Libocedrus

Erdtman H, Harmatha J (1979) Phenolic and terpenoid heartwood constituents of Libocedrus yateensis. Phytochemistry 18 1495-1500... 

Cedar Chamaecyparis, Thuja, Libocedrus Wood, bark Lumber, insect repellant... 

Koch/Tamarack Larix occidentalis Nutt./ Western larch Libocedrus decurrens Torn/ Incense cedar Picea engelmanni Parry ex Engelm./Engelman spruce Picea glauca (Moench) Voss/ White spruce... 

Libocedrus bidwillii Hook f. Bifluvones Amentoflavone (1) sequoiaflavone (2) 1-2,3-dihydroamentoflavone (31) 1-7-0-methyl-I-2,3-dihydroamentoflavone (32). Markham et al., 1990[461]. 

Cupressaceae Chamaecyparis lawsoniana Juniperus horizontalis Libocedrus decurrens Pinaceae Abies concolor... 

Libocedrus bidwillii LM Thin-walled phellem cells 68... 

Chan UL 1985 The anatomy of the bark of Libocedrus in New Zealand. lAWA Bull 6 23-34... 

Zavarin E, Anderson A B 1955 Extractive components from incence-cedar heartwood Libocedrus decurrens Torrey). I. Occurrence of carvacrol, hydrothymoquinone and thymo-quinone. J Org Chem 20 82-88... 

Sequirin D (19) from Sequoia sempervirens (12, 54) and yateresinol (20) of Libocedrus yateensis (41) are two compounds that may be mentioned in this context although they do not possess the characteristic C17 backbone of the conioids. A diphenylbutadiene (21) has also been isolated from the heartwood of L, yateensis (41). Possible biogenetic relationships between the common lignans, yateresinol (20), the conioids, and the diphenylbutadiene (21) have been discussed by Erdtman and co-workers (41) and by Whiting (121). 

Libocedrus Sequoia Taxodium Thuja Taxales Taxus baccata... 

Fragranol (85), a cyclobutane derivative, has been obtained from root of Artemisia fragrans, where several of its esters are also present (54). Eucarvone (86), which was isolated in 1905 (379) occurs in the essential oil from rhizomes of Asarum sieboldii. Two related compounds are the carboxylic acids, shonanic acid (87) from the wood of Libocedrus formosana and thujic acid (88) present in the heartwood of Thuja plicata, which also contains its methyl ester (140). 

Several other terpenoids have fungistatic properties. The phenolic diterpenes ferruginol and totarol, obtained from members of the genus Podocarpus, are inhibitory to some decay fungi but not to others (43). Hydrothymoquinone and p-methoxythymol, phenolic compounds with a p-cymene structure, isolated from Libocedrus heartwood, had broad-spectrum inhibitory effects on decay fungi (5). 

Durability of heartwood is dependent on the kinds and concentration of extractives present, their chemical stability, and their resistance to microbial inactivation. Many tree species (e.g., Madurapomifera or Robiniapseudoacacia) contain only one or two toxic compounds, often in very small quantities, yet the wood is extremely durable (45, 54). In other species a number of similar toxic compounds may occur together (Libocedrus decurrens (5)), or toxic compounds of a very different chemical nature may be present in the heartwood of a single species (stilbenes and ellagitannins in Eucalyptus sideroxylon (23). In either case, the combination of compounds acts additively or perhaps even synergistically to produce an inhibitory environment. 

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