Intra-and interannual climate variability drives the radial growth of Pinus wallichiana in the Nepalese Himalayas

ABSTRACT

Background

The Himalayas have been experiencing a higher rate of temperature increase than the global average. How such climate warming and changes in the precipitation regime may affect the growth responses of individual tree species is little known but is required so that adequate projections of future distributions and management plans can be formulated.

Aims

This study was carried out to investigate the influence of intra- and interannual climate variability on the radial growth of Pinus wallichiana, a conifer species that typically colonises glacier forelands and screes.

Methods

Tree core samples collected for chronology development that spanned over a 119-year-long (1899–2017) period and the relationship of ring width with climatic data was analysed using correlation analysis.

Results

Radial growth in P. wallichiana was negatively correlated with mean temperature in March and over the pre-monsoon (March – May) seasonal average and it was positively correlated with monthly precipitation in March and September. Monthly standardised precipitation index (SPI) values indicated that overall the growth of P. wallichiana was mainly controlled by precipitation availability during the pre-monsoon season, particularly in March.

Conclusion

Moisture availability especially in spring is crucial for the radial growth of P. wallichiana. However, how this response varies throughout the elevational range of the species deserves further study to be able to make projections on the likely range expansion or contraction of the species in response to ongoing climate change.

KEYWORDS:

• Blue pine
• climate change
• dendrochronology
• drought
• pre-monsoon rainfall

Acknowledgements

This study was funded by the Strategic Priority Research Program of Chinese Academy of Sciences, Pan-Third Pole Environment Study for a Green Silk Road (XDA 20040301). We thank the Beijing Forestry University, Nepal Academy of Science and Technology, and the Tribhuvan University, Institute of Forestry, Pokhara Campus for providing research facilities. The first author thanks the Chinese Government for the Ph.D. scholarship. We are also grateful to Mukti Subedi and all reviewers for their valuable comments and suggestions for improving the quality of this paper.

Disclosure statement

The authors declare no conflicts of interest.

Additional information

Notes on contributors

Deepak Gautam

Deepak Gautam is a Ph.D. student researching tree ring variability along elevation gradients in the Nepalese Himalaya. His research interest includes dendrochronology, ethnomedicine and climate change.

Jishan Karki

Jishan Karki is a post-graduate fellow and a forest officer and a member of tree-ring society, Nepal.

Narayan P. Gaire

Narayan P. Gaire is a post-doctoral fellow researching treeline dynamics and past climate reconstructions in the Nepalese Himalayas.

Brian E. Roth

Brian E. Roth is interested in research on seed trees in North America and Nepal.

Suman Bhattarai

Suman Bhattarai is an Assistant Professor. His research focuses on forest management and climate change.

Shivaraj Thapa

Shivaraj Thapa is a postgraduate student. His research interests include valuation of ecosystem services, dendrochronology and climate change.

Ram P. Sharma

Ram P. Sharma is a Professor. His main research interests include tree growth modelling, dendrochronology and biometrics.

Jun Li

Jun Li is an associate professor with an interest in vegetation productivity, phenology and the carbon cycle.

Xiaojuan Tong

Xiaojuan Tong is a Professor. Her research interests include forest ecology and vegetation productivity.

Qi Jing Liu

Qi Jing Liu is a Professor with an interest in forest management and dendrochronology.