Pre-monsoon precipitation signal in tree rings of timberline Betula utilis in the Central Himalayas

e-mail: dawadibinod@gmail.com

1,2Binod Dawadi, 2Eryuan Liang

1Central Department of Hydrology and Meteorology, Tribhuvan University, Kathmandu, Nepal

2Institute of Tibetan Plateu Research, Chinese Academy of Sciences, Beijing

19 March, 2015

Tree-ring studies in Himalayan and surrounding regionIndian Himalaya (Western and Eastern Himalaya)

Temperature reconstruction: Yadav et al. (1997); Borgaonkar et al. (1996); Pant et al. (1998); Yadav et al. (1999); Yadav and Singh (2002); Bhattachryya and Chaudhary (2003),Yadav et al (2011) etc.

Precipitation reconstruction: Yadav and Park (2000); Singh and Yadav (2005); Singh et al. (2006); Singh et al. (2009); Yadav (2011a); Yadav (2011b) etc.

Studies from Karakoroum/Tien Shan Mt range of Pakistan

Ahmed,M (1989); Ahmed,M (1991); Ahmed, et al (2009) Ahmed et al (2011); Esper et al.(1995); Esper J.(1995); Esper et al.(2001); Esper et al.(2002); Esper et al.(2003); Esper et al.(2007); Khan et al.(2008) etc.

Dendroclimatological studies from Tibetan Plateau

Precipitation reconstruction Zhang and Wu 1997; Gou et al. 2001; Kang et al.

2002; Qin et al. 2003; Zhang et al. 2003; Sheppard et al. 2004; Shao et al. 2005; Huang and Zhang 2007; Liu et al. 2006; Yin et al. 2008 etc.

Temperature reconstruction: Shao and Fan 1999; Bräuning and Mantwill 2004; Liu

et al. 2005; Gou et al. 2007; Fan et al. 2008; Liang et al. 2008; 2009, 2008; Zhu et al. 2008, 2011 etc.

.

[Suzuki(1990); Bhattachryya et al.(1992); Cook et al.(2003);Sano et al.(2005);Sano et al. (2009): Sano et al. (2011), Gaire et al (2012), Dawadi et al 2013, 2013, Liang et al 2014, Gaire et al 2014, Thapa et al 2014].

Studied species: Abies spectabilis,Pinus roxburgii,Pinus wallichiana,Tsuga dumosa, Picea smithiana,Juniperus recurva,Ulmus wallichiana,Larix potanini , Cupressus torulosa

Dendrochronological studies in Nepal

Cook et al 2003

Sano et al 2005Thapa et al 2014

Reconstructed temperature in Nepal

Tambora in 1815–1816

Multi-decadal to century-scale warming and cooling trends are matching.

Cooling AD1790-18101950- 2000

late-20th century warming,

Cooling from 1960s to 1991

Cook et al.,(2003)

Sano et al., 2005

Reconstructed temperature in Nepal

Thapa et al 2014

Different than Cook et al 2003 and Sano et al 2005, may be due to theReconstructed month/ season

Some gaps Dendrochroclimatological study in Central Himalaya

Suzuki E (1990) and Bhhatachrrya et al. (1992)

Did not find tree-ring climate correlation, why?

Cook et al (2003) They covered wide area from elevation 1830-

3630m but most of the samples were not from treeline/Timberline.

In spite of wide distribution of Himalayan birch in the high Asia from Afghanistan, Pakistan, India, Nepal, Bhutan, Southern China, Myanmar, why there is very a few dendrochronological studies on this species ?

Not only in Asia why there is a few studies on Himalayan birch worldwide?

Objectives

To investigate the dendroclimatic potentiality of Himalayan birch (betula Utilis)

To develop long tree-ring chronology from Nepal

To study the tree-ring based climate change from the tree ring of central Nepal

Sampling Area

Where: Central Himalaya, Nepal, Around 4000 m sal.How many sites: 4 sites but only 2 sites are usedSampling Place: Kaynjing ( LT1) & Langtang Village ( LT4)How many samples: 19 (23) LT1 & 23 (26) from LT4

Langtang National Park

Kyangjing

Landscape of the sampling site

Kyanjing

Birch trees near by Kaynjing

When moisten rings are clearly visible and easy to cross date

Clear Ring-width of Himalayan birch

41 trees, 49 cores, 458 Year Chronology (1552-2009)

Result and discussion

1550 1600 1650 1700 1750 1800 1850 1900 1950 2000

0

0.4

0.8

1.2

1.6

2

2.4

0

10

20

30

40

50(a)

Rin

g In

dex

1550 1600 1650 1700 1750 1800 1850 1900 1950 2000

0

0.05

0.1

0.15

0.2

0.25

0.3

0.5

0.6

0.7

0.8

0.9

RBA

R

EP

SS

ample

dep

th

(b)

E PS=0.85

E PS

R BAR

Fig (a) Tree-ring width chronology with its 9 year moving average curve (thick solid line) and sample depth (dashed line)

(b) Variation of RBAR and EPS over time.

Results and discussion

Parameters Duration/value

Chronology time span (year) 1552-2009 (458)

Mean sensitivity 0.19

Standard deviation 0.23

First-order autocorrelation 0.45

Expressed population signal* 0.93

Signal-to-noise ratio* 12.87

Variance in first eigenvector* 30%

Correlation among all radii* 0.26

* for the common interval from 1900-2000.

Correlation between Climate and RI

-0.4

-0.2

0

0.2

0.4

0.6Precip ita tion

Tem perature

AU G SEP O C T N O V D EC Jan Feb Apr M ay Jun Jul Aug Sep M AMM ar

Tim e Series

Co

rela

tion

co

effc

ien

ts

Ring index of Himalayan birch showed Positive correlation with Pre-monsoon precipitation and inverse relation with temperature

Elevation-dependent precipitation: Pre-monsoon precipitation at Kyangjing (3,950 meter)- 94 mm.

Under very strong solar radiation at high elevation, temperature could increase drought stress by enhancing evapo-transpiration, resulting in a negative correlation between tree growth and the mean March-May temperature, as reported by Liang et al. (2012).

The similar response of most of the conifers from

the Himalayan region: (Sano et al., 2005; Singh et al., 2009; Borgaonkar et al., 2011; Yadav, 2011) and inverse with temperature (Borgaonkar et al., 1996; Yadav et al., 2004)

Results and discussion

Results and discussion contd

1800 1850 1900 1950 20000

5

10

15

20

25

Pe

rce

nta

ge

of

mis

sin

g r

ing

sYear

Missing rings were dated well

1954 (5.8%)

1995 (7.8%)

1999 (13.5%)

2003 (23.6%)

2004 (22.0%)

The 2003,2004 and 1999 are the years with extreme pre monsoonal drought condition in South Asia including Nepal (Sigdel and Ikeda 2009; WMO 2011).

Occurrence of Missing rings in the extreme dry Year

LT4- South west facing slope produced higher frequency of missing rings than LT1.

High percentage of missing rings in the extreme drought year confirmed the growth of Himalayan birch was drought sensitive

Decrease in precipitation beyond certain elevation

Namche bazar (3400m)- 1000mm (Miehe et al. 2007), Pyramid (5050m)- 465mm (Bollasina et al. 2002), Khumbu

glacier (5300m)- 450mm( Dhara and Nandargi, 2000 )

(1998-2011)

Results and discussions contd..

Sigdel & Ikeda 2010

WMO, 2011

IPCC, 2007

Islam & Das 2009

Shakya &Yamaguchi 2007

Attri and Tyagi 2010

Late Victorian great drought (1876-1878)

Strange Parallels drought (1756-1768)

Other Megha drought 1560s

(Cook et al 2010)

Singh et al. 2009;Yadav 2011

Results and discussion contd

Regional historical drought

Tree-ring based precipitation

Instrumental/Satellite

East Indian drought(1796-1798)

2.4

2.0

Conclusion Developed a 458-year chronology of Himalayan birch, the

longest chronology of this species till date.

The chronology statistics showed its potentiality for dendroclimatic studies.

The climate and tree growth relationships demonstrated that the growth of Himalayan birch was an excellent proxy of March-May precipitation.

.Tree-ring captured most of the local and regional drought events.

Himalayan birch from the central Himalayas can be use for the reconstruction of pre-monsoon precipitation

Thank You