Search results for " timber"
showing 10 items of 12 documents
Airborne-laser-scanning-derived auxiliary information discriminating between broadleaf and conifer trees improves the accuracy of models for predicti…
2020
Managing forests for ecosystem services and biodiversity requires accurate and spatially explicit forest inventory data. A major objective of forest management inventories is to estimate the standing timber volume for certain forest areas. In order to improve the efficiency of an inventory, field based sample-plots can be statistically combined with remote sensing data. Such models usually incorporate auxiliary variables derived from canopy height models. The inclusion of forest type variables, which quantify broadleaf and conifer volume proportions, has been shown to further improve model performance. Currently, the most common way of quantifying broadleaf and conifer forest types is by ca…
Timber anti-seismic devices in historical architecture in the Mediterranean area
2017
Questo lavoro esamina l’uso di un dispositivo strutturale in legno storico utilizzato come rinforzo della muratura per i sistemi di prevenzione sismica nell'area mediterranea. Tale tecnologia viene realizzata mediante un telaio tridimensionale tridimensionale di legno incorporato nella muratura di pietra per legare insieme le varie parti strutturali e contribuire alla resistenza sismica complessiva. Molto spesso, questo principio costruttivo fu esteso non solo per le parti più deboli, ma per l'intero edificio, creando nuove configurazioni strutturali che erano in grado di assorbire gli effetti delle azioni sismiche. Dalle esperienze costruttive di epoca romana (opus craticium), questo siste…
A shear test for structural adhesives used in the consolidation of old timber
2001
A test method was developed specifically for structural adhesives used in thick joints. It is based on compressive shear loading of glued joints (GJ) and solid wood (SW) specimens, before and after a suitable accelerated ageing cycle. The evaluation of results is based on the ratios of wet strength to dry strength and on the comparison of GJ specimens to SW specimens which are prepared from the same batch of wood, in order to minimise the influence of the variability in wood characteristics. On a group of 10 epoxy-based adhesives, specifically marketed for the consolidation of old timber structures, the method has proved to be effective to differentiate the performances of each product. Amo…
Flexural behaviour of glulam timber beams reinforced with FRP cords
2015
Abstract Glued laminated timber (glulam) is widely used as a construction material to make up lightweight and large span structures. The basic principle of this material consists in bonding together a number of layers of dimensioned timber with structural adhesives, in order to increase strength and stiffness of the member, and allowing to make up sustainable structures with great visual impact. Recent applications showed the effectiveness of fibre-reinforced polymer (FRP) composites in enhancing the structural performances of glulam beams, with particular reference on their flexural and shear strength. In fact FRP reinforcements could be used to strengthen existing structures or to reduce …
Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe
2021
Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates…
Which are Southern Italy’s fastest growing tree species? Lessons from the past for future perspectives, with a special focus on Sicily
2020
Fast growing tree species can generate high wood production in a short time frame. However, maximum productivity is dependent on environmental and management conditions as well as intrinsic plant traits. Within this framework, our research was into tree species with the highest Mean Annual Increments (MAIs) in southern Italy, particularly in Sicily. Eucalyptus spp., Acacia saligna (Labill.) H. L. Wendl., Ailanthus altissima Mill. (Swingle), Pinus halepensis Mill. (including Pinus brutia Ten.), Pinus canariensis C.Sm. and Pinus radiata D. Don. were identified. In particularly suitable conditions, the MAI of eucalypt coppices ranged from 8 to 12 m3 ha-1, and from 13 to 19 m3 ha-1, in Eucalypt…
The evolution in time of the concept of fast growing tree species: is it possible to use a definition applicable to all environmental conditions?
2020
Although the expression “fast-growing species” (FGS) referred to tree species has been since long time used, a clear definition has not been adopted for decades. Starting from the Italian historical background, we searched for the definitions of FGS formulated over time at a national and international level. The mean annual increment (MAI) of 10 m3 ha-1, identified by the FAO, has been the most commonly considered threshold until recently. Subsequently, experimental activities and research efforts have consistently enhanced the productivity of FGS, and other definitions have been proposed accordingly. Hence, FGS should provide annual wood yields of 15-25 m3 ha-1 with rotations of less than …
Analisi tecnica di cantieri meccanizzati nelle operazioni di utilizzazioni forestali in Sicilia
2005
The authors describe the results of a research performed in a wood of the Western Sicily, covered with Pinus halepensis Mill. and Cupressus sempervirens L. Felling, delimbing, cross-cutting and extraction of the logs were carried out. The wood obtained was used as firewood. Two different methods of logs extraction were carried out: with transporters and with polyethylene timber chutes. The working time and the labour productivity recorded during each operations are reported. The results show that in the forest utilization performed in Sicily the mean labour productivity per operator is 2.4 t of firewood per day. This value fits well the mean value recorded in Italy (2-3 t of firewood per da…
Hygrothermal conditions in Cross Laminated Timber (CLT) dwellings
2020
The use of CLT has been increasing the last decade, and a subsequently focus on documentation of the accompanying indoor climate and exposed wooden surfaces on human well-being. This study presents the results of a measurement campaign conducted over one year of a CLT apartment building in Grimstad, Norway. The apartment building consists of three floors with 35 apartments and comply with the Norwegian passive house standard and energy grade A. Measurements of the relative humidity (RH), indoor air temperature and wood moisture content (MC) were performed in the exposed CLT spruce panels in three apartments in two different floors. The results from the three apartments show a relatively sma…
Improving Economic Management Decisions in Forestry with the SorSim Assortment Model
2020
The sustainable supply of timber is one of the most important forest ecosystem services and a decisive factor determining the long-term profitability of forest enterprises. If timber production is to be economically viable, there must always be a way to analyse forest stands and trees felled for exploitation with regard to the wood assortments they contain. Only then can the expected timber yields, achieved by various silvicultural strategies or actions and different sorting options, be quantified with sufficient accuracy. The SorSim assortment simulator was developed for forest practitioners and forest scientists in Switzerland to realistically simulate the sorting of individual trees and …