scholarly journals Drought-Affected Populus simonii Carr. Show Lower Growth and Long-Term Increases in Intrinsic Water-Use Efficiency Prior to Tree Mortality

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 564 ◽  
Author(s):  
Shoujia Sun ◽  
Lanfen Qiu ◽  
Chunxia He ◽  
Chunyou Li ◽  
Jinsong Zhang ◽  
...  
Keyword(s):  
Water Use ◽  
Tree Ring ◽  
Ring Width ◽  
Tree Ring Width ◽  
Lower Growth ◽  
Populus Simonii ◽  
Dead Trees ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

The Three-North Shelter Forest (TNSF) is a critical ecological barrier against sandstorms in northern China, but has shown extensive decline and death in Populus simonii Carr. in the last decade. We investigated the characteristics—tree-ring width, basal area increment (BAI), carbon isotope signature (13Ccor), and intrinsic water-use efficiency (iWUE)—of now-dead, dieback, and non-dieback trees in TNSF shelterbelts of Zhangbei County. Results from the three groups were compared to understand the long-term process of preceding drought-induced death and to identify potential early-warning proxies of drought-triggered damage. The diameter at breast height (DBH) was found to decrease with the severity of dieback, showing an inverse relationship. In all three groups, both tree-ring width and BAI showed quadratic relationships with age, and peaks earlier in the now-dead and dieback groups than in the non-dieback group. The tree-ring width and BAI became significantly lower in the now-dead and dieback groups than in the non-dieback group from 17 to 26 years before death, thus, these parameters can serve as early-warning signals for future drought-induced death. The now-dead and dieback groups had significantly higher δ13Ccor and iWUEs than the non-dieback group at 7–16 years prior to the mortality, indicating a more conservative water-use strategy under drought stress compared with non-dieback trees, possibly at the cost of canopy defoliation and long-term shoot dieback. The iWUE became significantly higher in the now-dead group than in the dieback group at 0–7 years before death, about 10 years later than the divergence of BAI. After the iWUE became significantly different among the groups, the now-dead trees showed lower growth and died over the next few years. This indicates that, for the TNSF shelterbelts studied, an abrupt iWUE increase can be used as a warning signal for acceleration of impending drought-induced tree death. In general, we found that long-term drought decreased growth and increased iWUE of poplar tree. Successive droughts could drive dieback and now-dead trees to their physiological limits of drought tolerance, potentially leading to decline and mortality episodes.

The GREASE project: Sustainable cultivation of Greco grapevine - Reconstruction of the vines ecophysiological behaviour

2021 ◽  
Author(s):  
Veronica De Micco ◽  
Alessia D'Auria ◽  
Francesco Niccoli ◽  
Francesca Petracca ◽  
Sara De Francesco ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Tree Ring ◽  
Southern Italy ◽  
Ring Width ◽  
Campania Region ◽  
Water Stress Tolerance ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Pruning Technique

<p>The increasing irregularity in precipitation patterns and frequency of extreme drought events in the Mediterranean area is challenging the sustainability of grapevine production, especially in some areas of southern Italy. Here, being the grapevine mostly rainfed-cultivated, there is a strong demand for cultivation techniques aiming to improve water use efficiency and water stress tolerance.</p><p>Pruning techniques and training system can have an effect on the hydraulic architecture of vines, thus on their hydraulic behavior that is strictly coordinated with photosynthetic efficiency and ultimately contribute to determine yield and grape quality.</p><p>In this study, we aimed to evaluate whether and to what extent a change in pruning technique can influence the efficiency and safety of water flow in vines. In order to pursue this objective, we combined the dendro-sciences approach, analysing tree-ring width and anatomical features of vines subjected to an abrupt change in the pruning technique. The study was conducted within the GREASE project, funded by the Campania Region through the Rural Development Programme 2014-2020, within the framework of the optimization of agricultural practices for improving grapevine resources-use efficiency for the sustainable management of vineyards.</p><p>The study was conducted in a vineyard of Vitis vinifera L. subsp. vinifera ‘Greco’ (Feudi di San Gregorio farm) located in southern Italy (Avellino) at a site where the pruning technique was changed in 2004 following the method by Simonit & Sirch (Simonit 2014 Manuale di potatura della vite Ed IA; Sun et al 2008 Am J Bot 95:1498-1505). This method applies pruning cuts oriented in a way to drive vine natural tendency in the branching, to reduce injuries stress, in order to modulate the hydraulic pathway to reduce resistances to flow. Wood cores were extracted by the vines trunk, tree-rings were dated and widths were measured according to dendro-chronological techniques using WinDENDRO software. Then the cores were subjected to thin sectioning to obtain tree-ring series that were analysed through microscopy and subjected to digital image analysis. Wood anatomical traits, linked with hydraulic conductivity and vulnerability, were quantified in each year. The tree-ring series were then annually separated and d<sup>13</sup>C was measured in each year, in order to obtain information on intrinsic water use efficiency. The overall wood anatomical and stable isotope parameters were integrated to reconstruct and interpret past eco-physiological vine behaviour in response to the change in pruning technique also taking into account the inter-annual environmental variability.</p><p>The analysis of wood anatomical functional traits linked with carbon stable isotopes of grapevine tree-ring series confirmed that vineyard management technique can severely affect the vine water use, thus affecting plant growth, productivity and ultimately plant ability to adapt to changing environmental conditions.</p><p>All these interactions and their effects on water use should be taken into account when designing management practices in vineyards for sustainable production.</p>

Site-level soil moisture controls water-use efficiency improvement and climate response in sugar maple: a dual dendroisotopic study

2021 ◽  
pp. 1-12
Author(s):  
R. Dietrich ◽  
F.W. Bell ◽  
M. Anand
Keyword(s):  
Soil Moisture ◽  
Water Use Efficiency ◽  
Water Use ◽  
Tree Ring ◽  
Sugar Maple ◽  
Photosynthetic Capacity ◽  
Environmental Drivers ◽  
Tree Level ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Given the large contribution of forests to terrestrial carbon storage, there is a need to resolve the environmental and physiological drivers of tree-level response to rising atmospheric CO2. This study examines how site-level soil moisture influences growth and intrinsic water-use efficiency in sugar maple (Acer saccharum Marsh.). We construct tree-ring, δ18O, and Δ13C chronologies for trees across a soil moisture gradient in Ontario, Canada, and employ a structural equation modelling approach to ascertain their climatic, ontogenetic, and environmental drivers. Our results support previous evidence for the presence of strong developmental effects in tree-ring isotopic chronologies — in the range of −4.7‰ for Δ13C and +0.8‰ for δ18O — across the tree life span. Additionally, we show that the physiological response of sugar maple to increasing atmospheric CO2 depends on site-level soil moisture variability, with trees only in relatively wet plots exhibiting temporal increases in intrinsic water-use efficiency. These results suggest that trees in wet and mesic plots have experienced temporal increases in stomatal conductance and photosynthetic capacity, whereas trees in dry plots have experienced decreases in photosynthetic capacity. This study is the first to examine sugar maple physiology using a dendroisotopic approach and broadens our understanding of carbon–water interactions in temperate forests.

The effect of long-term atmospheric CO2 enrichment on the intrinsic water-use efficiency of sour orange trees

Chemosphere ◽  
2003 ◽  
Vol 50 (2) ◽  
pp. 217-222 ◽  
Author(s):  
S.W. Leavitt ◽  
S.B. Idso ◽  
B.A. Kimball ◽  
J.M. Burns ◽  
A. Sinha ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Co2 Enrichment ◽  
Atmospheric Co2 ◽  
Sour Orange ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Orange Trees

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

ARCTIC ◽  
2017 ◽  
Vol 70 (4) ◽  
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.

scholarly journals 20th-century changes in carbon isotopes and water-use efficiency: Tree-ring based evaluation of the CLM4.5 and LPX-Bern models

2016 ◽  
Author(s):  
Kathrin M. Keller ◽  
Sebastian Lienert ◽  
Anil Bozbiyik ◽  
Thomas F. Stocker ◽  
Olga V. Churakova ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
20Th Century ◽  
Water Use ◽  
Tree Ring ◽  
Dynamic Global Vegetation Model ◽  
Isotopic Discrimination ◽  
Tree Ring Data ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Abstract. Measurements of the stable carbon isotope ratio (δ13C) on annual tree rings offer new opportunities to evaluate mechanisms of variations in photosynthesis and stomatal conductance under changing CO2 and climate, especially in conjunction with process-based biogeochemical model simulations. The isotopic discrimination is indicative of the ratio between the CO2 partial pressure in the intercellular cavities and the atmosphere (ci / ca) and of the ratio of assimilation to stomatal conductance, termed intrinsic water-use efficiency (iWUE). We performed isotope-enabled simulations over the industrial period with the land biosphere module (CLM4.5) of the Community Earth System Model and the LPX-Bern dynamic global vegetation model. Results for C3 tree species show good agreement with a global compilation of δ13C measurements on leaves, though modeled 13C discrimination by C3 trees is smaller in arid regions than measured. A compilation of seventy-six tree-ring records, mainly from Europe, boreal Asia, and western North America, suggest on average small 20th-century changes in isotopic discrimination and an increase in iWUE of about 27 % since 1900. LPX-Bern results match these century-scale reconstructions, supporting the idea that the physiology of stomata has evolved to optimize trade-offs between carbon gain by assimilation and water loss. In contrast, CLM4.5 simulates an increase in discrimination and in turn a change in iWUE that is almost twice as large as revealed by the tree-ring data. Factorial simulations show that these changes are mainly in response to rising atmospheric CO2. The results suggest that the down-regulation of ci / ca and of photosynthesis by nitrogen limitation is possibly too strong in the standard setup of CLM4.5 or there may be more fundamental problems associated with the prescribed relationship between conductance and assimilation.

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

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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