Combined effect of wood moisture content, drill bit rotational speed and feed rate on drilling resistance measurements in Norway spruce (Picea abies (L.) Karst.)

2018 ◽  
Vol 15 (4) ◽  
pp. 198-204 ◽  
Author(s):  
Evgenii Sharapov ◽  
Christian Brischke ◽  
Holger Militz ◽  
Elena Smirnova
Keyword(s):  
Picea Abies ◽  
Moisture Content ◽  
Norway Spruce ◽  
Feed Rate ◽  
Rotational Speed ◽  
Wood Moisture Content ◽  
Combined Effect ◽  
Drill Bit ◽  
Wood Moisture ◽  
Drilling Resistance

Three-dimensional structure of tubular air channels formed by Armillaria spp. in water-saturated logs of silver fir and Norway spruce

2004 ◽  
Vol 82 (9) ◽  
pp. 1338-1345 ◽  
Author(s):  
B Metzler ◽  
U Hecht
Keyword(s):  
Picea Abies ◽  
Moisture Content ◽  
Norway Spruce ◽  
Abies Alba ◽  
Wood Decay ◽  
Wood Moisture Content ◽  
Silver Fir ◽  
Wood Moisture ◽  
Air Channels ◽  
Water Saturated

Water saturation of wood impedes the availability of oxygen necessary for wood decay. Storage of logs under water sprinkling is therefore used as an economic method in forestry. However, sapwood decay caused by Armillaria spp. was found in logs under water sprinkling, even at a wood moisture content of more than 150% (dry weight basis). Decay was associated with the formation of tubular air channels discernible as bright streaks extending from the cambial region into the sapwood. Their light colour results from different refraction of light in gas-filled versus water-filled wood structures. To examine the structure of the tubular air spaces in greater detail, we sampled wood of Norway spruce (Picea abies (L.) Karst. and silver fir (Abies alba (Mill.)). Radial, transverse, as well as tangential sections of affected timber were examined, and a structural model of tubular air channels is presented. These structures are formed around wood rays by a tubular sheath of pseudoparenchymatous mycelium, which in its cellular structure is reminiscent of pseudosclerotial plates. This structure allows the efficiently located extrusion of water from water-saturated wood. The power necessary for this process is suggested to be the generation of gaseous CO2. Since the air channels are in contact with the external surface, they evidently act as a conduit allowing oxygen to enter and penetrate to a depth of several centimetres. By this unique arrangement of the tubular air channels, Armillaria spp. appear able to metabolize wood cells in an aerobic microenvironment within water-saturated wood. This results in wood decay leading to significant economic loss in stored timber despite the application of regular sprinkling.Key words: Armillaria spp., Picea abies, Abies alba, wood moisture content, oxygen supply, wood anatomy, wood decay.

scholarly journals Untersuchungen zum Einfluss der Holzfeuchtigkeit auf das Bruchverhalten von Fichte bei Zugbelastung in Faserrichtung | The influence of moisture content on the fracture behaviour of Norway spruce when tension is applied in the direction of the grain

2004 ◽  
Vol 155 (1) ◽  
pp. 1-5
Author(s):  
Jozsef Szalai ◽  
Peter Niemz ◽  
Krisztian Andor ◽  
Mihaly Bariska ◽  
Martin T. Howald
Keyword(s):  
Tensile Strength ◽  
Moisture Content ◽  
Norway Spruce ◽  
Fracture Behaviour ◽  
Wood Moisture Content ◽  
Wood Moisture

The influence of wood moisture content on the fracture behaviour of Norway spruce was investigated. The tensile strength rose to around 10% in samples with a lower moisture content. After reaching the maximum below the level of fibre saturation, it falls back, almost linearly. Irrespective of the moisture content, a rigid fracture behaviour was observed.

Effects of clear-cutting, thinning, and wood moisture content on the susceptibility of Norway spruce stumps to Heterobasidion annosum

1998 ◽  
Vol 28 (5) ◽  
pp. 759-765 ◽  
Author(s):  
Malin Bendz-Hellgren ◽  
Jan Stenlid
Keyword(s):  
Picea Abies ◽  
Moisture Content ◽  
Norway Spruce ◽  
Natural Infection ◽  
The Other ◽  
Heterobasidion Annosum ◽  
Wood Moisture ◽  
Clear Cut ◽  
Clear Cutting ◽  
Almost All

The effects of clear-cutting and thinning as well as heartwood and sapwood moisture content on spore infection by Heterobasidion annosum (Fr.) Bref. were investigated in summer cuttings in southern and central Sweden. At five sites, 20-100 stumps in clear-cut, thinned, and precommercially thinned stands of Norway spruce (Picea abies (L.) Karst.) were created and left for natural spore infection. An additional 20 stumps per stump type and site were artificially inoculated with conidiospores of H. annosum. The probability of natural infection was 0.73 and 0.53 for stumps in thinned and clear-cut stands, respectively. Almost all (95%) of the artificially inoculated stumps in thinned and clear-cut stands became colonized, and no differences due to stump type were found. The probability of infection of stumps in precommercially thinned stands was lower than for the other stump types of both naturally and artificially inoculated stumps. The proportion of colonized sapwood was reduced with increasing moisture content. Stump colonization seemed unaffected by temperature, even though stump temperatures exceeded 40°C for 2 h at one site.

scholarly journals Thermal conductivity and deformation of Taxodium hybrid ‘Zhongshanshan’ during heat transfer process

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2645-2655
Author(s):  
Yuehua Zhu ◽  
Yaoli Zhang ◽  
Biao Pan
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Moisture Content ◽  
Transfer Process ◽  
Dimensional Change ◽  
Testing Temperature ◽  
Scientific Basis ◽  
Heat Transfer Process ◽  
Wood Moisture Content ◽  
Wood Moisture

The thermal conductivity and the deformation of wood from the Taxodium hybrid ‘Zhongshanshan’ were studied in the process of heat transfer. The results showed that the average thermal conductivity of this wood was 0.1257 W/(m·K) under the condition of 12% wood moisture content and 30 °C heat transfer temperature. When the testing temperature exceeded 0 °C, the thermal conductivity increased linearly with both temperature and wood moisture content and was affected by the moisture content of the wood. During the heat transfer process, the deformation of features caused repeated swelling and shrinkage in the longitudinal, radial, and tangential directions. The dimensional change was greatly affected by the wood’s moisture content and was less affected by the temperature. These results are of great meaning for the study of the heat transfer process of Taxodium hybrid ‘Zhongshanshan’ wood. Furthermore, it provides a scientific basis for the heat preservation effect, drying treatment, and pyrolysis treatment of Taxodium hybrid ‘Zhongshanshan’ wood for use as a building material.

scholarly journals Improving the accuracy of wood moisture content estimation in four European softwoods from Spain

2021 ◽  
Vol 30 (1) ◽  
pp. e002
Author(s):  
Juan I. Fernández-Golfín ◽  
Maria Conde Garcia ◽  
Marta Conde Garcia
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Solid Wood ◽  
Wood Products ◽  
Wood Moisture Content ◽  
Accurate Estimation ◽  
Wood Moisture ◽  
Mathematical Functions ◽  
Measured Moisture Content

Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and  maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.

scholarly journals Monitoring of Beech Glued Laminated Timber and Delamination Resistance of Beech Finger-Joints in Varying Ambient Climates

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1672
Author(s):  
Hannes Stolze ◽  
Mathias Schuh ◽  
Sebastian Kegel ◽  
Connor Fürkötter-Ziegenbein ◽  
Christian Brischke ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Wood Moisture Content ◽  
Adhesive Systems ◽  
Wood Moisture ◽  
Near Surface ◽  
Finger Joints ◽  
Glued Laminated Timber ◽  
Delamination Resistance ◽  
Normative Requirements

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.

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