Fuel for collective action: A SWOT analysis to identify social barriers and drivers for a local woody biomass supply chain in an Italian alpine valley.

The role of woody biomass in the clean energy transition is substantial in the EU. Forest residues are one of the main biomass sources that can be used for energy production, but their use to support the energy transition is still limited for several reasons. Research has shown that the use of forest residues in energy production can be effectively stimulated through collective actions that aim to develop short and local supply chains. This study aims to identify the barriers and drivers for the development of a local supply chain for forest residues in an Italian alpine valley, gathering and analysing the perspectives of all involved local actors, that is, (i) suppliers - the communities that own the forest resources, (ii) intermediaries - the forest professionals providing extension and advice services to owners and the harvesting companies; and (iii) the final consumers, in this case the local municipalities and hospitality enterprises. Data are analysed using a SWOT analysis. The results show that the suppliers identified opportunities especially, while the final consumers focused more on strengths, weaknesses, and threats. The SWOT categories in terms of the number of different factors were weaknesses (37 %), strengths (27 %), threats (18 %), and opportunities (17 %). Opportunities and strengths were considered as drivers, while threats and weaknesses were barriers. Several drivers emerged, such as a general predisposition toward the development of a local supply chain for forest residues, social homogeneity in terms of knowledge and management of the land, and common challenges. Barriers also emerged in the form of limited know-how on the supply chain potential, but also in limited availability to concede control between different forest owners over their property. The SWOT results are useful to design strategies to support the development of the supply chain: four possible strategies, amongst which flexible cooperation processes between different categories of stakeholders, and the organisation of a buying group of the hospitality enterprises, were suggested.

Identification and Analysis of the Geohazards Located in an Alpine Valley Based on Multi-Source Remote Sensing Data.

Geohazards that have developed in densely vegetated alpine gorges exhibit characteristics such as remote occurrence, high concealment, and cascading effects. Utilizing a single remote sensing datum for their identification has limitations, while utilizing multiple remote sensing data obtained based on different sensors can allow comprehensive and accurate identification of geohazards in such areas. This study takes the Latudi River valley, a tributary of the Nujiang River in the Hengduan Mountains, as the research area, and comprehensively uses three techniques of remote sensing: unmanned aerial vehicle (UAV) Light Detection and Ranging (LiDAR), Small Baseline Subset interferometric synthetic aperture radar (SBAS-InSAR), and UAV optical remote sensing. These techniques are applied to comprehensively identify and analyze landslides, rockfalls, and debris flows in the valley. The results show that a total of 32 geohazards were identified, including 18 landslides, 8 rockfalls, and 6 debris flows. These hazards are distributed along the banks of the Latudi River, significantly influenced by rainfall and distribution of water systems, with deformation variables fluctuating with rainfall. The three types of geohazards cause cascading disasters, and exhibit different characteristics in the 0.5 m resolution hillshade map extracted from LiDAR data. UAV LiDAR has advantages in densely vegetated alpine gorges: after the selection of suitable filtering algorithms and parameters of the point cloud, it can obtain detailed terrain and geomorphological information on geohazards. The different remote sensing technologies used in this study can mutually confirm and complement each other, enhancing the capability to identify geohazards and their associated hazard cascades in densely vegetated alpine gorges, thereby providing valuable references for government departments in disaster prevention and reduction work.

Machine learning approaches to debris flow susceptibility analyses in the Yunnan section of the Nujiang River Basin.

Background: The Yunnan section of the Nujiang River (YNR) Basin in the alpine-valley area is one of the most critical areas of debris flow in China. Methods: We analyzed the applicability of three machine learning algorithms to model of susceptibility to debris flow-Random Forest (RF), the linear kernel support vector machine (Linear SVM), and the radial basis function support vector machine (RBFSVM)-and compared 20 factors to determine the dominant controlling in debris flow occurrence in the region. Results: We found that (1) RF outperformed RBFSVM and Linear SVM in terms of accuracy, (2) topographic conditions were prerequisites, and geology, precipitation, vegetation, and anthropogenic influence were critical to forming debris flows. Also, the relative elevation difference was the most prominent evaluation factor of debris flow susceptibility, and (3) susceptibility maps based on RF's debris flow susceptibility (DFS) showed that zones with very high susceptibility were distributed along the mainstream of the Nujiang River. These findings provide methodological guidance and reference for improvement of DFS assessment. It enriches the content of DFS studies in the alpine-valley areas.

Growing season water balance of an inner alpine Scots pine (Pinus sylvestris L.) forest.

We estimated components of the water cycle of a 150-year-old Pinus sylvestris forest in an inner Alpine dry valley of the Tyrol, Austria throughout five growing seasons. Forest canopy transpiration (TC) was measured by sap flow measurements scaled to the stand canopy level. Estimates of understory transpiration and forest floor evaporation (ETU) were derived from the soil water budget method, while interception (I) was modelled. Growing season cumulative evapotranspiration (ET = TC + ETU + I) varied between 256 and 322 mm or 51 to 79% of the growing season precipitation. The contribution of TC, ETU, and I to ET were 33, 40 and 27% respectively. Although these values of each layer (evapo)-transpiration are in good agreement with studies carried out in other European Scots pine forests, our estimated growing season total forest water use (Ttot = Tc + ETu) of 200-244 mm is at the lower end of values reported for coniferous forest ecosystems, and thus reflects an adaptation to the low shallow soil water availability. We conclude that Scots pine forests in inner alpine dry valleys are able to cope with high evaporative demand, even when shallow soil water availability is limited.

Tree water status and growth of saplings and mature Norway spruce (Picea abies) at a dry distribution limit.

We evaluated the size effect on stem water status and growth in Norway spruce (Picea abies (L.) Karst.) occurring at the edge of its natural range in a dry inner Alpine environment (750 m asl, Tyrol, Austria). Intra-annual dynamics of stem water deficit (ΔW), maximum daily shrinkage (MDS), and radial growth (RG) were compared among saplings (stem diameter/height: 2.2 cm/93 cm; n = 7) and mature adult trees (25 cm/12.7 m; n = 6) during 2014. ΔW, MDS, and RG were extracted from stem diameter variations, which were continuously recorded by automatic dendrometers and the influence of environmental drivers was evaluated by applying moving correlation analysis (MCA). Additionally, we used Morlet wavelet analysis to assess the differences in cyclic radial stem variations between saplings and mature trees. Results indicate that saplings and mature trees were experiencing water limitation throughout the growing season. However, saplings exhibited a more strained stem water status and higher sensitivity to environmental conditions than mature trees. Hence, the significantly lower radial increments in saplings (0.16 ± 0.03 mm) compared to mature trees (0.54 ± 0.14 mm) is related to more constrained water status in the former, affecting the rate and duration of RG. The wavelet analysis consistently revealed more distinct diurnal stem variations in saplings compared to mature trees. Intra-annual RG was most closely related to climate variables that influence transpiration, i.e., vapor pressure deficit, relative air humidity, and air temperature. MCA, however, showed pronounced instability of climate-growth relationships, which masked missing temporal or significant correlations when the entire study period (April-October) was considered. We conclude that an increase in evaporative demand will impair regeneration and long-term stability of drought-prone inner Alpine Norway spruce forests.

Large chemical characterisation of PM10 emitted from graphite material production: Application in source apportionment.

This work focuses on emissions from industrial sources that are still poorly understood in Europe, especially the "carbon industry". The study is based on two intensive sampling campaigns performed in a graphite material production plant for 2weeks in July 2013 and November 2013 in alpine valleys. The chemical characterization of PM10 was conducted at three sampling sites (outdoor and indoor sites) located inside one industrial area, which is considered as the highest emissions source of polycyclic aromatic hydrocarbons (PAHs) in the Arve valley. The identification of specific tracers among metals and trace elements is commonly used to characterize industrial emissions. In our study, original enrichment factors relative to the "rural exposed background" have been calculated, and the metallic fraction was not affected by this industrial source. In contrast, the organic fraction of PM10 has a number of features, providing a complete organic source profile and referred to as the "carbon industry". In particular, polycyclic aromatic sulfur heterocycles (PASH) have been largely detected from fugitive emissions with rather large concentrations. The average concentrations of benzo(b)naphtho(2,1-d)thiophene (BNT(2,1)) reached 2.35-6.56ng·m(-3) and 60.5-376ng·m(-3) for outdoor and indoor sites, respectively. The use of this reference profile in the chemical mass balance model (CMB) applied to samples collected in two sites near industrial areas shows that this source had an average contribution of 6% of the organic matter (OM) mass during the sampling period during the winter of 2013.

Drought sensitivity of three co-occurring conifers within a dry inner Alpine environment.

We applied dendroclimatological techniques to determine long-term stationarity of climate-growth relationships and recent growth trends of three widespread coniferous tree species of the central Austrian Alps, which grow intermixed at dry-mesic sites within a dry inner Alpine environment (750 m asl). Time series of annual increments were developed from > 120 mature trees of Picea abies, Larix decidua and Pinus sylvestris. Calculation of response functions for the period 1911 - 2009 revealed significant differences among species in response to climate variables. While precipitation in May - June favoured radial growth of Picea abies and Larix decidua, Pinus sylvestris growth mainly depended on April - May precipitation. P. abies growth was most sensitive to May - June temperature (inverse relationship). Moving response function coefficients indicated increasing drought sensitivity of all species in recent decades, which is related to a decline in soil moisture availability due to increasing stand density and tree size and higher evapotranspiration rates in a warmer climate. While recent trend in basal area increment (BAI) of L. decidua distinctly declined implying high vulnerability to drought stress, moderately shade-tolerant P. abies showed steadily increasing BAI and quite constant BAI was maintained in drought adapted P. sylvestris, although at lowest level of all species. We conclude that synergistic effects of stand dynamics and climate warming increased drought sensitivity, which changed competitive strength of co-occurring conifers due to differences in inherent adaptive capacity.

Cambial activity and xylem cell development in Pinus cembra and Pinus sylvestris at their climatic limits in the Eastern Alps in 2007.

It has been frequently stressed that at distributional boundaries, like at the Alpine timberline and within dry inner Alpine environments, tree growth will be affected first by changing climate conditions. Climate in 2007 was characterized by the occurrence of exceptionally mild temperatures in spring (3.4 and 2.7 °C above long-term mean (LTM) at timberline and the valley sites, respectively) with an almost continuous drought period recorded in April and slightly warmer than average temperatures throughout summer (1.3 °C above LTM at both sites). We compared temporal dynamics of cambial activity and xylem cell development in Pinus cembra at the Alpine timberline (1950 m a.s.l.) and Pinus sylvestris at a xeric inner Alpine site (750 m a.s.l.) by repeated cellular analyses of micro-cores (n = 5 trees/site). While onset of wood formation in P. sylvestris and P. cembra differed by about two weeks (12 and 27 April, respectively), maximum daily growth rates peaked on 6 May at the valley site and on 23 June at timberline. At both sites maximum tracheid production was reached prior to occurrence of more favourable climatic conditions during summer, i.e. an increase in precipitation and temperature. Xylem formation ended on 31 August and 28 October at the xeric site and at timberline, respectively. This study demonstrates the plasticity of tree-ring formation along an altitudinal transect in response to water availability and temperature. Whether early achievement of maximum growth rates is an adaptation to cope with extreme environmental conditions prevailing at limits of tree growth needs to be analysed more closely by taking belowground carbon allocation into account.