Timber Wood Research Articles

Lime and hemp concrete LCA: a dynamic approach of GHG emissions and capture

Lime and hemp concretes are well known and studied as low-impact materials for building. During the last two decades, a few studies have shown their interest in terms of environmental impacts such as embodied energy, air pollution or GHG emissions. On the other hand, new carbon footprint calculation methods were proposed to assess the value of temporarily storing carbon in long-lived products such as building structures and insulation. This is an important aspect for bio-based materials, as they capture and store carbon. From an environmental point of view, it would be of interest that GHG emissions due to cultivation, manufacturing, transportation, construction, demolition and end-of-life could be compensated by the beneficial effect of a long-term carbon storage. The principal aim of this study is to evaluate the long-term effect on climate change of using LHC in building. GHG emissions and uptakes were assessed using a dynamic life cycle assessment approach for several scenarios: 1) different cultivation practices for hemp (in the French context, surveys of 2014-2015 provided by the Cetiom), and 2) different mixes and formulations for the LHC, i.e. two classical ones: sprayed and cast LHC, and a more innovative one: compacted LHC. Whatever the formulation, a woody structural frame is necessary, composed of local timber wood (less than 100km from construction site). To take into account the emission dynamics, plants growing (trees and hemp) and carbonation of lime into the walls were considered. Optimum scenarios were compared, by taking the minimum and maximum impact for each mixes (different cultivation practices, transportation of lime and hemp, end-of-life scenarios). As a result, some LHC with high hemp/lime ratio, low-impact crop practices, and a proper end-of-life scenario could be a solution to stock carbon and keep a positive effect on climate, even on the long-term (more than 100 years).

Comparison of sound isolation performance of floor/ceiling assemblies across structural systems

The recent building boom in greater Boston has given rise to multifamily buildings utilizing a wide range of structural systems, including cast-in-place concrete, pre-cast concrete, steel, heavy timber, and various wood frame structural systems. Both laboratory and field measurements indicate that typical floor/ceiling assemblies utilized with each structural system have certain characteristic acoustical attributes. Although these assemblies perform differently, virtually all of these structural systems have been utilized in buildings advertising “luxury” residential living. This presentation compares recently obtained sound isolation data among the various structural types. Specific acoustical design challenges and constraints (such as budget, available floor-to-floor height, and others) are identified, and guidelines for achieving sound isolation commensurate with a “luxury” standard are outlined for each of the structural systems examined.

Fire performance of wood products and timber structures

ABSTRACTAn overview of the European requirements on fire safety in buildings is presented based on the construction products regulation and its essential requirements. These requirements are mandatory, to be used in all countries. They include classification systems for reaction to fire of building products, fire resistance of building elements and structural Eurocodes. The reaction-to-fire performance of wood products in accordance with the European classification system is given. Euroclass D is usually achieved. Higher classes can be reached by chemical treatments, but the durability of the reaction-to-fire performance needs to be fulfilled according to a new European system. The fire resistance of building elements can be either tested according to the European standards or calculated using design methods according to Eurocode 5, EN 1995-1-2. Both separating and load-bearing structures are included. Timber structures can obtain high fire resistance, e.g. REI 60, REI 90 or even higher.

Estimating the Impacts of Preservative Ports on Bridge Tie Strength

Abstract Scale models of wooden bridge timbers were broken in bending to assess the impact of holes drilled along their length to permit the addition of wood preservatives. The results indicate that the holes have minimal impact. However, the common practice of cutting “daps” on the underside of the beams to accommodate the supporting beams appears to have substantial strength-reducing effects. Railroads could consider using borate ports to improve the life of their bridge timbers and reducing the depth of, or eliminating, daps.

Soil carbon stocks along an altitudinal gradient in different land-use categories in Lesser Himalayan foothills of Kashmir

The carbon sequestration potential of soils plays an important role in mitigating the effect of climate change, because soils serve as sinks for atmospheric carbon. The present study was conducted to estimate the carbon stocks and their variation with altitudinal gradient in the Lesser Himalayan foothills of Kashmir. The carbon stocks were estimated in different land use categories, namely: closed canopy forests, open forests, disturbed forests, and agricultural lands within the altitudinal range from 900 to 2500 m. The soil carbon content was determined by the Walkley–Black titration method. The average soil carbon stock was found to be 2.59 kg m–2. The average soil carbon stocks in closed canopy forests, open forests, and disturbed forests were 3.39, 2.06, and 2.86 kg m–2, respectively. The average soil carbon stock in the agricultural soils was 2.03 kg m–2. The carbon stocks showed a significant decreasing trend with the altitudinal gradient with maximum values of 4.13 kg m–2 at 900–1200 m a.s.l. and minimum value of 1.55 kg m–2 at 2100–2400 m a.s.l. The agricultural soil showed the least carbon content values indicating negative impacts of soil plowing, overgrazing, and soil degradation. Lower carbon values at higher altitudes attest to the immature character of forest stands, as well as to degradation due to immense fuel wood extraction, timber extraction, and harsh climatic conditions. The study indicates that immediate attention is required for the conservation of rapidly declining carbon stocks in agricultural soils, as well as in the soils of higher altitudes.

Classification of creosote bleeding from timber bridges by means of wood anatomical factors

ABSTRACTCreosote is commonly used as a wood preservative for highway timber bridges in Norway. However, excessive creosote bleeding at various highway timber bridge sites lead to complaints, and a potentially bad reputation for wooden timber bridges. Macro-and micro-anatomical factors such as the amount of heartwood, annual ring width, annual ring orientation, ray-height and composition and resin canal area were investigated in order to classify seven timber bridges in Norway into bleeding- and non-bleeding bridges. A classification into bleeding and non-bleeding was possible for discriminant categories based on three anatomical factors analysed on wood core samples. The amount of heartwood content dominated the influencing factors, even obscuring the significance of other factors. Classification with a low amount of variables was done preferably on sample level instead of bridge level, due to the restricted number of 17 core samples per bridge.

English

Jackfruit (Artocarpus heterophyllus L.) is a cross pollinated fruit tree valued mainly for its fruit and timber wood. Although the crop has been introduced to Ethiopia and adapted well to the Jimma area, its potential for production has not been exploited due to the absence of an efficient method for large scale propagation. Micropropagation is a method for production of large number of genetically uniform planting materials with desired characteristics. The present study was initiated to determine the optimum concentration and combination of benzylaminopurine (BAP) and naphthaleneacetic acid (NAA) for in vitro shoot multiplication. For this study, shoot tips were used as an explant source. The shoot tips from mature trees were sterilized with 70% ethanol and HgCl2 before culturing on Murashige and Skoog (MS) medium supplemented with different combinations of BAP and NAA. The results show that, the combination of BAP and NAA resulted in significant (P<0.01) differences for shoot number, shoot length and leaf number, whereby 2 mg/L BAP alone was found to be the best with a mean shoot number of 5.12 and length of 0.89 cm. The optimized protocol could be used as a baseline for further studies on in vitro propagation of jackfruit.   Key words: Artocarpus heterophyllus L., mercuric chloride, auxiliary shoot.

Indoor Humidity Environment in Huizhou Traditional Vernacular Dwellings of China in Summer

A three-month field measurement of temperature and humidity was carried out in order to analyze the indoor humidity environment in a Huizhou traditional vernacular dwelling compared with that in a modern dwelling during summer. The results showed that the average relative humidity in the traditional vernacular dwelling over 83% was slightly higher than the corresponding value around 75% in the modern dwelling. The humidity fluctuation appeared stable in wing-room due to the moisture buffering effect of the internal timber wood while the humidity variation was drastic in bedroom with well air-tightness due to frequent application of air-condition. The dependency of indoor humidity on the outdoor humidity was strong resulted from a great effect of natural ventilation in the traditional vernacular dwelling with a correlation coefficient of 0.8. Although humidity was high, the thermal comfort was acceptable with the comfortable time near 60% in the traditional vernacular dwelling during summer. It is supposed to apply synthetic hygroscopic materials on the basis of the timber wood with ventilation to moderate indoor humidity in modern architectures in Huizhou area.

The Role of Plants in Human Welfare

After literature survey, the ethno-botanical information reveals that plant species are widely used throughout the world for different purposes like for instance medicine, edible fruits, vegetables, ornamentals, fencing, fuel wood, timber wood, fodder, agricultural tools and structural materials etc. Whereby all the growth forms like herbs, shrubs, trees, climbers, epiphytes and trailers plays their role. Nonetheless, the most important concern is that most plant species due to their dire need, improper collection, overgrazing, deforestation, pollution and other anthropogenic influences are proceeding towards the door steps of IUCN categories. For example, some of the very important and precious medicinal plants like Valeriana jatamansi, Acorus calamus, Podophyllum hexandrum and Poeonia emodi are threatened due to their unwise collection by the residents for medicinal purposes. So, it could be concluded and recommended that during field visits conservation status of such important plant species must be kept in mind to conserve their generation and biodiversity for future.

First report of Ceratocystis fimbriata causing wilt on Khaya senegalensis

Brazil has an active forestry sector, including production for both wood pulp and timber. The species Khaya senegalensis (African mahogany) has been introduced into the country because it produces good quality timber and its wood is valued…

An experimental characterization of physical properties of timber woods.

The present investigation was carried out to determine the different physical properties of various types of timbers used for agricultural implements in India. This study provides information for selection criteria of wood to make a different component of agriculture implement and tools. This article consists of detailed material and methods used in the study. This study was mainly targeted on utilization of different type of wood for their use to make different components of agricultural implements and tools.

Observations of Channel Change from Constructed Wood Jams on a Forested Gravel-Bed Stream

AbstractSalmonids in the Pacific Northwest face a number of threats: habit degradation, loss of habitat, overharvest, competition from hatchery fish, dams, and climate change. Wood has been shown to play a key role in many aspects of stream habitat quality; however, it is in low supply in many Pacific Northwest streams because of wood removal and timber harvest practices in riparian zones. Wood placement for restoration has the potential to benefit salmonid populations. However, common applications often fall short of producing the physical changes necessary to achieve the objectives, such as the formation of deep pools and cover. This study evaluated the hypothesis that wood jams constructed with whole-tree materials, high wood piece counts, and high wood volumes would be effective at creating instream geomorphic complexity, function, and aquatic habitat quality. Results were based on an evaluation of changes to surface sediment textures and channel morphology at eight constructed wood jams built with va...

PENAMPILAN RANDOM AMPLIFIED POLYMORPHIC DNA PADA Azadirachta indica A. Juss DARI TAMAN NASIONAL BALURAN

Azadirachta indica A. Juss (Apocynaceae) is a large tree of the lowland tropical rain forest of Southeast Asia that occurs in Thailand, the Malay Peninsula, on the island of Java (East Java) and Lesser Sunda Islands. Its economic value was in its wood (timber), and as medicinal plant. The information on genetic diversity of the species is very limited. Hence studies were initiated and genetic diversity estimated using RAPD markers in 27 accessions of A.indica procured from three geographical regions of TN Baluran and Balai Litbang Kehutanan. Seven selected Operon primers (10 mer) generated a total of 133 consistent amplification products ranging from 132 bp to 5.6 Kb. The cluster analysis separated the 27 individuals into 2 clusters. The range of genetic dissimilarityvalue among samples was from 0.07 to 0.33, while genetic distance among populations was from 0.04 to 0.10. These values showed that A. indica from TN Baluran was not genetically diverse population. Key words: Azadirachta indica, genetic diversity, RAPD

Self-extinction of timber

Self-extinction of timber after the removal of an external incident heat flux is necessary to ensure that structures with exposed wood do not contribute to a fire after the building contents are fully consumed. Two series of tests with solid wood and cross-laminated timber were conducted to study the conditions leading to self-extinction. The heat fluxes and heating duration were varied systematically. For each test, the evolution of the in-depth temperature distribution was measured using thermocouples while the mass loss rate was measured using a load cell. The experiments were allowed to reach a steady-state mass loss rate. The in-depth temperature gradient, which represents in-depth heat losses from the pyrolysis zone, was calculated from thermocouple measurements until it reached steady-state. As the external incident heat flux increases, the mass loss rate as well as the in-depth thermal gradient reach a steady-state value. Once the steady-state mass loss rate and temperature gradient were attained, the external heat flux was removed and the flame was allowed to extinguish. Over the entire range of heat fluxes (30–100kW/m2) and heating periods used in the tests, and for all the wood types used, self-extinction was observed.

Eucalyptus geometry in agroforestry on waterlogged saline soils influences plant and soil traits in North-West India

Impacts of agroforestry comprising wheat and rice crops in combination with Eucalyptus tereticornis trees having high transpiration rate were assessed for remediation of waterlogged saline soils. To find out optimum spacing of trees in strip plantation for higher water table draw down, wood production and crop yield, a study was carried on waterlogged fields by planting E. tereticornis (clone C-7) in paired rows on ridges (0.5-m height) made along the field boundaries in north-south direction at 1m×1m, 1m×2m and 1m×3m spacing resulting in population of 300, 150 and 100 treesha−1. The results were also compared with the control (field without tree plantation) and block plantation. During sixth year of growth, Eucalyptus attained the maximum growth in 1m×3m spacing followed by 1m×2m, 1m×1m; and minimum in block plantation. Due to higher number of trees per unit area, timber dry wood production was 33.5 Mgha−1 in spacing of 1m×1m; 19.1 Mgha −1 in 1m×2m and 13.5 Mgha−1 in 1m×3m and sequestered 15.2, 8.9 and 6.4 Mg Cha−1, respectively. Block plantations of Eucalyptus generated 141.7 Mgha−1 timber wood biomass and sequestered 66.5 Mg C ha−1. The transpiration rate of Eucalyptus in block plantation on an average was 40.0Lday−1tree−1 compared to 68.0, 71.5 and 73.8Lday−1tree−1 in 1m×1m, 1m×2m and 1m×3m tree spacing, respectively in strip plantation. The corresponding total amount of water transpired per annum was 1825mm in block plantation and 745, 391, 269mm in 1m×1m, 1m×2m and 1m×3m tree spacing. Due to high transpiration rate of Eucalyptus, water table was lowered by 43.0cm in 1m×1m; 38.5cm in 1m×2m and 31.5cm in 1m×3m spacing during the fourth year of plantation than in adjacent fields without plantation. Near the tree lines, grain yields of both wheat and rice were comparatively low. But lowering of water table resulted in improvement in soil properties which produced 1.7 and 1.3 folds higher grain yield of wheat and rice respectively compared to control. The results suggested that in a rotation of six years, 1m×1m spacing for strip plantation of Eucalyptus in paired rows on farm acre line was the optimum for achieving higher water table draw down, wood biomass production, carbon sequestration and crop productivity on waterlogged fields.

French summer droughts since 1326 CE: a reconstruction based on tree ring cellulose <i>δ</i><sup>18</sup>O

Abstract. The reconstruction of droughts is essential for the understanding of past drought dynamics and can help evaluate future drought scenarios in a changing climate. This article presents a reconstruction of summer droughts in France based on annually resolved, absolutely dated chronologies of oxygen isotope ratios (δ18O) in tree ring cellulose from Quercus spp. Samples were taken from living trees and timber wood from historic buildings at two sites: Fontainebleau (48°23′ N, 2°40′ E; 1326–2000 CE) and Angoulême (45°44′ N, 0°18′ E; 1360–2004 CE). Cellulose δ18O from these sites proved to be a good proxy of summer climate, as the trees were sensitive to temperature and moisture availability. However, offsets in average δ18O values between tree cohorts necessitated a correction before joining them to the final chronologies. Using the corrected δ18O chronologies, we developed models based on linear regression to reconstruct drought, expressed by the standardized precipitation evapotranspiration index (SPEI). The significant correlations between the SPEI and cellulose δ18O (r ≈ −0.70), as well as the verification of the models by independent data support the validity of these reconstructions. At both sites, recent decades are characterized by increasing drought. Fontainebleau displays dominantly wetter conditions during earlier centuries, whereas the current drought intensity is not unprecedented in the Angoulême record. While the δ18O chronologies at the two studied sites are highly correlated during the 19th and 20th centuries, there is a significant decrease in the correlation coefficient between 1600 and 1800 CE, which indicates either a weaker climate sensitivity of the tree ring proxies during this period, or a more heterogeneous climate in the north and the south of France. Future studies of tree ring isotope networks might reveal if the seasonality and spatial patterns of past droughts can explain this decoupling. A regional drought reconstruction based on a combination of the two sites shows good agreement with historical records of grape harvest dates in France, which provide another proxy of summer climate.

Enhance mechanical properties of timber, engineered wood products and timber structures. Special Issue based upon work from COST Action FP1004, supported by COST (European Cooperation in Science and Technology)

This Introductory Paper sets the scene for this special edition of the EuropeanJournal for Wood and Wood Products, which contains papers selected to demonstrate and record aspects of the COST Action, achieved through networking and collaboration. The paper discusses the context of COST Action FP1004, showing how it seeks to benefit designers and builders of timber buildings as well as enhancing performance and thus delivering a benefit to society as a whole.

Some Changes in Soil-protective Properties of Pre-Carpathian Forests Influenced by Selective and Continuous Felling

The number of seedlings indicators before and after the selective and continuous felling realization, damage and destruction are shown. The square and the depth of soil stripping at logging operations are characterized. The volumes of forest exploitation caused by soil erosion, depending on the degree of damage, especially in the tractor trail network are highlighted. The changes in the soil permeability under the influence of timber wood are analysed. The silvicultural effectiveness of different ways of cutting is reviewed. The classification of the log likelihood areas concerning water runoff and erosion is proposed.

Prefabricated timber-concrete composite floors

The presented investigation concerns the study of novel types of timber-concrete composite floors, manufactured with “dry connections” (Crocetti et al. In: 11th WCTE, Riva del Garda: international conference proceeding of 11th WCTE, Riva del Garda, 2010; In: RILEM 2013: Materials and Joints in Timber Structures—Recent Advancement of Technology Stuttgart, Germany, 2013: RILEM 2013, Stuttgart, 2013; Sartori et al. In: Enhance mechanical properties of timber, engineered wood products and timber structures. University of Bath, COST FP1004, Zagreb, 19 April 2012, 2012). Three full-scale nominally identical floor elements were investigated. The shear connector system used in the investigation was realized by means of self-tapping screws driven at an angle of 45° into the wood. First, the screws were inserted on the top of the glulam beams. Then, the beams were twisted upside-down and placed on concrete formwork (Fragiacomo In: Struct Eng Mech 20(2):173–189, 2005). Then fibre reinforced concrete (FRC) was cast in the formwork. Quasi-static bending tests and long-term bending test were performed. It was found that the proposed connection systems performed more than satisfactory in the short term, showing a very high degree of composite action even at load levels close to the failure load. However, long-term loading (Fragiacomo and Ceccotti In: J Struct Eng 132(1):13–22, 2006) induces increased deformation, which should be taken into account in SLS design.

Experimental thermal characterization of bio-based materials (Aleppo Pine wood, cork and their composites) for building insulation

This paper presents an experimental study of the thermal conductivity, thermal resistance, specific heat and thermal diffusivity of wood, cork and their composites. The first part is devoted to the determination of the thermal resistance of composite materials elaborated from solid Aleppo Pine wood, laminated timber wood and black agglomerated cork. From experimental results, we can predict the values of the thermal conductivity, specific heat using a modulated differential scanning calorimetry (MDSC) of different samples. For the thermal conductivity, we use two different methods: the flow meter and a thermal conductivity meter (TC meter) at laboratory conditions (23°C, 50% RH). However, we have the possibility to calculate the thermal resistance and the thermal diffusivity and make comparison between the two methods. The results have been compared with other experimental researches and usual building materials. Furthermore, the aim of this study is to show the influence of the moisture on the values of the thermal properties of wood and cork which has been performed in a climatic chamber (23°C, 80% RH). The results indicate that increasing the mass of the samples leads to an increase of the value of the thermal conductivity and a decrease in thermal resistance of sandwich structures.