Your search resulted in 13 documents.
Ultra-structural observations on the degradation of wood surfaces during weathering
1987 - IRG/WP 2280
Radiata pine (Pinus radiata D. Don) sapwood was converted into blocks with a transverse face about 5 mm square and measuring 8 mm longitudinally. Transverse (T.S.), Radial (R.L.S.) and Tangential (T.L.S.) surfaces were prepared and specimens exposed to the weather inclined at 45° facing equatorially for periods of between 20-60 days. After 30 days exposure erosion of the middle lamella was observ...
P D Evans, S Thein
A review of the configuration of bordered pits to stimulate the fluid flow
2005 - IRG/WP 05-40315
As the bordered pits have generally been thought to have an influence on the refractory nature of softwoods, structural behaviour of this conducting pathways is discussed according to the published literature. Various theories on the role of bordered pits to axial flow are expounded in respect to preservative treatment. Pit aspiration is also reviewed....
Water sprinkled pine wood: A microscope study on boards showing streaking
1993 - IRG/WP 93-10033
Boards sawn from the outer sapwood of pine lumber previously water sprinkled for periods of 10-18 weeks and kiln dried, showed streaking after staining. Two types of enhanced stain uptake were noted: 1) a more concentrated and localized form after 10 weeks and 2) a more diffuse type which developed in later stages of water sprinkling. Areas showing enhanced stain uptake were examined using light a...
G F Daniel, T Elowson, T Nilsson, A P Singh, K Liukko
Bordered Pit Imaging
2012 - IRG/WP 12-10773
New findings about bordered pits will be presented using the latest microscopy techniques. Three-dimensional imagery at the nanolevel is used, and short 3-D movies will shown as part of the discussion on this topic to reveal new features that have not previously been reported in pits. The implications for both microorganism penetration through lignified cells as well as preservative penetration i...
D Mascheck, B Goodell, H Militz, M Lessard, J Jellison
Studies on the permeability of Norway spruce (Picea abies)
1987 - IRG/WP 2295
It is well known that the bordered pits play a dominating role for liquid transport in softwoods. The mechanism behind pit aspiration during drying or heartwood formation seems to be well understood. The reason why the fixation of the membrane (torus) to the pit opening remains almost irreversible is, however, still unclear. A technique has been developed combining so-called "solvent exchange dryi...
I Johansson, K Nordman-Edberg
A comparison between high and conventional incision densities for improving preservative treatment of Douglas-fir heartwood lumber
1993 - IRG/WP 93-40009
Incising is required for the preservative treatment of most wood species from the western United States; however, there is considerable debate about the density of incisions required to achieve adequate treatment. Previous studies have shown that the incision effect on treatment is relatively narrow, suggesting that incision densities should be significantly increased over current practices and st...
S T Lebow, J J Morrell
Wood structure in relation to excessive absorption - a literature survey
1971 - IRG/WP 300
This literature study, composed in connection with 'the structure of wood in relation to the excessive absorption', started from the idea that the subject only could be dealt with successfully if the structure was taken into account in relation to a normal absorption pattern in so far as this knowledge can enlighten the understanding of the abnormal situation. The normal penetrat...
S M Jutte
Hydrolysis of bordered pits during colonization of conifers by brown-rot fungi
1995 - IRG/WP 95-10103
Brown-rot decay results in rapid reduction in degree of polymerization (DP) of holocellulose with concomitant strength loss (MOR) without removing lignin. Development of new methods of wood protection will require focusing on early events in the sequence of depolymerization. Bordered pit membranes (sapwood) represent a readily available source of non-lignified carbohydrate, ie. pectin and cellulos...
F Green III, J L Tschernitz, T A Kuster, T L Highley
Use of Variable Pressure Scanning Electron Microscopy for in situ Observation of Degradation of Wood Surfaces during Artificial Weathering
2012 - IRG/WP 12-20489
Variable pressure scanning electron microscopy (VPSEM) is capable of observing electrically non-conductive materials like wood without the need to render the surface conductive by applying a coating of gold, platinum or carbon. Hence, there is the possibility that VPSEM could be used to non-destructively follow the structural changes occurring at wood surfaces during weathering, because specimens ...
F Hatae, Y Kataoka, M Kiguchi, H Matsunaga, J Matsumura
Resistance of Alstonia scholaris vestures to degradation by tunnelling bacteria
1992 - IRG/WP 92-1547
Electron microscopic examination of vessels and fibre-tracheids in the wood of Alstonia scholaris exposed to tunnelling bacteria (TB) in a liquid culture showed degradation of all areas of the secondary wall. The highly lignified middle lamella was also degraded in advanced stages of TB attack. However, vestured pit membranes and vestures appeared to be resistant to degradation by TB even when oth...
A P Singh, T Nilsson, G F Daniel
Observations on preservative penetration in poplar
1991 - IRG/WP 3662
In the course of studies on the CCA treatment and durability of poplar timber a zone of refractory wood at the sapwood/heartwood boundary was observed. Further studies were conducted to investigate the causes of this refractory behaviour. The initial results have suggested that the presence of lipid storage products in the ray tissue may lead to impermeability, either by directly blocking pits or ...
R J Murphy, S U Din, M J Stone
Modelling hyphal growth of the bio-incising fungus Physisporinus vitreus
2010 - IRG/WP 10-10710
The white-rot fungus Physisporinus vitreus preferentially degrades the pit membranes of bordered pits in tracheids and subsequently enhances wood permeability. Thus, P. vitreus can be used to improve the uptake of wood preservatives and environmentally-benign wood modification substances. This process can be used to enhance the use and sustainability of native conifer wood species by the wood indu...
M Fuhr, C Stührk, F W M R Schwarze, M Schubert, H J Herrmann
Copper Nanoparticles in Southern Pine Wood Treated with a Micronised Preservative: Nanodistribution of Copper in the Pit Membrane and Border of an Earlywood Bordered Pit
2011 - IRG/WP 11-30566
Copper nanoparticles can penetrate the cell walls of unlignified parenchyma cells in southern pine wood treated with a micronised wood preservative, but they are excluded from lignified tracheid walls. This paper extends these observations to include the cell wall layers of the bordered pit. Focused ion beam and ion milling were used to make an ultra-thin section of the cell wall layers of an earl...
H Matsunaga, Y Kataoka, M Kiguchi, P Evans