Understanding the low-temperature limitations to forest growth through calibration of a forest dynamics model with tree-ring data

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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Climatic comparisons with tree-ring data from montane forests: are the climatic data appropriate?

Canadian Journal of Forest Research ◽

10.1139/x88-057 ◽

1988 ◽

Vol 18 (4) ◽

pp. 385-390 ◽

Cited By ~ 6

Author(s):

Kenneth D. Kimball ◽

MaryBeth Keifer

Keyword(s):

Tree Ring ◽

Montane Forest ◽

Temperature Data ◽

Growth Patterns ◽

Forest Growth ◽

Precipitation Data ◽

Montane Forests ◽

Monthly Temperature ◽

Tree Ring Data ◽

Mount Washington

The appropriateness of relating spatially proximate (40-km radius) temperature and precipitation data from different elevations to montane forest growth patterns was investigated for Mount Washington, New Hampshire. Monthly mean temperature and total precipitation data (1933–1983) were correlated (p < 0.05) among all pairs of meteorological stations (280, 420, 610, 1915 m and regional averages) on or near Mount Washington. The unexplained variance (1 − r2) for precipitation comparisons between meteorological stations was greater relative to temperature. When correlated with the average tree-ring index chronology of 90 red spruce trees on Mount Washington (800–1200 m), the monthly temperature data yielded similar correlative patterns among the four meteorological stations. However, the monthly temperature data from the meteorological stations (610 and 1915 m) most proximate to the montane forest study site were correlated (p < 0.10) with the tree-ring indices for two to three times as many months as the temperature data from the lower elevations. There was no consistency in correlative results of tree-ring indices with monthly precipitation data among the four meteorological stations. However, precipitation measurements and Palmer drought indices are poor indicators of moisture availability in montane forests. We conclude that spatially proximate, low elevation temperature data can underestimate correlative relationships between temperature and montane tree-ring data in the northeastern United States.

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Impacts of Change in Atmospheric CO2 Concentration on Larix gmelinii Forest Growth in Northeast China from 1950 to 2010

Forests ◽

10.3390/f10050454 ◽

2019 ◽

Vol 10 (5) ◽

pp. 454

Author(s):

Bin Wang ◽

Mingze Li ◽

Wenyi Fan ◽

Ying Yu ◽

Weiwei Jia

Keyword(s):

Tree Ring ◽

Northeast China ◽

Forest Growth ◽

Atmospheric Co2 ◽

Larix Gmelinii ◽

Biogeochemical Model ◽

Growth Enhancement ◽

Co2 Fertilization ◽

Tree Ring Data ◽

Residual Growth

Although CO2 fertilization on plant growth has been repeatedly modeled to be the main reason for the current changes in the terrestrial carbon sink at the global scale, there have been controversial findings on the CO2 fertilization effects on forests from tree-ring analyses. In this study, we employed conventional dendrochronological tree-ring datasets from Northeast China, to detect the effect of CO2 fertilization on Larix gmelinii growth from 1950 to 2010. Among four sites, there were two sites exhibiting a significant residual growth enhancement at a 90% confidence level after removing the size, age and climaterelated trends of tree-ring indices. In addition, we found consistency (R from 0.26 to 0.33, p < 0.1) between the high frequency CO2 fluctuation and residual growth indices at two of the four sites during the common period. A biogeochemical model was used to quantitatively predict the contribution of elevated atmospheric CO2 on accumulated residual growth enhancement. As found in the tree-ring data, 14% of the residual growth was attributed to the CO2 fertilization effect, while climate was responsible for approximately the remainding 86%.

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Boreal forest carbon exchange and growth recovery after the summer 2018 drought

10.5194/egusphere-egu2020-10559 ◽

2020 ◽

Author(s):

Maj-Lena Linderson ◽

Jutta Holst ◽

Michal Heliasz ◽

Leif Klemedtsson ◽

Anne Klosterhalfen ◽

...

Keyword(s):

Eddy Covariance ◽

Tree Ring ◽

Forest Ecosystem ◽

Carbon Fluxes ◽

Forest Growth ◽

Allocation Pattern ◽

Substantial Impact ◽

Growth Recovery ◽

Tree Ring Data ◽

The Impact

In summer 2018, Northern Europe experienced an extreme summer drought in combination with unusually high temperatures, which had a substantial impact on agricultural yields as well as on forest growth conditions in various ways. An ongoing study, using ICOS and other forest ecosystem stations in the Nordic region, shows that the drought dramatically decreased NEP in the southern Scandinavian and Baltic region, almost nullifying the carbon sinks in some of the forests. However, some of the forests that not were exposed to the most extreme drought actually increased their NEP because of the high evaporative demand. Such severe conditions during a single year could be expected to influence a forest over several following years. Reduced tree storage of carbohydrates leads to a changed carbon allocation pattern in spring that may affect both the woody growth and the resistance to pests. It is thus important to reveal the impact of such climatic events over a longer period. &#160;&#160;&#160;This study aims at assessing the carry-over effects of the extreme weather conditions on the carbon fluxes and the forest growth to the year after the event, 2019. The base of the analysis will be eddy covariance data combined with tree ring time series from measurement stations that has been shown to be significantly affected by the drought through reduced carbon fluxes: the spruce forests Hyltemossa and Skogaryd and the mixed forests Norunda, Svartberget, Soontaga and Rumper&#246;d. The eddy covariance and tree ring data will be used to assess the forest ecosystem carbon fluxes and growth recovery in 2019 by comparisons to earlier normal years and extreme events.

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Tree-ring growth curves as sources of climatic information

Quaternary Research ◽

10.1016/j.yqres.2004.06.005 ◽

2004 ◽

Vol 62 (2) ◽

pp. 126-133 ◽

Cited By ~ 28

Author(s):

Mukhtar M. Naurzbaev ◽

Malcolm K. Hughes ◽

Eugene A. Vaganov

Keyword(s):

Tree Ring ◽

Regional Growth ◽

Ring Width ◽

Growth Curves ◽

Elevational Gradient ◽

Forest Growth ◽

Tree Ring Width ◽

Cambial Age ◽

Tree Ring Data ◽

Subfossil Wood

Regional growth curves (RGCs) have been recently used to provide a new basis for removing nonclimatic trend from tree-ring data. Here we propose a different use for RGCs and explore their properties along two transects, one meridional and the other elevational. RGCs consisting of mean ring width plotted against cambial age were developed for larch samples from 34 sites along a meridional transect (55–72°N) in central Siberia, and for 24 sites on an elevational gradient (1120 and 2350 m a.s.l.) in Tuva and neighboring Mongolia at approximately 51°N. There are systematic gradients of the parameters of the RGCs, such as I0-maximum tree-ring width near pith, and Imin, the asymptotic value of tree-ring width in old trees. They are smaller at higher latitude and elevation. Annual mean temperature and mean May–September temperature are highly correlated with latitude here, and hence RGC parameters are correlated with these climatic variables. Correlations with precipitation are more complex, and contradictory between meridional and elevational transects. The presence of a similar gradient in the elevational transect is consistent with temperature being the causal factor for both gradients, rather than, for example, latitude-dependent patterns of seasonal photoperiod change. Taking ring measurements from collections of relict and subfossil wood, the RGC–latitude and RGC–temperature relationships are used to estimate paleo-temperatures on centennial time scales. These estimates are consistent with earlier "traditional" dendroclimatic approaches, and with independent information on the northern extent of forest growth in the early mid-Holocene. It may be possible to use this same approach to make estimates of century-scale paleo-temperatures in other regions where abundant relict wood is present.

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Supporting Restoration Decisions through Integration of Tree-Ring and Modeling Data: Reconstructing Flow and Salinity in the San Francisco Estuary over the Past Millennium

Water ◽

10.3390/w13152139 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2139

Author(s):

Paul H. Hutton ◽

David M. Meko ◽

Sujoy B. Roy

Keyword(s):

San Francisco ◽

Tree Ring ◽

San Francisco Estuary ◽

Salinity Intrusion ◽

Estuarine Ecosystem ◽

Freshwater Flow ◽

The Past ◽

Decadal Scale ◽

Tree Ring Data ◽

Past Millennium

This work presents updated reconstructions of watershed runoff to San Francisco Estuary from tree-ring data to AD 903, coupled with models relating runoff to freshwater flow to the estuary and salinity intrusion. We characterize pre-development freshwater flow and salinity conditions in the estuary over the past millennium and compare this characterization with contemporary conditions to better understand the magnitude and seasonality of changes over this time. This work shows that the instrumented flow record spans the range of runoff patterns over the past millennium (averaged over 5, 10, 20 and 100 years), and thus serves as a reasonable basis for planning-level evaluations of historical hydrologic conditions in the estuary. Over annual timescales we show that, although median freshwater flow to the estuary has not changed significantly, it has been more variable over the past century compared to pre-development flow conditions. We further show that the contemporary period is generally associated with greater spring salinity intrusion and lesser summer–fall salinity intrusion relative to the pre-development period. Thus, salinity intrusion in summer and fall months was a common occurrence under pre-development conditions and has been moderated in the contemporary period due to the operations of upstream reservoirs, which were designed to hold winter and spring runoff for release in summer and fall. This work also confirms a dramatic decadal-scale hydrologic shift in the watershed from very wet to very dry conditions during the late 19th and early 20th centuries; while not unprecedented, these shifts have been seen only a few times in the past millennium. This shift resulted in an increase in salinity intrusion in the first three decades of the 20th century, as documented through early records. Population growth and extensive watershed modification during this period exacerbated this underlying hydrologic shift. Putting this shift in the context of other anthropogenic drivers is important in understanding the historical response of the estuary and in setting salinity targets for estuarine restoration. By characterizing the long-term behavior of San Francisco Estuary, this work supports decision-making in the State of California related to flow and salinity management for restoration of the estuarine ecosystem.

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Cariaco Basin Calibration Update: Revisions to Calendar and 14C Chronologies for Core Pl07-58Pc

Radiocarbon ◽

10.1017/s0033822200033075 ◽

2004 ◽

Vol 46 (3) ◽

pp. 1161-1187 ◽

Cited By ~ 46

Author(s):

Konrad A Hughen ◽

John R Southon ◽

Chanda J H Bertrand ◽

Brian Frantz ◽

Paula Zermeño

Keyword(s):

Tree Ring ◽

Cariaco Basin ◽

Calibration Data ◽

Data Set ◽

Varve Chronology ◽

Pine Tree ◽

Tree Ring Data ◽

Calibration Data Set ◽

Recent Version ◽

Radiocarbon Calibration

This paper describes the methods used to develop the Cariaco Basin PL07-58PC marine radiocarbon calibration data set. Background measurements are provided for the period when Cariaco samples were run, as well as revisions leading to the most recent version of the floating varve chronology. The floating Cariaco chronology has been anchored to an updated and expanded Preboreal pine tree-ring data set, with better estimates of uncertainty in the wiggle-match. Pending any further changes to the dendrochronology, these results represent the final Cariaco 58PC calibration data set.

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Science and Decision Making: Water Management and Tree-Ring Data in the Western United States

JAWRA Journal of the American Water Resources Association ◽

10.1111/j.1752-1688.2009.00358.x ◽

2009 ◽

Vol 45 (5) ◽

pp. 1248-1259 ◽

Cited By ~ 38

Author(s):

Jennifer L. Rice ◽

Connie A. Woodhouse ◽

Jeffrey J. Lukas

Keyword(s):

Water Management ◽

United States ◽

Decision Making ◽

Tree Ring ◽

Western United States ◽

Tree Ring Data

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Developing a triple tree-ring constraint for tree growth and physiology in a global land surface model

10.5194/egusphere-egu21-13546 ◽

2021 ◽

Author(s):

Jonathan Barichivich ◽

Philippe Peylin ◽

Valérie Daux ◽

Camille Risi ◽

Jina Jeong ◽

...

Keyword(s):

Tree Ring ◽

Land Surface ◽

Forest Ecosystems ◽

Ring Width ◽

Land Surface Model ◽

Surface Model ◽

Growth Variability ◽

Tree Ring Data ◽

Surface Models ◽

Global Land

Gradual anthropogenic warming and parallel changes in the major global biogeochemical cycles are slowly pushing forest ecosystems into novel growing conditions, with uncertain consequences for ecosystem dynamics and climate. Short-term forest responses (i.e., years to a decade) to global change factors are relatively well understood and skilfully simulated by land surface models (LSMs). However, confidence on model projections weaken towards longer time scales and to the future, mainly because the long-term responses (i.e., decade to century) of these models remain unconstrained. This issue limits confidence on climate model projections. Annually-resolved tree-ring records, extending back to pre-industrial conditions, have the potential to constrain model responses at interannual to centennial time scales. Here, we constrain the representation of tree growth and physiology in the ORCHIDEE global land surface model using the simulated interannual variability of tree-ring width and carbon (&#916;13C) and oxygen (&#948;18O) stable isotopes in six sites in boreal and temperate Europe.&#160; The model simulates &#916;13C (r = 0.31-0.80) and &#948;18O (r = 0.36-0.74) variability better than tree-ring width variability (r < 0.55), with an overall skill similar to that of other state-of-the-art models such as MAIDENiso and LPX-Bern. These results show that growth variability is not well represented, and that the parameterization of leaf-level physiological responses to drought stress in the temperate region can be improved with tree-ring data. The representation of carbon storage and remobilization dynamics is critical to improve the realism of simulated growth variability, temporal carrying over and recovery of forest ecosystems after climate extremes. The simulated physiological response to rising CO2 over the 20th century is consistent with tree-ring data in the temperate region, despite an overestimation of seasonal drought stress and stomatal control on photosynthesis. Photosynthesis correlates directly with isotopic variability, but correlations with &#948;18O combine physiological effects and climate variability impacts on source water signatures. The integration of tree-ring data (i.e. the triple constraint: width, &#916;13C and &#948;18O) and land surface models as demonstrated here should contribute towards reducing current uncertainties in forest carbon and water cycling.

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A 368-year maximum temperature reconstruction based on tree-ring data in the northwestern Sichuan Plateau (NWSP), China

Climate of the Past ◽

10.5194/cp-12-1485-2016 ◽

2016 ◽

Vol 12 (7) ◽

pp. 1485-1498 ◽

Cited By ~ 8

Author(s):

Liangjun Zhu ◽

Yuandong Zhang ◽

Zongshan Li ◽

Binde Guo ◽

Xiaochun Wang

Keyword(s):

Tree Ring ◽

Land Surface ◽

Temperature Reconstruction ◽

Temperature Variability ◽

Ice Age ◽

Maximum Temperature ◽

Tree Ring Data ◽

The Mean ◽

Extreme Cold ◽

The 19Th Century

Abstract. We present a reconstruction of July–August mean maximum temperature variability based on a chronology of tree-ring widths over the period AD 1646–2013 in the northern part of the northwestern Sichuan Plateau (NWSP), China. A regression model explains 37.1 % of the variance of July–August mean maximum temperature during the calibration period from 1954 to 2012. Compared with nearby temperature reconstructions and gridded land surface temperature data, our temperature reconstruction had high spatial representativeness. Seven major cold periods were identified (1708–1711, 1765–1769, 1818–1821, 1824–1828, 1832–1836, 1839–1842, and 1869–1877), and three major warm periods occurred in 1655–1668, 1719–1730, and 1858–1859 from this reconstruction. The typical Little Ice Age climate can also be well represented in our reconstruction and clearly ended with climatic amelioration at the late of the 19th century. The 17th and 19th centuries were cold with more extreme cold years, while the 18th and 20th centuries were warm with less extreme cold years. Moreover, the 20th century rapid warming was not obvious in the NWSP mean maximum temperature reconstruction, which implied that mean maximum temperature might play an important and different role in global change as unique temperature indicators. Multi-taper method (MTM) spectral analysis revealed significant periodicities of 170-, 49–114-, 25–32-, 5.7-, 4.6–4.7-, 3.0–3.1-, 2.5-, and 2.1–2.3-year quasi-cycles at a 95 % confidence level in our reconstruction. Overall, the mean maximum temperature variability in the NWSP may be associated with global land–sea atmospheric circulation (e.g., ENSO, PDO, or AMO) as well as solar and volcanic forcing.

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