in the GST over the period 1971-2008 and captures four warm periods (1597-1603, 1716-1723, 1781-1788, and 1925-1929) and three cold periods (1639-1647, 1686-1711, and 1799-1805). The reconstructed GST is consistent with the northern hemisphere temperature in the Little Ice Age, and the warming rate from 1857 to 2008 is similar to a previously reported temperature reconstruction in the Xiao Xing’an Mountains. The low frequency of the reconstructed GST is well matched with that of the permafrost thawing depth. The reconstructed GST represents the longest temperature record in this study region and may be used as a reference for the permafrost thawing depth. [ABSTRACT FROM AUTHOR]

• The sap flow of Mongolian Scots pine has significant radial variation pattern. • The radial pattern of sap flow varies with age and growing season. • There is a considerable error in sap flow assessment if single point measurements are considered. • There is a stable conversion coefficient between Js 15mm and Js mean. • The radial variation of sap flow is different in response to meteorological factors. Mongolian Scots pine (Pinus sylvestris var. mongolica) is one of the main afforestation tree species in the Three North shelterbelt project in China, and an accurate estimation of its transpiration is of importance for plantation scientific density management especially under future climate change scenarios. While radial variation in tree species sap flow is an important factor for estimating transpiration, it is usually neglected. Thus, this study selected Mongolian Scots pine of different ages (10a, 20a, 30a, 40a) to study its radial variation pattern of sap flow using the multipoint (probes of different specifications) thermal dissipation method; additionally, its response characteristics to meteorological factors in northeast China were also discussed. The results show that the radial distribution of the sap flux density varied with age and growing season. It gradually decreased from the outside to the inside of the sapwood of the 10a stand. In contrast, the sap flux densities of the 20a, 30a and 40a stands had all typical single-peak patterns, with the highest value at 15 mm from the outside of the sapwood, and then sharply decreased with increasing distance. The sap flux density in both the 10a and 20a stands slightly changed, while it a significantly change in both the 30a and 40a stands between the middle and end of the growing season occurred. Further estimation of transpiration by single point and multipoint analyses was undertaken. The single point analysis resulted in large errors of -18.81%-11.02%, -52.44%-133.47%, -10.26%-130.38% and -48.78%-162.11% in the 10a, 20a, 30a and 40a stands, respectively. However, Js 15mm was significantly correlated with the mean sap flux density of a sapwood area (Js mean) and exhibited a constant conversion coefficient. The sap flux densities of separate sapwood depths were significantly affected by meteorological factors and varied according to different meteorological factors. [ABSTRACT FROM AUTHOR]

ABSTRACT Vegetation types are generally classified based only on remote sensing vegetation data, and yet they cannot reflect their connection with climate. Climatic vegetation types reflect the regional vegetation characteristics in terms of climate. The distribution of global climatic vegetation types were identified by K-means method based on vegetation and climate data. Fourteen climatic vegetation types were classified based on vegetation and climate data. Every type had distinct climate and vegetation characteristics. The regions with similar normalized difference vegetation index ( NDVI) values but with different climate values such as tropical desert and temperate desert could be distinguished. Our new updated climatic vegetation types agreed 'fair' with Koeppen climate types and climate type of Zhang and Yan while agreed 'good' with vegetation types when checked with Kappa test. [ABSTRACT FROM AUTHOR]

The Changbaishan volcano, located in northeast China, produced a large amount of charcoal during the "Millennium Eruption" (c. 946 CE). In this paper, we report a high-resolution date for the eruption using multiple methods applied to the fossil charcoal and living trees, including wood anatomy, radiocarbon dating and tree-ring cross-dating. In addition, we develop a new floating annual-resolution tree-ring chronology spanning nearly 200 years that provides information about paleoclimate conditions. In our study, we identified 60 samples of charcoal as Larix olgensis based on anatomical characteristics and geographical location. Using these materials, we dated the eruption to the winter of 946 CE based on a combination of radiocarbon dating, traditional dendrochronological cross-dating and cambial cell growth status. This allowed us to develop an L. olgensis tree-ring width chronology covering 764–946 CE and 1715–2016 CE, with significant sensitivities to April–September temperature (p < 0.05). The tree-ring data have great potential to indicate extreme climate events; for example, we identify an extremely cold year in 903 CE. Such marker years can improve the reliability and accuracy of tree-ring data. Our study provides direct and precise tree-ring evidence for volcanic eruptions and anomalous climate years in the Middle Ages. [Display omitted] • Cambial activity enables us to date the Millennium Eruption to winter 946 CE. • The first chronology reaching the Middle Ages so far developed in northeastern China. • The chronology was assembled from volcanic charcoal and living larch. • This chronology is sensitive to temperature. [ABSTRACT FROM AUTHOR]

Abstract: 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 reconstruction shows eleven persistent dry periods (e.g. 1856–1866, 1886–1891, 1898–1905), and eleven persistent wet periods (e.g. 1835–1855, 1867–1878, 1892–1897). Spectral analysis of the reconstruction shows several significant spectral peaks in the ca. 2–4-year periodicity band, suggesting inter-annual variability of El Niño-Southern Oscillation (ENSO). The precipitation reconstruction shows correlations related to the East Asian Monsoon and possible teleconnection of regional moisture variations to Pacific Ocean signals, such as El Niño and La Niña. [Copyright &y& Elsevier]

[Display omitted] • A temperature of 5.5 °C is critical for earlywood onset growth in spring. • A temperature of 2.5 °C may be critical for pine end growth in autumn. • Warming advanced and lengthened the xylem growing season. • An earlier and longer growing season resulted in a greater radial increment. Temperature plays a key role in phenology and growth of dominant tree species and hence in the structure and function of coniferous forests in cold temperate zones. We used a dendrochronological method to determine the critical temperatures of Pinus sylvestris var. mongolica (Mongolian pine) radial growth and the xylem growing season. Results showed that Mongolian pine radial growth is sensitive to daily mean temperatures of 4.0–5.5 °C in early spring, 14.0 °C in summer and 2.0–2.5 °C in autumn. A temperature of 4 °C might be the initial temperature required for sap flow, photosynthesis and tree germination in this area in early spring, and 5.5 °C is the most critical temperature for earlywood onset growth. The advance and extension of temperature 14.0 °C in summer can exacerbate water stress for trees and inhibit earlywood growth under the condition of insufficient precipitation. In autumn, 2.0–2.5 °C may be the minimum temperature for the xylem growth. These critical temperatures are important in predicting the changes in the phenology of cambial activity and the growth of conifers in cold temperate regions under a scenario of a warming climate. We defined the mean xylem growing season of pines in this region as 151 days from early May to early October. With the increase in temperatures during 1972–2015, the start date of the xylem growing season advanced by 0.24 days/year, the duration of the xylem growing season increased by 0.27 days/year and the basal area increment of Mongolian pine increased significantly (P < 0.01). The influence of the earlier and longer xylem growing season compensated the negative effect of high initial temperature (14.0–15.0 °C) in some months, resulting in an increase in tree radial increment in this area. The warmer climate will lead to a longer xylem growing season, resulting in greater wood production with an adequate supply of water available. [ABSTRACT FROM AUTHOR]