Non-linear Response to Cell Number Revealed and Eliminated From Long-Term Tracheid Measurements of Scots Pine in Southern Siberia

Dendroclimatic research offers insight into tree growth–climate response as a solution to the forward problem and provides reconstructions of climatic variables as products of the reverse problem. Methodological developments in dendroclimatology have led to the inclusion of a variety of tree growth parameters in this field. Tree-ring traits developed during short time intervals of a growing season can potentially provide a finer temporal scale of both dendroclimatic applications and offer a better understanding of the mechanisms of tree growth reaction to climatic variations. Furthermore, the transition from classical dendroclimatic studies based on a single integral variable (tree-ring width) to the modern multitude of quantitative variables (e.g., wood anatomical structure) adds a lot of complexity, which mainly arises from intrinsic feedbacks between wood traits and muddles seasonality of registered climatic signal. This study utilized life-long wood anatomical measurements of 150- to 280-year-old trees of Pinus sylvestris L. growing in a moisture-sensitive habitat of the forest-steppe of Southern Siberia (Russia) to investigate and eliminate legacy effect from cell production in tracheid traits. Anatomical parameters were calculated to describe the results of the three main subsequent stages of conifer xylem tracheid development, namely, cell number per radial file in the ring, mean and maximum cell radial diameter, and mean and maximum cell-wall thickness. Although tree-ring width was almost directly proportional to cell number, non-linear relationships with cell number were revealed in tracheid measurements. They exhibited a stronger relationship in the areas of narrow rings and stable anatomical structure in wider rings. The exponential models proposed in this study demonstrated these relationships in numerical terms with morphometric meaning. The ratio of anatomical measurements to their modeled values was used to develop long-term anatomical chronologies, which proved to retain information about climatic fluctuations independent of tree-ring width (cell number), despite decreased common signal.

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Retrospective Analysis of Tree Decline Based on Intrinsic Water-Use Efficiency in Semi-Arid Areas of North China

Atmosphere ◽

10.3390/atmos11060577 ◽

2020 ◽

Vol 11 (6) ◽

pp. 577

Author(s):

Weiwei Lu ◽

Xinxiao Yu ◽

Guodong Jia

Keyword(s):

Climate Change ◽

Tree Ring ◽

Tree Growth ◽

North China ◽

Isotope Composition ◽

Ring Width ◽

Carbon Isotope Composition ◽

Tree Decline ◽

Tree Ring Width

Long-term tree growth is significantly affected by climate change, which have become a global concern. Tree-ring width and isotopic information can show how trees respond to climate change on a long-term scale and reveal some phenomena of tree decline or death. In this study, we used isotopic techniques and investigated annual changes in carbon isotope composition and tree-ring width of Populus simonii Carr. in Zhangbei, as well as trends in tree-ring carbon discrimination (Δ13C) and iWUE in normal, mildly declining and severely declining trees, in order to make a retrospective analysis and further understand the process of tree decline. We found that there were significant differences (p < 0.01 **) in δ13C, Δ13C, ci and iWUE at different decline stages, meaning that the δ13C and iWUE could be new indicators of tree health. The iWUE of all groups increased significantly, while the growth rate of declined P. simonii was much higher than that of normal growth P. simonii. According to the analysis, there may be a threshold of iWUE for healthy trees, which once the threshold value is exceeded, it indicates that trees are resistant to adversity and their growth is under stress. Similarly, the changing trend of BAI supports our conclusion with its changes showed that tree growth became slower and slower as degradation progressed. iWUE inferred from tree-ring stable carbon isotope composition is a strong modulator of adaptation capacity in response to environmental stressors under climate change. Elevated annual temperatures and increased groundwater depth are all contributing to the decline of P. simonii in north China.

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Tree-ring responses to extreme climate events as benchmarks for terrestrial dynamic vegetation models

Biogeosciences Discussions ◽

10.5194/bgd-11-2537-2014 ◽

2014 ◽

Vol 11 (2) ◽

pp. 2537-2568 ◽

Cited By ~ 12

Author(s):

A. Rammig ◽

M. Wiedermann ◽

J. F. Donges ◽

F. Babst ◽

W. von Bloh ◽

...

Keyword(s):

Tree Ring ◽

Tree Growth ◽

Extreme Events ◽

Ring Width ◽

Climate Extremes ◽

Tree Ring Width ◽

Model Data ◽

Vegetation Models ◽

The Impact

Abstract. Climate extremes can trigger exceptional responses in terrestrial ecosystems, for instance by altering growth or mortality rates. Effects of this kind are often manifested in reductions of the local net primary production (NPP). Investigating a set of European long-term data on annual radial tree growth confirms this pattern: we find that 53% of tree ring width (TRW) indices are below one standard deviation, and up to 16% of the TRW values are below two standard deviations in years with extremely high temperatures and low precipitation. Based on these findings we investigate if climate driven patterns in long-term tree growth data may serve as benchmarks for state-of-the-art dynamic vegetation models such as LPJmL. The model simulates NPP but not explicitly the radial tree ring growth, hence requiring a generic method to ensure an objective comparison. Here we propose an analysis scheme that quantifies the coincidence rate of climate extremes with some biotic responses (here TRW or simulated NPP). We find that the reduction in tree-ring width during drought extremes is lower than the corresponding reduction of simulated NPP. We identify ten extreme years during the 20th century in which both, model and measurements indicate high coincidence rates across Europe. However, we detect substantial regional differences in simulated and observed responses to extreme events. One explanation for this discrepancy could be that the tree-ring data have preferentially been sampled at more climatically stressed sites. The model-data difference is amplified by the fact that dynamic vegetation models are designed to simulate mean ecosystem responses at landscape or regional scale. However, we find that both model-data and measurements display carry-over effects from the previous year. We conclude that using radial tree growth is a good basis for generic model-benchmarks if the data are analyzed by scale-free measures such as coincidence analysis. Our study shows strong reductions in carbon sequestration during extreme years. However, for a better understanding of the impact of extreme events on e.g. the long-term fate of the European carbon balance, more long-term measurement data and improved process-based models are needed.

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Tree growth across the Nepal Himalaya during the last four centuries

Progress in Physical Geography Earth and Environment ◽

10.1177/0309133317714247 ◽

2017 ◽

Vol 41 (4) ◽

pp. 478-495 ◽

Cited By ~ 15

Author(s):

UK Thapa ◽

S St. George ◽

DK Kharal ◽

NP Gaire

Keyword(s):

Tree Ring ◽

Tree Growth ◽

Environmental Changes ◽

Ring Width ◽

High Elevation ◽

Forest Growth ◽

Tree Ring Width ◽

Early 19Th Century ◽

Tree Ring Data ◽

Instrumental Records

The climate of Nepal has changed rapidly over the recent decades, but most instrumental records of weather and hydrology only extend back to the 1980s. Tree rings can provide a longer perspective on recent environmental changes, and since the early 2000s, a new round of field initiatives by international researchers and Nepali scientists have more than doubled the size of the country’s tree-ring network. In this paper, we present a comprehensive analysis of the current tree-ring width network for Nepal, and use this network to estimate changes in forest growth nation-wide during the last four centuries. Ring-width chronologies in Nepal have been developed from 11 tree species, and half of the records span at least 290 years. The Nepal tree-ring width network provides a robust estimate of annual forest growth over roughly the last four centuries, but prior to this point, our mean ring-width composite fluctuates wildly due to low sample replication. Over the last four centuries, two major events are prominent in the all-Nepal composite: (i) a prolonged and widespread growth suppression during the early 1800s; and (ii) heightened growth during the most recent decade. The early 19th century decline in tree growth coincides with two major Indonesian eruptions, and suggests that short-term disturbances related to climate extremes can exert a lasting influence on the vigor of Nepal’s forests. Growth increases since AD 2000 are mainly apparent in high-elevation fir, which may be a consequence of the observed trend towards warmer temperatures, particularly during winter. This synthesis effort should be useful to establish baselines for tree-ring data in Nepal and provide a broader context to evaluate the sensitivity or behavior of this proxy in the central Himalayas.

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Development of tree-ring width chronologies and tree-growth response to climate in the mountains surrounding the Issyk-Kul Lake, Central Asia

Dendrochronologia ◽

10.1016/j.dendro.2014.03.002 ◽

2014 ◽

Vol 32 (3) ◽

pp. 230-236 ◽

Cited By ~ 14

Author(s):

Tongwen Zhang ◽

Yujiang Yuan ◽

Qing He ◽

Wenshou Wei ◽

Mamatkanov Diushen ◽

...

Keyword(s):

Central Asia ◽

Tree Ring ◽

Tree Growth ◽

Growth Response ◽

Ring Width ◽

Tree Ring Width

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Assimilation of Pseudo-Tree-Ring-Width observations into an Atmospheric General Circulation Model

10.5194/cp-2016-92 ◽

2016 ◽

Cited By ~ 1

Author(s):

Walter Acevedo ◽

Bijan Fallah ◽

Sebastian Reich ◽

Ulrich Cubasch

Keyword(s):

Tree Ring ◽

Tree Growth ◽

General Circulation ◽

Climate Model ◽

Global Climate Model ◽

Ring Width ◽

Circulation Model ◽

Forward Model ◽

Limiting Factors ◽

Tree Ring Width

Abstract. We investigate the assimilation of Tree-Ring-Width (TRW) chronologies into an atmospheric global climate model using Ensemble Kalman Filter (EnKF) techniques and a process-based tree-growth forward model as observation operator. Our results, within a perfect-model experiment setting, indicate that the non-linear response of tree-growth to surface temperature and soil moisture does deteriorate the operation of the time-averaged (EnKF) methodology. Moreover, this skill loss appeared significantly sensitive to the structure of growth rate function, used to represent the Principle of Limiting Factors (PLF)s within the forward model. On the other hand, it was observed that the error reduction achieved by assimilating a particular pseudo-TRW chronology is modulated by the strength of the yearly internal variability of the model at the chronology site. This result might help the dendrochronology community to optimize their sampling efforts. In our experiments, the ''online'' (with cycling) paleao Data Assimilation (DA) approach did not outperform the ''offline'' (no-cycling) one, despite its considerable additional implementation complexity.

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Episodic and Systematic Tree Ring-Width Variation (AD 1763–2013) in the Takhini Valley, Southwest Yukon, Canada

ARCTIC ◽

10.14430/arctic4685 ◽

2017 ◽

Vol 70 (4) ◽

Cited By ~ 2

Author(s):

Wayne L Strong

Keyword(s):

Tree Ring ◽

Polynomial Regression ◽

Ring Width ◽

Steady Increase ◽

Tree Ring Width ◽

Moisture Index ◽

Local Climate ◽

Ring Analysis ◽

Environmental Events

A tree-ring analysis of 764 western white spruce (Picea albertiana) in the Takhini Valley of southwest Yukon was conducted to assess short- and long-term variation in growth and local climate. The resulting chronology spanned the period from AD 1763 to 2013. A polynomial regression (R = 0.720, p < 0.001) indicated that the pre-1840 segment of the chronology had below-normal tree ring-width index (RWI) values (average 0.64, with modest variation), but the subsequent segment had greater variation and a steady increase in RWI values (average 0.89) until ~1920. After 1930, RWI values began to increase again (average 1.06) with 51% more variation than had previously occurred. Peak RWI values after 1930 were double those of the early 1800s. RWI values were uncorrelated with air temperature variables (except September minima), but weakly and positively correlated (r < 0.35) with precipitation variables. RWI values were moderately correlated with annual heat-moisture index values (r = −0.415, p < 0.001), although more strongly with RWI values less than 1.1 (R = −0.631, p < 0.001). Therefore, the RWI chronology was interpreted from an ecological moisture-balance perspective, with possible long-term temperature changes estimated from archival sources. The latter suggested a 2.1˚ – 3.1˚C rise since the early 1800s. Extreme RWI values and portions of the chronology were associated with known environmental events.

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A Method for Reconstructing the Past Soil Temperature Based on Tree-Ring Widths

Forest Science ◽

10.1093/forsci/fxaa001 ◽

2020 ◽

Vol 66 (4) ◽

pp. 393-402

Author(s):

Shuai Yuan ◽

Yonghong Zheng ◽

Yongdong Qi ◽

Fanxi Kong ◽

Dan Wang ◽

...

Keyword(s):

Soil Temperature ◽

Tree Ring ◽

Climatic Factors ◽

Ring Width ◽

Reconstruction Method ◽

Dabie Mountains ◽

Tree Ring Width ◽

Soil Temperatures ◽

High Elevations

Abstract Soil temperature can affect tree growth and is one of the most important types of basic data for forest cultivation and management. To obtain a long-term time series of soil temperatures, we explored the utility of dendroclimatology in a subtropical area of China. In this study, the relations between tree-ring-width chronologies and climate factors were explored by correlation analysis. The results indicated that the limiting climatic factors for the radial growth of Huangshan pine were elevation-specific. Further investigation found that chronology at high elevations was significantly correlated with soil temperature. Then, we described a reconstruction of the soil temperatures of the Dabie Mountains area using the tree-ring width chronology from 1869 to 2015 and showed that the reconstruction explained 42.9 percent of the instrumental soil temperature variation in the common years. We found that the 1970s and 2000s were the coldest and warmest decades since 1884, respectively. The results of the reconstruction method for describing past soil temperatures can provide a reference for other subtropical forests. Furthermore, the results of our research also have a certain significance for guiding policymaking related to forest cultivation and management.

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On the ‘Divergence Problem’ in the Alatau Mountains, Central Asia: A Study of the Responses of Schrenk Spruce Tree-Ring Width to Climate under the Recent Warming and Wetting Trend

Atmosphere ◽

10.3390/atmos10080473 ◽

2019 ◽

Vol 10 (8) ◽

pp. 473 ◽

Cited By ~ 3

Author(s):

Zhang ◽

Jiang ◽

Bagila ◽

Ainur ◽

...

Keyword(s):

Central Asia ◽

Tree Ring ◽

Tree Growth ◽

Tree Species ◽

Climatic Factors ◽

Ring Width ◽

Tree Ring Width ◽

Recent Warming ◽

Divergence Problem ◽

The Stability

The divergence problem, which manifests as an unstable response relationship between tree-ring growth and climatic factors under the background of global warming, poses a challenge to both the traditional theory of dendroclimatology and the reliability of climatic reconstructions based on tree-ring data. Although Schrenk spruce, as the dominant tree species in the Tianshan Mountains, is frequently applied in the dendrochronological studies, the understanding of the divergence problem of this tree species is still limited. This study conducted correlation analysis between climatic factors and tree-ring width chronologies from 51 living and healthy specimens of Schrenk spruce at sites of high and low elevation in the Alatau Mountains to determine the stability of the response. The results revealed that the tree-ring width of the spruce specimens was correlated positively with precipitation and correlated negatively with temperature. Although the variations of the two tree-ring chronologies were similar, the radial growth of the spruce at the low elevation was found more sensitive to climatic factors. Furthermore, the sensitivity of tree growth to climate demonstrated an obvious increase after an abrupt change of climate under the background of the recent warming and wetting trend. Increased drought stress, calculated based on climatic data, was regarded as the main reason for this phenomenon. The results supply the gap of the stability of climatic response of tree growth in Central Asia to some extent.

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Assimilation of pseudo-tree-ring-width observations into an atmospheric general circulation model

Climate of the Past ◽

10.5194/cp-13-545-2017 ◽

2017 ◽

Vol 13 (5) ◽

pp. 545-557 ◽

Cited By ~ 9

Author(s):

Walter Acevedo ◽

Bijan Fallah ◽

Sebastian Reich ◽

Ulrich Cubasch

Keyword(s):

Tree Ring ◽

Tree Growth ◽

General Circulation ◽

Climate Model ◽

Global Climate Model ◽

Ring Width ◽

Circulation Model ◽

Forward Model ◽

Limiting Factors ◽

Tree Ring Width

Abstract. Paleoclimate data assimilation (DA) is a promising technique to systematically combine the information from climate model simulations and proxy records. Here, we investigate the assimilation of tree-ring-width (TRW) chronologies into an atmospheric global climate model using ensemble Kalman filter (EnKF) techniques and a process-based tree-growth forward model as an observation operator. Our results, within a perfect-model experiment setting, indicate that the "online DA" approach did not outperform the "off-line" one, despite its considerable additional implementation complexity. On the other hand, it was observed that the nonlinear response of tree growth to surface temperature and soil moisture does deteriorate the operation of the time-averaged EnKF methodology. Moreover, for the first time we show that this skill loss appears significantly sensitive to the structure of the growth rate function, used to represent the principle of limiting factors (PLF) within the forward model. In general, our experiments showed that the error reduction achieved by assimilating pseudo-TRW chronologies is modulated by the magnitude of the yearly internal variability in the model. This result might help the dendrochronology community to optimize their sampling efforts.

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Xylogenesis of Scots Pine in an Uneven-Aged Stand of the Minusinsk Depression (Southern Siberia)

Journal of Siberian Federal University Biology ◽

10.17516/1997-1389-0323 ◽

2020 ◽

pp. 197-207

Author(s):

Marina V. Fonti ◽

Elena A. Babushkina ◽

Dina F. Zhirnova ◽

Eugene A. Vaganov

Keyword(s):

Tree Ring ◽

Scots Pine ◽

Annual Ring ◽

Ring Width ◽

Anatomical Structure ◽

Ring Formation ◽

Tree Age ◽

Wall Thickening ◽

Southern Siberia ◽

The Impact

Tree-ring formation studies are important for assessing the impact of environmental factors on tree growth at intra-seasonal resolution. This information is necessary for understanding plant acclimatization to current and expected climate changes. Little is still known about how tree age may affect the duration and rate of annual ring formation. In this study, we investigated tree-ring formation in Scots pine (Pinus sylvestris L.) trees of different ages (30- and 95-year-old trees) from the foreststeppe zone in Southern Siberia. The main objectives were 1) to estimate the timing of cambial activity by distinguishing the phases of division, enlargement, wall thickening, and maturation of tracheids and 2) to compare the anatomical structure of the tracheids forming the annual rings of the differently aged trees. Stem tissue was sampled weekly from April to September 2014. The results showed a 1-2 week difference in duration of the phases of xylem formation between the groups; in addition, the ring width of the young trees was slightly narrower. The size of the tracheids of the entirely formed ring (i.e. the results of the enlargement phase) did not differ between the groups whereas the dynamics of the cell-wall thickness showed significant differences. The data obtained in the present study can provide references to calibrate process-based models linking environment to wood formation. These data can be used to benchmark time-explicit simulated measurements of annual ring increment and cell anatomical structure against the corresponding parameters of mature trees growing under natural conditions

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