Swiss Federal Institute for Forest, Snow and Landscape Research WSL

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Avalanche Bulletin

The Pfynwald research platform

At the beginning of this century, numerous Scots 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. Many older trees had already died. To investigate the causes of the pine dieback, the WSL launched a long-term irrigation experiment in the Pfyn-Finges Nature Park in summer 2003. Since then, the WSL has been comparing the responses of several hundred Scots pines in irrigated forest plots with those of trees that continued to receive only the natural amount of precipitation.

Since 2024, we have implemented an additional, world-wide unique approach to disentangle the processes affected by atmospheric and soil droughts. For more details, see VPDrought-Experiment.

Abb. 1: Blick auf den Pfynwald aus Nordosten vom Gegenhang. Bild: M. Schaub/ WSL
Figure 1. View on the Pfyn Forest from the opposite hillside in the northeast. Photo: M. Schaub/WSL.
Abb. 2: Während April-Oktober werden einzelne Parzellen zusätzlich bewässert. Image: M. Schaub/WSL
Figure 2: Randomly selected plots are irrigated from April to October. Photo: M. Schaub/WSL.

Results from experiments in dry areas with a long series of in-situ measurements are necessary for a better understanding of the medium- to long-term effects of drought periods on forests.

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 set up a long-term experiment that is to last 30 years in this forest.  The average temperature here is 10.6°C (average 1995-2014), the yearly accumulated precipitation is 575 mm (average 1995-2014). The pines are about 130 years old and 12 m high. The test area comprises approx. 800 trees over a surface of 1.2 ha divided into 8 plots of 1000 m2 each (Figure 4). Between April and October, four of these plots are irrigated by a sprinkler system which provides an additional 600 mm of water annually. In the other four plots, the trees grow under natural, hence relatively dry conditions.

 

Results to date

Abb. 3: Um den Wasser- und Kohlenstoffhaushalt in Echtzeit zu verfolgen, wurde den Baumkronen markiertes CO2 und H2O zugeführt. Bild: C. Hug/WSL
Figure 3: In order to monitor the water and carbon balance in real time, ten (5 irrigated, 5 non-watered) trees were packed airtight for several hours in the summer of 2017 and the indoor air was enriched with marked CO2 and H2O. (Photo: C. Hug/WSL)

Almost immediately after measurements began in 2003, a considerable increase in the production of mycorrhiza fruit bodies was noticeable in the irrigated subplots. After a one-year lag, the pines have been forming wider tree rings and longer needles than before since 2004. In the following years, the length of the height and branch shoots and the stand density increased as well. From the summer 2006, irrigation has also increased root growth and led to more biomass, especially in the fine roots (Brunner et al. 2009). The growth period of irrigated trees was extended by 2 to 5 weeks (Eilmann et al. 2010).

Over the entire experimental period from 2003 to 2019, the irrigation experiment allowed us to track the recovery trajectories in trees and in the whole ecosystem released from the natural dry conditions. The monitoring data over 16 years showed that irrigation improved the soil water availability, and 120-year-old Scots pine trees were able to regain vigor by increasing shoot length, needle length and leaf area, and by decreasing crown transparency.

We detected rapid and stronger responses from above-ground tree traits compared to below-ground tree traits. The altered above-ground traits during the initial years of irrigation increased the water demand. Trees adjusted by increasing root biomass during the later years of irrigation, resulting in an increased survival rate of Scots pine trees in irrigated plots. However, after reaching the peak in 2006, the magnitude of the impact of irrigation on a number of tree-related variables declined in the following years. This declining trend after reaching the peak may indicate that the water supply at a constant rate over the years did not meet the progressively increasing water demand from increasing vegetation activities.

The results indicate that increased water availability in the long term changed tree and ecosystem properties in a way that a new balance between soil water availability and water demand is reached, which changed the boundary conditions of the ecosystem. The irrigation also stimulated foliar decomposition rate at ecosystem level, biomass of fungal fruit body, and abundance of regeneration in broadleaved tree species. However, irrigation did not promote the regeneration of Scots pine trees, which are reported to be vulnerable to extreme droughts (Bose et al. 2022).

Figure 4. The Pfyn Forest irrigation experiment consists of four irrigated plots and four control plots (25 m x 40 m, covered with 60-100 trees each). In the light blue sub-areas, irrigation was stopped temporarily at the end of 2013. Map: F. Sutter/WSL

The map can be downloaded and printed in A3 or A0 format for field work.

In Switzerland, the temperature increase from the end of the 20th century to the beginning of the 21st was more than twice 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. As this rainfall will increase surface water runoff and will not seep into the soil, plants will increasingly suffer from stress caused by drought. Consequently, the vitality and growth of the pines will drop. 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).

Links to the topic: Long-term Forest Ecosystem Research LWF, Sanasilva inventory

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WSL publications

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2021
Available languages: German, French

Publications

For an adequate citation of Pfyn forest studies and data, please include the following citation in the acknowledgements:

"Evaluations are based on data from the long-term experimental research platform Pfynwald, which is part of the Swiss Forest Lab and the eLTER research infrastructures. We are in particular grateful to X who provided the Z data and the Pfynwald core team for their support."

Cuartero J., Brunner I., Schaub M., Gwiazdowicz D.J., Skubała P., Qin J., … Frey B. (2025) Comparing soil microarthropod communities derived directly from soil DNA metabarcoding with those from morphological assessment in a drought-prone and irrigated pine forest. Appl. Soil Ecol. 209, 106042 (14 pp.). https://doi.org/10.1016/j.apsoil.2025.106042Institutional Repository DORA

Chin A.R.O., Gessler A., Laín O., Østerlund I., Schaub M., Théroux-Rancourt G., … Lambers J.H.R. (2025) The memory of past water abundance shapes trees 7 years later. Am. J. Bot. 112(1), e16452 (10 pp.). https://doi.org/10.1002/ajb2.16452Institutional Repository DORA

Chin A., Hille Ris Lambers J., Schaub M. (2025) Trees 'remember' wetter times − never having known abundant rain could buffer today’s young forests against climate change. The Conversation. Institutional Repository DORA

Shakas A., Hediger R., Gessler A., Singha K., de Pasquale G., D'Odorico P., … Meusburger K. (2025) Does optimality partitioning theory fail for belowground traits? Insights from geophysical imaging of a drought‐release experiment in a Scots Pine forest. New Phytol. 245(2), 546-558. https://doi.org/10.1111/nph.20245 Institutional Repository DORA

Cuartero J., Frey B., Eder R., Brunner I. (2024) More than a decade of irrigation alters soil nematode communities in a drought-prone Scots pine forest. Appl. Soil Ecol. 203, 105621 (10 pp.). https://doi.org/10.1016/j.apsoil.2024.105621Institutional Repository DORA

Gauthey A., Bachofen C., Chin A., Cochard H., Gisler J., Mas E., … Grossiord C. (2024) Twenty years of irrigation acclimation is driven by denser canopies and not by plasticity in twig- and needle-level hydraulics in a Pinus sylvestris forest. J. Exp. Bot. 75(10), 3141-3152. https://doi.org/10.1093/jxb/erae066 Institutional Repository DORA

Hunziker S., Nazarova T., Kather M., Hartmann M., Brunner I., Schaub M., … Gessler A. (2024) The metabolic fingerprint of Scots pine – root and needle metabolites show different patterns in dying trees. Tree Physiol. 44(4), tpae036 (10 pp.). https://doi.org/10.1093/treephys/tpae036Institutional Repository DORA

Vitali V., Schuler P., Holloway‐Phillips M., D'Odorico P., Guidi C., Klesse S., … Saurer M. (2024) Finding balance: tree‐ring isotopes differentiate between acclimation and stress‐induced imbalance in a long‐term irrigation experiment. Glob. Chang. Biol. 30(3), e17237 (20 pp.). https://doi.org/10.1111/gcb.17237Institutional Repository DORA

Gao D., Luster J., Zürcher A., Arend M., Bai E., Gessler A., … Hagedorn F. (2024) Drought resistance and resilience of rhizosphere communities in forest soils from the cellular to ecosystem scale – insights from 13C pulse labeling. New Phytol. 242(3), 960-974. https://doi.org/10.1111/nph.19612 Institutional Repository DORA

Hartmann M., Herzog C., Brunner I., Stierli B., Meyer F., Buchmann N., Frey B. (2023) Long-term mitigation of drought changes the functional potential and life-strategies of the forest soil microbiome involved in organic matter decomposition. Front. Microbiol. 14, 1267270 (16 pp.). https://doi.org/10.3389/fmicb.2023.1267270Institutional Repository DORA

Gauthey A., Bachofen C., Deluigi J., Didion-Gency M., D'Odorico P., Gisler J., … Grossiord C. (2023) Absence of canopy temperature variation despite stomatal adjustment in Pinus sylvestris under multidecadal soil moisture manipulation. New Phytol. 240(1), 127-137. https://doi.org/10.1111/nph.19136 Institutional Repository DORA

Guidi C., Lehmann M.M., Meusburger K., Saurer M., Vitali V., Peter M., … Hagedorn F. (2023) Tracing sources and turnover of soil organic matter in a long-term irrigated dry forest using a novel hydrogen isotope approach. Soil Biol. Biochem. 184, 109113 (10 pp.). https://doi.org/10.1016/j.soilbio.2023.109113Institutional Repository DORA

Zhang Y.L., Yang Y., Saurer M., Schaub M., Gessler A., Lehmann M.M., … Li M.H. (2023) Sugar infusion into trees: a novel method to study tree carbon relations and its regulations. Front. Plant Sci. 14, 1142595 (11 pp.). https://doi.org/10.3389/fpls.2023.1142595Institutional Repository DORA

Zweifel R., Pappas C., Peters R.L., Babst F., Balanzategui D., Basler D., … Sterck F. (2023) Networking the forest infrastructure towards near real-time monitoring - a white paper. Sci. Total Environ. 872, 162167 (11 pp.). https://doi.org/10.1016/j.scitotenv.2023.162167Institutional Repository DORA

Saurer M., Sahlstedt E., Rinne-Garmston K.T., Lehmann M.M., Oettli M., Gessler A., Treydte K. (2023) Progress in high-resolution isotope-ratio analysis of tree rings using laser ablation. Tree Physiol. 43(5), 694-705. https://doi.org/10.1093/treephys/tpac141 Institutional Repository DORA

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. Front. For. Glob. Change. 5, 874100 (20 pp.). https://doi.org/10.3389/ffgc.2022.874100Institutional Repository DORA

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.). https://doi.org/10.1371/journal.pone.0263618Institutional Repository DORA

Guidi C., Frey B., Brunner I., Meusburger K., Vogel M.E., Chen X., … Hagedorn F. (2022) Soil fauna drives vertical redistribution of soil organic carbon in a long‐term irrigated dry pine forest. Glob. Chang. Biol. 28(9), 3145-3160. https://doi.org/10.1111/gcb.16122 Institutional Repository DORA

Bose A.K., Rigling A., Gessler A., Hagedorn F., Brunner I., Feichtinger L., … Schaub M. (2022) Lessons learned from a long‐term irrigation experiment in a dry Scots pine forest: impacts on traits and functioning. Ecol. Monogr. 92(2), e1507 (18 pp.). https://doi.org/10.1002/ecm.1507Institutional Repository DORA

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 Environ. 45(1), 23-40. https://doi.org/10.1111/pce.14219 Institutional Repository DORA

D'Odorico P., Schönbeck L., Vitali V., Meusburger K., Schaub M., Ginzler C., … Ensminger I. (2021) Drone‐based physiological index reveals long‐term acclimation and drought stress responses in trees. Plant Cell Environ. 44(11), 3552-3570. https://doi.org/10.1111/pce.14177 Institutional Repository DORA

Eugster W., Baumgartner L.P., Bachmann O., Baltensperger U., Dèzes P., Dubois N., … RoTaGeo team (2021) Geosciences roadmap for research infrastructures 2025–2028 by the Swiss Geosciences Community. (Swiss Academies reports, Report No.: 16/4). Swiss Academy of Sciences (SCNAT). 55 p. https://doi.org/10.5281/zenodo.4588881Institutional Repository DORA

Gao D., Joseph J., Werner R.A., Brunner I., Zürcher A., Hug C., … 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. Glob. Chang. Biol. 27, 2491-2506. https://doi.org/10.1111/gcb.15557 Institutional Repository DORA

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. Environ. Exp. Bot. 185, 104410 (13 pp.). https://doi.org/10.1016/j.envexpbot.2021.104410Institutional Repository DORA

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. For. Ecol. Manag. 481, 118666 (10 pp.). https://doi.org/10.1016/j.foreco.2020.118666Institutional Repository DORA

Wang A., Siegwolf R.T.W., Joseph J., Thomas F.M., Werner W., Gessler A., … 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 Physiol. 41(1), 50-62. https://doi.org/10.1093/treephys/tpaa114 Institutional Repository DORA

Joseph J., Gao D., Backes B., Bloch C., Brunner I., Gleixner G., … Gessler A. (2020) Rhizosphere activity in an old-growth forest reacts rapidly to changes in soil moisture and shapes whole-tree carbon allocation. Proc. Natl. Acad. Sci. U. S. A. 117(40), 24885-24892. https://doi.org/10.1073/pnas.2014084117 Institutional Repository DORA

Timofeeva G., Treydte K., Bugmann H., Salmon Y., Rigling A., Schaub M., … Saurer M. (2020) How does varying water supply affect oxygen isotope variations in needles and tree rings of Scots pine? Tree Physiol. 40(10), 1366-1380. https://doi.org/10.1093/treephys/tpaa082 Institutional Repository DORA

Schönbeck L.C. (2019) Drought effects on carbon and nutrient dynamics in Scots pine. Homeostasis, thresholds and tipping points. [Doctoral dissertation] University of Basel. 131 p. https://doi.org/10.5451/unibas-007175123 Institutional Repository DORA

Zweifel R., Etzold S., Sterck F., Gessler A., Anfodillo T., Mencuccini M., … Rigling A. (2020) Determinants of legacy effects in pine trees - implications from an irrigation-stop experiment. New Phytol. 227(4), 1081-1096. https://doi.org/10.1111/nph.16582 Institutional Repository DORA

Bose A.K., Moser B., Rigling A., Lehmann M.M., Milcu A., Peter M., … Gessler A. (2020) Memory of environmental conditions across generations affects the acclimation potential of scots pine. Plant Cell Environ. 43(5), 1288-1299. https://doi.org/10.1111/pce.13729 Institutional Repository DORA

Hagedorn F., Walthert L., Luster J. (2019) Föhrensterben im Walllis: Auswirkung von Trockenheit auf den Wasser- und Kohlenstoffkreislauf des Pfynwaldes. In DBG Mitteilungen: Vol. 119. Exkursionsführer Bern 2019. Erd-reich und Boden-Landschaften. Kiel; Göttingen: DGB. 125-136. Institutional Repository DORA

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. Front. Plant Sci. 10, 701 (10 pp.). https://doi.org/10.3389/fpls.2019.00701Institutional Repository DORA

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 J. 13(9), 2346-2362. https://doi.org/10.1038/s41396-019-0436-6 Institutional Repository DORA

Rigling A., Etzold S., Bebi P., Brang P., Ferretti M., Forrester D., … Wohlgemuth T. (2019) Wie viel Trockenheit ertragen unsere Wälder? Lehren aus extremen Trockenjahren. In M. Bründl & J. Schweizer (Eds.), WSL Berichte: Vol. 78. Lernen aus Extremereignissen. Birmensdorf: Eidg. Forschungsanstalt für Wald, Schnee und Landschaft. 39-51. https://doi.org/10.55419/wsl:19983 Institutional Repository DORA

Wohlgemuth T., Doublet V., Nussbaumer C., Feichtinger L., Rigling A. (2018) Baumartenwechsel in den Walliser Waldföhrenwäldern verstärkt nach grossen Störungen. Schweiz. Z. Forstwes. 169(5), 260-268. https://doi.org/10.3188/szf.2018.0260 Institutional Repository DORA

He P., Fontana S., Sui X., Gessler A., Schaub M., Rigling A., … Li M.H. (2018) Scale dependent responses of pine reproductive traits to experimental and natural precipitation gradients. Environ. Exp. Bot. 156, 62-73. https://doi.org/10.1016/j.envexpbot.2018.08.028 Institutional Repository DORA

Solly E.F., Brunner I., Helmisaari H.S., Herzog C., Leppälammi-Kujansuu J., Schöning I., … Hagedorn F. (2018) Unravelling the age of fine roots of temperate and boreal forests. Nat. Commun. 9(1), 3006 (8 pp.). https://doi.org/10.1038/s41467-018-05460-6Institutional Repository DORA

Grossiord C., Sevanto S., Limousin J.M., Meir P., Mencuccini M., Pangle R.E., … McDowell N.G. (2018) Manipulative experiments demonstrate how long-term soil moisture changes alter controls of plant water use. Environ. Exp. Bot. 152, 19-27. https://doi.org/10.1016/j.envexpbot.2017.12.010 Institutional Repository DORA

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 Physiol. 37(8), 1028-1041. https://doi.org/10.1093/treephys/tpx041 Institutional Repository DORA

Boesch R. (2017) Thermal remote sensing with UAV-based workflows. In C. Stachniss, W. Förstner, & J. Schneider (Eds.), The international archives of the photogrammetry, remote sensing and spatial information sciences: Vol. XLII-2. The international archives of the photogrammetry, remote sensing and spatial information sciences. International Society for Photogrammetry and Remote Sensing. 41-46. https://doi.org/10.5194/isprs-archives-XLII-2-W6-41-2017 Institutional Repository DORA

Dobbertin M., Giuggiola A. (2006) Baumwachstum und erhöhte Temperaturen. In T. Wohlgemuth (Ed.), Forum für Wissen: Vol. 2006. Wald und Klimawandel. Birmensdorf: Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft. 35-45. Institutional Repository DORA

von Arx G., Arzac A., Fonti P., Frank D., Zweifel R., Rigling A., … Olano J.M. (2017) Responses of sapwood ray parenchyma and non-structural carbohydrates of Pinus sylvestris to drought and long-term irrigation. Funct. Ecol. 31(7), 1371-1382. https://doi.org/10.1111/1365-2435.12860 Institutional Repository DORA

Hartmann M., Brunner I., Hagedorn F., Bardgett R.D., Stierli B., Herzog C., … Frey B. (2017) A decade of irrigation transforms the soil microbiome of a semi-arid pine forest. Mol. Ecol. 26(4), 1190-1206. https://doi.org/10.1111/mec.13995 Institutional Repository DORA

Mencuccini M., Salmon Y., Mitchell P., Hölttä T., Choat B., Meir P., … 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 Environ. 40(2), 290-303. https://doi.org/10.1111/pce.12863 Institutional Repository DORA

Gessler A., Schaub M., McDowell N.G. (2017) The role of nutrients in drought-induced tree mortality and recovery. New Phytol. 214(2), 513-520. https://doi.org/10.1111/nph.14340 Institutional Repository DORA

Brunner I. (2006) Licht ins Dunkel der Wurzelwelt. In Tagungsband der 24. Osnabrücker Baumpflegetage 2006. Osnabrück: Fachbereich Grün und Umwelt. 35-40. Institutional Repository DORA

Martinéz-Vilalta J., Cochard H., Mencuccini M., Sterck F., Herrero A., Korhonen J.F.J., … Zweifel R. (2009) Hydraulic adjustment of Scots pine across Europe. New Phytol. 184(2), 353-364. https://doi.org/10.1111/j.1469-8137.2009.02954.x Institutional Repository DORA

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 Physiol. 29(4), 541-550. https://doi.org/10.1093/treephys/tpn046 Institutional Repository DORA

Dobbertin M., Eilmann B., Bleuler P., Giuggiola A., Graf Pannatier E., Landolt W., … Rigling A. (2010) Effect of irrigation on needle morphology, shoot and stem growth in a drought-exposed Pinus sylvestris forest. Tree Physiol. 30(3), 346-360. https://doi.org/10.1093/treephys/tpp123 Institutional Repository DORA

Yan C.F., Gessler A., Rigling A., Dobbertin M., Han X.G., Li M.H. (2016) Effects of mistletoe removal on growth, N and C reserves, and carbon and oxygen isotope composition in Scots pine hosts. Tree Physiol. 36(5), 562-575. https://doi.org/10.1093/treephys/tpw024 Institutional Repository DORA

Eilmann B., Dobbertin M., Rigling A. (2013) Growth response of Scots pine with different crown transparency status to drought release. Ann. For. Sci. 70(7), 685-693. https://doi.org/10.1007/s13595-013-0310-z Institutional Repository DORA

Sterck F.J., Martínez-Vilalta J., Mencuccini M., Cochard H., Gerrits P., Zweifel R., … Sass-Klaassen U. (2012) Understanding trait interactions and their impacts on growth in Scots pine branches across Europe. Funct. Ecol. 26(2), 541-549. https://doi.org/10.1111/j.1365-2435.2012.01963.x Institutional Repository DORA

Eilmann B., Zweifel R., Buchmann N., Graf Pannatier E., Rigling A. (2011) Drought alters timing, quantity, and quality of wood formation in Scots pine. J. Exp. Bot. 62(8), 2763-2771. https://doi.org/10.1093/jxb/erq443 Institutional Repository DORA

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 Environ. 33(8), 1351-1360. https://doi.org/10.1111/j.1365-3040.2010.02153.x Institutional Repository DORA

von Arx G., Arzac A., Olano J.M., Fonti P. (2015) Assessing conifer ray parenchyma for ecological studies: pitfalls and guidelines. Front. Plant Sci. 6(11), 1016 (10 pp.). https://doi.org/10.3389/fpls.2015.01016Institutional Repository DORA

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.). https://doi.org/10.1371/journal.pone.0096321Institutional Repository DORA

Breitenmoser P., Brönnimann S., Frank D. (2014) Forward modelling of tree-ring width and comparison with a global network of tree-ring chronologies. Clim. Past. 10(2), 437-449. https://doi.org/10.5194/cp-10-437-2014 Institutional Repository DORA

Projects

INSIghtForest: IN SItu tracking of water fluxes in Forest ecosystems through novel high-resolution monitoring of stable water isotopes

INSIghtForest will accompany the Cost Action WATSON "WATer isotopeS in the critical zONeproposes" by establishing a unique data set of high frequency in-situ measured water isotopes located in a long-term irrigation experiment Pfynwald in the naturally dry valley of Valais, Switzerland.

VPDrought

The VPDrought Experiment aims to disentangle the effects of air and soil drought on forests. This is the first time worldwide that such an experiment is being conducted in this combination and quality. It is being carried out in the Pfynwald forest on an existing WSL research site.

High-resolution stable isotope analysis of tree rings

Tree-ring d13C variations are a valuable archive of climatic information. A novel laser-ablation isotope-ratio mass-spectrometer enables to study variations within a single tree ring. We therefore plan to determine the occurrence of dry and wet periods of the past with unprecedented resolution.

Detecting temperature thresholds for photosynthesis and understanding how they are controlled by long-term acclimation to soil drought

We evaluate the potential of thermal imaging with unmanned aerial vehicles (UAV) to detect drought stress in Pinus sylvestris in a long-term irrigation experiment in the Pfyn forest in Valais (southern Switzerland).

TreeNet - The biological drought and growth indicator network - Phase 4

TreeNet ist ein internationales Beobachtungs- und Forschungsnetzwerk, in dem Punktdendrometer automatisch die täglichen Stammradiusschwankungen von Bäumen erfassen. Der kontinuierliche Fluss von Daten liefert Echtzeitinformationen über die Wasserverhältnisse im Baum und das radial Stammwachstum

Keeping an eye on drought stress

In this project, we investigate the potential of spectral proxies, obtained from unmanned aerial vehicles (UAV) high-resolution multispectral and thermal imaging, to detect trees pre-visual drought stress responses.

DRYSOM: Soil organic matter dynamics under drought

DRYSOM assesses soil organic matter (SOM) to drought in a long-term irrigation experiment (Pfynwald). Responses range from a suppressed processing through microbial and faunal communities, decreases in carbon inputs from trees into soils, to shifts in soil carbon storage.

Isodrought

We want to explore a stable isotope tree-ring approach for analyzing physiological drought responses of trees. The results are expected to provide a novel diagnostic tool for understanding causes of tree decline.

Understory removal experiment Salgesch

Long-term research on the interactions between changes in land use and climate and their consequences regarding forest health and dynamic in the pine forests at low elevation of Central Alps

Multimedia

Kaisa Rissanen's video shows a day in life of a forest scientist: studying the effects of drought and irrigation on Scots pine resin dynamics and the emissions of volatile organic compounds (VOCs) from the pine stems.
In a new study, researchers from the Swiss Federal Institute for Forest, Snow and Landscape Research WSL show how tree stress can be detected before it becomes visible to the eye, extracting information from spectral data collected using drones.

More info at https://www.wsl.ch/drone-pfynwald-EN

VPD (Vapor Pressure Deficit) is one of the main forces governing plant transpiration. Prof. Charlotte Grossiord and her team try to disentangling the effects of VPD from those of other factors such as heat and drought.
As a tree physiologist at WSL, Leonie Schönbeck researches how trees take up and store energy, and how they use their reserves to recover from drought.

In the media

Dans le bois de Finges, des chercheurs étudient les effets de la sècheresse sur les arbres au moyen de brumisateurs géants

Reportage du 19h30 (RTS La Première) le 28 août 2024

Un brouillard artificiel pour tester l'impact du changement climatique sur les forêts

Dossier de la RTS La Première du 29 août 2024, reportage de La Matinale (2') et sujet de CQFD (14'49")

New study in the Pfyn Forest shows: Drought inhibits carbon storage by earthworms.

Earthworms in drought sleep: Due to climate change, dry periods are getting longer and longer, which is putting a strain on soil organisms. A long-term study in the Pfynwald forest shows just how much. (Kanal 9, 9.06.2022).

Michèle Ursprung

Researchers: Dry forest soils can store less CO2 in the long term

[Translate to Englisch:] Trockene Waldböden können langfristig weniger CO2 speichern

Dry forest soils have a negative effect on climate change because earthworms in particular can no longer contribute well to fixing carbon in the soils, explains material cycle expert Frank Hagedorn in Dlf. Earthworms decompose less leaf litter during drought. In the long term, less carbon and thus also climate-impacting CO2 would be stored in the soil.

Krauter, Ralf, Deutschlandfunk | 01. 06. 2022, 16:47

Mysterious network: How trees are connected in the forest

A report by [w] wie Wissen about the 'Wood Wide Web' in the Pfynwald, with Martina Peter and members of her team (Das Erste, 26.09.2020).

 

Ecoacoustics: The soundtrack of climate change. SRF Einstein

What does it sound like in the ground? What does the forest sound like in a dry summer? Eco-acousticians like the Swiss sound researcher Marcus Maeder describe nature in a completely new way with the help of sound recordings. Sound becomes an indicator of an ecosystem. "Einstein" shows what opportunities ecoacoustics opens up.

 

Pine dieback in Valais - researchers wrap the trees in plastic.

The pine forests in the Valais are threatened. In some regions, up to 40 percent of the trees have died during the last two years. This is because it has been particularly hot and dry. This reduces the protection that the affected forests offer against rockfall and avalanches.

 

Metadata and Maps

Metadata

  • Are you starting a new study or updating an ongoing 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_vrs49.xlsx

 

Map

Terms of Use and Safety Concept

Collaboration on the Pfynwald research platform is highly welcome! For your safety and for the integrity of the forest site, we kindly ask the collaborators to take note of the following Terms of Use and the Safety Concept.

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