Large scale assessment of post-drought climate sensitivity of tree-growth

2021 ◽  
Author(s):  
Christopher Leifsson ◽  
Allan Buras ◽  
Anja Rammig ◽  
Christian Zang
Keyword(s):  
Climate Sensitivity ◽  
Tree Growth ◽  
Secondary Growth ◽  
Safety Margin ◽  
Ring Width ◽  
High Plasticity ◽  
Legacy Effect ◽  
Tree Ring Data ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

<p>Hotter droughts will have an increasingly influential role in shaping forest ecosystems in the future. Risks include decreases in species richness, altered species distributions, forest dieback and changed function as carbon sink. A common method to study the impacts of droughts on forests is the quantification of reductions in biomass productivity via secondary growth – approximated by ring-width measurements –, including duration until growth rates return to pre-drought levels, so-called legacy periods. However, while these metrics are practical and relatively easy to measure, the underlying governing mechanisms are not, and thus poorly understood. Consequently, it is uncertain if drought-induced reductions in secondary growth are due to corresponding decreases in total physiological function or high plasticity, and if recovery times are due to lasting damage or adaptation with more carbon allocated to drought-mitigating structures.</p><p>The principle of the most limiting factor for tree-growth can be used to track temporal variations in climate-growth relationships. Similarly, the considerable strain hotter drought constitutes for tree-growth, and the need to repair damaged structures or alter carbon allocation, may imply temporary climate sensitivity deviations during legacy periods. Identifying their existence and quantifying subsequent differences in these deviations can help to shed light on strategies used by trees to respond to droughts.</p><p>Here, we detect and quantify deviations in climate-growth relationships during hotter drought legacy periods and assess how they differ according to clade (angiosperms – gymnosperms), site aridity and hydraulic safety margin. We do this by applying a linear mixed model on all ring-width indices (RWI) in the global-scale International Tree-Ring Data Bank (ITRDB) which exhibit a positive correlation with Standardized Precipitation-Evapotranspiration Index (SPEI). We apply a combined climatological and ecological definition for drought events and use site-dependent SPEI time-scales to allow for specific climate dependencies.</p><p>Results show heterogeneous post-drought climate sensitivity deviations, which are broadly categorized in three groups: 1) angiosperms growing in arid sites become increasingly sensitive to climate for 2 – 4 years; 2) angiosperms in mesic sites and or with high hydraulic safety margin show abrupt and complete disruption of the climate-growth relationship for the first year after droughts, which turn into a decrease in climate sensitivity for an additional 1 – 3 years; 3) gymnosperms in arid sites become less sensitive to climate for 2 – 4 years, although without the abrupt disruption seen in group 2. We discuss these results and their implications in an ecophysiological context, including future research avenues.</p><p>In conclusion, the results clearly show a functional legacy effect that is not detected through measurements of reductions in biomass accumulation alone, hinting at differential strategies employed by trees to cope with hotter droughts. This is a first step towards a better understanding of the mechanisms underlying hotter drought legacies which may help to improve ecosystem models and better predict how trees will respond to drought in a warming future climate.</p>

Tree growth across the Nepal Himalaya during the last four centuries

2017 ◽  
Vol 41 (4) ◽  
pp. 478-495 ◽  
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.

scholarly journals Zuwachs und Klimasensitivität von Baumarten im Ökogramm der kollinen und submontanen Stufe

2015 ◽  
Vol 166 (6) ◽  
pp. 380-388 ◽  
Author(s):  
Pascale Weber ◽  
Caroline Heiri ◽  
Mathieu Lévesque ◽  
Tanja Sanders ◽  
Volodymyr Trotsiuk ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Properties ◽  
Climate Sensitivity ◽  
Tree Species ◽  
Ring Width ◽  
Basal Area ◽  
Growth Potential ◽  
Basal Area Increment ◽  
Tree Ring Data ◽  
Mean Sensitivity

Growth potential and climate sensitivity of tree species in the ecogram for the colline and submontane zone In forestry practice a large amount of empirical knowledge exists about the productivity of individual tree species in relation to site properties. However, so far, only few scientific studies have investigated the influence of soil properties on the growth potential of various tree species along gradients of soil water as well as nutrient availability. Thus, there is a research gap to estimate the productivity and climate sensitivity of tree species under climate change, especially regarding productive sites and forest ad-mixtures in the lower elevations. Using what we call a «growth ecogram», we demonstrate species- and site-specific patterns of mean annual basal area increment and mean sensitivity of ring width (strength of year-to-year variation) for Fagus sylvatica, Quercus spp., Fraxinus excelsior, Picea abies, Abies alba and Pinus sylvestris, based on tree-ring data from 508 (co-)dominant trees on 27 locations. For beech, annual basal area increment ( average 1957–2006) was significantly correlated with tree height of the dominant sampling trees and proved itself as a possible alternative for assessing site quality. The fact that dominant trees of the different tree species showed partly similar growth potential within the same ecotype indicates comparable growth limitation by site conditions. Mean sensitivity of ring width – a measure of climate sensitivity – had decreased for oak and ash, while it had increased in pine. Beech showed diverging reactions with increasing sensitivity at productive sites (as measured by the C:N ratio of the topsoil), suggesting an increasing limitation by climate at these sites. Hence, we derive an important role of soil properties in the response of forests to climate change at lower elevations, which should be taken into account when estimating future forest productivity.

scholarly journals Leaf hydraulic safety margin and safety–efficiency trade-off across angiosperm woody species

2020 ◽  
Vol 16 (11) ◽  
pp. 20200456
Author(s):  
Chao-Long Yan ◽  
Ming-Yuan Ni ◽  
Kun-Fang Cao ◽  
Shi-Dan Zhu
Keyword(s):  
Water Potential ◽  
Global Analysis ◽  
Safety Margin ◽  
Woody Species ◽  
Hydraulic Conductance ◽  
Plant Distribution ◽  
Mean Annual Precipitation ◽  
Leaf Hydraulic Conductance ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

Leaf hydraulic conductance and the vulnerability to water deficits have profound effects on plant distribution and mortality. In this study, we compiled a leaf hydraulic trait dataset with 311 species-at-site combinations from biomes worldwide. These traits included maximum leaf hydraulic conductance ( K leaf ), water potential at 50% loss of K leaf (P50 leaf ), and minimum leaf water potential ( Ψ min ). Leaf hydraulic safety margin (HSM leaf ) was calculated as the difference between Ψ min and P50 leaf . Our results indicated that 70% of the studied species had a narrow HSM leaf (less than 1 MPa), which was consistent with the global pattern of stem hydraulic safety margin. There was a positive relationship between HSM leaf and aridity index (the ratio of mean annual precipitation to potential evapotranspiration), as species from humid sites tended to have larger HSM leaf . We found a significant relationship between K leaf and P50 leaf across global angiosperm woody species and within each of the different plant groups. This global analysis of leaf hydraulic traits improves our understanding of plant hydraulic response to environmental change.

scholarly journals Last 1100 yr of precipitation variability in western central Asia as revealed by tree-ring data from the Pamir-Alay

2018 ◽  
Vol 91 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Magdalena Opała-Owczarek ◽  
Tadeusz Niedźwiedź
Keyword(s):  
Central Asia ◽  
Tree Ring ◽  
Tree Growth ◽  
Palmer Drought Severity Index ◽  
Ring Width ◽  
Severity Index ◽  
Drought Severity ◽  
Mountainous Area ◽  
Transfer Function Method ◽  
Tree Ring Data

AbstractWe developed a 1108 yr chronology of tree-ring widths, based on 64 Himalayan pencil juniper (Juniperus semiglobosa Regel) trees, for the Pamir-Alay Mountains, central Asia. Dendroclimatological analysis demonstrates that precipitation has significant effects on tree growth in the semiarid mountainous area of northwestern Tajikistan located on the edge of the great midlatitude Karakum and Kyzylkum deserts. The highest level of linear correlation (r=0.67) is observed between tree growth and seasonalised winter (previous December–February) precipitation. Our studies also show that moisture (precipitation/Palmer Drought Severity Index) from the previous June to the current September was the dominant climatic factor accounting for interannual variations in tree-ring width, suggesting that this should be considered in climate reconstruction. Using the transfer function method, we reconstructed the region’s drought history over the period AD 908–2015. The results of this moisture reconstruction showed that the most recent millennium was characterised by series of dry and wet stages. The driest periods occurred before 1000, 1200–1250, and at the end of the eighteenth century and beginning of the nineteenth century. The wettest conditions existed in 1650–1700 and after 1990.

scholarly journals Using Tree Rings to Predict the Response of Tree Growth to Climate Change in the Continental United States during the Twenty-First Century

2010 ◽  
Vol 14 (19) ◽  
pp. 1-20 ◽  
Author(s):  
A. Park Williams ◽  
Joel Michaelsen ◽  
Steven W. Leavitt ◽  
Christopher J. Still
Keyword(s):  
Climate Change ◽  
United States ◽  
Tree Ring ◽  
Tree Growth ◽  
Ring Width ◽  
First Century ◽  
Annual Growth ◽  
Climate Variations ◽  
Tree Ring Data ◽  
Twenty First Century

Abstract In the early 1900s, tree-ring scientists began analyzing the relative widths of annual growth rings preserved in the cross sections of trees to infer past climate variations. Now, many ring-width index (RWI) chronologies, each representing a specific site and species, are archived online within the International Tree-Ring Data Bank (ITRDB). Comparing annual tree-ring-width data from 1097 sites in the continental United States to climate data, the authors quantitatively evaluated how trees at each site have historically responded to interannual climate variations. For each site, they developed a climate-driven statistical growth equation that uses regional climate variables to model RWI values. The authors applied these growth models to predict how tree growth will respond to twenty-first-century climate change, considering four climate projections. Although caution should be taken when extrapolating past relationships with climate into the future, the authors observed several clear and interesting patterns in the growth projections that seem likely if warming continues. Most notably, the models project that productivity of dominant tree species in the southwestern United States will decrease substantially during this century, especially in warmer and drier areas. In the northwest, nonlinear growth relationships with temperature may lead to warming-induced declines in growth for many trees that historically responded positively to warmer temperatures. This work takes advantage of the unmatched temporal length and spatial breath of annual growth data available within the ITRDB and exemplifies the potential of this ever-growing archive of tree-ring data to serve in meta-analyses of large-scale forest ecology.

scholarly journals Hydraulic safety margin of 17 co-occurring woody plants in a seasonal rain forest in Guangxi’s Southwest karst landscape, China

2019 ◽  
Vol 43 (3) ◽  
pp. 227-237
Author(s):  
Feng-Sen TAN ◽  
Hui-Qing SONG ◽  
Zhong-Guo LI ◽  
Qi-Wei ZHANG ◽  
Shi-Dan ZHU ◽  
...  
Keyword(s):  
Rain Forest ◽  
Woody Plants ◽  
Safety Margin ◽  
Karst Landscape ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

scholarly journals Trees tell of past climates: but are they speaking less clearly today?

1998 ◽  
Vol 353 (1365) ◽  
pp. 65-73 ◽  
Author(s):  
K. R. Briffa ◽  
F. H Schweingruber ◽  
P. D. Jones ◽  
T. J. Osborn ◽  
I. C. Harris ◽  
...  
Keyword(s):  
Climate Variability ◽  
Tree Growth ◽  
Growth Rates ◽  
Large Scale ◽  
Scale Effects ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Past Climate ◽  
Tree Ring Data ◽  
Past Climate Variability

The annual growth of trees, as represented by a variety of ring–width, densitometric, or chemical parameters, represents a combined record of different environmental forcings, one of which is climate. Along with climate, relatively large–scale positive growth influences such as hypothesized ‘fertilizationrsquo; due to increased levels of atmospheric carbon dioxide or various nitrogenous compounds, or possibly deleterious effects of ‘acid rain’ or increased ultra–violet radiation, might all be expected to exert some influence on recent tree growth rates. Inferring the details of past climate variability from tree–ring data remains a largely empirical exercise, but one that goes hand–in–hand with the development of techniques that seek to identify and isolate the confounding influence of local and larger–scale non–climatic factors. By judicious sampling, and the use of rigorous statistical procedures, dendroclimatology has provided unique insight into the nature of past climate variability, but most significantly at interannual, decadal, and centennial timescales. Here, examples are shown that illustrate the reconstruction of annually resolved patterns of past summer temperature around the Northern Hemisphere, as well as some more localized reconstructions, but ones which span 1000 years or more. These data provide the means of exploring the possible role of different climate forcings; for example, they provide evidence of the large–scale effects of explosive volcanic eruptions on regional and hemispheric temperatures during the last 400 years. However, a dramatic change in the sensitivity of hemispheric tree–growth to temperature forcing has become apparent during recent decades, and there is additional evidence of major tree–growth (and hence, probably, ecosystem biomass) increases in the northern boreal forests, most clearly over the last century. These possibly anthropogenically related changes in the ecology of tree growth have important implications for modelling future atmospheric CO 2 concentrations. Also, where dendroclimatology is concerned to reconstruct longer (increasingly above centennial) temperature histories, such alterations of ‘normal’ (pre–industrial) tree–growth rates and climate–growth relationships must be accounted for in our attempts to translate the evidence of past tree growth changes.

The legacy of water deficit on populations having experienced negative hydraulic safety margin

2017 ◽  
Vol 27 (3) ◽  
pp. 346-356 ◽  
Author(s):  
Marta Benito Garzón ◽  
Noelia González Muñoz ◽  
Jean-Pierre Wigneron ◽  
Christophe Moisy ◽  
Juan Fernández-Manjarrés ◽  
...  
Keyword(s):  
Water Deficit ◽  
Safety Margin ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

scholarly journals Changes in Sensitivity of Tree-Ring Widths to Climate in a Tropical Moist Forest Tree in Bangladesh

Forests ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 761 ◽  
Author(s):  
Mizanur Rahman ◽  
Mahmuda Islam ◽  
Jakob Wernicke ◽  
Achim Bräuning
Keyword(s):  
Climate Sensitivity ◽  
Tree Growth ◽  
Radial Growth ◽  
Forest Type ◽  
Ring Width ◽  
Geographic Location ◽  
Growing Season ◽  
Positive Trend ◽  
Growth Responses ◽  
Moist Forest

Tree growth in the tropics is strongly influenced by climate. However, reported tree growth responses to climate are largely inconsistent, varying with geographic location, forest type, and tree species. It is thus important to study the growth responses of tropical trees in sites and species that are under-represented so far. Bangladesh, a country influenced by the Asian monsoon climate, is understudied in terms of tree growth response to climate. In the present study, we developed a 121-year-long regional ring-width index chronology of Chukrasia tabularis A. Juss. sampled in two moist forest sites in Bangladesh to investigate tree growth responses to climate in monsoon South Asia. Standard dendrochronological methods were used to produce the ring-width chronologies. The climate sensitivity of C. tabularis was assessed through bootstrap correlation analysis and the stationarity and consistency of climate–growth relationships was evaluated using moving correlation functions and comparing the regression slopes of two sub-periods (1950–1985 and 1986–2015). Tree growth was negatively correlated with the mean, minimum, and maximum temperatures, particularly during the early growing season (March). Likewise, precipitation negatively influenced tree growth in the later growing season (October). Besides, radial growth of Chukrasia sharply ceased in years following strong and moderate El Niño events. In parallel with a significant positive trend in local temperatures, tree growth sensitivity to early growing season (March–April) mean temperatures and July minimum temperatures increased in recent decades. Tree growth sensitivity to October precipitation and April vapor pressure deficit also increased. Overall, climate–growth relationships were stronger during the period 1986–2015 than during 1950–1985. Changes in climate sensitivity might be linked to a warming trend that induced an increase in the dry season length during recent decades. With a further predicted temperature increase at our study sites, our results suggest that radial growth of C. tabularis will further decline in response to climate warming.

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