Characterisation of Woody Necromass in Beech Forests with Different Anthropic Accessibility: The Case of La Rioja (Spain)

In this study, a comprehensive analysis of deadwood was conducted in four macro-areas located in two beech forests of public utility in Enciso (La Rioja, Spain). Dendrometric data, as well as qualitative and quantitative characteristics of deadwood, were collected and analysed with respect to the degree of accessibility to the forest to determine the effect of different levels of forest accessibility on deadwood volume and carbon stocks. All decomposition classes were present except the first, highlighting the development of natural degradation dynamics. Deadwood stored 6.9 t/ha of C in the easy accessibility class, 5.7 t/ha of C in the medium accessibility class and 2.2 t/ha of C in the difficult accessibility class. The average volume of deadwood and carbon stored calculated in this study were higher than the values reported in the Spanish and Italian national forest inventories, including one developed for Riojan beech forests. Deadwood volume was on average 22.5 m3/ha, showing an unequal distribution, with the lowest values found far from the access roads, despite forest accessibility generally being considered a factor that facilitates the human collection of deadwood. The distribution patterns of deadwood in beech forests of La Rioja, apparently counterintuitive, were due to a combination of different factors, including slope, cattle grazing, and weather conditions which might have favoured downward movement of the deadwoodThis research was funded by the Spanish Ministry of Science, Innovation and Universities, AGL2016-76769-C2-2-RS

La valutazione sperimentale dei consolidanti per il legno

The aim of this work has been to test some commercial products as consolidants of the structure of two wooden species: poplar (Populus sp.) and walnut (Juglans regia L.). The chosen products are acrylic, epoxy and aliphatic compounds available in commerce and often employed for other applications. The wooden samples have been prepared according to the UNI ISO instructions. The wood characteristic parameters have been measured: density, basic density, shrinkage, porosity, colour. The wooden samples have been artificial aged by means of frost/thaw cycles. The consolidants have been applied to the wood samples aged and not by means of under vacuum immersion. At the end the wood characteristic parameters and the FTIR spectra have been measured to evaluate the product effectiveness for the wood treatment

Corsican Pine (Pinus laricio Poiret) Stand Management: Medium and Long Lasting Effects of Thinning on Biomass Growth

With the aim of acquiring better comprehension of the ecological and productive aspects of the management of pine forests, we monitored logging damage and evaluated the effects of thinning on stand growth 20 years after the treatment in a Pinus laricio Poiret stand in central Italy. The objectives of the present study were to estimate the injury levels to the remaining trees after thinning; to assess logging damage in the long-term by monitoring residual trees at the end of thinning; to evaluate the effect of damage on the radial growth of trees; to assess the stand dynamics in relation to injury levels and the treatment applied in a twenty-year range; to understand a possible treatment return time; and to evaluate the existence of the “thinning shock”. The results were that 20 years after treatment, the stand dynamics showed a complete recovery; logging damage did not affect the radial growth of P. laricio over time; a second treatment seem to be sustainable starting from the fifteenth year after the previous treatment; and the thinning shock can be clearly evaluated in the first six to seven years after the treatment

Colour modifications and hyperspectral imaging: non-invasive analysis of photo-degraded wood surfaces

The aim of this investigation is to study the changes occurring on the surface of poplar wood exposed to solar irradiation, in a controlled environment. Poplar is poor of coloured extractive, so that the surface changes are attributed to the main wood constituents’ modifications and the contribution of extraneous substances to holocellulose and lignin can be considered negligible. The poplar wood samples were irradiated in a Solar Box chamber, equipped with a 280 nm UV filter, until reaching 504 hours. The colour changes were monitored with the reflectance spectrophotometer of X-Rite CA22 according to the CIELAB system. The surface chemical modifications were evaluated by measuring the infrared spectra with a Fourier Transform Infrared spectrometer (FT-IR) operating in DRIFT modality. Hyperspectral imaging (HSI) was also applied to study the surface wood changes by using a SisuCHEMA XL Workstation operating in the SWIR range (1000-2500 nm). The data obtained from the different techniques applied were put in comparison in order to find possible correlations between them also with the aim to evaluate the applicability of the HSI technique to the investigation of wood modifications, in a totally non-invasive modality. The possibility to find a correlation between colour changes and chemical modifications, investigated both with traditional and innovative methodologies, in wood surfaces can have practical application in cultural heritage and contemporary objects

Surface Investigation of Photo-Degraded Wood by Colour Monitoring, Infrared Spectroscopy, and Hyperspectral Imaging

The aim of this investigation is to study the changes occurring on the surface of poplar wood exposed to artificial irradiation in a Solar Box. Colour changes were monitored with a reflectance spectrophotometer. Surface chemical modifications were evaluated by measuring the infrared spectra. Hyperspectral imaging was also applied to study the surface wood changes in the visible-near infrared and the short wave infrared wavelength ranges. The data obtained from the different techniques were compared to find the possible correlations in order to evaluate the applicability of the Hyperspectral imaging to investigate wood modifications in a non-invasive modality. The study of colour changes showed an important variation due to photo-irradiation which is the greatest change occurring within the first 24 hours. Infrared spectroscopy revealed that lignin degrades mainly in the first 48 hours. Concerning Hyperspectral imaging, the spectral features in the visible-near infrared range are mainly linked to the spectral shape, whereas in the short wave infrared cellulose and lignin affect shape and reflectance levels. The proposed approach showed that a correlation can be established between colour variation and wood degradation in the visible-near infrared range; furthermore in the short wave infrared region surface chemical changes can be assessed

Study of Forest Road Effect on Tree Community and Stand Structure in Three Italian and Iranian Temperate Forests

Roads are built in forests for two main reasons, but always in function of management of forest ecosystems, and these reasons are to provide access to the forest area for transportation mobility and wood extraction. This creates a relatively even network in the forest. This topic has received much attention in recent years due to its function and effect on forested rural landscapes and the related environment. Forest road network is important for various types of functional use, such as the interface between forested lands and roads. The aim of this study is to assess the effects of road existence and use on the occurrence of tree dieback and on the composition of the tree community in three forest areas (two in Italy and one in Iran). The effort to determine the dynamics of the effects caused by road use was done by examining the changes in stand structure and abundance of species. As demonstrated by the results, the edges (20 m) of the forest road network are a fine mosaic composed of different trees (qualitative and quantitative), coupled with the moderate presence of dead trees. In the three areas, from the road edges to the interior forest, a similar taxonomic composition of forest community was found. The first main difference was related to the abundance of less shadow tolerant species along the road. The second main difference was related to the tree biodiversity indices that are higher along the road. The main similarities are in the structure of live and dead trees