White fir wood

Methyl Esters Isolated in Oxidizing White Fir Wood ... 

In all reactions, wood of white fir Abies concolor) has been used. For the alkaline nitrobenzene reactions, extractive-free —20+40 mesh heart-wood sawdust containing 28.0% Klason lignin was used. Sequential extraction of the original sawdust with alcohol-benzene, 95% ethanol, and hot water gave extractives amounting to 4.9, 0.5, and 1.2%, respectively. In the other oxidation reactions, nominal 5 -in. wood chips, commonly used in pulping procedures, were employed. The mixed sap wood-heart-wood chips contained 26.5% Klason lignin and sequential extractives of 3.3, 0.5, and 3.2%, respectively. 

The thermal properties of composite boards were the subject of a recent report by Place and Maloney (58). Thermal conductivity tests were made on three-layer boards with surfaces of white pine wood flakes and cores of either Douglas-fir or grand fir bark. Density was varied at 34, 42, and 52 pounds per cubic foot. The composite boards containing bark proved to be better insulators than wood particleboard of comparable density. Douglas-fir bark cores had lower thermal conductivity than did grand fir. 

Figure 22. SEM of ray cross-field pits in softwoods as seen on the wood rcmial surface. Key A, pits to ray parenchyma (RP) in western white fir and B, pits to ray parenchyma and ray tracheids (RT) in lodgepole pine.

Our estimates of the acid contents of heartwoods and sapwoods of red oak, hickory, southern pine, white fir, and Douglas-fir are given in Table I. The acid contents were correlated with the gel times of urea-formaldehyde resins (36) in contact with the same sample lots of the different species of wood. The correlations are presented in Table II. It is seen from Table II that the best correlation of gel times is obtained with insoluble acid content for each of the empirical fits that were tried. Similarly, the pH of the sodium acetate extracts showed better correlations with the gel times than the pH of the water extracts (37). 

Fir woods closely resemble the pines in being needleleaf or toft woods but have no resin ducts. The variety mostly favoured is the white or silver fir. 

FIGURE 40.7 Compression wood compared with normal wood. (ESEM photographs White fir [Abies alba], LERMAB-ENGREF, Nancy, France.)... 

Joints bonded with casein glue will average better than 90% wood failure when the following softer wood species are used redwood, western red cedar, white fir, Sitka spruce, southern cypress, western hemlock, eastern red cedar, chestnut, red alder, and northern white pine. With the harder woods—red oak, maple, white ash, yellow birch, and persimmon—the joints will show 30-50% wood failure. 

Wood and Wood-Lined Steel Pipe Douglas fir, white pine, redwood, and cypress are the most common woods used for wood pipe. Wood-lined steel pipe is suitable for temperatures up to 82°C (180°F) and for pressures from 1.4 MPa (200 Ibhin ) for the 4-in size, through 0.86 MPa (125 IbFin ) for the 10-in size, to 0.7 MPA (100 Ibf/ in") for sizes larger than 10 in. For fume stacks and similar uses, wood-stave pipe with rods on 0.3-m (1-ft) centers is most satisfactory because it permits periodic tightening. In recent years reinforced plastics have supplanted wood pipe in most applications. 

In the United States, woods which have been used for tight cooperage include white oak, red oak, chestnut oak, red or sweet gum, sugar maple, yellow or sweet birch, white ash, Douglas fir, beech, black cherry, sycamore, redwood, spruce, bald cypress, elm, and basswood (2, 3, 4). In Europe, cooperage for wine or brandy has been made from... 

Douglas-fir, birch, southern pine, and sweetgum blocks were treated with 1% aqueous ammonia or sodium hydroxide for various times, temperatures, and pressures (9). These samples were submitted to soil-block tests with two brown-rot fungi Poria monticola (Madison 698) and Lentinus lepideus (Madison 534) and two white-rot fungi Polyporus versicolor (Coriolus versicolor) (Madison 697) and P. anceps (F 784-5) as well as outside exposure tests (10). In the soil-block tests, the treated wood was resistant to the two brown rotters, but was not resistant to the two white rotters. In the outdoor stake tests, the average lifetime was 3.5 years while untreated controls had an average lifetime of 3.6 years. The outdoor tests show that there is no increase in rot resistance by this treatment. 

C. Heat Treatments. Several woods have been heated under wet and dry heating conditions to determine the effect heat has on the decay resistance of these woods. Alaska-cedar, Atlantic white-cedar, bald cypress, Douglas-fir, mahogany, redwood, white oak, Sitka spruce, and western redcedar were heated under dry conditions or wet conditions at temperatures of 80-180°C for varying lengths of time. Boyce (11) found that dry heat at 100°C or steam heat at 120°C for 20 minutes had no effect on the decay resistance. Similar results were observed by Scheffer and Eslyn (12) in soil-block tests with Lenzites trabea for the heated softwoods and Polyporus versicolor for the heated hardwoods. 

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