text:
@article{llorens_multi-year_2010,
	title = {A multi-year study of rainfall and soil water controls on {Scots} pine transpiration under {Mediterranean} mountain conditions},
	volume = {24},
	abstract = {This study is focused on the analysis of the relationship between sap-flow-derived transpiration measured in a Scots pine stand in the Vallcebre research catchments (NE Iberian Peninsula) and meteorological and rainfall data. The first part of the study is focused on the analysis of temperature and rainfall anomalies. Then, the Scots pine transpiration response to inter-annual rainfall variability, soil water stress and water table depth variations during the period 1997-2000 is analysed. This period includes the extremely dry year of 1998, which allows us to infer the response of Scots pine transpiration to severe droughts. Scots pine transpiration during the summer presented a high inter-annual variability, largely related to rainfall amounts. Daily transpiration during dry summers was 40\% of the transpiration of a summer day with average rainfall. Moreover, during dry summers, transpiration rates were not fully recovered even after significant rainfall events. The analysis of the dependence of Scots pine transpiration on available water indicated the strong limitation on transpiration induced by water content in the whole soil profile as well as by water table position. Under these drought conditions, a reduction of runoff and deep water stores was observed at the catchment scale, suggesting that the predicted increase in the frequency of severe summer droughts may threaten the current role of Mediterranean mountain catchments as suppliers of water resources for lowland areas. © 2010 John Wiley \& Sons, Ltd.},
	number = {21},
	journal = {Hydrological Processes},
	author = {Llorens, P. and Poyatos, R. and Latron, J. and Delgado, J. and Oliveras, I. and Gallart, F.},
	year = {2010},
	keywords = {Water table depth, drought, Transpiration, Soil water content, Pinus sylvestris, Mediterranean area, water table depth},
	pages = {3053--3064},
	file = {Llorens et al_2010_A multi-year study of rainfall and soil water controls on Scots pine.pdf:C\:\\Documents and Settings\\r.poyatos\\ConfiguraciÃ³n local\\Temp\\7720_ftp.pdf:application/pdf;Llorens et al_2010_A multi-year study of rainfall and soil water controls on Scots pine.pdf:/media/rafap/Data/Documents/Zotero/storage/3VD5RPN3/Llorens et al_2010_A multi-year study of rainfall and soil water controls on Scots pine.pdf:application/pdf;Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/AINMWVMM/display.html:text/html}
}

@article{martinez-vilalta_hydraulic_2009,
	title = {Hydraulic adjustment of {Scots} pine across {Europe}},
	volume = {184},
	abstract = {Summary The variability of branch-level hydraulic properties was assessed across 12 Scots pine populations covering a wide range of environmental conditions, including some of the southernmost populations of the species. The aims were to relate this variability to differences in climate, and to study the potential tradeoffs between traits. Traits measured included wood density, radial growth, xylem anatomy, sapwood- and leaf-specific hydraulic conductivity (KS and KL), vulnerability to embolism, leaf-to-sapwood area ratio (AL : AS), needle carbon isotope discrimination (Δ13C) and nitrogen content, and specific leaf area. Between-population variability was high for most of the hydraulic traits studied, but it was directly associated with climate dryness (defined as a combination of atmospheric moisture demand and availability) only for A L : AS, KL and Δ13C. Shoot radial growth and AL : AS declined with stand development, which is consistent with a strategy to avoid exceedingly low water potentials as tree size increases. In addition, we did not find evidence at the intraspecific level of some associations between hydraulic traits that have been commonly reported across species. The adjustment of Scots pine's hydraulic system to local climatic conditions occurred primarily through modifications of AL : AS and direct stomatal control, whereas intraspecific variation in vulnerability to embolism and leaf physiology appears to be limited. © 2009 New Phytologist.},
	number = {2},
	journal = {New Phytologist},
	author = {Martínez-Vilalta, J. and Cochard, H. and Mencuccini, M. and Sterck, F. and Herrero, A. and Korhonen, J.F.J. and Llorens, P. and Nikinmaa, E. and Nolè, A. and Poyatos, R. and Ripullone, F. and Sass-Klaassen, U. and Zweifel, R.},
	year = {2009},
	keywords = {Embolism, Hydraulic conductivity, Intraspecific variation, Leaf-to-sapwood area ratio, drought, Water relations, Xylem anatomy, Pinus sylvestris},
	pages = {353--364},
	file = {Martínez-Vilalta et al_2009_Hydraulic adjustment of Scots pine across Europe.doc:/media/rafap/Data/Documents/Zotero/storage/NE5BPGFC/Martínez-Vilalta et al_2009_Hydraulic adjustment of Scots pine across Europe.doc:application/msword;Martínez-Vilalta et al_2009_Hydraulic adjustment of Scots pine across Europe.doc:/media/rafap/Data/Documents/Zotero/storage/6EUFKPZ6/Martínez-Vilalta et al_2009_Hydraulic adjustment of Scots pine across Europe.doc:application/msword;Martínez-Vilalta et al_2009_Hydraulic adjustment of Scots pine across Europe.pdf:/media/rafap/Data/Documents/Zotero/storage/VJP4N2DS/Martínez-Vilalta et al_2009_Hydraulic adjustment of Scots pine across Europe.pdf:application/pdf;Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/A79KEMBP/display.html:text/html}
}

@article{poyatos_response_2008,
	title = {Response of {Scots} pine (\textit{{Pinus} sylvestris} {L}.) and pubescent oak (\textit{{Quercus} pubescens} {Willd}.) to soil and atmospheric water deficits under {Mediterranean} mountain climate},
	volume = {65},
	abstract = {The physiological responses to water deficits of Scots pine (Pinus sylvestris L.) and pubescent oak (Quercus pubescens Willd.) were studied under Mediterranean mountain climate. Minimum leaf water potentials were -3.2 MPa for oak and -2.1 MPa for pine, with higher predawn values for pubescent oak. Relative sap flow declined in both species when vapour pressure deficit (D) went above ca. 1.2 kPa, but stomatal control was stronger for pine during the 2003 summer drought. P. sylvestris plant hydraulic conductance on a half-total leaf area basis (kL, s-1) was 1.2-2.6 times higher than the values shown by Q. pubescens, and it showed a considerably steeper decrease during summer. Leaf-level gas exchange was positively related to kL, s-1 in both species. Scots pine was more vulnerable to xylem embolism and closed stomata to prevent substantial conductivity losses. The results of this study confirm that pubescent oak is more resistant to extreme drought events. © 2008 INRA EDP Sciences.},
	number = {3},
	journal = {Annals of Forest Science},
	author = {Poyatos, R. and Llorens, P. and Piñol, J. and Rubio, C.},
	year = {2008},
	keywords = {Canopy stomatal conductance, drought, Sap flow, Mediterranean climate, hydraulic conductance},
	pages = {306},
	file = {Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/CFGKXS28/display.html:text/html}
}

@article{poyatos_modelling_2007,
	title = {Modelling evapotranspiration in a {Scots} pine stand under {Mediterranean} mountain climate using the {GLUE} methodology},
	volume = {146},
	abstract = {Canopy transpiration (Ec) and soil evaporation (Es) in a Mediterranean Scots pine stand were simulated using a two-layer model, with a Jarvis-type submodel of canopy stomatal conductance (Gs) and a soil resistance to evaporation expressed as a function of superficial soil moisture. Sap flow measurements and soil evaporation data, together with meteorological and soil moisture variables were used to calibrate the model. Gs was calibrated using the generalized likelihood uncertainty estimation (GLUE) methodology, first with data from the year 2004, a year characterised by mild meteorological conditions. Then, data from the year 2003, which included an intense summer drought, was used to update the results from the previous calibration. The discrepancy between the diurnal courses of modelled and measured Ec using best-fit parameters was not related to any particular situation of meteorology or soil moisture. Model performance improved at the daily scale, but the model failed to simulate Ec adequately during the year 2005. Maximum modelled Es rates were 0.7 mm day-1 with the ratio Es/Ec being typically under 0.3 during the growing season. The GLUE analysis revealed that parameters representing reference stomatal aperture at a vapour pressure deficit (D) value equal to 1 kPa (Gs,ref), and sensitivity to D (m) were the most relevant, and were consistent with the hydraulic theory of stomatal regulation. Parameters controlling the response to superficial soil moisture deficit only appeared sensitive in the calibration with data from the year 2003, suggesting that response to deeper soil layers should also be considered in the model. Updating the original calibration reduced predictive uncertainty and constrained the value of some parameters. Nevertheless, it seems that representations of variable plant and soil hydraulic resistances, are required to simulate long-term Ec in seasonally-dry Mediterranean forest stands. © 2007 Elsevier B.V. All rights reserved.},
	number = {1-2},
	journal = {Agricultural and Forest Meteorology},
	author = {Poyatos, R. and Villagarcía, L. and Domingo, F. and Piñol, J. and Llorens, P.},
	year = {2007},
	keywords = {Equifinality, Jarvis-type model, Stomatal conductance, Sap flow, Pinus sylvestris L.},
	pages = {13--28},
	file = {Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/DQ3WVVDR/display.html:text/html}
}

@article{poyatos_plasticity_2007,
	title = {Plasticity in hydraulic architecture of {Scots} pine across {Eurasia}},
	volume = {153},
	abstract = {Widespread tree species must show physiological and structural plasticity to deal with contrasting water balance conditions. To investigate these plasticity mechanisms, a meta-analysis of Pinus sylvestris L. sap flow and its response to environmental variables was conducted using datasets from across its whole geographical range. For each site, a Jarvis-type, multiplicative model was used to fit the relationship between sap flow and photosynthetically active radiation, vapour pressure deficit (D) and soil moisture deficit (SMD); and a logarithmic function was used to characterize the response of stomatal conductance (G s) to D. The fitted parameters of those models were regressed against climatic variables to study the acclimation of Scots pine to dry/warm conditions. The absolute value of sap flow and its sensitivity to D and SMD increased with the average summer evaporative demand. However, relative sensitivity of G s to D (m/G s,ref, where m is the slope and G s,ref is reference G s at D = 1 kPa) did not increase with evaporative demand across populations, and transpiration per unit leaf area at a given D increased accordingly in drier/warmer climates. This physiological plasticity was linked to the previously reported climate- and size-related structural acclimation of leaf to sapwood area ratios. G s,ref, and its absolute sensitivity to D (m), tended to decrease with age/height of the trees as previously reported for other pine species. It is unclear why Scots pines have higher transpiration rates at drier/warmer sites, at the expense of lower water-use efficiency. In any case, our results suggest that these structural adjustments may not be enough to prevent lower xylem tensions at the driest sites. © 2007 Springer-Verlag.},
	number = {2},
	journal = {Oecologia},
	author = {Poyatos, R. and Martínez-Vilalta, J. and Čermák, J. and Ceulemans, R. and Granier, A. and Irvine, J. and Köstner, B. and Lagergren, F. and Meiresonne, L. and Nadezhdina, N. and Zimmermann, R. and Llorens, P. and Mencuccini, M.},
	year = {2007},
	note = {00000},
	keywords = {Hydraulic plasticity, Leaf area:sapwood area, Stomatal conductance, Sap flow, Pinus sylvestris},
	pages = {245--259},
	file = {Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/V85CG9VH/display.html:text/html}
}

@article{poyatos_variation_2007,
	title = {Variation in the radial patterns of sap flux density in pubescent oak ({Quercus} pubescens) and its implications for tree and stand transpiration measurements},
	volume = {27},
	abstract = {Radial variation in sap flux density across the sapwood was assessed by the heat field deformation method in several trees of Quercus pubescens Wild., a ring-porous species. Sapwood depths were delimited by identifying the point of zero flow in radial patterns of sap flow, yielding tree sapwood areas that were 1.5-2 times larger than assumed based on visual examinations of wood cores. The patterns of sap flow varied both among trees and diurnally. Rates of sap flow were higher close to the cambium, although there was a significant contribution from the inner sapwood, which was greater (up to 60\% of total flow) during the early morning and late in the day. Accordingly, the normalized difference between outer and inner sapwood flow was stable during the middle of the day, but showed a general decline in the afternoon. The distribution of sap flux density across the sapwood allowed us to derive correction coefficients for single-point heat dissipation sap flow measurements. We used daytime-averaged coefficients that depended on the particular shape of the radial profile and ranged between 0.45 and 1.28. Stand transpiration calculated using the new method of estimating sapwood areas and the radial correction coefficients was similar to (Year 2003), or about 25\% higher than (Year 2004), previous uncorrected values, and was 20-30\% of reference evapotranspiration. We demonstrated how inaccuracies in determining sapwood depths and mean sap flux density across the sapwood of ring-porous species could affect tree and stand transpiration estimates. © 2007 Heron Publishing.},
	number = {4},
	journal = {Tree Physiology},
	author = {Poyatos, R. and Čermák, J. and Llorens, P.},
	year = {2007},
	keywords = {Diurnal variability, Radial patterns, Ring-porous species, Transpiration, Scaling},
	pages = {537--548},
	file = {Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/55A44ABX/display.html:text/html}
}

@article{poyatos_transpiration_2005,
	title = {Transpiration of montane {Pinus} sylvestris {L}. and {Quercus} pubescens {Willd}. forest stands measured with sap flow sensors in {NE} {Spain}},
	volume = {9},
	abstract = {Stand transpiration was measured during the 2003 and 2004 growing seasons using heat dissipation sap flow sensors in a Scots pine (Pinus sylvestris L.) and a pubescent oak (Quercus pubescens Willd.) forests located in a montane area of the Eastern Pyrenees (NE Spain). The first aim of the study was to assess the differences in quantitative estimates of transpiration (Ec) and the response to evaporative demand of the two stands. Over the studied period of 2003, characterised by a severe drought episode during the summer, the oak stand E2 was only 110 turn compared to the 239 mm transpired by the Scots pine stand, although the ratio of transpiration to reference evapotranspiration (Ec/ET0) in the oak stand compares well with the expected values predicted for low leaf area index (LAI) oak forests in southern Europe. Scots pine showed a strong reduction in Ec/ET0) as the drought developed, whereas pubescent oak was less affected by soil moisture deficits in the upper soil. As a second objective, and given the contrasting meteorological conditions between 2003 and 2004 summer periods, the interannual variability of transpiration was studied in the Scots pine plot. Rainfall during the summer months (June-September) in 2003 was almost 40\% less than in the same interval in 2004. Accordingly, transpiration was also reduced about 25\% in 2003. Finally, Scots pine data from 2003 and 2004 was used to calibrate a simple transpiration model using ET0 and soil moisture deficit (SMD) as input variables, and implicitly including stomatal responses to high vapour pressure deficits (Dd) and soil water status. © 2005 Author(s). This work is licensed under a Creative Commons License.},
	number = {5},
	journal = {Hydrology and Earth System Sciences},
	author = {Poyatos, R. and Llorens, P. and Gallart, F.},
	year = {2005},
	pages = {493--505},
	file = {Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/NSGSQXU8/display.html:text/html}
}

@article{poyatos_land_2003,
	title = {Land use and land cover change after agricultural abandonment: {The} case of a {Mediterranean} {Mountain} area ({Catalan} {Pre}-{Pyrenees})},
	volume = {23},
	shorttitle = {Land use and land cover change after agricultural abandonment},
	abstract = {Land cover mapping obtained from photointerpretation of aerial photographs and orthophotographs was used to quantify land cover changes between 1957 and 1996 in a Mediterranean middle mountain area. Expansion of forested area is clearly the main land cover change caused by the abandonment of traditional agricultural activities and by the use of other materials and energy sources instead of forest resources. As a result, about 64\% of the area was covered by forest by 1996, whereas in 1957 forests accounted for only 40\% of the land cover. Spontaneous afforestation of abandoned fields with Scots pine (Pinus sylvestris L.) in terraced areas and areas of sparse scrub vegetation, coupled with an increase in the density of forest canopies, has been responsible for this expansion of woodland. The influence of physiographic factors in land cover change processes in the terraced areas of the catchment was also considered. The results demonstrate that within the terraced areas, north-facing and more elevated steeper slopes are more intensely afforested. However, an accurate analysis of the role played by these factors in land cover change cannot be carried out because the pattern of land abandonment is not independent of these physiographic characteristics. Furthermore, field observations at the terrace scale are evidence of the relevant influence of local topography in afforestation dynamics.},
	number = {4},
	journal = {Mountain Research and Development},
	author = {Poyatos, R. and Latron, J. and Llorens, P.},
	year = {2003},
	keywords = {Mediterranean mountains, Afforestation, Land use-land cover change, Photointerpretation, Terraces, GIS},
	pages = {362--368},
	file = {Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/TNRKVIJR/display.html:text/html}
}

@article{fletcher_photosynthesis_2012,
	title = {Photosynthesis and productivity in heterogeneous arctic tundra: consequences for ecosystem function of mixing vegetation types at stand edges},
	volume = {100},
	issn = {1365-2745},
	shorttitle = {Photosynthesis and productivity in heterogeneous arctic tundra},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2745.2011.01913.x/abstract},
	doi = {10.1111/j.1365-2745.2011.01913.x},
	abstract = {1. Arctic vegetation tends to be spatially heterogeneous and can have large areas of mixed ‘transition zone’ vegetation between stands dominated by a single or few species. If plant photosynthesis and growth within these transition zones differs significantly from main vegetation stands, and if transition zones are not considered when extrapolating stand-level findings to larger scales in space, then transition zones will provide considerable error to landscape-level estimates of gross primary productivity (GPP).},
	language = {en},
	number = {2},
	journal = {Journal of Ecology},
	author = {Fletcher, Benjamin J and Gornall, Jemma L and Poyatos, Rafael and Press, Malcolm C and Stoy, Paul C and Huntley, Brian and Baxter, Robert and Phoenix, Gareth K},
	year = {2012},
	keywords = {growth, Growth, biodiversity, carbon balance, competition, ecophysiology, facilitation, GPP, realised niche, transition zones, upscaling},
	pages = {441--451},
	file = {Fletcher et al__Photosynthesis and productivity in heterogeneous arctic tundra.doc:C\:\\Documents and Settings\\r.poyatos\\ConfiguraciÃ³n local\\Temp\\JEC_1913_sm_TableS1-AppendixS1-S2-FigS1-S3.doc:application/msword;Fletcher et al__Photosynthesis and productivity in heterogeneous arctic tundra.doc:/media/rafap/Data/Documents/Zotero/storage/KGV3PHAF/JEC_1913_sm_TableS1-AppendixS1-S2-FigS1-S3.doc:application/msword;Fletcher et al_2012_Photosynthesis and productivity in heterogeneous arctic tundra.pdf:/media/rafap/Data/Documents/Zotero/storage/PXHUIK86/Fletcher et al_2012_Photosynthesis and productivity in heterogeneous arctic tundra.pdf:application/pdf}
}

@article{poyatos_environmental_2014,
	title = {Environmental and {Vegetation} {Drivers} of {Seasonal} {CO}2 {Fluxes} in a {Sub}-arctic {Forest}–{Mire} {Ecotone}},
	volume = {17},
	issn = {1432-9840, 1435-0629},
	url = {http://link.springer.com/article/10.1007/s10021-013-9728-2},
	doi = {10.1007/s10021-013-9728-2},
	abstract = {Unravelling the role of structural and environmental drivers of gross primary productivity (GPP) and ecosystem respiration (R eco) in highly heterogeneous tundra is a major challenge for the upscaling of chamber-based CO2 fluxes in Arctic landscapes. In a mountain birch woodland-mire ecotone, we investigated the role of LAI (and NDVI), environmental factors (microclimate, soil moisture), and microsite type across tundra shrub plots (wet hummocks, dry hummocks, dry hollows) and lichen hummocks, in controlling net ecosystem CO2 exchange (NEE). During a growing season, we measured NEE fluxes continuously, with closed dynamic chambers, and performed multiple fits (one for each 3-day period) of a simple light and temperature response model to hourly NEE data. Tundra shrub plots were largely CO2 sinks, as opposed to lichen plots, although fluxes were highly variable within microsite type. For tundra shrub plots, microsite type did not influence photosynthetic parameters but it affected basal (that is, temperature-normalized) ecosystem respiration (R 0). PAR-normalized photosynthesis (P 600) increased with air temperature and declined with increasing vapor pressure deficit. R 0 declined with soil moisture and showed an apparent increase with temperature, which may underlie a tight link between GPP and R eco. NDVI was a good proxy for LAI, maximum P 600 and maximum R 0 of shrub plots. Cumulative CO2 fluxes were strongly correlated with LAI (NDVI) but we observed a comparatively low GPP/LAI in dry hummocks. Our results broadly agree with the reported functional convergence across tundra vegetation, but here we show that the role of decreased productivity in transition zones and the influence of temperature and water balance on seasonal CO2 fluxes in sub-Arctic forest–mire ecotones cannot be overlooked.},
	language = {en},
	number = {3},
	urldate = {2014-07-03},
	journal = {Ecosystems},
	author = {Poyatos, Rafael and Heinemeyer, Andreas and Ineson, Phil and Evans, Jonathan G. and Ward, Helen C. and Huntley, Brian and Baxter, Robert},
	month = apr,
	year = {2014},
	keywords = {soil moisture, leaf area index, NDVI, tundra, Ecosystem respiration, carbon balance, transition zones, Ecology, gross primary productivity, Plant Sciences, Zoology, Environmental Management, Geoecology/Natural Processes, net ecosystem exchange, Hydrology/Water Resources, lichen},
	pages = {377--393},
	file = {Poyatos et al_2014_Environmental and Vegetation Drivers of Seasonal CO2 Fluxes in a Sub-arctic.pdf:/media/rafap/Data/Documents/Zotero/storage/JSIJS4EN/Poyatos et al_2014_Environmental and Vegetation Drivers of Seasonal CO2 Fluxes in a Sub-arctic.pdf:application/pdf}
}

@article{poyatos_seasonal_2012,
	title = {Seasonal controls on net branch {CO}2 assimilation in sub-{Arctic} {Mountain} {Birch} ({Betula} pubescens ssp. czerepanovii ({Orlova}) {Hamet}-{Ahti})},
	volume = {158–159},
	issn = {0168-1923},
	url = {http://www.sciencedirect.com/science/article/pii/S0168192312000743},
	doi = {10.1016/j.agrformet.2012.02.009},
	abstract = {Forests at northern high latitudes are experiencing climate-induced changes in growth and productivity, but our knowledge on the underlying mechanisms driving seasonal CO2 fluxes in northern boreal trees comes almost exclusively from ecosystem-level studies on evergreen conifers. In this study, we measured growing season whole-branch CO2 exchange in a deciduous tree species of the tundra-taiga ecotone, Mountain Birch (Betula pubescens ssp. czerepanovii (Orlova) Hamet-Ahti), at two locations in northern Fennoscandia: Abisko (Sweden) and Kevo (Finland). We identified strong seasonal and environmental controls on both photosynthesis and respiration by analysing the parameters of light response curves. Branch-level photosynthetic parameters showed a delayed response to temperature, and, at Kevo, they were well described by sigmoid functions of the state of acclimation (S). Temperature acclimation was slower (time constant, τ\&\#xa0;=\&\#xa0;7\&\#xa0;days) for maximum photosynthesis (βbr) than for quantum efficiency (αbr) (τ\&\#xa0;=\&\#xa0;5\&\#xa0;days). High temperature-independent values of the respiration parameter (γbr) during leaf and shoot expansion were consistent with associated higher growth respiration rates. The ratio γbr/βbr was positively related to temperature, a result consistent with substrate-induced variations in leaf respiration rates at the branch level. Differences in stand structure and within-site variation in the active period of C uptake determined the spatiotemporal patterns in net assimilation amongst branches. Growing season CO2 uptake of individual branches on a leaf area basis did not show a significant relationship with total incident photosynthetically active radiation, and did not differ across sites, averaging ca. 640\&\#xa0;g\&\#xa0;CO2\&\#xa0;m−2.},
	urldate = {2012-03-20},
	journal = {Agricultural and Forest Meteorology},
	author = {Poyatos, Rafael and Gornall, Jemma and Mencuccini, Maurizio and Huntley, Brian and Baxter, Robert},
	month = jun,
	year = {2012},
	keywords = {Arctic, light response curve, Branch bags, Phenology, Respiration, State of acclimation, photosynthesis},
	pages = {90--100},
	file = {Poyatos et al_2012_Seasonal controls on net branch CO2 assimilation in sub-Arctic Mountain Birch.pdf:/media/rafap/Data/Documents/Zotero/storage/9D4P5AKA/Poyatos et al_2012_Seasonal controls on net branch CO2 assimilation in sub-Arctic Mountain Birch.pdf:application/pdf}
}

@article{sus_time_2014,
	title = {Time variable hydraulic parameters improve the performance of a mechanistic stand transpiration model. {A} case study of {Mediterranean} {Scots} pine sap flow data assimilation},
	volume = {198–199},
	issn = {0168-1923},
	url = {http://www.sciencedirect.com/science/article/pii/S0168192314002007},
	doi = {10.1016/j.agrformet.2014.08.009},
	abstract = {Tree transpiration is regulated by short-term physiological adjustments and long-term shifts in hydraulic architecture in response to fluctuating evaporative demand and water supply. Despite the tight interdependence of plant water loss and carbon uptake and its crucial implications for plant growth and survival under drought conditions, the underlying mechanisms remain incompletely represented in most state-of-the-art mechanistic models. Important process information is resolved in tree transpiration (sap flow) data, which are the measurable outcome of water transport through the soil-plant-atmosphere continuum under variable environmental conditions. Here, we assimilated sap flow data measured in two Scots pine stands from climatically contrasting sites – one of which experiencing a strong drought during the study period – in NE Spain into a process-based ecophysiological model (SPA) using the Ensemble Kalman Filter (EnKF) in order to: (1) distinguish differences in hydraulic characteristics between sites and between healthy and defoliated individuals within a site; (2) identify possible structural model deficiencies, particularly regarding temporal changes in plant hydraulic conductance which the model assumes constant; and (3) derive implications for gross photosynthesis and carbon cycling. In terms of stomatal control, the assimilation of sap flow data into SPA showed a more conservative water use under dry conditions. Time-varying plant conductivity substantially improved model performance under severe drought, while seasonally varying capacitance and stomatal efficiency only resulted in marginal improvements. Not accounting for this seasonal variability would translate into a 30–60\% overestimation of modelled GPP during drought. Our results suggest that an explicit representation of mechanisms leading to temporal changes in hydraulic conductivity (i.e., xylem embolism) is required for models to reproduce tree functioning under extreme drought.},
	urldate = {2014-09-18},
	journal = {Agricultural and Forest Meteorology},
	author = {Sus, Oliver and Poyatos, Rafael and Barba, Josep and Carvalhais, Nuno and Llorens, Pilar and Williams, Mathew and Vilalta, Jordi Martínez},
	month = nov,
	year = {2014},
	keywords = {drought, Mediterranean, Sap flow, plant hydraulics, data assimilation, Ecosystem modelling},
	pages = {168--180},
	file = {Sus et al_2014_Time variable hydraulic parameters improve the performance of a mechanistic.pdf:/media/rafap/Data/Documents/Zotero/storage/FQHJPPI8/Sus et al_2014_Time variable hydraulic parameters improve the performance of a mechanistic.pdf:application/pdf}
}

@article{arnan_age_2012,
	title = {The age of monumental olive trees ({Olea} europaea) in northeastern {Spain}},
	volume = {30},
	issn = {1125-7865},
	url = {http://leizqsd.myipcn.org/science/article/pii/S1125786511000361},
	abstract = {Trees can reach ages that in some cases amount to thousands of years. In the Mediterranean region, olive trees (Olea europaea) have traditionally been considered a particularly long-lived species. The main objective of this study was to assess the age of large olive trees considered to be millenarian and classified as monumental trees in northeastern Spain. We extracted cores of 14 individuals and obtained 8 sections of trees which had already been cut in the area where the largest olive trees in the northeastern Iberian Peninsula are found. The age of the sampled olive trees was assessed by counting the number of annual growth rings. Tree rings did not cross-date well, neither within nor between individuals, but boundaries between likely annual rings were clearly distinct. We found a linear relationship between DBH and tree age (in years) (Age = 2.11 × diameter(cm) + 88.93, R2 = 0.80), which was used to estimate the age of unsampled olive trees. The maximum estimated age (627 ± 110 years) is among the greatest ages reported for olive trees around the world (700 years) and among the oldest trees in Mediterranean ecosystems.},
	number = {1},
	journal = {Dendrochronologia},
	author = {Arnan, X. and López, B. C. and Martínez-Vilalta, J. and Estorach, M. and Poyatos, R.},
	year = {2012},
	keywords = {Long-lived trees, Mediterranean, Tree age, Olive tree, Tree rings},
	pages = {11--14}
}

@article{moran-lopez_effects_2014,
	title = {Effects of past growth trends and current water use strategies on {Scots} pine and pubescent oak drought sensitivity},
	volume = {133},
	issn = {1612-4669, 1612-4677},
	url = {http://link.springer.com/article/10.1007/s10342-013-0768-0},
	doi = {10.1007/s10342-013-0768-0},
	abstract = {Drought-induced decline is affecting Pinus sylvestris populations in southern Europe, with very little impact on the more drought-tolerant Quercus pubescens. Although multiple studies have investigated interspecific differences in water use and growth strategies, the link between these two processes and how they vary within drought-exposed populations remains poorly understood. Here, we analysed tree ring and sap flow data from P. sylvestris and Q. pubescens stands in the Pyrenees in order to (1) evaluate differences in climate–growth responses among species, (2) disentangle the role of past growth trends and water use strategies in individual trees drought sensitivity and (3) assess whether such intraspecific patterns vary between species. Both species have suffered recent climatic constraints related to increased aridity. However, the effects of past growth trends and current water use traits on drought sensitivity varied among them. Initially, fast-growing ‘drought-sensitive’ pines displayed a higher gas exchange potential but were more sensitive to evaporative demand and soil moisture. They also showed lower water use efficiency for growth (WUEBAI) and current growth decline. In contrast, initially, slow-growing ‘drought-tolerant’ pines showed the opposite water use traits and currently maintain the highest growth rates. In comparison, neither current WUEBAI nor recent growth trends varied across Q. pubescens climate–growth groups. Nonetheless, ‘drought-sensitive’ oaks showed the lowest gas exchange potential and the highest growth rates under milder conditions. Our results show a strong effect of past growth trends and current water use strategies on tree resilience to increased aridity, which is more evident in P. sylvestris.},
	language = {en},
	number = {2},
	urldate = {2014-03-02},
	journal = {European Journal of Forest Research},
	author = {Morán-López, T. and Poyatos, R. and Llorens, P. and Sabaté, S.},
	month = mar,
	year = {2014},
	keywords = {Forestry, Sap flow, Pinus sylvestris, Quercus pubescens, Climate–growth relationships, Plant ecology, Plant Sciences, Drought-induced decline, Water use efficiency (WUE)},
	pages = {369--382}
}

@article{martinez-vilalta_new_2014,
	title = {A new look at water transport regulation in plants},
	volume = {204},
	copyright = {© 2014 The Authors. New Phytologist © 2014 New Phytologist Trust},
	issn = {1469-8137},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/nph.12912/abstract},
	doi = {10.1111/nph.12912},
	abstract = {* Plant function requires effective mechanisms to regulate water transport at a variety of scales. Here, we develop a new theoretical framework describing plant responses to drying soil, based on the relationship between midday and predawn leaf water potentials. The intercept of the relationship (Λ) characterizes the maximum transpiration rate per unit of hydraulic transport capacity, whereas the slope (σ) measures the relative sensitivity of the transpiration rate and plant hydraulic conductance to declining water availability.

* This framework was applied to a newly compiled global database of leaf water potentials to estimate the values of Λ and σ for 102 plant species.

* Our results show that our characterization of drought responses is largely consistent within species, and that the parameters Λ and σ show meaningful associations with climate across species. Parameter σ was ≤1 in most species, indicating a tight coordination between the gas and liquid phases of water transport, in which canopy transpiration tended to decline faster than hydraulic conductance during drought, thus reducing the pressure drop through the plant.

* The quantitative framework presented here offers a new way of characterizing water transport regulation in plants that can be used to assess their vulnerability to drought under current and future climatic conditions.},
	language = {en},
	number = {1},
	urldate = {2014-10-06},
	journal = {New Phytologist},
	author = {Martínez-Vilalta, Jordi and Poyatos, Rafael and Aguadé, David and Retana, Javier and Mencuccini, Maurizio},
	month = oct,
	year = {2014},
	keywords = {water transport, drought stress, leaf water potential, plant hydraulics, xylem embolism, water availability, stomatal responses, isohydric/anisohydric behaviour},
	pages = {105--115},
	file = {Martínez-Vilalta et al_2014_A new look at water transport regulation in plants.docx:/media/rafap/Data/Documents/Zotero/storage/Z8DUMAR4/Martínez-Vilalta et al_2014_A new look at water transport regulation in plants.docx:application/vnd.openxmlformats-officedocument.wordprocessingml.document;Martínez-Vilalta et al_2014_A new look at water transport regulation in plants.pdf:/media/rafap/Data/Documents/Zotero/storage/5PA97J8J/Martínez-Vilalta et al_2014_A new look at water transport regulation in plants.pdf:application/pdf}
}

@article{doblas-miranda_reassessing_2015,
	title = {Reassessing global change research priorities in mediterranean terrestrial ecosystems: how far have we come and where do we go from here?},
	volume = {24},
	copyright = {© 2014 John Wiley \& Sons Ltd},
	issn = {1466-8238},
	shorttitle = {Reassessing global change research priorities in mediterranean terrestrial ecosystems},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/geb.12224/abstract},
	doi = {10.1111/geb.12224},
	abstract = {Aim

Mediterranean terrestrial ecosystems serve as reference laboratories for the investigation of global change because of their transitional climate, the high spatiotemporal variability of their environmental conditions, a rich and unique biodiversity and a wide range of socio-economic conditions. As scientific development and environmental pressures increase, it is increasingly necessary to evaluate recent progress and to challenge research priorities in the face of global change.

Location

Mediterranean terrestrial ecosystems.

Methods

This article revisits the research priorities proposed in a 1998 assessment.

Results

A new set of research priorities is proposed: (1) to establish the role of the landscape mosaic on fire-spread; (2) to further research the combined effect of different drivers on pest expansion; (3) to address the interaction between drivers of global change and recent forest management practices; (4) to obtain more realistic information on the impacts of global change and ecosystem services; (5) to assess forest mortality events associated with climatic extremes; (6) to focus global change research on identifying and managing vulnerable areas; (7) to use the functional traits concept to study resilience after disturbance; (8) to study the relationship between genotypic and phenotypic diversity as a source of forest resilience; (9) to understand the balance between C storage and water resources; (10) to analyse the interplay between landscape-scale processes and biodiversity conservation; (11) to refine models by including interactions between drivers and socio-economic contexts; (12) to understand forest–atmosphere feedbacks; (13) to represent key mechanisms linking plant hydraulics with landscape hydrology.

Main conclusions

(1) The interactive nature of different global change drivers remains poorly understood. (2) There is a critical need for the rapid development of regional- and global-scale models that are more tightly connected with large-scale experiments, data networks and management practice. (3) More attention should be directed to drought-related forest decline and the current relevance of historical land use.},
	language = {en},
	number = {1},
	urldate = {2014-12-05},
	journal = {Global Ecology and Biogeography},
	author = {Doblas-Miranda, E. and Martínez-Vilalta, J. and Lloret, F. and Álvarez, A. and Ávila, A. and Bonet, F. J. and Brotons, L. and Castro, J. and Curiel Yuste, J. and Díaz, M. and Ferrandis, P. and García-Hurtado, E. and Iriondo, J. M. and Keenan, T. F. and Latron, J. and Llusià, J. and Loepfe, L. and Mayol, M. and Moré, G. and Moya, D. and Peñuelas, J. and Pons, X. and Poyatos, R. and Sardans, J. and Sus, O. and Vallejo, V. R. and Vayreda, J. and Retana, J.},
	year = {2015},
	keywords = {climate change, biodiversity, forest management, fire regime, land-use change, Assessment, atmosphere–biosphere interaction, factors interaction, research gaps, water reserves},
	pages = {25--43},
	file = {Doblas-Miranda et al_2015_Reassessing global change research priorities in mediterranean terrestrial.pdf:/media/rafap/Data/Documents/Zotero/storage/IDFSJW35/Doblas-Miranda et al_2015_Reassessing global change research priorities in mediterranean terrestrial.pdf:application/pdf}
}

@article{cristobal_combining_2011,
	title = {Combining remote sensing and {GIS} climate modelling to estimate daily forest evapotranspiration in a {Mediterranean} mountain area},
	volume = {15},
	issn = {1607-7938},
	url = {http://www.hydrol-earth-syst-sci.net/15/1563/2011/},
	doi = {10.5194/hess-15-1563-2011},
	abstract = {Evapotranspiration monitoring allows us to assess the environmental stress on forest and agricultural ecosystems. Nowadays, Remote Sensing and Geographical Information Systems (GIS) are the main techniques used for calculating evapotranspiration at catchment and regional scales. In this study we present a methodology, based on the energy balance equation (B-method), that combines remote sensing imagery with GIS-based climate modelling to estimate daily evapotranspiration (ETd) for several dates between 2003 and 2005. The three main variables needed to compute ETd were obtained as follows: (i) Land surface temperature by means of the Landsat-5 TM and Landsat-7 ETM+ thermal band, (ii) air temperature by means of multiple regression analysis and spatial interpolation from meteorological ground stations data at satellite pass, and (iii) net radiation by means of the radiative balance. We calculated ETd using remote sensing data at different spatial and temporal scales (Landsat-7 ETM+, Landsat-5 TM and TERRA/AQUA MODIS, with a spatial resolution of 60, 120 and 1000 m, respectively) and combining three different approaches to calculate the B parameter, which represents an average bulk conductance for the daily-integrated sensible heat flux. We then compared these estimates with sap flow measurements from a Scots pine (Pinus sylvestris L.) stand in a Mediterranean mountain area. This procedure allowed us to better understand the limitations of ETd modelling and how it needs to be improved, especially in heterogeneous forest areas. The method using Landsat data resulted in a good agreement, R2 test of 0.89, with a mean RMSE value of about 0.6 mm day−1 and an estimation error of ±30 \%. The poor agreement obtained using TERRA/AQUA MODIS, with a mean RMSE value of 1.8 and 2.4 mm day−1 and an estimation error of about ±57 and 50 \%, respectively. This reveals that ETd retrieval from coarse resolution remote sensing data is troublesome in these heterogeneous areas, and therefore further research is necessary on this issue. Finally, implementing regional GIS-based climate models as inputs in ETd retrieval have has provided good results, making possible to compute ETd at regional scales.},
	number = {5},
	urldate = {2014-12-05},
	journal = {Hydrol. Earth Syst. Sci.},
	author = {Cristóbal, J. and Poyatos, R. and Ninyerola, M. and Llorens, P. and Pons, X.},
	month = may,
	year = {2011},
	pages = {1563--1575},
	file = {Cristóbal et al_2011_Combining remote sensing and GIS climate modelling to estimate daily forest.pdf:/media/rafap/Data/Documents/Zotero/storage/5SDPXK86/Cristóbal et al_2011_Combining remote sensing and GIS climate modelling to estimate daily forest.pdf:application/pdf}
}

@article{sterck_understanding_2012,
	title = {Understanding trait interactions and their impacts on growth in {Scots} pine branches across {Europe}},
	volume = {26},
	copyright = {© 2012 The Authors. Functional Ecology © 2012 British Ecological Society},
	issn = {1365-2435},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2012.01963.x/abstract},
	doi = {10.1111/j.1365-2435.2012.01963.x},
	abstract = {1. Plants exhibit a wide variety in traits at different organizational levels. Intraspecific and interspecific studies have potential to demonstrate functional relationships and trade-offs amongst traits, with potential consequences for growth. However, the distinction between the correlative and functional nature of trait covariation presents a challenge because traits interact in complex ways.2. We present an intraspecific study on Scots pine branches and use functional multi-trait concepts to organize and understand trait interactions and their impacts on growth. Branch-level traits were assessed for 97 branches from 12 Scots pine sites across Europe.3. To test alternative hypotheses on cause–effect relationships between anatomical traits, hydraulic traits and branch growth, we measured for each branch: the tracheid hydraulic diameter, double cell wall thickness, cell lumen span area, wood density, cavitation vulnerability, wood-specific hydraulic conductivity, the leaf area to sapwood area ratio and branch growth. We used mixed linear effect models and path models to show how anatomical traits determine hydraulic traits and, in turn, how those traits influence growth.4. Tracheid hydraulic diameter was the best predictor of cavitation vulnerability (R2 = 0·09 explained by path model) and specific conductivity (R2 = 0·19) amongst anatomical traits. Leaf area to sapwood area ratio had the strongest direct effect on branch growth (R2 = 0·19) and was positively associated with the tracheid hydraulic diameter (R2 = 0·22). A number of bivariate correlations between traits could be explained by these functional relationships amongst traits.5. The plasticity in tracheid hydraulic diameter (10.0–15.1 μm) and leaf area to sapwood area ratio (600–6051 cm2 cm−2) and the maintenance of a minimum leaf water potential (between −2 and −2·5 MPa) appear to drive the anatomical and hydraulic traits of Scots pine across Europe. These properties are major drivers of the functional trait network underlying the growth variation amongst pine branches and thus possibly contribute to the ecological success of pines at a local and continental scale.},
	language = {en},
	number = {2},
	urldate = {2012-06-07},
	journal = {Functional Ecology},
	author = {Sterck, Frank J. and Martínez-Vilalta, Jordi and Mencuccini, Maurizio and Cochard, Hervé and Gerrits, Pieter and Zweifel, Roman and Herrero, Asier and Korhonen, Janne F.J. and Llorens, Pilar and Nikinmaa, Eero and Nolè, Angelo and Poyatos, Rafael and Ripullone, Francesco and Sass-Klaassen, Ute},
	year = {2012},
	keywords = {growth, cavitation resistance, wood density, specific conductivity, cavitation vulnerability, functional trait, P50, implosion, wood anatomy, Ψ50},
	pages = {541--549},
	file = {Sterck et al_2012_Understanding trait interactions and their impacts on growth in Scots pine.pdf:/media/rafap/Data/Documents/Zotero/storage/NHTPDCU9/Sterck et al_2012_Understanding trait interactions and their impacts on growth in Scots pine.pdf:application/pdf}
}

@article{salmon_balancing_2015,
	title = {Balancing the risks of hydraulic failure and carbon starvation: a twig scale analysis in declining {Scots} pine},
	volume = {38},
	issn = {1365-3040},
	shorttitle = {Balancing the risks of hydraulic failure and carbon starvation},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/pce.12572/abstract},
	doi = {10.1111/pce.12572},
	abstract = {Understanding physiological processes involved in drought-induced mortality is important for predicting the future of forests and for modelling the carbon and water cycles. Recent research has highlighted the variable risks of carbon starvation and hydraulic failure in drought-exposed trees. However, little is known about the specific responses of leaves and supporting twigs, despite their critical role in balancing carbon acquisition and water loss. Comparing healthy (non-defoliated) and unhealthy (defoliated) Scots pine at the same site, we measured the physiological variables involved in regulating carbon and water resources. Defoliated trees showed different responses to summer drought compared with non-defoliated trees. Defoliated trees maintained gas exchange while non-defoliated trees reduced photosynthesis and transpiration during the drought period. At the branch scale, very few differences were observed in non-structural carbohydrate concentrations between health classes. However, defoliated trees tended to have lower water potentials and smaller hydraulic safety margins. While non-defoliated trees showed a typical response to drought for an isohydric species, the physiology appears to be driven in defoliated trees by the need to maintain carbon resources in twigs. These responses put defoliated trees at higher risk of branch hydraulic failure and help explain the interaction between carbon starvation and hydraulic failure in dying trees.},
	language = {en},
	number = {12},
	urldate = {2016-04-11},
	journal = {Plant, Cell \& Environment},
	author = {Salmon, Yann and Torres-Ruiz, José M. and Poyatos, Rafael and Martinez-Vilalta, Jordi and Meir, Patrick and Cochard, Hervé and Mencuccini, Maurizio},
	year = {2015},
	note = {00002},
	keywords = {drought, photosynthesis, Transpiration, tree, ecophysiology, Mortality, leaf gas exchange, NSC},
	pages = {2575--2588},
	file = {Salmon_2015_Balancing the risks of hydraulic failure and carbon starvation - a twig scale.pdf:/media/rafap/Data/Documents/Zotero/storage/X92STZB3/Salmon_2015_Balancing the risks of hydraulic failure and carbon starvation - a twig scale.pdf:application/pdf}
}

@article{sanchez-costa_contrasting_2015,
	title = {Contrasting growth and water use strategies in four co-occurring {Mediterranean} tree species revealed by concurrent measurements of sap flow and stem diameter variations},
	volume = {207},
	issn = {0168-1923},
	url = {http://www.sciencedirect.com/science/article/pii/S0168192315000908},
	doi = {10.1016/j.agrformet.2015.03.012},
	abstract = {Drought limits tree water use and growth of Mediterranean trees. However, growth and water use strategies are rarely addressed simultaneously across species and drought conditions. Here, we investigate the link between stem diameter variations and sap flow in four co-existing Mediterranean trees (Pinus halepensis Mill., Quercus pubescens Willd., Quercus ilex L. and Arbutus unedo L.), under relatively wet (2011) and dry (2012) conditions. Continuous stem diameter variations were converted to basal area increment (BAI) and de-trended to estimate tree water deficit (ΔW), an indicator of stem hydration. P. halepensis and Q. pubescens showed the most and the least conservative sap flow density (JS) regulation under drought, respectively, with Q. ilex and A.unedo showing intermediate drought responses. All species, except A. unedo, showed some between-year variability in the environmental control of JS. Seasonal stem shrinkage in response to drought (i.e., increasing ΔW) and subsequent trunk rehydration after rainfall (i.e., decreasing ΔW) occurred in all species. Vapor pressure deficit (VPD) and soil moisture (θ) interacted to determine seasonal variation in ΔW. Interestingly, in the dry year, 2012, more species-specific differences were found in the responses of ΔW to θ and VPD. Across species, JS and ΔW began to decline at similar soil moisture thresholds, underpinning the tight link between JS and ΔW under varying drought conditions. Annual BAI decreased proportionally more than tree-level transpiration (JT) between the wet (2011) and the dry (2012) year, hence growth-based WUE (WUEBAI = BAI/JT) decreased for all species, albeit less acutely for P. halepensis. Overall, despite their contrasting leaf habit and wood type, the studied Mediterranean tree species show coordinated responses of transpiration, water storage dynamics and growth-based WUE which allow them to cope with seasonal and interannual drought.},
	urldate = {2016-04-11},
	journal = {Agricultural and Forest Meteorology},
	author = {Sánchez-Costa, Elisenda and Poyatos, Rafael and Sabaté, Santiago},
	month = jul,
	year = {2015},
	note = {00005},
	keywords = {Automatic dendrometer, Tree transpiration, water availability, tree water deficit, Growth-based water use efficiency},
	pages = {24--37},
	file = {Sánchez-Costa_2015_Contrasting growth and water use strategies in four co-occurring Mediterranean.pdf:/media/rafap/Data/Documents/Zotero/storage/99DJ77ZT/Sánchez-Costa_2015_Contrasting growth and water use strategies in four co-occurring Mediterranean.pdf:application/pdf}
}

@article{aguade_role_2015,
	title = {The role of defoliation and root rot pathogen infection in driving the mode of drought-related physiological decline in {Scots} pine ({Pinus} sylvestris {L}.)},
	volume = {35},
	issn = {0829-318X, 1758-4469},
	url = {http://treephys.oxfordjournals.org/content/35/3/229},
	doi = {10.1093/treephys/tpv005},
	abstract = {Drought-related tree die-off episodes have been observed in all vegetated continents. Despite much research effort, however, the multiple interactions between carbon starvation, hydraulic failure and biotic agents in driving tree mortality under field conditions are still not well understood. We analysed the seasonal variability of non-structural carbohydrates (NSCs) in four organs (leaves, branches, trunk and roots), the vulnerability to embolism in roots and branches, native embolism (percentage loss of hydraulic conductivity (PLC)) in branches and the presence of root rot pathogens in defoliated and non-defoliated individuals in a declining Scots pine (Pinus sylvestris L.) population in the NE Iberian Peninsula in 2012, which included a particularly dry and warm summer. No differences were observed between defoliated and non-defoliated pines in hydraulic parameters, except for a higher vulnerability to embolism at pressures below −2 MPa in roots of defoliated pines. No differences were found between defoliation classes in branch PLC. Total NSC (TNSC, soluble sugars plus starch) values decreased during drought, particularly in leaves. Defoliation reduced TNSC levels across tree organs, especially just before (June) and during (August) drought. Root rot infection by the fungal pathogen Onnia P. Karst spp. was detected but it did not appear to be associated to tree defoliation. However, Onnia infection was associated with reduced leaf-specific hydraulic conductivity and sapwood depth, and thus contributed to hydraulic impairment, especially in defoliated pines. Infection was also associated with virtually depleted root starch reserves during and after drought in defoliated pines. Moreover, defoliated and infected trees tended to show lower basal area increment. Overall, our results show the intertwined nature of physiological mechanisms leading to drought-induced mortality and the inherent difficulty of isolating their contribution under field conditions.},
	language = {en},
	number = {3},
	urldate = {2016-04-11},
	journal = {Tree Physiology},
	author = {Aguadé, D. and Poyatos, R. and Gómez, M. and Oliva, J. and Martínez-Vilalta, J.},
	month = mar,
	year = {2015},
	pmid = {25724949},
	note = {00006 },
	keywords = {hydraulic failure, non-structural carbohydrates, Global change, Die-off, fungi pathogen},
	pages = {229--242},
	file = {Aguadé_2015_The role of defoliation and root rot pathogen infection in driving the mode of.pdf:/media/rafap/Data/Documents/Zotero/storage/EEX6QND5/Aguadé_2015_The role of defoliation and root rot pathogen infection in driving the mode of.pdf:application/pdf}
}

@article{cristobal_combining_2011-1,
	title = {Combining remote sensing and {GIS} climate modelling to estimate daily forest evapotranspiration in a {Mediterranean} mountain area},
	volume = {8},
	abstract = {Evapotranspiration monitoring allows us to assess the environmental stress on forest and agricultural ecosystems. Nowadays, Remote Sensing and Geographical Information Systems (GIS) are the main techniques used for calculating evapotranspiration at catchment and regional scales. In this study we present a methodology, based on the energy balance equation (B-method), that combines remote sensing imagery with GIS climate modelling to estimate daily evapotranspiration (ETd) for several dates between 2003 and 2005. The three main variables needed to compute ETd were obtained as follows: (i) Land surface temperature by means of the Landsat-5 TM and Landsat-7 ETM+ thermal band, (ii) air temperature by means of multiple regression analysis and spatial interpolation from meteorological ground stations data at satellite pass, and (iii) net radiation by means of the radiative balance. We calculated ETd using remote sensing data at different spatial and temporal scales (TERRA/AQUA MODIS and Landsat-5 TM/Landsat-7 ETM+) and combining three different approaches to calculate the B parameter. We then compared these estimates with sap flow measurements from a Scots pine (Pinus sylvestris L.) stand in a Mediterranean mountain area. This procedure allowed us to better understand the limitations of ETd modelling and how it needs to be improved, especially in heterogeneous forest areas. The method using Landsat data resulted in a good agreement, with a mean RMSE value of about 0.6 mm day-1 and an estimation error of ±30\%. The poor agreement obtained using MODIS data reveals that ETd retrieval from coarse resolution remote sensing data is troublesome in these heterogeneous areas, and therefore further research is necessary on this issue. © 2011 Author(s).},
	number = {1},
	journal = {Hydrology and Earth System Sciences},
	author = {Cristóbal, J. and Poyatos, R. and Ninyerola, M. and Llorens, P. and Pons, X.},
	year = {2011},
	pages = {1125--1159},
	file = {Cristóbal_2011_Combining remote sensing and GIS climate modelling to estimate daily forest.pdf:/media/rafa/Data/Recerca/Bibliografia/Zotero/Cristóbal/Hydrol. Earth Syst. Sci./2011/Cristóbal_2011_Combining remote sensing and GIS climate modelling to estimate daily forest.pdf:application/pdf;Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/7S7TT57W/display.html:text/html;Scopus - Document details:/media/rafap/Data/Documents/Zotero/storage/2V2PQD4R/display.html:text/html}
}

@article{poyatos_drought-induced_2013,
	title = {Drought-induced defoliation and long periods of near-zero gas exchange play a key role in accentuating metabolic decline of {Scots} pine},
	volume = {200},
	copyright = {© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust},
	issn = {1469-8137},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/nph.12278/abstract},
	doi = {10.1111/nph.12278},
	abstract = {* Drought-induced defoliation has recently been associated with the depletion of carbon reserves and increased mortality risk in Scots pine (Pinus sylvestris). We hypothesize that defoliated individuals are more sensitive to drought, implying that potentially higher gas exchange (per unit of leaf area) during wet periods may not compensate for their reduced photosynthetic area. * We measured sap flow, needle water potentials and whole-tree hydraulic conductance to analyse the drought responses of co-occurring defoliated and nondefoliated Scots pines in northeast Spain during typical (2010) and extreme (2011) drought conditions. * Defoliated Scots pines showed higher sap flow per unit leaf area during spring, but were more sensitive to summer drought, relative to nondefoliated pines. This pattern was associated with a steeper decline in soil-to-leaf hydraulic conductance with drought and an enhanced sensitivity of canopy conductance to soil water availability. Near-homeostasis in midday water potentials was observed across years and defoliation classes, with minimum values of −2.5 MPa. Enhanced sensitivity to drought and prolonged periods of near-zero gas exchange were consistent with low levels of carbohydrate reserves in defoliated trees. * Our results support the critical links between defoliation, water and carbon availability, and their key roles in determining tree survival and recovery under drought.},
	language = {en},
	number = {2},
	urldate = {2013-11-15},
	journal = {New Phytologist},
	author = {Poyatos, Rafael and Aguadé, David and Galiano, Lucía and Mencuccini, Maurizio and Martínez-Vilalta, Jordi},
	year = {2013},
	keywords = {tree mortality, Stomatal conductance, Sap flow, water potential, canopy defoliation, Pinus sylvestris, hydraulic limits, nonstructural carbohydrates},
	pages = {388--401},
	file = {Poyatos et al_2013_Drought-induced defoliation and long periods of near-zero gas exchange play a.pdf:/media/rafap/Data/Documents/Zotero/storage/ZJP7APCJ/Poyatos et al_2013_Drought-induced defoliation and long periods of near-zero gas exchange play a.pdf:application/pdf}
}

@article{barba_strong_2016,
	title = {Strong resilience of soil respiration components to drought-induced die-off resulting in forest secondary succession},
	volume = {182},
	issn = {0029-8549, 1432-1939},
	url = {http://link.springer.com.are.uab.cat/article/10.1007/s00442-016-3567-8},
	doi = {10.1007/s00442-016-3567-8},
	abstract = {How forests cope with drought-induced perturbations and how the dependence of soil respiration on environmental and biological drivers is affected in a warming and drying context are becoming key questions. The aims of this study were to determine whether drought-induced die-off and forest succession were reflected in soil respiration and its components and to determine the influence of climate on the soil respiration components. We used the mesh exclusion method to study seasonal variations in soil respiration (RS) and its components: heterotrophic (RH) and autotrophic (RA) [further split into fine root (RR) and mycorrhizal respiration (RM)] in a mixed Mediterranean forest where Scots pine (Pinus sylvestris L.) is undergoing a drought-induced die-off and is being replaced by holm oak (Quercus ilex L.). Drought-induced pine die-off was not reflected in RS nor in its components, which denotes a high functional resilience of the plant and soil system to pine die-off. However, the succession from Scots pine to holm oak resulted in a reduction of RH and thus in an important decrease of total respiration (RS was 36 \% lower in holm oaks than in non-defoliated pines). Furthermore, RS and all its components were strongly regulated by soil water content-and-temperature interaction. Since Scots pine die-off and Quercus species colonization seems to be widely occurring at the driest limit of the Scots pine distribution, the functional resilience of the soil system over die-off and the decrease of RS from Scots pine to holm oak could have direct consequences for the C balance of these ecosystems.},
	language = {en},
	number = {1},
	journal = {Oecologia},
	author = {Barba, Josep and Yuste, Jorge Curiel and Poyatos, Rafael and Janssens, Ivan A. and Lloret, Francisco},
	month = feb,
	year = {2016},
	pages = {27--41},
	file = {Barba et al. - 2016 - Strong resilience of soil respiration components t.pdf:/media/rafap/Data/Documents/Zotero/storage/Y6EQ7P27/Barba et al. - 2016 - Strong resilience of soil respiration components t.pdf:application/pdf}
}

@article{caceres_coupling_2015,
	title = {Coupling a water balance model with forest inventory data to predict drought stress: the role of forest structural changes vs. climate changes},
	volume = {213},
	issn = {0168-1923},
	shorttitle = {Coupling a water balance model with forest inventory data to predict drought stress},
	url = {http://www.sciencedirect.com/science/article/pii/S0168192315001914},
	doi = {10.1016/j.agrformet.2015.06.012},
	abstract = {Mechanistic water balance models can be used to predict soil moisture dynamics and drought stress in individual forest stands. Predicting current and future levels of plant drought stress is important not only at the local scale, but also at larger, landscape to regional, scales, because these are the management scales at which adaptation and mitigation strategies are implemented. To obtain reliable predictions of soil moisture and plant drought stress over large extents, water balance models need to be complemented with detailed information about the spatial variation of vegetation and soil attributes. We designed, calibrated and validated a water balance model that produces annual estimates of drought intensity and duration for all plant cohorts in a forest stand. Taking Catalonia (NE Spain) as a case study, we coupled this model with plot records from two Spanish forest inventories in which species identity, diameter and height of plant cohorts were available. Leaf area index of each plant cohort was estimated from basal area using species-specific relationships. Vertical root distribution for each species in each forest plot was estimated by determining the distribution that maximized transpiration in the model, given average climatic conditions, soil attributes and stand density. We determined recent trends (period 1980–2010) in drought stress for the main tree species in Catalonia; where forest growth and densification occurs in many areas as a result of rural abandonment and decrease of forest management. Regional increases in drought stress were detected for most tree species, although we found high variation in stress changes among individual forest plots. Moreover, predicted trends in tree drought stress were mainly due to changes in leaf area occurred between the two forest inventories rather than to climatic trends. We conclude that forest structure needs to be explicitly considered in assessments of plant drought stress patterns and trends over large geographic areas, and that forest inventories are useful sources of data provided that reasonably good estimates of soil attributes and root distribution are available. Our approach coupled with recent improvements in forest survey technologies may allow obtaining spatially continuous and precise assessments of drought stress. Further efforts are needed to calibrate drought-related demographic processes before water balance and drought stress estimates can be fully used for the accurate prediction of drought impacts.},
	journal = {Agricultural and Forest Meteorology},
	author = {Cáceres, Miquel De and Martínez-Vilalta, Jordi and Coll, Lluís and Llorens, Pilar and Casals, Pere and Poyatos, Rafael and Pausas, Juli G. and Brotons, Lluís},
	month = nov,
	year = {2015},
	keywords = {Drought stress, Mediterranean forests, Forest inventory data, Water balance model},
	pages = {77--90},
	file = {ScienceDirect Full Text PDF:/media/rafap/Data/Documents/Zotero/storage/VVXNMKUK/Cáceres et al. - 2015 - Coupling a water balance model with forest invento.pdf:application/pdf}
}

@article{poyatos_sapfluxnet:_2016,
	title = {{SAPFLUXNET}: towards a global database of sap flow measurements},
	volume = {36},
	issn = {0829-318X},
	shorttitle = {{SAPFLUXNET}},
	url = {https://academic.oup.com/treephys/article/36/12/1449/2571314},
	doi = {10.1093/treephys/tpw110},
	abstract = {Plant transpiration is the main evaporative flux from terrestrial ecosystems; it controls land surface energy balance, determines catchment hydrological responses and influences regional and global climate. Transpiration regulation by plants is a key (and still not completely understood) process that underlies vegetation drought responses and land evaporative fluxes under global change scenarios. Thermometric methods of sap flow measurement have now been widely used to quantify whole-plant and stand transpiration in forests, shrublands and orchards around the world. A large body of research has applied sap flow methods to analyse seasonal and diurnal patterns of transpiration and to quantify their responses to hydroclimatic variability, but syntheses of sap flow data at regional to global scales are extremely rare. Here we present the SAPFLUXNET initiative, aimed at building the first global database of plant-level sap flow measurements. A preliminary metadata survey launched in December 2015 showed an encouraging response by the sap flow community, with sap flow data sets from field studies representing \>160 species and \>120 globally distributed sites. The main goal of SAPFLUXNET is to analyse the ecological factors driving plant- and stand-level transpiration. SAPFLUXNET will open promising research avenues at an unprecedented global scope, namely: (i) exploring the spatio-temporal variability of plant transpiration and its relationship with plant and stand attributes, (ii) summarizing physiological regulation of transpiration by means of few water-use traits, usable for land surface models, (iii) improving our understanding of the coordination between gas exchange and plant-level traits (e.g., hydraulics) and (iv) analysing the ecological factors controlling stand transpiration and evapotranspiration partitioning. Finally, SAPFLUXNET can provide a benchmark to test models of physiological controls of transpiration, contributing to improve the accuracy of individual water stress responses, a key element to obtain robust predictions of vegetation responses to climate change.},
	number = {12},
	urldate = {2017-12-21},
	journal = {Tree Physiology},
	author = {Poyatos, Rafael and Granda, Víctor and Molowny-Horas, Roberto and Mencuccini, Maurizio and Steppe, Kathy and Martínez-Vilalta, Jordi},
	month = dec,
	year = {2016},
	pages = {1449--1455},
	file = {Poyatos et al_2016_SAPFLUXNET.pdf:/media/rafap/Data/Documents/Zotero/storage/H87G4EEB/Poyatos et al_2016_SAPFLUXNET.pdf:application/pdf}
}

@article{aguade_comparative_2015,
	title = {Comparative {Drought} {Responses} of {Quercus} ilex {L}. and {Pinus} sylvestris {L}. in a {Montane} {Forest} {Undergoing} a {Vegetation} {Shift}},
	volume = {6},
	copyright = {http://creativecommons.org/licenses/by/3.0/},
	url = {http://www.mdpi.com/1999-4907/6/8/2505},
	doi = {10.3390/f6082505},
	abstract = {Different functional and structural strategies to cope with water shortage exist both within and across plant communities. The current trend towards increasing drought in many regions could drive some species to their physiological limits of drought tolerance, potentially leading to mortality episodes and vegetation shifts. In this paper, we study the drought responses of Quercus ilex and Pinus sylvestris in a montane Mediterranean forest where the former species is replacing the latter in association with recent episodes of drought-induced mortality. Our aim was to compare the physiological responses to variations in soil water content (SWC) and vapor pressure deficit (VPD) of the two species when living together in a mixed stand or separately in pure stands, where the canopies of both species are completely exposed to high radiation and VPD. P. sylvestris showed typical isohydric behavior, with greater losses of stomatal conductance with declining SWC and greater reductions of stored non-structural carbohydrates during drought, consistent with carbon starvation being an important factor in the mortality of this species. On the other hand, Q. ilex trees showed a more anisohydric behavior, experiencing more negative water potentials and higher levels of xylem embolism under extreme drought, presumably putting them at higher risk of hydraulic failure. In addition, our results show relatively small changes in the physiological responses of Q. ilex in mixed vs. pure stands, suggesting that the current replacement of P. sylvestris by Q. ilex will continue.},
	language = {en},
	number = {8},
	urldate = {2017-12-21},
	journal = {Forests},
	author = {Aguadé, David and Poyatos, Rafael and Rosas, Teresa and Martínez-Vilalta, Jordi},
	month = jul,
	year = {2015},
	keywords = {Scots pine, water potential, global change, non-structural carbohydrates, drought response, holm oak, stomatal conductance, leaf conductance},
	pages = {2505--2529},
	file = {Aguadé et al_2015_Comparative Drought Responses of Quercus ilex L.pdf:/media/rafap/Data/Documents/Zotero/storage/J9I722TL/Aguadé et al_2015_Comparative Drought Responses of Quercus ilex L.pdf:application/pdf}
}

@article{da_costa_stand_2018,
	title = {Stand dynamics modulate water cycling and mortality risk in droughted tropical forest},
	volume = {24},
	issn = {1365-2486},
	url = {http://dx.doi.org/10.1111/gcb.13851},
	doi = {10.1111/gcb.13851},
	abstract = {Transpiration from the Amazon rainforest generates an essential water source at a global and local scale. However, changes in rainforest function with climate change can disrupt this process, causing significant reductions in precipitation across Amazonia, and potentially at a global scale. We report the only study of forest transpiration following a long-term ({\textgreater}10 year) experimental drought treatment in Amazonian forest. After 15 years of receiving half the normal rainfall, drought-related tree mortality caused total forest transpiration to decrease by 30\%. However, the surviving droughted trees maintained or increased transpiration because of reduced competition for water and increased light availability, which is consistent with increased growth rates. Consequently, the amount of water supplied as rainfall reaching the soil and directly recycled as transpiration increased to 100\%. This value was 25\% greater than for adjacent nondroughted forest. If these drought conditions were accompanied by a modest increase in temperature (e.g., 1.5°C), water demand would exceed supply, making the forest more prone to increased tree mortality.},
	number = {1},
	journal = {Global Change Biology},
	author = {da Costa, Antonio C. L. and Rowland, Lucy and Oliveira, Rafael S. and Oliveira, Alex A. R. and Binks, Oliver J. and Salmon, Yann and Vasconcelos, Steel S. and Junior, João A. S. and Ferreira, Leandro V. and Poyatos, Rafael and Mencuccini, Maurizio and Meir, Patrick},
	year = {2018},
	keywords = {tree mortality, drought, tropical forest, sap flux, transpiration, water cycling},
	pages = {249--258},
	file = {da Costa et al_Stand dynamics modulate water cycling and mortality risk in droughted tropical.pdf:/media/rafap/Data/Documents/Zotero/storage/NC5Z9Q5M/da Costa et al_Stand dynamics modulate water cycling and mortality risk in droughted tropical.pdf:application/pdf}
}

@article{barba_multi-temporal_2018,
	title = {Multi-temporal influence of vegetation on soil respiration in a drought-affected forest},
	volume = {11},
	copyright = {(c) SISEF - Italian Society of Silviculture and Forest Ecology},
	issn = {1971-7458},
	url = {http://www.sisef.it/iforest/contents/?id=ifor2448-011},
	doi = {10.3832/ifor2448-011},
	abstract = {Abstract: Aboveground plant activity influences fine roots and rhizosphere activity, which is reflected on soil respiration (SR). However, it is still unclear and poorly understood the nature of plant activity control over SR, especially under drought conditions. We studied the plant activity-SR relationship at different timescales in a water-limited mixed Mediterranean forest where Scots pines (Pinus sylvestris L.) are undergoing drought-induced die-off and are being replaced by the more drought-resistant Holm oak (Quercus ilex L.). Half-hourly sap flow (SF), as a proxy of photosynthesis, coupled with measures of SR using solid-state CO2 sensors, were monitored during nine months in four different trees, representative of the diversity and health condition of the forest. SF was strongly associated with SR at both daily and seasonal timescales. At daily timescales, almost no lags were found between SF and SR, indicating a fast control of photosynthesis on SR. However, the association between SF and SR weakened during the summer drought. These temporal patterns were not constant across the trees representing the die-off and replacement processes. SR beneath living pines was highly controlled by SF at daily scale, whereas Holm oak seemed to be more controlled by SF at seasonal scale. The relationship between SF and SR measured beneath dead pine and Holm oak at the daily and seasonal scales was consistent with the colonization of soil gaps by holm oak roots following Scots pine death and suggests that surviving Scots pines are unable to expand their root system in these gaps. Our results collectively show how drought modulates the link between canopy photosynthesis and soil respiration, and increase our understanding on how belowground processes may be affected by the successional dynamics following drought-induced forest mortality.},
	language = {en-US},
	number = {2},
	urldate = {2018-03-05},
	journal = {iForest - Biogeosciences and Forestry},
	author = {Barba, J. and Lloret, F. and Poyatos, R. and Molowny-Horas, R. and Yuste, J. C.},
	year = {2018},
	pmid = {ifor2448-011},
	pages = {189--198},
	file = {Barba et al_2018_Multi-temporal influence of vegetation on soil respiration in a.pdf:/media/rafap/Data/Documents/Zotero/storage/YE4IKM9X/Barba et al_2018_Multi-temporal influence of vegetation on soil respiration in a.pdf:application/pdf;iForest_ifor2448-011_Barba.pdf:/media/rafap/Data/Documents/Zotero/storage/6A4G38KN/iForest_ifor2448-011_Barba.pdf:application/pdf}
}

@article{poyatos_gap-filling_2018,
	title = {Gap-filling a spatially explicit plant trait database: comparing imputation methods and different levels of environmental information},
	volume = {15},
	issn = {1726-4189},
	shorttitle = {Gap-filling a spatially explicit plant trait database},
	url = {https://www.biogeosciences.net/15/2601/2018/},
	doi = {10.5194/bg-15-2601-2018},
	abstract = {The ubiquity of missing data in plant trait databases may hinder trait-based analyses of ecological patterns and processes. Spatially explicit datasets with information on intraspecific trait variability are rare but offer great promise in improving our understanding of functional biogeography. At the same time, they offer specific challenges in terms of data imputation. Here we compare statistical imputation approaches, using varying levels of environmental information, for five plant traits (leaf biomass to sapwood area ratio, leaf nitrogen content, maximum tree height, leaf mass per area and wood density) in a spatially explicit plant trait dataset of temperate and Mediterranean tree species (Ecological and Forest Inventory of Catalonia, IEFC, dataset for Catalonia, north-east Iberian Peninsula, 31 900 km2). We simulated gaps at different missingness levels (10–80 \%) in a complete trait matrix, and we used overall trait means, species means, k nearest neighbours (kNN), ordinary and regression kriging, and multivariate imputation using chained equations (MICE) to impute missing trait values. We assessed these methods in terms of their accuracy and of their ability to preserve trait distributions, multi-trait correlation structure and bivariate trait relationships. The relatively good performance of mean and species mean imputations in terms of accuracy masked a poor representation of trait distributions and multivariate trait structure. Species identity improved MICE imputations for all traits, whereas forest structure and topography improved imputations for some traits. No method performed best consistently for the five studied traits, but, considering all traits and performance metrics, MICE informed by relevant ecological variables gave the best results. However, at higher missingness ({\textgreater} 30 \%), species mean imputations and regression kriging tended to outperform MICE for some traits. MICE informed by relevant ecological variables allowed us to fill the gaps in the IEFC incomplete dataset (5495 plots) and quantify imputation uncertainty. Resulting spatial patterns of the studied traits in Catalan forests were broadly similar when using species means, regression kriging or the best-performing MICE application, but some important discrepancies were observed at the local level. Our results highlight the need to assess imputation quality beyond just imputation accuracy and show that including environmental information in statistical imputation approaches yields more plausible imputations in spatially explicit plant trait datasets.},
	number = {9},
	urldate = {2018-06-04},
	journal = {Biogeosciences},
	author = {Poyatos, R. and Sus, O. and Badiella, L. and Mencuccini, M. and Martínez-Vilalta, J.},
	month = may,
	year = {2018},
	pages = {2601--2617},
	file = {bg-15-2601-2018-supplement.pdf:/media/rafap/Data/Documents/Zotero/storage/5W4C2AZB/bg-15-2601-2018-supplement.pdf:application/pdf;Poyatos et al_2018_Gap-filling a spatially explicit plant trait database.pdf:/media/rafap/Data/Documents/Zotero/storage/7CIWW9LJ/Poyatos et al_2018_Gap-filling a spatially explicit plant trait database.pdf:application/pdf}
}

@article{cabon_applying_2018,
	title = {Applying the eco-hydrological equilibrium hypothesis to model root distribution in water-limited forests},
	volume = {11},
	copyright = {© 2018 John Wiley \& Sons, Ltd.},
	issn = {1936-0592},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/eco.2015},
	doi = {10.1002/eco.2015},
	abstract = {Drought is a key driver of vegetation dynamics, but plant water-uptake patterns and consequent plant responses to drought are poorly understood at large spatial scales. The capacity of vegetation to use soil water depends on its root distribution (RD). However, RD is extremely variable in space and difficult to measure in the field, which hinders accurate predictions of water fluxes and vegetation dynamics. We propose a new method to estimate RD within water balance models, assuming that vegetation is at eco-hydrological equilibrium (EHE). EHE conditions imply that vegetation optimizes RD such that transpiration is maximized within the limits of bearable drought stress, characterized here by species-specific hydraulic thresholds. Optimized RD estimates were validated against RD estimates obtained by model calibration from sap flow or soil moisture from 38 forest plots in Catalonia (NE Spain). In water-limited plots, optimized RD was similar to calibrated RD, but estimates diverged with higher water availability, suggesting that the EHE may not be assumed when water is not limiting. Thereafter, we applied the optimization procedure at the regional scale, to estimate RD for the water-limited forests of Catalonia. Regional variations of optimum RD reproduced many expected patterns in response to climate, soil physical properties, forest structure, and species hydraulic traits. We conclude that RD optimization, based on the EHE hypothesis and a simple description of plant hydraulics, produces realistic estimates of RD that can be used for model parameterization and shows promise to improve our ability to forecast vegetation dynamics under increased drought.},
	language = {en},
	number = {7},
	urldate = {2018-11-13},
	journal = {Ecohydrology},
	author = {Cabon, Antoine and Martínez‐Vilalta, Jordi and Aragón, Juan Martínez de and Poyatos, Rafael and Cáceres, Miquel De},
	month = oct,
	year = {2018},
	keywords = {plant hydraulics, modelling, transpiration, water balance, eco-hydrological equilibrium, root distribution},
	pages = {e2015},
	file = {Cabon et al_2018_Applying the eco-hydrological equilibrium hypothesis to model root distribution.pdf:/media/rafap/Data/Documents/Zotero/storage/LDNTPN5P/Cabon et al_2018_Applying the eco-hydrological equilibrium hypothesis to model root distribution.pdf:application/pdf}
}

@article{peters_quantification_2018,
	title = {Quantification of uncertainties in conifer sap flow measured with the thermal dissipation method},
	volume = {219},
	copyright = {© 2018 The Authors. New Phytologist © 2018 New Phytologist Trust},
	issn = {1469-8137},
	url = {http://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.15241},
	doi = {10.1111/nph.15241},
	abstract = {Trees play a key role in the global hydrological cycle and measurements performed with the thermal dissipation method (TDM) have been crucial in providing whole-tree water-use estimates. Yet, different data processing to calculate whole-tree water use encapsulates uncertainties that have not been systematically assessed. We quantified uncertainties in conifer sap flux density (Fd) and stand water use caused by commonly applied methods for deriving zero-flow conditions, dampening and sensor calibration. Their contribution has been assessed using a stem segment calibration experiment and 4 yr of TDM measurements in Picea abies and Larix decidua growing in contrasting environments. Uncertainties were then projected on TDM data from different conifers across the northern hemisphere. Commonly applied methods mostly underestimated absolute Fd. Lacking a site- and species-specific calibrations reduced our stand water-use measurements by 37\% and induced uncertainty in northern hemisphere Fd. Additionally, although the interdaily variability was maintained, disregarding dampening and/or applying zero-flow conditions that ignored night-time water use reduced the correlation between environment and Fd. The presented ensemble of calibration curves and proposed dampening correction, together with the systematic quantification of data-processing uncertainties, provide crucial steps in improving whole-tree water-use estimates across spatial and temporal scales.},
	language = {en},
	number = {4},
	urldate = {2019-06-27},
	journal = {New Phytologist},
	author = {Peters, Richard L. and Fonti, Patrick and Frank, David C. and Poyatos, Rafael and Pappas, Christoforos and Kahmen, Ansgar and Carraro, Vinicio and Prendin, Angela Luisa and Schneider, Loïc and Baltzer, Jennifer L. and Baron‐Gafford, Greg A. and Dietrich, Lars and Heinrich, Ingo and Minor, Rebecca L. and Sonnentag, Oliver and Matheny, Ashley M. and Wightman, Maxwell G. and Steppe, Kathy},
	year = {2018},
	keywords = {sap flux density, calibration, thermal dissipation probes, transpiration, night-time transpiration, uncertainty analysis, wounding effects},
	pages = {1283--1299},
	file = {Peters et al_2018_Quantification of uncertainties in conifer sap flow measured with the thermal.pdf:/media/rafap/Data/Documents/Zotero/storage/CV8DDC4Q/Peters et al_2018_Quantification of uncertainties in conifer sap flow measured with the thermal.pdf:application/pdf}
}

@article{barba_automated_2019,
	title = {Automated measurements of greenhouse gases fluxes from tree stems and soils: magnitudes, patterns and drivers},
	volume = {9},
	copyright = {2019 The Author(s)},
	issn = {2045-2322},
	shorttitle = {Automated measurements of greenhouse gases fluxes from tree stems and soils},
	url = {https://www.nature.com/articles/s41598-019-39663-8},
	doi = {10.1038/s41598-019-39663-8},
	abstract = {Tree stems exchange CO2, CH4 and N2O with the atmosphere but the magnitudes, patterns and drivers of these greenhouse gas (GHG) fluxes remain poorly understood. Our understanding mainly comes from static-manual measurements, which provide limited information on the temporal variability and magnitude of these fluxes. We measured hourly CO2, CH4 and N2O fluxes at two stem heights and adjacent soils within an upland temperate forest. We analyzed diurnal and seasonal variability of fluxes and biophysical drivers (i.e., temperature, soil moisture, sap flux). Tree stems were a net source of CO2 (3.80 ± 0.18 µmol m−2 s−1; mean ± 95\% CI) and CH4 (0.37 ± 0.18 nmol m−2 s−1), but a sink for N2O (−0.016 ± 0.008 nmol m−2 s−1). Time series analysis showed diurnal temporal correlations between these gases with temperature or sap flux for certain days. CO2 and CH4 showed a clear seasonal pattern explained by temperature, soil water content and sap flux. Relationships between stem, soil fluxes and their drivers suggest that CH4 for stem emissions could be partially produced belowground. High-frequency measurements demonstrate that: a) tree stems exchange GHGs with the atmosphere at multiple time scales; and b) are needed to better estimate fluxes magnitudes and understand underlying mechanisms of GHG stem emissions.},
	language = {En},
	number = {1},
	urldate = {2019-06-27},
	journal = {Scientific Reports},
	author = {Barba, Josep and Poyatos, Rafael and Vargas, Rodrigo},
	month = mar,
	year = {2019},
	pages = {4005},
	file = {Barba et al_2019_Automated measurements of greenhouse gases fluxes from tree stems and soils.pdf:/media/rafap/Data/Documents/Zotero/storage/UKA4M4NZ/Barba et al_2019_Automated measurements of greenhouse gases fluxes from tree stems and soils.pdf:application/pdf}
}

@article{flo_synthesis_2019,
	title = {A synthesis of bias and uncertainty in sap flow methods},
	volume = {271},
	issn = {0168-1923},
	url = {http://www.sciencedirect.com/science/article/pii/S0168192319301248},
	doi = {10.1016/j.agrformet.2019.03.012},
	abstract = {Sap flow measurements with thermometric methods are widely used to measure transpiration in plants. Different method families exist depending on how they apply heat and track sapwood temperature (heat pulse, heat dissipation, heat field deformation or heat balance). These methods have been calibrated for many species, but a global assessment of their uncertainty and reliability has not yet been conducted. Here we perform a meta-analysis of 290 individual calibration experiments assembled from the literature to assess calibration performance and how this varies across methods, experimental conditions and wood properties (density and porosity types). We used different metrics to characterize mean accuracy (closeness of the measurements to the true, reference value), proportional bias (resulting from an effect of measured flow on the magnitude of the error), linearity in the relationship between measurements and reference values, and precision (reproducibility and repeatability). We found a large intra- and inter-method variability in calibration performance, with a low proportion of this variability explained by species. Calibration performance was best when using stem segments. We did not find evidence of strong effects of wood density or porosity type in calibration performance. Dissipation methods showed lower accuracy and higher proportional bias than the other methods but they showed relatively high linearity and precision. Pulse methods also showed significant proportional bias, driven by their overestimation of low flows. These results suggest that Dissipation methods may be more appropriate to assess relative sap flow (e.g., treatment effects within a study) and Pulse methods may be more suitable to quantify absolute flows. Nevertheless, all sap flow methods showed high precision, allowing potential correction of the measurements when a study-specific calibration is performed. Our understanding of how sap flow methods perform across species would be greatly improved if experimental conditions and wood properties, including changes in wood moisture, were better reported.},
	urldate = {2019-07-02},
	journal = {Agricultural and Forest Meteorology},
	author = {Flo, Víctor and Martinez-Vilalta, Jordi and Steppe, Kathy and Schuldt, Bernhard and Poyatos, Rafael},
	month = jun,
	year = {2019},
	keywords = {Sap flow, Bias, Meta-analysis, Calibrations, Error, Methods},
	pages = {362--374}
}

@article{stoy_reviews_2019,
	title = {Reviews and syntheses: {Turning} the challenges of partitioning ecosystem evaporation and transpiration into opportunities},
	volume = {16},
	issn = {1726-4170},
	shorttitle = {Reviews and syntheses},
	url = {https://www.biogeosciences.net/16/3747/2019/},
	doi = {https://doi.org/10.5194/bg-16-3747-2019},
	abstract = {{\textless}p{\textgreater}{\textless}strong{\textgreater}Abstract.{\textless}/strong{\textgreater} Evaporation ({\textless}span class="inline-formula"{\textgreater}\textit{E}{\textless}/span{\textgreater}) and transpiration ({\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater}) respond differently to ongoing changes in climate, atmospheric composition, and land use. It is difficult to partition ecosystem-scale evapotranspiration (ET) measurements into {\textless}span class="inline-formula"{\textgreater}\textit{E}{\textless}/span{\textgreater} and {\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater}, which makes it difficult to validate satellite data and land surface models. Here, we review current progress in partitioning {\textless}span class="inline-formula"{\textgreater}\textit{E}{\textless}/span{\textgreater} and {\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater} and provide a prospectus for how to improve theory and observations going forward. Recent advancements in analytical techniques create new opportunities for partitioning {\textless}span class="inline-formula"{\textgreater}\textit{E}{\textless}/span{\textgreater} and {\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater} at the ecosystem scale, but their assumptions have yet to be fully tested. For example, many approaches to partition {\textless}span class="inline-formula"{\textgreater}\textit{E}{\textless}/span{\textgreater} and {\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater} rely on the notion that plant canopy conductance and ecosystem water use efficiency exhibit optimal responses to atmospheric vapor pressure deficit ({\textless}span class="inline-formula"{\textgreater}\textit{D}{\textless}/span{\textgreater}). We use observations from 240 eddy covariance flux towers to demonstrate that optimal ecosystem response to {\textless}span class="inline-formula"{\textgreater}\textit{D}{\textless}/span{\textgreater} is a reasonable assumption, in agreement with recent studies, but more analysis is necessary to determine the conditions for which this assumption holds. Another critical assumption for many partitioning approaches is that ET can be approximated as {\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater} during ideal transpiring conditions, which has been challenged by observational studies. We demonstrate that {\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater} can exceed 95\ \% of ET from certain ecosystems, but other ecosystems do not appear to reach this value, which suggests that this assumption is ecosystem-dependent with implications for partitioning. It is important to further improve approaches for partitioning {\textless}span class="inline-formula"{\textgreater}\textit{E}{\textless}/span{\textgreater} and {\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater}, yet few multi-method comparisons have been undertaken to date. Advances in our understanding of carbon–water coupling at the stomatal, leaf, and canopy level open new perspectives on how to quantify {\textless}span class="inline-formula"{\textgreater}\textit{T}{\textless}/span{\textgreater} via its strong coupling with photosynthesis. Photosynthesis can be constrained at the ecosystem and global scales with emerging data sources including solar-induced fluorescence, carbonyl sulfide flux measurements, thermography, and more. Such comparisons would improve our mechanistic understanding of ecosystem water fluxes and provide the observations necessary to validate remote sensing algorithms and land surface models to understand the changing global water cycle.{\textless}/p{\textgreater}},
	language = {English},
	number = {19},
	urldate = {2019-10-01},
	journal = {Biogeosciences},
	author = {Stoy, Paul C. and El-Madany, Tarek S. and Fisher, Joshua B. and Gentine, Pierre and Gerken, Tobias and Good, Stephen P. and Klosterhalfen, Anne and Liu, Shuguang and Miralles, Diego G. and Perez-Priego, Oscar and Rigden, Angela J. and Skaggs, Todd H. and Wohlfahrt, Georg and Anderson, Ray G. and Coenders-Gerrits, A. Miriam J. and Jung, Martin and Maes, Wouter H. and Mammarella, Ivan and Mauder, Matthias and Migliavacca, Mirco and Nelson, Jacob A. and Poyatos, Rafael and Reichstein, Markus and Scott, Russell L. and Wolf, Sebastian},
	month = oct,
	year = {2019},
	pages = {3747--3775},
	file = {Stoy et al_2019_Reviews and syntheses.pdf:/media/rafap/Data/Documents/Zotero/storage/4BN64RVV/Stoy et al_2019_Reviews and syntheses.pdf:application/pdf}
}

repository: rafapoyatos/academic-kickstart

repo_name: rafapoyatos/academic-kickstart