Post-fire restoration in Alpine environment: from the microsite to the landscape. Multi-scale approach for the definition of mitigation strategies

Forest fires in the Alps are increasing both in frequency and size, especially on southern slopes where environmental conditions are more suitable for fire ignition and spread. Post-fire restoration activities are often applied without considering the large heterogeneity and variability of ecological constraints. Fire severity, species composition and site characteristics heavily affect vegetation recovery dynamics. The main objectives of this study were to test the hypothesis that post-fire burned wood management may greatly affect forest recovery and to identify the main environmental variables affecting seedling establishment and survival. We investigated restoration dynamics following high severity crown fire in two forests located in Western (Bourra site - Aosta Valley) and Eastern (Barcis site - Friuli Venezia Giulia) Italian Alps. Fires burnt large area of pine forests (P. sylvestris, P. nigra) located on southern slopes, characterized by harsh conditions (dry environment with high solar radiation exposure). In both sites active restoration strategies were adopted in the following years. These practices consisted in Salvage logging (cut and deadwood removal) followed by plantation or not, and Cut and release (living deadwood on site). Passive management area (remnants of burnt stand trees, where no intervention occurred) was also considered and compared. The recovery processes of vegetation were explored through methods of integrated analysis, using different spatial- and temporal-scale approaches. Field-data measures on regeneration, shelter elements and environmental variables were analyzed at microsite scale. Maps of fire severity were created by means of change-detection techniques on Landsat TM/ETM+ images. A scan through the time of forest recovery was performed associating regeneration and environmental data with Vegetation Indices (VIs) derived from a chronosequence of multispectral images. The evaluation of post-fire recovery dynamics, their relationships with fire severity and restoration activities are analyzed at a landscape scale, combining field-data, VIs, topographic and vegetation parameters extracted from LiDAR data. The influence of post-fire management on microclimate was investigated by means of instrumental measurements of environmental parameters affecting the regeneration dynamics. Measurements of soil temperature and moisture together with estimates of near-ground solar radiation were carried during a whole growing season within areas subjected to different restoration practices. Differences in species composition were found in the study sites among treatments. Regeneration density and diversity were positively associated with deadwood presence. Early establishment of pine seedlings was associated with the presence of standing or lying deadwood. Conversely, Populus tremula, regenerating mostly vegetatively, showed a different behaviour from the other tree species. Ground cover conditions contributed to patterns of seedling occurrence. The strong spatial association of seedlings with deadwood suggests that this latter produces microsites that enhance the establishment of regeneration. The relationship between nurse deadwood elements and regeneration was found to be highly anisotropic, as a consequence of the higher protection from radiation and lower soil moisture loss in the shady sides of the shelter element. Marked differences in incoming solar radiation, soil moisture and temperature were detected among treatments, in particular, salvaged areas resulted strongly associated with severe environmental conditions. Higher fire severity diminishes seed availability reducing the seeders, thus the distance from seed source has emerged as an important constraint for pine regeneration establishment. In relation to different spatio-temporal scales of analysis, this research reports a significant impact of the post-fire management actions on forest recovery. Restoration practices may significantly affect environmental parameters, particularly in stressful conditions,. The presence of burnt wood provides an amelioration of microsite reducing the extreme values, buffering microclimatic fluctuations thus favoring the establishment of regeneration. Standing and lying deadwood, also resulting from active management, should be leaved in situ during restoration activities

Analysis of the structural behavior of an innovative reinforced ski boot

Abstract The effect on the boot structural behavior of a stiffening aluminum bootboard has been investigated by laboratory and field tests. Stiffness tests on the boot with the bootboard screwed to the shell (state ON) showed a 20% increase with respect to the unscrewed state (OFF). Lateral stiffness tests conducted on a servohydraulic test bench together with motion capture techniques did not show significant increases due to the bootboard. Strain gauges applied to the bootboard for measuring torsion and bending moments in the field confirmed the intervention of the bootboard torsional stiffness at the edge changes during slalom turns

Analysis of RGB-D camera technologies for supporting different facial usage scenarios

AbstractRecently a wide variety of applications has been developed integrating 3D functionalities. Advantages given by the possibility of relying on depth information allows the developers to design new algorithms and to improve the existing ones. In particular, for what concerns face morphology, 3D has led to the possibility to obtain face depth maps highly close to reality and consequently an improvement of the starting point for further analysis such as Face Detection, Face Authentication, Face Identification and Face Expression Recognition. The development of the aforementioned applications would have been impossible without the progress of sensor technologies for obtaining 3D information. Several solutions have been adopted over time. In this paper, emphasis is put on passive stereoscopy, structured light, time-of-flight (ToF) and active stereoscopy, namely the most used technologies for the cameras design and fulfilment according to the literature. The aim of this article is to investigate facial applications and to examine 3D camera technologies to suggest some guidelines for addressing the correct choice of a 3D sensor according to the application that has to be developed