Cedar, Western

Avramidis etal. (1996) Mixture of western red cedar, western hemlock and amahilis fir, 71-152 mm thick 80 16 0.12... 

Rohacts has asaminod the cedar oil distilled from the wood of the Deodar tree, Cedrut dfodarii, a native of the Western Himalayas, which ia widely disfrihnted in Northern India. The samples esamined were of a reddish colour and characteristic balsamic odour. They had the following characters —... 

A few acid woods, such as oak, chestnut and Western red cedar, accelerate surface weathering of aluminium, but do not usually give rise to serious attack . Timber preservatives containing soluble copper compounds should be avoided creosote and zinc napthenate are satisfactory preservatives for wood in contact with aluminium. 

Zinc in contact with wood Zinc is not generally affected by contact with seasoned wood, but oak and, more particularly, western red cedar can prove corrosive, and waters from these timbers should not drain onto zinc surfaces. Exudations from knots in unseasoned soft woods can also affect zinc while the timber is drying out. Care should be exercised when using zinc or galvanised steel in contact with preservative or fire-retardant-treated timber. Solvent-based preservatives are normally not corrosive to zinc but water-based preservatives, such as salt formulated copper-chrome-arsenic (CCA), can accelerate the rate of corrosion of zinc under moist conditions. Such preservatives are formulated from copper sulphate and sodium dichromate and when the copper chromium and arsenic are absorbed into the timber sodium sulphate remains free and under moist conditions provides an electrolyte for corrosion of the zinc. Flame retardants are frequently based on halogens which are hygroscopic and can be aggressive to zinc (see also Section 18.10). 

Smith, R. S., Johnson, E. L. and Cserjesi, A. J., Corrosion of Zinc-Coated Nails Used with Preservative-Treated Western Red Cedar Shakes in Service. Document No. IRG/WP/ 3197, International Research Group on Wood Preservation, Stockholm (1982)... 

Certain LMW agents will cause OA via a poorly defined mechanism. Only about 20% of workers with OA to toluene diisocyanate (TDI) have IgE detectable to TDI indicating that IgE antibody may be more an indicator of exposure rather than a mediator of the disease [10], Similar data exist for workers with asthma caused by plicatic acid from western red cedar [11], The inability to detect IgE antibody in the majority of these workers may be based in technical issues such as the nature of the chemical-protein... 

Tse, K.S., Chan, H., and Chan-Yeung, M., Specific IgE antibodies in workers with occupational asthma due to western red cedar, Clin Allergy, 12, 249, 1982. 

Chan-Yeung, M., Giclas, PC., and Henson, P.M., Activation of complement by plicatic acid, the chemical compound responsible for asthma due to western red cedar (Thuja plicata), J. Allergy Clin Immunol., 65, 333, 1980. 

One way to avoid the use of any preservative is to use wood that is naturally resistant to decay. The heartwood of more naturally rot-resistant species, such as oak, can be used untreated. Other woods that last well without treatment are larch, which will last about 10 years in contact with the soil, or up to 20 years if not in contact with soil Western red cedar, which will give service for about 20 years and sweet chestnut, traditionally used for fence palings and posts. Untreated pine lasts for about five years. Well-seasoned wood that has been allowed to dry out evenly is more expensive than greenwood (freshly cut undried wood), but in its favor, it tends to last longer and can be less prone to distortion as it weathers. 

Even that kind of information is not available for forest species. Other than chronic injury to white pine (associated with ozone, sulfur dioxide, and their mixtures), no clearly defined examples of chronic injury from ozone have been reported for eastern forests, and no information is available on PAN. It is of interest that both Virginia and jack pine appear more sensitive than white pine to acute ozone exposures, but chronic symptoms have not been observed in either species. The relationship between oxidant dose and injury in the San Bernardino Mountains area suggests that ponderosa pine is moderately to severely injured in areas that receive oxidant at above 0.08 ppm for 12-13 h each day (Chapter 12). Ponderosa pine seems to be the most sensitive western pine, but in some areas Jeffrey pine is about as sensitive. White fir, incense cedar, and sugar pine all appear more tolerant, even to the high oxidant concentrations in the San Bernardino Mountains. PAN may play some role in the chronic responses noted in the western forest species, particularly by broadleaf deciduous trees and some shrubs. 

Fujita M, Gang DR, Davin LB et al (1999) Recombinant pinoresinol-lariciresinol reductases from western red cedar Thuja plicatd) catalyze opposite enantiospecific conversions. J Biol Chem 274 618-627... 

Primary irritant dermatitis caused by wood contact consists of erythema and blistering, which may be accompanied by erosions and secondary infections. Irritant chemicals typically are found in the bark or the sap of the outer part of the tree. Therefore, loggers and persons involved in initial wood processing are most affected. In most reports of contact dermatitis, hardwoods of tropical origin have been implicated, although other woods, including pine, spruce, western red cedar, elm, and alder, have been cited. 

Extensive studies have been done on a clearly defined asthma syndrome produced by exposure to western red cedar. ° Plicatic acid has been identified as the etiologic agent. The western red cedar asthma syndrome includes rhinitis, conjunctivitis, wheezing, cough, and nocturnal attacks of breathlessness characterized by a precipitous decline in FEVi. There is no apparent relation between skin sensitivity and respiratory changes. No precipitating IgG antibodies are found in the serum of sensitized individuals, and circulating IgE antibodies are present in about one-third of affected individuals. 

Chan-Yeung M, et al Occupational asthma and rhinitis due to Western red cedar (Thuja plicata). Am Rev Respir Dis 108 1094-1102, 1973... 

Lake and Mountain Lake evaporative losses exceed precipitation in the west (Cedar and Mountain), but represent only about 60% of the precipitation falling in northern Wisconsin (Little Rock). Precipitation chemistry varies along the same gradient, with pH increasing from 4.6 in northern Wisconsin to 4.8 in northeastern Minnesota and 5.2 in western Minnesota. The corresponding values for wet sulfate deposition decrease from 15 kg/ha per... 

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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