Spring precipitation effects on formation of first row of earlywood vessels in Quercus variabilis at Qinling Mountain (China)

The interannual variations and the prediction of the leading two empirical orthogonal function (EOF) modes of spring (April–May) precipitation over China for the period from 1951 to 2014 are investigated using both observational data and the seasonal forecast made by six coupled climate models. The leading EOF mode of spring precipitation over China (EOF1-prec) features a monosign pattern, with the maximum loading located over southern China. The ENSO-related tropical Pacific SST anomalies in the previous winter can serve as a precursor for EOF1-prec. The second EOF mode of spring precipitation (EOF2-prec) over China is characterized by a dipole structure, with one pole near the Yangtze River and the other one with opposite sign over the Pearl River delta. A North Atlantic sea surface temperature (SST) anomaly dipole in the preceding March is found contribute to the prec-EOF2 and can serve as its predictor. A physics-based empirical (P-E) model is then formulated using the two precursors revealed by the observational analysis to forecast the variations of EOF1-prec and EOF2-prec. Compared to coupled climate models, which have little skill in forecasting the time variations of the two EOF modes, this P-E model can significantly improve the forecast skill of their time variations. A linear regression model is further established using the time series forecast by the P-E model to forecast the spring precipitation over China. Results suggest that the seasonal forecast skill of the spring precipitation over southeastern China, especially over the Yangtze River area, can be significantly improved by the regression model.

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Biomass, Carbon and Nutrient Storage in a 30-Year-Old Chinese Cork Oak (Quercus Variabilis) Forest on the South Slope of the Qinling Mountains, China

Forests ◽

10.3390/f6041239 ◽

2015 ◽

Vol 6 (12) ◽

pp. 1239-1255 ◽

Cited By ~ 6

Author(s):

Yang Cao ◽

Yunming Chen

Keyword(s):

Cork Oak ◽

Biomass Carbon ◽

Qinling Mountains ◽

The South ◽

Nutrient Storage ◽

Old Chinese ◽

Quercus Variabilis ◽

South Slope ◽

Chinese Cork Oak

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Ensuring a representative sample of earlywood vessels for dendroecological studies: an example from two ring-porous species

Trees ◽

10.1007/s00468-007-0180-9 ◽

2007 ◽

Vol 22 (2) ◽

pp. 237-244 ◽

Cited By ~ 33

Author(s):

Ignacio García-González ◽

Patrick Fonti

Keyword(s):

Representative Sample ◽

Earlywood Vessels

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Assessing Climatic Drivers of Spring Mean and Annual Maximum Flows in Western Canadian River Basins

Water ◽

10.3390/w13121617 ◽

2021 ◽

Vol 13 (12) ◽

pp. 1617

Author(s):

Yonas B. Dibike ◽

Rajesh R. Shrestha ◽

Colin Johnson ◽

Barrie Bonsal ◽

Paulin Coulibaly

Keyword(s):

Snow Water Equivalent ◽

Climate Model ◽

Regional Climate ◽

River Basins ◽

Snow Accumulation ◽

Spatial Variations ◽

Annual Maximum ◽

Spring Precipitation ◽

Average Maximum ◽

Maximum Flows

Flows originating from cold and mountainous watersheds are highly dependent on temperature and precipitation patterns, and the resulting snow accumulation and melt conditions, affecting the magnitude and timing of annual peak flows. This study applied a multiple linear regression (MLR) modelling framework to investigate spatial variations and relative importance of hydroclimatic drivers of annual maximum flows (AMF) and mean spring flows (MAMJflow) in 25 river basins across western Canada. The results show that basin average maximum snow water equivalent (SWEmax), April 1st SWE and spring precipitation (MAMJprc) are the most important predictors of both AMF and MAMJflow, with the proportion of explained variance averaging 51.7%, 44.0% and 33.5%, respectively. The MLR models’ abilities to project future changes in AMF and MAMJflow in response to changes to the hydroclimatic controls are also examined using the Canadian Regional Climate Model (CanRCM4) output for RCP 4.5 and RCP8.5 scenarios. The results show considerable spatial variations depending on individual watershed characteristics with projected changes in AMF ranging from −69% to +126% and those of MAMJflow ranging from −48% to +81% by the end of this century. In general, the study demonstrates that the MLR framework is a useful approach for assessing the spatial variation in hydroclimatic controls of annual maximum and mean spring flows in the western Canadian river basins. However, there is a need to exercise caution in applying MLR models for projecting changes in future flows, especially for regulated basins.

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EARLYWOOD VESSELS IN RING-POROUS TREES BECOME FUNCTIONAL FOR WATER TRANSPORT AFTER BUD BURST AND BEFORE THE MATURATION OF THE CURRENT-YEAR LEAVES

IAWA Journal ◽

10.1163/22941932-20160136 ◽

2016 ◽

Vol 37 (2) ◽

pp. 315-331 ◽

Cited By ~ 40

Author(s):

Peter Kitin ◽

Ryo Funada

Keyword(s):

Water Transport ◽

Time Course ◽

Growing Season ◽

Early Spring ◽

Vessel Element ◽

Full Time ◽

Bud Burst ◽

Long Time ◽

Wall Perforation ◽

Earlywood Vessels

This paper reviews the development of xylem vessels in ring-porous dicots and the corresponding leaf phenology. Also included are our original observations on the time-course of vessel element growth, secondary wall deposition, and end wall perforation in the deciduous hardwood Kalopanax septemlobus. Different patterns of xylem growth and phenology serve different strategies of the species for adaptation to seasonal climates. Trees with ring-porous xylem form wide earlywood vessels (EWV) in spring and narrow latewood vessels in summer. The wide EWV become embolized or blocked with tyloses by the end of the growing season while the narrow vessels may remain functional for many years. The co-occurrence of wide and narrow vessels provides both efficiency and safety of the water transport as well as a potentially longer growing season. It has for a long time been assumed that EWV in ring-porous hardwoods are formed in early spring before bud burst in order to supply sap to growing leaves and shoots.However, the full time-course of development of EWV elements from initiation of growth until maturation for water transport has not been adequately studied until recently. Our observations clarify a crucial relationship between leaf maturation and the maturation of earlywood vessels for sap transport. Accumulated new evidence shows that EWV in branches and upper stem parts develop earlier than EWV lower in the stem. The first EWV elements are fully expanded with differentiated secondary walls by the time of bud burst. In lower stem parts, perforations in vessel end walls are formed after bud burst and before the new leaves have achieved full size. Therefore, the current-year EWV network becomes functional for water transport only by the time when the first new leaves are mature.

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