TREELINE-II | University of Tübingen

Fig. 1: a) Location of study areas including (1) Rolwaling Valley (Gaurishankar Conservation Area), (2) Tsum Valley (Manaslu Conservation Area), and (3, 4) Langtang Valley (Langtang National Park); b) Location of the Rolwaling study area of TREELINE-I; c) TREELINE-I study slopes and sites at Rolwaling

Climate warming has become the most important driver of modern treeline research. Most of the treeline studies focused on to address the key question of how treeline response to climate warming and the potential upslope of climatic treelines. However, there is still inconsistency regarding currently observed treeline responses with treeline advancing upslope and others showing insignificant responses. The major deficit in Himalayan treeline research is that to what extent the treeline form (e.g. Krummholz form) is an indicator of the responsiveness of the treeline dynamics.

In this current research project, TREELINE- II, will test the hypothesis that Krummholz zone are the crucial structural component of the Himalayan treeline ecotones controlling any treeline shift. TREELINE-II, implementing the landscape approach used in TREELINE -I, in addition with comparative study of Krummholz and non-Krummholz forest including additional fields (Fig. 1) and integrating in-situ field measurements, remote sensing studies, and climate and environmental modelling to deliver new understanding of the dynamics of Himalayan Krummholz and non-Krummholz treeline.

As the specific objectives, the soil properties effect to elucidate the role of Krummholz zone in treeline and underline mechanisms and feedbacks that maintain the comparativeness of Krummholz zone (R. Campanulatum forest) will be exploited through (i) the analysis of inhibition of plant growth driven by allelopathy of R.campanulatum, (ii) low nutrient availability driven by soil characteristics and (iii) growing season drought stress (pre-monsoon drought) caused by change in climatic patterns in the Himalaya.

TREELINE – II research project is the continued collaborative research since 2013 (TREELINE -I) in the high-altitude Nepal Himalaya. Since the inception of the TREELINE research project in Nepal, wealth of novel findings was published (some of them are listed below). For the further information, please contact Rabindra Adhikari or Prof. Thomas Scholten.

Overview

Title:	Sensitivity and Response of Treeline Ecotones in the Nepal Himalaya to Climate Warming (TREELINE-II)
Start/End:	2023 – 2026
Funding:	German Research Foundation (DFG)
Key Words:	Treeline ecotone, Krummholz, Soil Properties, Climate Change, Himalaya
Contact:	Rabindra Adhikari, Prof. Thomas Scholten

TREELINE research project related publication (10 are listed)

1. BÜRZLE, B., SCHICKHOFF, U., SCHWAB, N.,WERNICKE, L., MÜLLER, Y., BÖHNER, J., CHAUDHARY, R.P., SCHOLTEN, T. & OLDELAND, J. (2018): Seedling recruitment and facilitation dependence on safe site characteristics in a Himalayan treeline ecotone. Plant Ecology 219: 115-132. https://doi.org/10.1007/s11258-017-0782-2

2. GERLITZ, L., BECHTEL, B., BÖHNER, J., BOBROWSKI, M., BÜRZLE, B., MÜLLER, M., SCHOLTEN, T., SCHICKHOFF, U., SCHWAB, N. & WEIDINGER, J. (2016): Analytic comparison of temperature lapse rates and precipitation gradients in a Himalayan treeline environment – Implications for statistical downscaling. In: SINGH, R.B., SCHICKHOFF, U. & MAL, S. [eds.]: Climate Change, Glacier Response, and Vegetation Dynamics in the Himalaya, pp. 49-64. Springer, Switzerland. https://doi.org/10.1007/978-3-319-28977-9_3

3. KARKI, R., HASSON, S., GERLITZ, L., SCHICKHOFF, U., SCHOLTEN, T. & BÖHNER, J. (2017): Quantifying the added value of convection-permitting climate simulations in complex terrain: A systematic evaluation of WRF over the Himalayas. Earth System Dynamics 8: 507-528. https://esd.copernicus.org/articles/8/507/2017/esd-8-507-2017.html

4. MÜLLER, M., OELMANN, Y., SCHICKHOFF, U., BÖHNER, J. & SCHOLTEN, T. (2017): Himalayan treeline soil and foliar C:N:P stoichiometry indicate nutrient shortage with elevation. Geoderma 291: 21-32. https://doi.org/10.1016/j.geoderma.2016.12.015

5. MÜLLER, M., SCHICKHOFF, U., SCHOLTEN, T., DROLLINGER, S., BÖHNER, J. & CHAUDHARY, R.P. (2016a): How do soil properties affect alpine treelines? General principles in a global perspective and novel findings from Rolwaling Himal, Nepal. Progress in Physical Geography 40: 135-160. https://doi.org/10.1177/0309133315615802

6. MÜLLER, M., SCHWAB, N., SCHICKHOFF, U., BÖHNER, J. & SCHOLTEN, T. (2016b): Soil temperature and soil moisture patterns in a Himalayan alpine treeline ecotone. Arctic, Antarctic, and Alpine Research 48: 501-521. https://doi.org/10.1657/AAAR0016-004

7. SCHICKHOFF, U., BOBROWSKI, M., BÖHNER, J., BÜRZLE, B., CHAUDHARY, R.P., GERLITZ, L., HEYKEN, H., LANGE, J., MÜLLER, M., SCHOLTEN, T., SCHWAB, N. &WEDEGÄRTNER, R. (2015): Do Himalayan treelines respond to recent climate change? An evaluation of sensitivity indicators. Earth System Dynamics 6: 245-265. https://esd.copernicus.org/articles/6/245/2015/esd-6-245-2015.pdf

8. Schickhoff, U., M. Bobrowski, J. Böhner, B. Bürzle, R. P. Chaudhary, M. Müller, T. Scholten, N. Schwab, and J. Weidinger. 2023. "The treeline ecotone in Rolwaling Himal, Nepal: Pattern-process relationships and treeline shift potential." In Ecology of Himalayan Treeline Ecotone, pp. 95-145. Singapore: Springer Nature Singapore. https://doi.org/10.1007/978-981-19-4476-5_5

9. SCHWAB, N., JANECKA, K., KACZKA, R.J., BÖHNER, J., CHAUDHARY, R.P., SCHOLTEN, T. & SCHICKHOFF, U. (2020): Ecological relationships at a near-natural treeline, Rolwaling valley, Nepal Himalaya: implications for the sensitivity to climate change. Erdkunde 74: 15-44. https://doi.org/10.3112/erdkunde.2020.01.02

10. SCHWAB, N., KACZKA, R.J., JANECKA, K., BÖHNER, J., CHAUDHARY, R.P., SCHOLTEN, T. & SCHICKHOFF, U. (2018): Climate change-induced shift of tree growth sensitivity at a central Himalayan treeline ecotone. Forests 2018, 9(5), 267. https://doi.org/10.3390/f9050267

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