Elsevier

Dendrochronologia

Volume 63, October 2020, 125742
Dendrochronologia

ORIGINAL ARTICLE
Drought signal in the tree rings of three conifer species from Northern Pakistan

https://doi.org/10.1016/j.dendro.2020.125742Get rights and content

Abstract

Anthropogenic and climatic stressors have affected the forests of northern Pakistan in recent decades. Several studies have been conducted to understand forest growth and its relation to the changing climate in this region, but more work needs to be done to understand this complex environment. In this study, we have collected tree core samples of three conifer species (Pinus wallichiana, Picea smithiana, and Abies pindrow) from three different sites in northern Pakistan to understand their radial growth pattern with the goal of finding a relationship between ring-width and climatic parameters (temperature, precipitation, and drought). A 610-year (AD 1406–2015), a 538-year (AD 1478–2015), and a 306-year (AD 1710–2015) long tree-ring width chronology of Pinus wallichiana, Picea smithiana, and Abies pindrow were developed, respectively, using living trees. The ring-width chronologies of these three species showed a strong positive link with the self-calibrated Palmer Drought Severity Index (scPDSI) rather than precipitation or temperature alone, indicating that soil moisture is the primary limiting climatic factor for the growth of these species in the sampling locations. The chronologies of Pinus wallichiana and Picea smithiana exhibited growth suppressions during AD 1570–1610 and the second half of 17th century while their growth was heightened from AD 1540–1560. We have found the lowest growth in Abies pindrow and Picea smithiana from AD 1900–1920, suggesting dry conditions. All three chronologies have exhibited the most rapid increase in growth during the recent decades, suggesting that this region is experiencing climate change with a strong trend towards wetter conditions.

Section snippets

Background

The northern region of Pakistan is mostly forested and the people living in the northern mountains depend on the trees for firewood and timber. This region is also the watershed for most of the major rivers of Pakistan, making the forests an important factor for stream health and water quality. Because of the high demand for timber since the administrative reformation in the 1970s and construction of the Karakorum highway, anthropogenic pressure has increased (Kreutzmann, 1991; Gohar, 2002).

Study site and sample collection

Pinus wallichiana (Blue pine), Picea smithiana (Himalayan Spruce), and Abies pindrow (West Himalayan fir) are native conifer tree species to the Himalayas. Pinus wallichiana is distributed from northeast Pakistan to Yunnan in southwest China, while Picea smithiana and Abies pindrow occur from northeast Afghanistan to central Nepal (Devkota, 2013). In the present study, we have collected tree-ring samples of Pinus wallichiana from Rama, Picea smithiana from Chaprot, and Abies pindrow from

Tree-ring width chronologies

We developed a 306-year (AD 1710–2015), a 538-year (AD 1478–2015), and a 610-year (AD 1406–2015) long tree-ring chronology from Abies pindrow, Picea smithiana, and Pinus wallichiana, respectively, at three different sites in Pakistan (Fig. 5). In the Shirial (Abies pindrow) sampling site twenty samples exceeded 200 years. The mean length of the series for Abies pindrow is 223 years. Likewise, the mean length for the series of Picea smithiana is 243 years from the Chaprot region with six samples

Conclusion

We developed three new chronologies of Abies pindrow, Picea smithiana, and Pinus wallichiana extending back 306-years (AD 1710–2015), 538-years (AD 1478–2015), and 610-years (AD 1406–2015), respectively, from three different sites of the Gilgit-Baltistan region of northern Pakistan. Tree core samples were only taken from living trees to build these chronologies. Considering that our Pinus wallichiana chronology was over 600 years in length, we believe that there is good potential for a

Declaration of Competing Interest

The author and co-authors have no conflict of interest or competing interests with this manuscript.

Acknowledgements

The Department of Earth and Environmental System at Indiana State University provided a graduate teaching assistantship for the first author. We would like to thank Indiana State University’s Research Committee for seed funding for this research work. We thank Hamim Munir, Javed Iqbal, and Muhammad Akbar for their work in the field. We would also like to thank to Dr. Connie Woodhouse, Dr. Karla Hansen-Speer, and two anonymous reviewers for their critical suggestion to improve this manuscript.

References (49)

  • M. Ahmed

    Dendrochronology and its scope in Pakistan

  • M. Ahmed et al.

    Tree-ring chronology of Picea smithiana (Wall.) Boiss, and its quantitative vegetation description from Himalayan region of Pakistan

    Pak. J. Bot.

    (2005)
  • M. Ahmed et al.

    Age and growth-rates of some gymnosperms in Pakistan - a dendrochronological approach

    Pak. J. Bot.

    (2009)
  • M. Ahmed et al.

    Tree-ring chronologies from Upper Indus Basin of Karakorum Range of Pakistan

    Pak. J. Bot.

    (2010)
  • M. Ahmed et al.

    Climate/growth correlations of tree species in the Indus basin of the Karakorum range, north Pakistan

    IAWA J.

    (2012)
  • M. Ahmed et al.

    Dendroclimatic and dendrohydrological response of two tree species from Gilgit valleys

    Pak. J. Bot.

    (2013)
  • F. Asad et al.

    Are Karakoram temperatures out of phase compared to hemispheric trends?

    Clim. Dyn.

    (2016)
  • F. Asad et al.

    Growth response of Pinus wallichiana to climatic factors from the Chiraah Karakoram region, Northern Pakistan

    Pak. J. Bot.

    (2018)
  • S. Bhandari et al.

    A 307-year tree-ring SPEI reconstruction indicates modern drought in western Nepal himalayas

    Tree. Res.

    (2019)
  • F. Cannon et al.

    Multi-annual variations in winter westerly disturbance activity affecting the Himalaya

    Clim. Dyn.

    (2015)
  • A. Devkota

    Biodiversity: gymnosperms

  • J. Esper et al.

    1300 years of climatic history for Western Central Asia inferred from tree-rings

    Holocene

    (2002)
  • Z.X. Fan et al.

    Tree-ring based drought reconstruction in the central Hengduan Mountains region (China) since AD 1655

    Int. J. Climatol.

    (2008)
  • H.C. Fritts

    Tree Rings and Climate

    (1976)
  • Cited by (6)

    View full text