Inter-Tree Variation of Essential Oil Composition of Thuja occidentalis L.

ABSTRACT

Variation in the composition and yield of the essential oils of Michigan grown northern white cedar (Thuja occidentalis L.) is reported. Comparison of oil isolated from the foliage of individual trees revealed significant inter-tree variation in oil composition. The optimal pilot scale distillation time was found to be about 40 minutes. Total oil yield using steam distillation is almost identical among the ten trees analyzed, but ketone content and diterpene percentages vary significantly from tree to tree. Ketone content of T. occidentalis can be used as criteria for tree selection since its percentage varies widely from 58 to 77%. Diterpene content may also prove useful as markers but more work is needed to help quantify the genetic and environmental components of phenotypic variation.

KEY WORD INDEX:

• Thuja occidentalis
• Taxodiaceae
• inter-tree variation
• essential oil
• thujone
• steam distillation