Metodi integrati per la valutazione delle caratteristiche tecnologiche del legno di castagno di diverse provenienze nella Regione Lazio. Analisi fisico-chimiche-meccaniche e xilogenesi
Author(s)
Spina, Stefano
Date Issued
March 11, 2011
Type
Doctoral Thesis
Abstract
Chestnut is one of the best forest interest species in the Italian forest landscape: its value for both economic and environmental stresses its role as the first plan in an mountain economy facing side to maximize profits and the other to protect the environment and the rural landscape. The chestnut has the characteristics technology which makes it very listed for multiple purposes, and shows a rapid surprising growth, especially in some areas. The wood to its high technology and aesthetics that make it very appreciated by the market, in addition to its natural durability allow a wide use in Construction of buildings, also new industrial applications related to tannins still in testing and gives hope opening of new markets and economies. The species, however, has many limitations and selvicultural problems. Ringshake more than any other, conditions the use of wood material. The study has as its principal purpose to increase knowledge on the chestnut tree in order to understand the real potential technology of the different areas, in the Lazio Region, to prospect alternative employment, in technological innovation, for the rational use of biomass, not only for energy purpose. The main goal through the exploration and study of some of main issues related to the species. The research explores the following fact topics:
• the Ringshake; • physical- mechanical analysis; • study of xylogenesis; • chemical analysis of lignin; • Innovative technological experimentation the use of tannin;
The study about the ringshake has clarified,, but not resolved, some issues related to the defect, allowing to propose selvicultural solutions and appropriate action to contain it; a proper forest management could reduce risk and produce material best quality: it is not recommended lengthen the rotation of the coppice, if you do not take early thinning, beyond the limit production allowed by the station (as dendrochronological study shows). Indeed it was observed that age is main factor to cause and to increase the risk and the extent of defect, which manifests itself in an obvious in old coppice with age above 30 years. Therefore, the standard are more affected trees. The research conducted under this thesis showed that the limit of 12 - 14 years is considered a critical period for manifestation of the shake, because of internal stresses that may occur into development of trees. However, the cracks beginning to emerge already at 7 years. The age of 12-14 years is not related to defined diameter, the plants size, at the same age, don’t have a great effect about the shake. Restrict the defect by appropriate forest management is not easy, it a check on each situation. In the Cimini Mountains has been shown the shakes occur at cutting or pruning time, and how selvicultural actions have a retroactive effect in manifestation of the defect, ie cracks appear before year of cutting. In general, the thinning create disturbances in the balance Static plant that can cause or accentuate the shake, then, according other researchers, interventions should proceed in a gradual and continues because it was observed that the quality of material (ie mechanical properties and wood density) decreases at to increase of the ring: ring width should not exceed 5 mm per year, although this is variable in relation the origin area of trees. The study has clarified the factor that affects greater quality material and ringshake: source area. Research has shown that the characteristics of a particular area, together with differences selvicultural management, cause very different quality wood. It then becomes necessary greater attention to productive vocation an area, trying to enhance and intensify forestry where the chestnut shows a high wood quality.
Besides the results of silvicultural order, research has allowed us to understand many little known aspects of variability of wood quality, inherent in tree. The results showed that wood quality decreases increasing age of the timber, more as we move towards the bark.: the wood rings closer to the bark has physical and mechanical properties lower than wood near to the pith. At present it was not possible identify certainly an alteration of cambium related to the ringshake.
However, the study of xylogenesis allowed to establish some milestones in the cellars genesis, which contribute to chestnut characterization as bio-environmental indicator. The species, indeed, has great role in wide landscapes characterization, often mono-specific. The research site Pian dei Fraticelli, showed that the growing season is on average of 165 days; although there is a considerable variability within the population, higher than that recorded between one year (2008) and subsequent (2009). It is still unclear the role of the parameters climate in the making xylem, generally, we can say that temperature exerts a crucial role to reactivation of vegetation.
Rainfall play a more important role to increase width ring, especially during summer months. The Gompertz curves have identified the period of greatest intensive vegetation, the period or, where there is a higher growth of the chestnut tree: June. From the second half of May production begins late wood, while the earlywood is formed in an average of ¼ time throughout the growing season.
The study has extended knowledge on the chemical structure of the chestnut wood. The lignin percentage was 26%, and study with Py-GC/MS method has allowed to characterize the structure of polimer: identifying 16 phenolic polymer. The greater variability in the structure lignin is related to the area of origin, while it seems that the age and ringshake don’t show significant correlations with the structure of the polymer. Have been identified related phenolic compounds (both in a direct and reverse) with the characteristics Physico-mechanical properties of wood. But the stakes about chestnut are addressed also to the innovations related to a wider use of simple materials wood. Already in the past was known to use the tannin for the tanning skins, today this polymer has new prospects employment in industry, cosmetics, in animal food and so on. Research carried out in this work (in press is a article in the journal J. Adhesion Sci.Technology) have demonstrated the efficiency tannin chestnut as a component in production of phenolic resins with low toxicity, for the construction of particles boards. This is a result interesting because it was obtained on hydrolysable tannins, yet not enough explored their potential use composite wood products.
The possibility of exploring new paths production, mainly by rationalizing residues from forest harvesting and industrial waste, opens new perspectives for the species and local economies to it related. With this thesis was to give a both scientific and practical contribution, learn more about a species of great for the territory and its economy. Not final solutions have been proposed for ringshake problem, but surely were investigated factors that may cause and aggravate. Were identifies the principles that can inspire guidelines for obtaining timber good technical quality and were identified areas with high vocation production of the Lazio Region. The opportunity to investigate some issues addressed in this research could certainly improve the exploitation and management of chestnut. to test tannin chestnut as an adhesive, at concentration above of 50%, could be very useful to break down significantly the levels of toxicity of phenolic resins in the production of chipboard. The lessons can help you have a more rational use of Chestnut resource, identifying areas more productive than those that vocation instead take the most value landscape and environment.
Additional information
Dottorato di ricerca in Scienze e tecnologie per la gestione forestale e ambientale
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