
Long-term irrigation experiment Pfynwald
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At the beginning of this century, numerous pines in the Rhone Valley, one of the driest inner alpine valleys of the European Alps, situated between Brig and Sion (Canton Valais), started showing symptoms of drought; several older trees having already died. With a view to uncovering the causes of these pines dying, the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) launched a long-term irrigation experiment in summer 2003 in the Nature Park of Pfyn-Finges. Since then, the WSL has been comparing the growth of several hundred pines in irrigated forest plots with trees that only receive the natural amount of precipitation.
For a better understanding of the medium-to long-term effects of drought periods on forests, results from experiments in dry areas with an extended series of in situ measurements are required.
As the largest contiguous pine forest in Switzerland, the Pfyn forest in Canton Valais (46° 18' N, 7° 36' E, 615 m ASL) offers the best conditions for such measurements. In light of this, a WSL research team installed a long-term experiment of 20 years duration in the Pfyn forest. The average temperature here is 9.2°C, the yearly accumulated precipitation is 657 mm (average 1961-1990). The pines in the middle of the forest are about 100 years old and 10.8 m high. The test area has 876 trees covering 1.2 ha divided into 8 plots of 1'000 m2 each (Image 4). Between the months of April and October four of these plots are irrigated by a sprinkler system providing an additional 700 mm of water, annually. In the other four plots, the trees grow under natural, hence relatively dry conditions.
Results to date
Almost immediately after the start of the measurements in 2003, there was a considerable increase in the production of mycorrhiza fruit bodies in the irrigated subplots (Hutter et al. in prep.). One year later, from 2004 onwards, the pines started forming wider annual rings and longer needles. Subsequently, the vertical shoots and branch shoots also showed an increase in length and the stand density grew too. Furthermore, irrigation boosted root growth and led to an increased biomass as of summer 2006, especially in the fine roots (Brunner et al. 2009). The growth period of irrigated trees was extended by 2 -5 weeks (Image 3) (Eilmann et al. 2010).
In Switzerland, the temperature increase from the end of the 20th century to the beginning of the 21st was more than double the global average. Climate models suggest that the 21st century will see a further rise in temperatures. In conjunction with the heat-related increase in evaporation and more frequent heat waves, it is safe to assume that the water supply available to trees is steadily deteriorating and that heavy rainfall is to be increasingly expected in the summer months. This rainfall will increase surface water runoff and will not seep into the soil, meaning that plants will increasingly suffer from stress caused by drought. Consequently, the vitality and growth of the pines will fall. In the long term, drought may lead to an increasing number of tree deaths and cause vegetation areas to shift. This is particularly true for the forest ecosystem of inner-alpine dry valleys such as those in Valais (Rigling et al. 2013).
Sponsors
We appreciate the long standing support received from HYDRO Exploitation SA in Sion.
FURTHER INFORMATION
Publications
For an adequate citation of Pfyn forest studies and data, please include the following citation in your paragraph about "Methods" or "Acknowledgements":
The analysis was based on data from the long-term irrigation experiment Pfyn forest, which is part of Swiss Long-term Forest Ecosystem Research Program LWF (www.lwf.ch). We would like to extend special thanks to X, who put the Z-data at our disposal.
Guidi, C.; Frey, B.; Brunner, I.; Meusburger, K.; Vogel, M.E.; Chen, X.; Stucky, T.; Gwiazdowicz, D.J.; Skubała, P.; Bose, A.K.; Schaub, M.; Rigling, A.; Hagedorn, F., 2022: Soil fauna drives vertical redistribution of soil organic carbon in a long‐term irrigated dry pine forest. Global Change Biology, 28, 9: 3145-3160. doi: 10.1111/gcb.16122
Gao, D.; Joseph, J.; Werner, R.A.; Brunner, I.; Zürcher, A.; Hug, C.; Wang, A.; Zhao, C.; Bai, E.; Meusburger, K.; Gessler, A.; Hagedorn, F., 2021: Drought alters the carbon footprint of trees in soils—tracking the spatio-temporal fate of 13C-labelled assimilates in the soil of an old-growth pine forest. Global Change Biology, 27: 2491-2506. doi: 10.1111/gcb.15557
Hunziker, S.; Begert, M.; Scherrer, S.C.; Rigling, A.; Gessler, A., 2022: Below average midsummer to early autumn precipitation evolved into the main driver of sudden scots pine vitality decline in the Swiss Rhône Valley. Frontiers in Forests and Global Change, 5: 874100 (20 pp.). doi: 10.3389/ffgc.2022.874100
Maeder, M.; Guo, X.; Neff, F.; Schneider Mathis, D.; Gossner, M.M., 2022: Temporal and spatial dynamics in soil acoustics and their relation to soil animal diversity. PLoS One, 17, 3: e0263618 (22 pp.). doi: 10.1371/journal.pone.0263618
Bose, A.K.; Rigling, A.; Gessler, A.; Hagedorn, F.; Brunner, I.; Feichtinger, L.; Bigler, C.; Egli, S.; Etzold, S.; Gossner, M.M.; Guidi, C.; Lévesque, M.; Meusburger, K.; Peter, M.; Saurer, M.; Scherrer, D.; Schleppi, P.; Schönbeck, L.; Vogel, M.E.; ... Schaub, M., 2022: Lessons learned from a long‐term irrigation experiment in a dry Scots pine forest: impacts on traits and functioning. Ecological Monographs, 92, 2: e1507 (18 pp.). doi: 10.1002/ecm.1507
Rissanen, K.; Aalto, J.; Gessler, A.; Hölttä, T.; Rigling, A.; Schaub, M.; Bäck, J., 2022: Drought effects on volatile organic compound emissions from Scots pine stems. Plant, Cell and Environment, 45, 1: 23-40. doi: 10.1111/pce.14219
Mathys, A.S.; Brang, P.; Stillhard, J.; Bugmann, H.; Hobi, M.L., 2021: Long-term tree species population dynamics in Swiss forest reserves influenced by forest structure and climate. Forest Ecology and Management, 481: 118666 (10 pp.). doi: 10.1016/j.foreco.2020.118666
D'Odorico, P.; Schönbeck, L.; Vitali, V.; Meusburger, K.; Schaub, M.; Ginzler, C.; Zweifel, R.; Velasco, V.M.E.; Gisler, J.; Gessler, A.; Ensminger, I., 2021: Drone‐based physiological index reveals long‐term acclimation and drought stress responses in trees. Plant, Cell and Environment, 44, 11: 3552-3570. doi: 10.1111/pce.14177
Rissanen, K.; Hölttä, T.; Bäck, J.; Rigling, A.; Wermelinger, B.; Gessler, A., 2021: Drought effects on carbon allocation to resin defences and on resin dynamics in old-grown Scots pine. Environmental and Experimental Botany, 185: 104410 (13 pp.). doi: 10.1016/j.envexpbot.2021.104410
Wang, A.; Siegwolf, R.T.W.; Joseph, J.; Thomas, F.M.; Werner, W.; Gessler, A.; Rigling, A.; Schaub, M.; Saurer, M.; Li, M.; Lehmann, M.M., 2021: Effects of soil moisture, needle age and leaf morphology on carbon and oxygen uptake, incorporation and allocation: a dual labeling approach with 13CO2 and H218O in foliage of a coniferous forest. Tree Physiology, 41, 1: 50-62. doi: 10.1093/treephys/tpaa114
Timofeeva, G.; Treydte, K.; Bugmann, H.; Salmon, Y.; Rigling, A.; Schaub, M.; Vollenweider, P.; Siegwolf, R.; Saurer, M., 2020: How does varying water supply affect oxygen isotope variations in needles and tree rings of Scots pine?. Tree Physiology, 40, 10: 1366-1380. doi: 10.1093/treephys/tpaa082
Joseph, J.; Gao, D.; Backes, B.; Bloch, C.; Brunner, I.; Gleixner, G.; Haeni, M.; Hartmann, H.; Hoch, G.; Hug, C.; Kahmen, A.; Lehmann, M.M.; Li, M.; Luster, J.; Peter, M.; Poll, C.; Rigling, A.; Rissanen, K.A.; Ruehr, N.K.; ... Gessler, A., 2020: Rhizosphere activity in an old-growth forest reacts rapidly to changes in soil moisture and shapes whole-tree carbon allocation. Proceedings of the National Academy of Sciences of the United States of America PNAS, 117, 40: 24885-24892. doi: 10.1073/pnas.2014084117
Bose, A.K.; Moser, B.; Rigling, A.; Lehmann, M.M.; Milcu, A.; Peter, M.; Rellstab, C.; Wohlgemuth, T.; Gessler, A., 2020: Memory of environmental conditions across generations affects the acclimation potential of scots pine. Plant, Cell and Environment, 43, 5: 1288-1299. doi: 10.1111/pce.13729
Zweifel, R.; Etzold, S.; Sterck, F.; Gessler, A.; Anfodillo, T.; Mencuccini, M.; Von Arx, G.; Lazzarin, M.; Haeni, M.; Feichtinger, L.; Meusburger, K.; Knuesel, S.; Walthert, L.; Salmon, Y.; Bose, A.K.; Schoenbeck, L.; Hug, C.; De Girardi, N.; Giuggiola, A.; ... Rigling, A., 2020: Determinants of legacy effects in pine trees - implications from an irrigation-stop experiment. New Phytologist, 227, 4: 1081-1096. doi: 10.1111/nph.16582
Herzog, C.; Hartmann, M.; Frey, B.; Stierli, B.; Rumpel, C.; Buchmann, N.; Brunner, I., 2019: Microbial succession on decomposing root litter in a drought-prone Scots pine forest. ISME Journal, 13, 9: 2346-2362. doi: 10.1038/s41396-019-0436-6
Brunner, I.; Herzog, C.; Galiano, L.; Gessler, A., 2019: Plasticity of fine-root traits under long-term irrigation of a water-limited scots pine forest. Frontiers in Plant Science, 10: 701 (10 pp.). doi: 10.3389/fpls.2019.00701
Grossiord, C.; Sevanto, S.; Limousin, J.; Meir, P.; Mencuccini, M.; Pangle, R.E.; Pockman, W.T.; Salmon, Y.; Zweifel, R.; McDowell, N.G., 2018: Manipulative experiments demonstrate how long-term soil moisture changes alter controls of plant water use. Environmental and Experimental Botany, 152: 19-27. doi: 10.1016/j.envexpbot.2017.12.010
Solly, E.F.; Brunner, I.; Helmisaari, H.; Herzog, C.; Leppälammi-Kujansuu, J.; Schöning, I.; Schrumpf, M.; Schweingruber, F.H.; Trumbore, S.E.; Hagedorn, F., 2018: Unravelling the age of fine roots of temperate and boreal forests. Nature Communications, 9, 1: 3006 (8 pp.). doi: 10.1038/s41467-018-05460-6
He, P.; Fontana, S.; Sui, X.; Gessler, A.; Schaub, M.; Rigling, A.; Jiang, Y.; Li, M., 2018: Scale dependent responses of pine reproductive traits to experimental and natural precipitation gradients. Environmental and Experimental Botany, 156: 62-73. doi: 10.1016/j.envexpbot.2018.08.028
Gessler, A.; Schaub, M.; McDowell, N.G., 2017: The role of nutrients in drought-induced tree mortality and recovery. New Phytologist, 214, 2: 513-520. doi: 10.1111/nph.14340
Mencuccini, M.; Salmon, Y.; Mitchell, P.; Hölttä, T.; Choat, B.; Meir, P.; O'Grady, A.; Tissue, D.; Zweifel, R.; Sevanto, S.; Pfautsch, S., 2017: An empirical method that separates irreversible stem radial growth from bark water content changes in trees: theory and case studies. Plant, Cell and Environment, 40, 2: 290-303. doi: 10.1111/pce.12863
Timofeeva, G.; Treydte, K.; Bugmann, H.; Rigling, A.; Schaub, M.; Siegwolf, R.; Saurer, M., 2017: Long-term effects of drought on tree-ring growth and carbon isotope variability in Scots pine in a dry environment. Tree Physiology, 37, 8: 1028-1041. doi: 10.1093/treephys/tpx041
Von Arx, G.; Arzac, A.; Fonti, P.; Frank, D.; Zweifel, R.; Rigling, A.; Galiano, L.; Gessler, A.; Olano, J.M., 2017: Responses of sapwood ray parenchyma and non-structural carbohydrates of Pinus sylvestris to drought and long-term irrigation. Functional Ecology, 31, 7: 1371-1382. doi: 10.1111/1365-2435.12860
Hartmann, M.; Brunner, I.; Hagedorn, F.; Bardgett, R.D.; Stierli, B.; Herzog, C.; Chen, X.; Zingg, A.; Graf-Pannatier, E.; Rigling, A.; Frey, B., 2017: A decade of irrigation transforms the soil microbiome of a semi-arid pine forest. Molecular Ecology, 26, 4: 1190-1206. doi: 10.1111/mec.13995
Yan, C.; Gessler, A.; Rigling, A.; Dobbertin, M.; Han, X.; Li, M., 2016: Effects of mistletoe removal on growth, N and C reserves, and carbon and oxygen isotope composition in Scots pine hosts. Tree Physiology, 36, 5: 562-575. doi: 10.1093/treephys/tpw024
Von Arx, G.; Arzac, A.; Olano, J.M.; Fonti, P., 2015: Assessing conifer ray parenchyma for ecological studies: pitfalls and guidelines. Frontiers in Plant Science, 6, 11: 1016 (10 pp.). doi: 10.3389/fpls.2015.01016
Herzog, C.; Steffen, J.; Graf Pannatier, E.; Hajdas, I.; Brunner, I., 2014: Nine years of irrigation cause vegetation and fine root shifts in a water-limited pine forest. PLoS One, 9, 5: e96321 (11 pp.). doi: 10.1371/journal.pone.0096321
Breitenmoser, P.; Brönnimann, S.; Frank, D., 2014: Forward modelling of tree-ring width and comparison with a global network of tree-ring chronologies. Climate of the Past, 10, 2: 437-449. doi: 10.5194/cp-10-437-2014
Eilmann, B.; Dobbertin, M.; Rigling, A., 2013: Growth response of Scots pine with different crown transparency status to drought release. Annals of Forest Science, 70, 7: 685-693. doi: 10.1007/s13595-013-0310-z
Sterck, F.J.; Martínez-Vilalta, J.; Mencuccini, M.; Cochard, H.; Gerrits, P.; Zweifel, R.; Herrero, A.; Korhonen, J.F.J.; Llorens, P.; Nikinmaa, E.; Nolè, A.; Poyatos, R.; Ripullone, F.; Sass-Klaassen, U., 2012: Understanding trait interactions and their impacts on growth in Scots pine branches across Europe. Functional Ecology, 26, 2: 541-549. doi: 10.1111/j.1365-2435.2012.01963.x
Eilmann, B.; Zweifel, R.; Buchmann, N.; Graf Pannatier, E.; Rigling, A., 2011: Drought alters timing, quantity, and quality of wood formation in Scots pine. Journal of Experimental Botany, 62, 8: 2763-2771. doi: 10.1093/jxb/erq443
Dobbertin, M.; Eilmann, B.; Bleuler, P.; Giuggiola, A.; Graf Pannatier, E.; Landolt, W.; Schleppi, P.; Rigling, A., 2010: Effect of irrigation on needle morphology, shoot and stem growth in a drought-exposed Pinus sylvestris forest. Tree Physiology, 30, 3: 346-360. doi: 10.1093/treephys/tpp123
Eilmann, B.; Buchmann, N.; Siegwolf, R.; Saurer, M.; Cherubini, P.; Rigling, A., 2010: Fast response of Scots pine to improved water availability reflected in tree-ring width and δ13C. Plant, Cell and Environment, 33, 8: 1351-1360. doi: 10.1111/j.1365-3040.2010.02153.x
Brunner, I.; Graf Pannatier, E.; Frey, B.; Rigling, A.; Landolt, W.; Zimmermann, S.; Dobbertin, M., 2009: Morphological and physiological responses of Scots pine fine roots to water supply in a dry climatic region in Switzerland. Tree Physiology, 29, 4: 541-550. doi: 10.1093/treephys/tpn046
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Warum können Steine schwimmen, sind die Tage des Aletschgletschers gezählt, wieso archivieren Bäume das Klima? Acht Wanderungen durch das Mittel- und Oberwallis führen an Orte, die Antworten auf solche Fragen liefern – dorthin, wo geforscht wird. Die Eidg. Forschungsanstalt für Wald, Schnee und Landschaft WSL befasst sich in dieser Region seit dreissig Jahren mit Lebensräumen und Naturgefahren und gibt nun entlang von Wanderwegen faszinierende Einblicke in ihre Arbeit. Hintergrundinformationen zu einzelnen Tier- und Pflanzenarten und eine App für unterwegs ergänzen den reich bebilderten Wissenschafts- und Wanderführer.
Quand les pierres se mettent-elles à flotter? Les jours du glacier d'Aletsch sont-ils comptés? En quoi les arbres sont-ils des archives du climat? Au fil de huit randonnées en Valais, les réponses à ces questions et à bien d’autres offrent un aperçu fascinant des observations à ciel ouvert des scientifiques. Depuis trente ans, l'Institut fédéral de recherches sur la forêt, la neige et le paysage WSL étudie les écosystèmes et les dangers naturels dans cette région. Des informations sur diverses espèces animales et végétales ainsi qu'une application mobile complètent ce guide de randonnée et de découverte des sciences de la nature.
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Rigling, A.; Etzold, S.; Bebi, P.; Brang, P.; Ferretti, M.; Forrester, D.; Gärtner, H.; Gessler, A.; Ginzler, C.; Moser, B.; Schaub, M.; Stroheker, S.; Trotsiuk, V.; Walthert, L.; Zweifel, R.; Wohlgemuth, T., 2019: Wie viel Trockenheit ertragen unsere Wälder? Lehren aus extremen Trockenjahren. In: Bründl, M.; Schweizer, J. (eds), 2019: Lernen aus Extremereignissen. Forum für Wissen 2019: Lernen aus Extremereignissen, Davos, Switzerland. 39-51.
Wohlgemuth, T.; Doublet, V.; Nussbaumer, C.; Feichtinger, L.; Rigling, A., 2018: Baumartenwechsel in den Walliser Waldföhrenwäldern verstärkt nach grossen Störungen. Schweizerische Zeitschrift für Forstwesen, 169, 5: 260-268. doi: 10.3188/szf.2018.0260
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Zweifel R, Basler D, Braun S, Buchmann N, Conedera M, De Girardi N, Etzold S, Eugster W, Fonti P, Gessler A, Haeni M, Hoch G, Kahmen A, Koechli R, Maeder M, Nievergelt D, Peter M, Peters R, Schaub M, Trotsiuk T, Walthert L, Wilhelm M (2021) TreeNet Technischer Bericht 2021.
Schönbeck L, Grossiord C, Gessler A, Gisler J, Meusburger K, D’Odorico P, Rigling A, Salmon A, Stocker BD, Zweifel R, Schaub M (2021) Photosynthetic acclimation and sensitivity to short- and long-term environmental changes.Preprint BioRxiv. Doi:10.1101/2021.01.04.425174
Schönbeck L, d'Odorico P, Gisler J, Gessler A, Schaub M (2021) 2013-2020 gas exchange at Pfynwald.EnviDat. Doi:10.16904/envidat.238
Sutter F, Schaub M (2019) LWF Pfynwald long-term experimental irrigation site. EnviDat
Schaub M, Häni M, Hug C, Gessler A, Rigling A (2016) Tree measurements 2002-2016 from the long-term irrigation experiment Pfynwald, Switzerland; Swiss Federal Research Institute WSL / SwissForestLab. EnviDat. Doi:10.16904/11
Simeon C (2015) The effects of drought on resin production of Pinus sylvestris in a long-term irrigation experiment in Pfynwald in the canton of Valais. Masterarbeit am Departement Umweltsystemwissenschaften ETHZürich.
Meta data and Maps
Meta Data & Scaffolds
- Are you starting a new study or updating anongoing one? Please download the excel-sheet with the metadata from Pfyn forest, complete it with your up-to-date information in red and send the file by mail to Marcus Schaub.
- Pfyn_Metadata_vrs42.xlsx
Maps
- Pfyn Trees (1.2 MB)
- Pfyn Measurements (1.4 MB)
- Pfyn Trees & Measurements installations (3.8 MB)
- Pfyn Plan north (0.97 MB)
- Pfyn Plan south (0.99 MB)
- Pfyn Overview (0.54 MB)
Workshops
Workshops
- Pfynwald Workshop, WSL, 14 Feb 2022
Pfynwald Workshop, WSL (virtual, 70 participants), 17 Sept 2020
- 2014 Pfyn Workshop
- 2013 Pfyn Workshop
Contact
Dr. Marcus Schaub
Groupleader, Senior Scientist
Jonas Gisler
Technical staff member
Christian Hug
Technical staff member
Dr. Stefan Hunziker
scientific staff member
Prof. Dr. Charlotte Grossiord
Groupleader, Head of Lausanne location
Prof. Dr. Andreas Rigling
Visiting scientist