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Healing rate of logging wounds on broadleaf trees in hyrcanian forest with some technological implications
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Study of the effect of protective on wood photo-degradation by colour measurements, FT-IR spectroscopy and hyperspectral imaging
No full textThe aim of this work is to investigate the effect of protective materials on poplar (Populus spp.) wood modifications as consequence of artificial photo-degradation in controlled environment. Starting from previous results [1-4], this study tried to understand what happens to wood surface under the protective layer.
As protective materials, shellac, beeswax and Linfoil® were tested to compare traditional and novel products generally used for wood. The samples covered by these protective layers were artificially aged in Solar Box for 1064 hours. As comparison, also uncovered samples were tested.
At chosen times, the samples were investigated by reflectance spectrophotometry, Fourier transform infrared spectroscopy and hyperspectral imaging in order to study the colour and chemical modification occurred to wood both covered and uncovered with the protective products. The obtained data were statistically elaborated in order to verify their significance.
Colour measurements highlighted that the protective materials reduced the wood colour changes in respect to un-protected samples. FT-IR spectroscopy demonstrated that photo-degradation caused mainly lignin decomposition with the production of new chromophore groups on wood surface. Also in this case un-covered wood underwent greater modifications in respect to protected one. Hyperspectral imaging in the SWIR range (1000-2500 nm), coupled with chemometric methods, clearly showed the variation between the spectral behavior of poplar wood for ageing time 0 and 1064 hours, with different protective layers.
It is interesting to note that protective materials have a partial effect on wood photo-degradation by little reducing the changes.
Such results can contribute to evaluate the effect of protective materials on wood during sun exposure
Hyperspectral imaging as a technique for investigating the effect of consolidating materials on wood
No full textThe focus of this study was to investigate the potential of hyperspectral imaging (HSI) in the monitoring
of commercial consolidant products applied on wood samples. Poplar (Populus spp.) and walnut (Juglans
Regia L.) were chosen for the consolidant application. Both traditional and innovative products were selected,
based on acrylic, epoxy, and aliphatic compounds. Wood samples were stressed by freeze/thaw cycles in order
to cause material degradation without the loss of wood components. Then the consolidant was applied under
vacuum. The samples were finally artificially aged for 168 h in a solar box chamber. The samples were acquired
in the short wave infrared (1000 to 2500 nm) range by SISUChema XLTMdevice (Specim, Finland) after 168 h of
irradiation. As comparison, color measurement was also used as an economic, simple, and noninvasive technique
to evaluate the deterioration and consolidation effects on wood. All data were then processed adopting a
chemometric approach finalized to define correlation models, HSI based, between consolidating materials, wood
species, and short-time aging effects
Snow damages on trees of an uneven age in mixed broadleaf forests: effects of topographical conditions and tree characteristics
Full text linkSnow damage on natural stands is an important problem concerning mountainous forest management. In the present research, the frequency and intensity of heavy snow damage on natural stands and the relationship of damages with characteristics of trees, stand and topography were studied in mountainous forests of northern Iran. A systematic sampling design was applied to the study area (140 ha), with 122 circular plots. The grid dimension was 100 m and each plot area was 1000 m2. The four types of snow damage to trees include: crown damage (8.6%), stem breakage (5.4%), uprooting (3.2%), and bending (1.4%). The frequency of crown damage grew with an increase in the diameter at breast height (DBH), while the frequency of stem breakage, uprooting and bending decreased with an increase the DBH. The frequency of crown damage, stem breakage, and total damages was related to tree species (p < 0.01). Not all tree species were equally susceptible to snow damage. The amount of damage grew with increasing elevation and slope angle and decreased with increasing soil depth. Young trees (DBH < 25 cm) were more susceptible to snow damage than other trees. Snow damage decreased by as the trees in the stand became more mixed in age. The susceptibility of trees to snow damage increased by height and slenderness coefficient. With adequate silvicultural operation, snow damage can be reduced to a minimum level in these natural forests.6s
Study of forest road effect on tree community and stand structure in three italian and Iranian temperate forests
Full text linkRoads 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
Healing ability and diameter growth of lime-trees (Tilia begonifolia Stev.) following logging wounds
Full text linkCorsican pine (Pinus laricio Poiret) stand management: Medium and long lasting effects of thinning on biomass growth
Full text linkWith 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
Modeling color and chemical changes on normal and red heart beech wood by reflectance spectrophotometry, Fourier Transform Infrared spectroscopy and hyperspectral imaging
No full textThe use of beech is a key topic for Europe as it is one of the most important and abundant broad-leaf species. Physical, mechanical and esthetical features influence both the value and the usage of this wood in each commercial product. In this sense, the comprehension of the surface color modifications induced by solar irradiation is of crucial importance to define the commercial value of the beech wood.
Starting from these general remarks, the aim of this work is to study the surface modifications on beech wood with and without red heartwood by different spectroscopic techniques and to obtain a modeling of the changes validated by rigorous statistical and chemometric methods together with principal component analysis.
The artificial photo-irradiation of the wood samples was performed in a Solar Box. Reflectance spectrophotometry, Fourier Transform Infrared spectroscopy and hyperspectral imaging were used to assess artificial sunlight influence. The experimental data were statistically treated in order to evaluate their significance.
Color monitoring allowed to find that the chromatic coordinates (L*a*b*) in normal wood and in red heartwood tended to similar values after 504 h of photo-irradiation.
Fourier Transform Infrared spectroscopy showed the rate of photo-degradation of wood surface due to lignin oxidation and the statistical analysis allowed to demonstrate that red heart and normal wood have the same behavior.
Concerning hyperspectral imaging (HSI), the detected spectral features were correlated to color changes in the Visible-Near Infrared (VIS-NIR) range (400-1000 nm) and to the variations of cellulose and lignin during accelerated aging in the Short-Wave Infrared (SWIR) range (1000-2500 nm).
The most important result is that a correlation, validated by statistical analysis, of the color changes may be derived with the photo-degradation of wood components obtained by spectral analysis. This fact suggests the possibility to choose the reflectance spectrophotometry as a non-invasive, simple standard method to monitor the state of preservation of the wood surfaces
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