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Comparative studies on the distribution of lignin and CCA elements in birch using electron microscopic X-ray microanalysis
1987 - IRG/WP 1328
The microdistribution of metal preservatives in treated wood has received considerable research over the last two decades. Despite this, little effort seems to have been made to try and correlate the distribution of CCA elements with respect to naturally occurring wood cell wall components in wood. In the present preliminary study an attempt is made to relate the distribution of lignin in-situ with that of CCA elements. For the study matched samples of Betula verrucosa were first either mercurized to specifically label the lignin or vacuum impregnated with a commercial 2% K33 CCA preservative solution. Thereafter using SEM-EDXA, the relative distribution of labelled lignin and CCA elements were compared for both different cell types and cell wall regions. Results showed the relative microdistribution of CCA to follow closely that of the lignin distribution. Regions showing high lignin levels showed high CCA levels and vice-versa. Highest CCA and lignin levels were recorded in the vessel, fibre and ray middle lamella cell corners regions while the lowest levels were detected in the fibre (S2) secondary walls. Both the low lignin level (and syringyl type) and CCA uptake in fibre S2 walls would seem in close agreement with the known high susceptibility of these elements to soft rot attack in both treated and untreated birch. Comparisons made between the lignin content of the S2 layer for birch fibres and other known soft rot resistant species (e.g. Alstonia scholaris) showed great differences, with the latter showing much higher lignin (ca 3x) levels.
G F Daniel, T Nilsson

Copper naphthenate-treated Southern Pine pole stubs in field exposure. -Part 2: Chemical characterization of full size pole stubs 12 years after treatment
2000 - IRG/WP 00-30246
This study examines the influence of pre-treatment and post-treatment steaming on the character and physio-chemical nature of copper naphthenate in hydrocarbon solvent treated pine in larger, pole diameter, pole stub-length samples. This work is the continuation of two projects that began almost a decade ago. Previous reports indicated that certain morphological changes might occur in small laboratory steamed samples of copper naphthenate treated southern pine. Toluene-methanol extraction, UV-Vis spectroscopy, X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM) were used to investigate the nature and properties of the copper naphthenate present in the wood after 12 years of exposure. The formation of solid cuprous oxide occurred regardless of pre- or post-steaming conditioning.
H M Barnes, D P Kamdem, M H Freeman

X-ray analysis of selected anatomical structures in copper/chrome/arsenic treated wood
1973 - IRG/WP 320
Application of analytical electron microscopy to problems in wood preservation has been very limited. Indeed, less than ten workers appear to have published their results using the technique, and of these' only two papers deal with energy dispersion procedures in the scanning electron microscope; the others employ the more familiar wavelength dispersive methods of the electron probe.
H Greaves

Occurrence of manganese deposits in test stakes exposed in groung contact situations
1996 - IRG/WP 96-10182
Dark spots and flecks were frequently recognized on the surface and within non-preservative treated hard- and softwood test stakes placed in soil contact. Energy dispersive X-ray microanalysis in conjunction with electron microscopy showed the flecks to be composed primarily of manganese dioxide. Detailed transmission electron microscopy observations indicated intrusion of manganese into the wood cell lumena and into areas of erosion, cavity formation and decayed middle lamella regions in wood cells attacked by fungi and/or bacteria. Distinct zones of apparent delignification were also noted in the secondary cell walls and middle lamella regions of attacked cells. Manganese is thought to play a major regulating role in both lignin depolymerization and minerialization in the presence of organic acids and has been reported previously in white rotted wood removed from standing trees. Present observations also suggest the uptake of manganese into wood stakes during microbial degradation results from biotic activity. Soil type appears to be of major significance.
G F Daniel, T Nilsson, J Volc

Visualization of inorganic element distribution in preservative treated wood by SEM-EDXA
2001 - IRG/WP 01-40208
SEM-EDXA was found to be an effective way of visualizing inorganic element distribution in wood as it was possible to examine some inorganic elements at the same time and map the concentration differences in color. Japanese cedar sapwoods were impregnated by vacuum treatment with CuAz or by pressure treatment with CCA preservatives and then distribution of Cu, Cr and As elements in wood were examined by SEM-EDXA. For sapwood treated by CuAz, Cu element was more distributed in latewood tracheids near growth ring boundary, axial parenchyma cells (resin cells) and ray parenchyma cells. Sapwood treated by CCA seemed to have the same distribution of Cu as sapwood treated by CuAz. In resin cells, a lot of crystalline deposits were fringed with CuAz and CCA preservatives. This may indicate predominant interactions between preservatives and chemical constituents of the parenchyma cells.
H Matsunaga, R Matsumura, K Oda

Preliminary study on relation of wood structure to copper/chrome/arsenic (CCA) distribution in kempas (Koompassia malaccensis)
1995 - IRG/WP 95-40054
Kempas had been treated with copper/chrome/arsenic (CCA) preservative using full cell process. Analysis of preservative distribution at the micro level in relation to wood structure was carried out using scanning electron microscope (SEM) and energy dispersive X-ray (EDXA) analysis. The results showed that CCA elements were detected in all wood tissues at different ratios. Distribution of chemical elements appeared to be much greater in the tangential longitudinal section (TLS) than the transverse section (TS). Though the amount of chemical elements had not been quantified from the radial longitudinal section (RLS), the SEM observations showed a high distribution of chemical precipitate. In all the wood tissues observed, Cr appeared in highest amount. The precipitate analysed by EDXA, showed As in greater amount than Cr or Cu. Silica content was highest in fibres and rays as determined by EDXA but could not be detected in structural form under SEM or light microscope.
S Ani, S Salamah

Anatomical Characteristics to the Distribution of Water-borne Copper Wood Preservatives in Wood
2004 - IRG/WP 04-40277
The objective of this study was to understand the micro-distribution of a copper-based preservative in wood in connection with anatomical morphology and to consider the fixation of copper in wood. Bulk specimens and semi-ultra thin sections (0.5µm) obtained from Japanese cedar were treated with a CuAz preservative solution. After fixation, SEM-EDXA was used to investigate the micro-distribution of copper. In sapwood, copper was more abundant in the compound middle lamellae than in the secondary wall in both earlywood and latewood, and also concentrated in the tori. Copper was most concentrated as crystalline deposits in longitudinal parenchyma cells. Semi-quantitative analysis revealed the copper amount to increase in this order: secondary wall in tracheid < middle lamellae < membrane of half-bordered pit < tori in tracheid < deposits in longitudinal parenchyma cell. These different concentrations may indicate significant interactions between the amine-copper complex in CuAz and chemical constituents of wood.
H Matsunaga, J Matsumura, K Oda

Fixation and leaching of selected Malaysian tropical hardwood after treated with CCA
2001 - IRG/WP 01-40207
The objective of this study is to investigate the fixation and leaching properties of selected Malaysian tropical hardwood (sentang wood (sapwood and heartwood) and rubberwood) after being treated with copper chrome arsenate (CCA) type-C preservative. The samples were treated with retention level of 0.5%, 2.0% and 5.0%. The samples were leached and the leachate were analyzed by AAS and the amount of remaining CCA elements in the cell (lumen and cell wall) were observed and analyzed using SEM and EDXA. The remaining CCA elements in sample/cell wall indicate the ability of fixation of the samples. Sentang wood could be successfully treated with CCA. Sentang heartwood is harder to treat compared to sentang sapwood and rubberwood. Copper and chromium have higher fixation properties in sentang heartwood compared to sentang sapwood and rubberwood. Arsenic element showed less fixation in sentang heartwood compared to sentang sapwood and rubberwood. Observation and analysis with EDXA showed that the microdistribution of the elements in the cell wall is distributed ununiformly throughout the cell wall and cell lumen.
R Hashim, O Sulaiman, Tan Siew Ching, K Yamamoto

Improvement of some technological and biological properties of poplar wood by impregnation with aqueous macromolecular compounds
1992 - IRG/WP 92-3721
Poplars (Populus spp) belong to the most important tree species in afforestation programs of the Netherlands. Due to their rapid growth, the wood quality is usually low. Therefore, studies were performed to elucidate whether some technological properties and the resistance against fungal attack could be improved by impregnation with water-soluble resins. The results showed that swelling and shrinkage of poplar wood may considerably be reduced by a treatment with certain resins. The anti-shrink efficiency (ASE) strongly depends upon the resin type. An air-curing alkydresin based on polybutadiene and an air-curing acrylate modified alkydresin emulsion caused the best effects. Additions of wood preservatives to the resins further improved the ASE. Some disadvatages of the tested resins may be seen in their leachability with consequent loss of the dimension-stabilizing effects. The resins by themselves don&apos;t reveal fungistatic properties but an impregnation of poplar wood with these materials led in all cases to a better durability against Coniophora puteana and Coriolus versicolor. Leaching procedures influenced the durability in various ways. With resin/fungicide combinations, a good resistance against Coriolus versicolor could be reached even after leaching. SEM and EDXA methods were used to localize the resins in the cell walls and lumina and to detect the growth of mycelium in the specimens.
R D Peek, H Militz, J J Kettenis

Cell wall microdistribution of chloropicrin and methylisothiocyanate in treated spruce
1989 - IRG/WP 3548
Chloropicrin and methylisothiocyanate (MIT) residues were observed using SEM/EDXA and TEM/EDXA in treated spruce wafers that had been exposed to the vapors of the two fumigant preservatives. Chlorinated residues from chloropicrin were found throughout the wood cell wall, even in acetone extracted material. The residues were most heavily concentrated in extractive materials in the rays, but unlike previous work, no preferential binding to the middle lamellae lignin was noted. This could be a reflection of the different wood species used, or because of the SEM techniques used previously. Sulfur residues from MIT were also observed throughout the wood cell wall of wood treated with this fumigant. Preferential binding of MIT residues to the middle lamellae cell corners was noted in the TEM/EDXA analysis of the samples, suggesting possible preferential binding of MIT residues to the lignin component of the middle lamellae.
G F Daniel, B Goodell

Utilization of coconut timber from north Sulawesi, Indonesia. Part 2: Treatability
1994 - IRG/WP 94-40025
Under tropical conditions coconut wood is quickly degraded by mold and blue stain fungi. Low density wood in ground contact is commonly decomposed by wood destroying fungi within a period of only a few months, higher density wood from the outer stem regions within 24 to 30 months (MOSTEIRO, CASIN, SERIBAN 1976; McQUIRE 1975). Moreover, according to McQUIRE (1975) green wood of lower density is highly susceptible to ambrosia beetles (Ambrosia sp.). For these reasons freshly sawn wood must be treated immediately, preferably by pressure treatment. Impregnation by a vacuum-pressure process of dry coconut wood with water-soluble CCA preservative had been carried out repeatedly and results published by PALOMAR (1979), JENSEN (1979), and SULC (1976). If, however, green coconut wood could be successfully pressure-treated immediately after sawing the time-consuming and costly intermediate dip treatment would become obsolete. Yet, previous trials by PALOMAR (1979) with traditional vacuum-pressure techniques were little successful as preservative retention, decreasing disproportionately with moisture content, proved ineffective at high moisture levels. On the other hand, an oscillating pressure process for impregnating green softwood has also proven effective with impregnating tropical hardwoods such as Rubberwood (Hevea brasiliensis). There are as yet no reports in literature about the application to coconut wood of this treating process. Equally, little research has been dedicated so far to distribution and mode of fixation of chromium-based preservatives in monocots (WILLEITNER, CHEN 1985; WILLEITNER, BRANDT 1985; PEEK, WILLEITNER, BRANDT 1987). Hence, testing of the oscillating vacuum/pressure treatment with coconut wood was the objective of an investigations carried out partly at FRIM, Malaysia, and partly at the Federal Research Centre for Forestry and Forest Products (BFH), Hamburg, FRG.
R-D Peek

Diffusion and interaction of components of water-borne preservatives in the wood cell wall
1988 - IRG/WP 3474
This study investigates the rates of diffusion and ultimate distributions of copper and arsenate components of wood preservatives in wood cell walls following vacuum treatment. Adsorption studies of copper on red pine (Pinus resinosa) and trembling aspen (Populus tremuloides) wood confirm the importance of cation exchange reactions on the ultimate distribution of copper in the wood substance and its strong dependence on pH of the treating solution. Formulations containing both copper and zinc preferentially adsorb or exchange copper relative to zinc. Under high pH conditions, the arsenate anion is significantly adsorbed into the cell wall. The combined adsorption and fixation of low pH CCA solutions is much slower than adsorption of high pH ACA and CZA formulations, but the reaction with wood is more complete. Diffusion coefficients were estimated for the movement of copper and arsenate components of ACA in cell wall material of both aspen and pine sapwood using a simple membrane model for non-steady state diffusion. The longer diffusion paths inherent in the diffuse porous hardwood (aspen) resulted in much slower equalization of the solute in the cell wall matrix than in red pine. However, in both species, equalization was achieved in a relative short time compared to accepted fixation times for conventional waterborne wood preservatives.
P A Cooper

Microdistribution of Copper in Copper-Ethanolamine (Cu-EA) Treated Southern Yellow Pine (Pinus spp.) related to density distribution
2004 - IRG/WP 04-40270
The relationship between copper absorption and density distribution in wood cell walls was investigated in this study. The density distribution on layer level was obtained from two approaches: (1) calculation by using data obtained from literature; (2) microdistribution of carbon and oxygen atoms in the wood cell. The microdistribution of carbon and oxygen in untreated southern yellow pine (Pinus spp.) sapwood, as well as copper in cell walls of copper-ethanolamine (Cu-EA) treated wood was determined by scanning electron microscopy coupled with energy dispersive X-Ray analysis (SEM-EDXA). Both approaches for density distribution led to the same result: the density was higher in the compound middle lamella (ML) and cell corners (CC) than in the secondary wall. The concentration / intensity of Cu, C and O in the cell wall follow the same trend as the density distribution; suggesting that density may play a major role in SEM-EDXA study of the distribution of metal-containing wood preservatives within the wood cell wall.
Jinzhen Cao, D P Kamdem, E Pasek

Microdistribution of water-borne preservatives in blue gum treated by full-cell process
1990 - IRG/WP 3617
The present work deals with the study of the microdistribution of copper, chrome and arsenic elements in Eucalyptus globulus Labill. sapwood, treated with a CCA water-borne preservative by full-cell process, with the help of scanning electron microscopy together with energy dispersion X-ray analysis technique. The work shows that the retention of CCA elements is high in vessels and vasicentric parenchyma as well as in the wood rays, whereas it is quite low in fibres. There are also some differences between retention obtained in the two levels of depth of radial penetration considered, increasing or constant rate of variation with depth having been found. Conclusion reached point to the need of obtaining high enough salt retention in sapwood in order to avoid this irregularity of microdistribution of CCA preservatives in Eucalyptus globulus round wood and ensure adequate durability.
D De Sousa Castro Reimão, J M Palacios

SEM-EDXA of CCA-treated Rubberwood (Hevea brasiliensis)
2009 - IRG/WP 09-20399
The microdistribution of chromated copper arsenate (CCA) preservative in rubberwood was studied using scanning electron microscope in conjunction with energy dispersive X-ray analyzer (SEM-EDXA). Bulk X-ray analysis showed that there was a high accumulation of chromium, copper, and arsenic in the vessels and lower concentration of the three preservative elements in fibres. Chromium appeared to record the highest while copper the lowest X-ray intensity in all cells. SEM-EDXA of semi-thin sections demonstrated that X-ray intensities of Cr, Cu, and As were concentrated in the fibre-to-vessel cell corner (FVCC) and fibre-to-vessel middle lamella (FVML) while the lowest intensity was recorded in S2 layer of fibre. Linescan analyses illustrated that higher count rates of chromium, copper, and arsenic were found in the middle lamella compared to the fibre S2 layer in CCA-treated rubberwood. The increase of the solution strength in chromium, copper, and arsenic corresponds to an increase in Cr, Cu, and As level in wood cells.
I Jusoh, D P Kamdem