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Buntgen U.,Swiss Federal Institute of forest | Buntgen U.,Oeschger Center for Climate Change Research | Buntgen U.,Academy of Sciences of the Czech Republic | Egli S.,Swiss Federal Institute of forest | And 10 more authors.
Agriculture, Ecosystems and Environment | Year: 2015

The Périgord black truffle is an exclusive culinary delicacy, but its Mediterranean harvests have declined, despite cultivation efforts since the 1970s. The role of long-term irrigation, symbiotic fungus-host interaction, and microbial belowground progression remain poorly understood, because generally too short experimental settings miss the necessary degree of real world complexity and reliable information from truffle orchards is limited. Here, we conduct the first dendrochronological and wood anatomical assessment of 295 holm oaks, which have been growing under different irrigation intensities in the world's largest truffle orchard in Spain. The relationships between different climatic variables (monthly temperature means and precipitation totals) and dendro-parameters (ring width, vessel count and vessel size) of the oak hosts are utilized to disentangle direct and indirect drivers of truffle fruit body production. Irrigation at medium - instead of high - intensity is most beneficial for oak growth. Non-irrigated trees reveal overall lower stem increments. Warmer temperatures from February to April and wetter conditions from May to July enhance host vitality and possibly also its interplay with fungi symbionts via increased fine root production and mycorrhizal colonization. Adequately irrigated Mediterranean orchards may counteract some of the drought-induced natural truffle decline, and help stabilizing rural tourism, regional agriculture and global markets. © 2014 Elsevier B.V.

Buntgen U.,Swiss Federal Institute of forest | Buntgen U.,Oeschger Center for Climate Change Research | Buntgen U.,Academy of Sciences of the Czech Republic | Egli S.,Swiss Federal Institute of forest | And 6 more authors.
Fungal Ecology | Year: 2015

Mushrooms are amongst the most important of non-timber forest products, with growing economic value in many rural areas of the Mediterranean region. At the same time, the effects of climate variability on fungal ecology and productivity are insufficiently understood, because the belowground life cycle of fungi is mediated in many different ways and observational field surveys at the community level are generally too short. Here, we assess records of 48, 348 mycorrhizal and saprotrophic fungal fruit bodies that were recorded at weekly intervals between 1995 and 2013 in Pinar Grande, the largest Spanish Scots pine forest. Autumnal fruiting was delayed by one week after 2004 compared with the period before, the mean annual number of sporocarps dropped from 2880 to 2045, and mean species richness declined from 55 to 51. Trends in the phenology and productivity of Boletus edulis and Lactarius spp., the most profitable edible species, were associated with decreasing Jul.-Sep. precipitation totals, whereas the mean fruit body weight of B. edulis significantly increased from 71 to 123 g (pre and post 2004). In tandem with declining Spanish tree growth and truffle harvest since the 1970s, this study reveals a strong dependency of drought-prone Iberian forest ecosystem productivity on hydroclimatic variability. In light of a predicted drier Mediterranean climate, our results further emphasize the importance of long and well-replicated field inventories at high spatiotemporal resolution for informing forest service and management strategies, as well as gastronomy and tourist industries. © 2015 Elsevier Ltd and The British Mycological Society.

Alonso Ponce R.,Research Center Forestal Of Valonsadero Consejeria Of Fomento dio Ambiente | Agreda T.,Research Center Forestal Of Valonsadero Consejeria Of Fomento dio Ambiente | Agueda B.,Research Center Forestal Of Valonsadero Consejeria Of Fomento dio Ambiente | Aldea J.,Research Center Forestal Of Valonsadero Consejeria Of Fomento dio Ambiente | And 3 more authors.
Mycorrhiza | Year: 2014

Although the important effects of pH and carbonate content of soils on "black truffle" (Tuber melanosporum) production are well known, we poorly understand the influence of soil physical properties. This study focuses on physical soil characteristics that drive successful production of black truffles in plantations. Seventy-eight Quercus ilex ssp. ballota plantations older than 10 years were studied in the province of Teruel (eastern Spain). Soil samples were analyzed for various edaphic characteristics and to locate T. melanosporum ectomycorrhizae. The influence of cultivation practices, climatic features, and soil properties on sporocarp production was assessed using multivariate analyses. Low contents of fine earth and silt and high levels of bulk density, clay content, and water-holding capacity appear to promote fructification. Watering is also highly positive for truffle fructification. We develop and discuss a logistic model to predict the probability of truffle fructification in field sites under consideration for truffle plantation establishment. The balance between water availability and aeration plays a crucial role in achieving success in black truffle plantations. © 2014 Springer-Verlag Berlin Heidelberg.

Buntgen U.,Swiss Federal Institute of forest | Buntgen U.,University of Bern | Buntgen U.,Academy of Sciences of the Czech Republic | Martinez-Pena F.,Research Unit of Forestry Mycology and Trufficulture | And 9 more authors.
Global and Planetary Change | Year: 2013

Growing evidence suggests environmental change to be most severe across the semi-arid subtropics, with past, present and projected drying of the Mediterranean Basin posing a key multidisciplinary challenge. Consideration of a single climatic factor, however, often fails to explain spatiotemporal growth dynamics of drought-prone ecosystems. Here, we present annually resolved and absolutely dated ring width measurements of 871 Scots pines (Pinus sylvestris) from 18 individual plot sites in the Central Spanish Pinar Grande forest reserve. Although comprising tree ages from 6 to 175years, this network correlates surprisingly well with the inverse May-July diurnal temperature range (r=0.84; p<0.00011956-2011). Ring width extremes were triggered by pressure anomalies of the North Atlantic Oscillation, and the long-term growth decline coincided with Iberian-wide drying since the mid-1970s. Climate model simulations not only confirm this negative trend over the last decades but also project drought to continuously increase over the 21st century. Associated ecological effects and socio-economic consequences should be considered to improve adaptation strategies of agricultural and forest management, as well as biodiversity conservation and ecosystem service. © 2013 Elsevier B.V.

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