Responses of alpine tree line ecosystems to increasing atmospheric CO2 concentrations and global warming are poorly understood. We used an experiment at the Swiss tree line to investigate changes in vegetation biomass after 9\uffc2\uffa0years of free air CO2 enrichment (+200\uffc2\uffa0ppm; 2001\uffe2\uff80\uff932009) and 6\uffc2\uffa0years of soil warming (+4\uffc2\uffa0\uffc2\uffb0C; 2007\uffe2\uff80\uff932012). The study contained two key tree line species, Larix decidua and Pinus uncinata, both approximately 40\uffc2\uffa0years old, growing in heath vegetation dominated by dwarf shrubs. In 2012, we harvested and measured biomass of all trees (including root systems), above\uffe2\uff80\uff90ground understorey vegetation and fine roots. Overall, soil warming had clearer effects on plant biomass than CO2 enrichment, and there were no interactive effects between treatments. Total plant biomass increased in warmed plots containing Pinus but not in those with Larix. This response was driven by changes in tree mass (+50%), which contributed an average of 84% (5.7\uffc2\uffa0kg\uffc2\uffa0m\uffe2\uff88\uff922) of total plant mass. Pinus coarse root mass was especially enhanced by warming (+100%), yielding an increased root mass fraction. Elevated CO2 led to an increased relative growth rate of Larix stem basal area but no change in the final biomass of either tree species. Total understorey above\uffe2\uff80\uff90ground mass was not altered by soil warming or elevated CO2. However, Vaccinium myrtillus mass increased with both treatments, graminoid mass declined with warming, and forb and nonvascular plant (moss and lichen) mass decreased with both treatments. Fine roots showed a substantial reduction under soil warming (\uffe2\uff88\uff9240% for all roots <2\uffc2\uffa0mm in diameter at 0\uffe2\uff80\uff9320\uffc2\uffa0cm soil depth) but no change with CO2 enrichment. Our findings suggest that enhanced overall productivity and shifts in biomass allocation will occur at the tree line, particularly with global warming. However, individual species and functional groups will respond differently to these environmental changes, with consequences for ecosystem structure and functioning.
", "keywords": ["0106 biological sciences", "2. Zero hunger", "Models", " Statistical", "Temperature", "Larix", "Carbon Dioxide", "15. Life on land", "Pinus", "Global Warming", "01 natural sciences", "Soil", "Species Specificity", "13. Climate action", "Biomass", "Tundra", "Switzerland"]}, "links": [{"href": "https://doi.org/10.1111/gcb.12819"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/gcb.12819", "name": "item", "description": "10.1111/gcb.12819", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/gcb.12819"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2015-01-30T00:00:00Z"}}, {"id": "10.1007/s11104-017-3235-8", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-28T16:15:25Z", "type": "Journal Article", "created": "2017-03-29", "title": "Responses Of Soil Extracellular Enzyme Activities To Experimental Warming And Co2 Enrichment At The Alpine Treeline", "description": "Climate warming and elevated CO2 can modify nutrient cycling mediated by enzymes in soils, especially in cold-limited ecosystems with a low availability of nutrients and a high temperature sensitivity of decomposition and mineralization. We estimated responses of soil extracellular enzyme activities (EEAs) to 6\u00a0years of soil warming and 9\u00a0years of CO2 enrichment at an Alpine treeline site. EEAs were measured in the litter (L), fermentation (F) and humified (H) horizons under Larix decidua and Pinus uncinata trees. Soil warming indirectly affected EEAs through altered soil moisture, fine root biomass, and C:N ratio of the organic horizons. Warming increased \u03b2-glucosidase and \u03b2-xylosidase activities in the F horizon but led to reduced laccase activity in the L horizon, probably caused by drying of the litter horizon associated with the treatment. In the H horizon, previous CO2 enrichment altered the activity of leucine amino peptidase, N-acetylglucosaminidase, and phosphatase. No interactive effects between warming and CO2 enrichment were detected. Warming affected the temperature sensitivity of \u03b2-xylosidase but not of the other enzymes. Altered EEAs after six years of soil warming indicate a sustained stimulation of carbon, nitrogen and nutrient cycling under climatic warming at the alpine treeline.", "keywords": ["0106 biological sciences", "High Temperature", "Nutrient Cycling", "Climate Change", "Larix Decidua", "Fine Root", "04 agricultural and veterinary sciences", "Alpine Environment", "Carbon Dioxide", "15. Life on land", "01 natural sciences", "Treeline", "Enzyme Activity", "10122 Institute of Geography", "Coniferous Tree", "Pinus Uncinata", "13. Climate action", "Fermentation", "1110 Plant Science", "0401 agriculture", " forestry", " and fisheries", "Global Change", "Warming", "910 Geography & travel", "1111 Soil Science"]}, "links": [{"href": "https://doi.org/10.1007/s11104-017-3235-8"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20and%20Soil", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s11104-017-3235-8", "name": "item", "description": "10.1007/s11104-017-3235-8", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s11104-017-3235-8"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2017-03-29T00:00:00Z"}}, {"id": "10.1111/gcb.70247", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-28T16:18:41Z", "type": "Journal Article", "created": "2025-05-23", "title": "Carbon Emissions From Fires in Eastern Siberian Larch Forests", "description": "ABSTRACTSiberian boreal forests have experienced increases in fire extent and intensity in recent years, which may threaten their role as carbon (C) sinks. Larch forests (Larix spp.) cover approximately 2.6 million km2 across Siberia, yet little is known about the magnitude and drivers of carbon combustion in these ecosystems. To address the paucity of field\uffe2\uff80\uff90based estimates of fuel load and consumption in Siberian larch forests, we sampled 41 burned plots, one to two years after fire, in Cajander larch (Larix cajanderi) forests in the Republic of Sakha (Yakutia), Russia. We estimated pre\uffe2\uff80\uff90fire carbon stocks and combustion with the objective of identifying the main drivers of carbon emissions. Pre\uffe2\uff80\uff90fire aboveground (trees and woody debris) and belowground carbon stocks at our study plots were 3.12\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff891.26\uffe2\uff80\uff89kg C m\uffe2\uff88\uff922 (mean\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89standard deviation) and 3.50\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.93\uffe2\uff80\uff89kg C m\uffe2\uff88\uff922. We found that combustion averaged 3.20\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.75\uffe2\uff80\uff89kg C m\uffe2\uff88\uff922, of which 78% (2.49\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.56\uffe2\uff80\uff89kg C m\uffe2\uff88\uff922) stemmed from organic soil layers. These results suggest that severe fires in Cajander larch forests can result in combustion rates comparable to those observed in North American boreal forests and exceeding those previously reported for other forest types and burning conditions in Siberia. Carbon combustion was driven by both fire weather conditions and landscape variables, with pre\uffe2\uff80\uff90fire organic soil depth being the strongest predictor across our plots. Our study highlights the need to better account for Siberian larch forest fires and their impact on the carbon balance, especially given the expected climate\uffe2\uff80\uff90induced increase in fire extent and severity in this region.
The imbalance between nitrogen (N) and phosphorus (P) deposition may shift temperate ecosystems from N\uffe2\uff80\uff90 to P\uffe2\uff80\uff90limitation. However, it is unclear how the imbalanced N\uffc2\uffa0:\uffc2\uffa0P input affects the strategies of plants to acquire P and, therefore, the growth of plants and the competition among species.
We conducted a 4\uffe2\uff80\uff90yr N\uffe2\uff80\uff90addition experiment in young and mature larch (Larix principis\uffe2\uff80\uff90rupprechtii) stands. Plant growth and P acquisition strategies were assessed for larch and understorey vegetation.
N addition stimulated the aboveground productivity of understorey vegetation in the young stand and larch in the mature stand, with other species unaffected. The competitive advantages of understorey vegetation in the young stand and larch in the mature stand were associated with their high stoichiometric homoeostasis. To maintain the N\uffc2\uffa0:\uffc2\uffa0P homoeostasis of these species, an increase in phosphatase activity but not P resorption efficiency increased the supply of P. Additionally, N addition accelerated P mineralization by decreasing the fungal\uffe2\uff80\uff90to\uffe2\uff80\uff90bacterial ratios and improved uptake of soil P by increasing the arbuscular mycorrhizas\uffe2\uff80\uff90to\uffe2\uff80\uff90ectomycorrhizas ratios.
Our results suggest that plants with high stoichiometric homoeostasis could better cope with N deposition\uffe2\uff80\uff90induced P\uffe2\uff80\uff90deficiency. Although P resorption efficiency showed little plasticity in response, plants activated a variety of P\uffe2\uff80\uff90acquisition pathways to alleviate the P\uffe2\uff80\uff90deficiency caused by N deposition.
", "keywords": ["2. Zero hunger", "Analysis of Variance", "Bacteria", "Nitrogen", "Acid Phosphatase", "Fatty Acids", "Fungi", "Larix", "Phosphorus", "04 agricultural and veterinary sciences", "15. Life on land", "Plant Roots", "Phosphates", "Plant Leaves", "Species Specificity", "Mycorrhizae", "Homeostasis", "0401 agriculture", " forestry", " and fisheries", "Biomass", "Phospholipids"]}, "links": [{"href": "https://doi.org/10.1111/nph.14083"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/New%20Phytologist", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/nph.14083", "name": "item", "description": "10.1111/nph.14083", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/nph.14083"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2016-07-11T00:00:00Z"}}, {"id": "10.1371/journal.pone.0153415", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-28T16:19:23Z", "type": "Journal Article", "created": "2016-04-12", "title": "Seasonality, Rather Than Nutrient Addition Or Vegetation Types, Influenced Short-Term Temperature Sensitivity Of Soil Organic Carbon Decomposition", "description": "Open AccessLa r\u00e9ponse de la respiration microbienne de la d\u00e9composition du carbone organique du sol (COS) aux changements environnementaux joue un r\u00f4le cl\u00e9 dans la pr\u00e9diction des tendances futures de la concentration de CO2 atmosph\u00e9rique. Cependant, il n'est pas certain qu'il existe une tendance universelle dans la r\u00e9ponse de la respiration microbienne \u00e0 l'augmentation de la temp\u00e9rature et \u00e0 l'ajout de nutriments parmi les diff\u00e9rents types de v\u00e9g\u00e9tation. Dans cette \u00e9tude, les sols ont \u00e9t\u00e9 \u00e9chantillonn\u00e9s au printemps, en \u00e9t\u00e9, en automne et en hiver \u00e0 partir de cinq types de v\u00e9g\u00e9tation dominants, y compris les for\u00eats de pins, de m\u00e9l\u00e8zes et de bouleaux, les arbustes et les prairies, dans la r\u00e9gion de Saihanba, dans le nord de la Chine. Les \u00e9chantillons de sol de chaque saison ont \u00e9t\u00e9 incub\u00e9s \u00e0 1, 10 et 20 \u00b0C pendant 5 \u00e0 7 jours. L'azote (N\u00a0; 0,035 mM sous forme de NH4NO3) et le phosphore (P\u00a0; 0,03 mM sous forme de P2O5) ont \u00e9t\u00e9 ajout\u00e9s aux \u00e9chantillons de sol, et les r\u00e9ponses de la respiration microbienne du sol \u00e0 l'augmentation de la temp\u00e9rature et \u00e0 l'ajout de nutriments ont \u00e9t\u00e9 d\u00e9termin\u00e9es. Nous avons constat\u00e9 une tendance universelle selon laquelle la respiration microbienne du sol augmentait avec l'augmentation de la temp\u00e9rature, ind\u00e9pendamment de la saison d'\u00e9chantillonnage ou du type de v\u00e9g\u00e9tation. La sensibilit\u00e9 \u00e0 la temp\u00e9rature (indiqu\u00e9e par Q10, l'augmentation du taux de respiration avec une augmentation de 10\u00b0C de la temp\u00e9rature) de la respiration microbienne \u00e9tait plus \u00e9lev\u00e9e au printemps et en automne qu'en \u00e9t\u00e9 et en hiver, quel que soit le type de v\u00e9g\u00e9tation. Le Q10 \u00e9tait significativement corr\u00e9l\u00e9 positivement avec la biomasse microbienne et le rapport champignon\u00a0: bact\u00e9rie. La respiration microbienne (ou Q10) n'a pas r\u00e9pondu de mani\u00e8re significative \u00e0 l'addition d'azote ou de phosphore. Nos r\u00e9sultats sugg\u00e8rent que l'apport en nutriments \u00e0 court terme pourrait ne pas modifier le taux de d\u00e9composition du COS ou sa sensibilit\u00e9 \u00e0 la temp\u00e9rature, alors que l'augmentation de la temp\u00e9rature pourrait am\u00e9liorer consid\u00e9rablement la d\u00e9composition du COS au printemps et en automne, par rapport \u00e0 l'hiver et \u00e0 l'\u00e9t\u00e9.", "keywords": ["Biomass (ecology)", "Atmospheric Science", "Microbial population biology", "Larix", "Carbon Dynamics in Peatland Ecosystems", "Forests", "Agricultural and Biological Sciences", "Soil", "Soil water", "Pathology", "Carbon Feedback", "Biomass", "Betula", "Soil Microbiology", "2. Zero hunger", "Ecology", "Q10", "Respiration", "Q", "R", "Temperature", "Life Sciences", "Soil respiration", "04 agricultural and veterinary sciences", "Soil carbon", "Grassland", "Earth and Planetary Sciences", "Physical Sciences", "Respiration rate", "Medicine", "Seasons", "Vegetation (pathology)", "Research Article", "China", "Nitrogen", "Science", "Soil Science", "Environmental science", "Shrubland", "Genetics", "Arctic Permafrost Dynamics and Climate Change", "Soil Carbon Sequestration", "Biology", "Ecosystem", "Soil science", "Soil organic matter", "Soil Fertility", "Bacteria", "Fungi", "Botany", "15. Life on land", "Pinus", "Vegetation Change", "Carbon", "Agronomy", "13. Climate action", "FOS: Biological sciences", "Environmental Science", "Growing season", "0401 agriculture", " forestry", " and fisheries", "Soil Carbon Dynamics and Nutrient Cycling in Ecosystems", "Nutrient"], "contacts": [{"organization": "Yu-Qi Qian, Fangliang He, Wei Wang,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1371/journal.pone.0153415"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/PLOS%20ONE", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1371/journal.pone.0153415", "name": "item", "description": "10.1371/journal.pone.0153415", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1371/journal.pone.0153415"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2016-04-12T00:00:00Z"}}, {"id": "1871.1/99fbf6ac-45d6-419d-b11b-fc8a31b9e59f", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-28T16:24:17Z", "type": "Journal Article", "created": "2025-05-23", "title": "Carbon Emissions From Fires in Eastern Siberian Larch Forests", "description": "ABSTRACTSiberian boreal forests have experienced increases in fire extent and intensity in recent years, which may threaten their role as carbon (C) sinks. Larch forests (Larix spp.) cover approximately 2.6 million km2 across Siberia, yet little is known about the magnitude and drivers of carbon combustion in these ecosystems. To address the paucity of field\uffe2\uff80\uff90based estimates of fuel load and consumption in Siberian larch forests, we sampled 41 burned plots, one to two years after fire, in Cajander larch (Larix cajanderi) forests in the Republic of Sakha (Yakutia), Russia. We estimated pre\uffe2\uff80\uff90fire carbon stocks and combustion with the objective of identifying the main drivers of carbon emissions. Pre\uffe2\uff80\uff90fire aboveground (trees and woody debris) and belowground carbon stocks at our study plots were 3.12\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff891.26\uffe2\uff80\uff89kg C m\uffe2\uff88\uff922 (mean\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89standard deviation) and 3.50\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.93\uffe2\uff80\uff89kg C m\uffe2\uff88\uff922. We found that combustion averaged 3.20\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.75\uffe2\uff80\uff89kg C m\uffe2\uff88\uff922, of which 78% (2.49\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.56\uffe2\uff80\uff89kg C m\uffe2\uff88\uff922) stemmed from organic soil layers. These results suggest that severe fires in Cajander larch forests can result in combustion rates comparable to those observed in North American boreal forests and exceeding those previously reported for other forest types and burning conditions in Siberia. Carbon combustion was driven by both fire weather conditions and landscape variables, with pre\uffe2\uff80\uff90fire organic soil depth being the strongest predictor across our plots. Our study highlights the need to better account for Siberian larch forest fires and their impact on the carbon balance, especially given the expected climate\uffe2\uff80\uff90induced increase in fire extent and severity in this region.