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Late spring frost plays a major role in the structure and function of forest ecosystems with potential consequences on species distribution at both local and regional scales. Paradoxically, in a warmer world the incidence and impact of frost is increasing because of earlier leaf unfolding and flowering as a response to warmer temperatures. In this regard, European Beech (Fagus sylvatica L.), a native tree species widely distributed in European forests, is considered particularly sensitive to changes in spring temperature regimes associated with climate change and thus especially subject to the risk of frost damage. Although several studies concerning F. sylvatica frost damage have been conducted in northern and central Europe, no extensive studies are available for the southern part of its range, i.e. central and southern Italy as well as Greece. In this paper the effect of a late spring frost occurring at the end of April 2016 is extensively documented with high spatial detail all along the Apennine Chain through satellite image data. Three different remote-sensing greenness indexes, namely the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and the greenness index (GI) derived from Landsat-8 satellite images acquired from May to July in the years 2014, 2015, and 2016 at a spatial resolution of 30 m, were used to gauge the spatial response of common beech forests to this late frost event with relation to latitude, altitude and slope exposure. Frost damage was evaluated as a difference (Δ) of NDVI, GI and EVI between the mean of years 2014 and 2015 (i.e. MRY, mean of reference years), and 2016 (i.e. FEY, frost reference year). The three satellite remote-sensing indexes were efficient at detecting leaf damage with detailed spatial resolution and proved consistent with one another. The greatest damage occurred in the middle altitudinal range between 1500 and 1700 m a.s.l. with a decreasing trend toward both lower and higher elevations due to warmer temperatures below, and delayed phenology above. Exposure also influenced frost injury, with south-facing slopes of the mountain more damaged than the north. This difference was due to earlier spring leaf phenology of southern beech trees in response to a greater heat sum in the warm weeks preceding. Less damage in the northern Apennines is consistent with the spatial extent of minimum freezing temperatures. To sum up, frost damage is strongly related to site-specific conditions, i.e. on the one hand to minimum temperatures, and on the other to the phenological stage of the trees involving both altitude and exposure. Hence focusing on detailed sub-regional studies can be helpful for predicting future consequences of climate change on forests.

Study region: The study region is represented by seven irrigation districts distributed under different climate and topography conditions in Italy. Study focus: This study explores the reliability and consistency of the global ERA5 single levels and ERA5-Land reanalysis datasets in predicting the main agrometeorological estimates commonly used for crop water requirements calculation. In particular, the reanalysis data was compared, variable-by-variable (e.g., solar radiation, R; air temperature, T; relative humidity, RH; wind speed, u; reference evapotranspiration, ET), with in situ agrometeorological observations obtained from 66 automatic weather stations (2008–2020). In addition, the presence of a climate-dependency on their accuracy was assessed at the different irrigation districts. New hydrological insights for the region: A general good agreement was obtained between observed and reanalysis agrometeorological variables at both daily and seasonal scales. The best performance was obtained for T, followed by RH, R, and u for both reanalysis datasets, especially under temperate climate conditions. These performances were translated into slightly higher accuracy of ET estimates by ERA5-Land product, confirming the potential of using reanalysis datasets as an alternative data source for retrieving the ET and overcoming the unavailability of observed agrometeorological data.

Soil bioengineering techniques to repair slope failures and increase slope stability are often used, if possible, as alternatives to traditional structures in order to mitigate the environmental impact without losing the effectiveness of the work. These techniques use live plants and entrust most of their structural resistance to wood members whose mechanical characteristics, however, decrease with time. Very few investigations have dealt with the decay of mechanical characteristics of wood elements employed in soil bioengineering techniques and lifetime predictions. This information is also important for durability forecasting. In this paper we present the results of experimental analyses carried out to evaluate the degradation of mechanical properties of untreated timber elements, which were collected from single and double live cribwalls or check-dams built about 10 years ago in the Vesuvius National Park (Naples, Southern Italy). To help in adequately interpreting the behavior of a complex material such as wood, a novelty of this study is not only the coupling of the ultrasonic and sclerometric nondestructive testing (NDT) methods so as to reduce measurement errors, but also to frame the outcomes from mechanical tests within the biological analysis of fungi detected on the timbers. Exploratory statistical analyses have revealed that there exist nearly no correlations between moisture contents in the timber elements and both transversal and longitudinal ultrasonic velocities, but some clustering provides insights in the results obtained. Comparisons between results using data measured on “old” and “new” timber elements enable some evaluations of residual safety factor assessment to be carried out.

A generalised framework of space-time variability in flood response is used to characterise five flood events of different type in the Kamp area in Austria: one long-rain event, two short-rain events, one rain-on-snow event and one snowmelt event. Specifically, the framework quantifies the contributions of the space-time variability of rainfall/snowmelt, runoff coefficient, hillslope and channel routing to the flood runoff volume and the delay and spread of the resulting hydrograph. The results indicate that the components obtained by the framework clearly reflect the individual processes which characterise the event types. For the short-rain events, temporal, spatial and movement components can all be important in runoff generation and routing, which would be expected because of their local nature in time and, particularly, in space. For the long-rain event, the temporal components tend to be more important for runoff generation, because of the more uniform spatial coverage of rainfall, while for routing the spatial distribution of the produced runoff, which is not uniform, is also important. For the rain-on-snow and snowmelt events, the spatio-temporal variability terms typically do not play much role in runoff generation and the spread of the hydrograph is mainly due to the duration of the event. As an outcome of the framework, a dimensionless response number is proposed that represents the joint effect of runoff coefficient and hydrograph peakedness and captures the absolute magnitudes of the observed flood peaks.

This study presents a methodology to assess uncertainties resulting from the use of pedotransfer functions (PTFs) when soil water budget is modelled at a hillslope scale. Two sources of uncertainty are examined: (i) errors in the assessment of the soil physical and chemical properties at unsampled locations, as related to the spatial spacing of the sample measurements across the entire study area, and (ii) errors associated to the PTF relations and parameters. This methodology is applied to an experimental hillslope in Southern Italy, where an intensive field campaign has been conducted to gather several soil physical and chemical properties and soil hydraulic properties. A sequential Gaussian simulation algorithm is used to generate multiple equally probable images of PTF input soil data, consistent with the estimated spatial structure and conditioned to the measured soil core properties. Two PTFs commonly used in Europe, Vereecken's PTF [Vereecken, H., Diels, J., van Orshoven, J., Feyen, J., Bouma, J., 1992. Functional evaluation of pedotransfer functions for the estimation of soil hydraulic properties. Soil Sci. Soc. Am. J. 56, 1371–1378] and HYPRES PTF [Wosten, J.H.M., Lilly, A., Nemes, A., Le Bas, C., 1999. Development and use of a database of hydraulic properties of European soils. Geoderma 90, 169–185] are applied to predict the soil hydraulic properties, which in turn are employed into a soil–vegetation–atmosphere model to evaluate the propagated uncertainty in simulated target variables, such as evaporation, transpiration and root zone soil water content variation during a wet-to-dry transition season. The outcomes of this case study suggest that accurate estimates of transpiration and soil water storage variation at the hillslope scale are obtained even when PTF input data are collected with a relatively coarse sampling strategy. The examined PTFs show worse level of performance with respect to the simulated evaporation. The simulated evaporation is much more affected by the PTF model error than by the input data error. A major implication of these results is that if one would reduce the prediction uncertainty in simulated evaporation, the PTF model structure has to be improved prior of reducing the uncertainty into the PTF input data.