Big cone Douglas fir

The third paper in this set Zavarin and Snajberk (1976) described their efforts to detect chemical races within big cone Douglas fir. Analysis of the cortical monoterpenoid fraction of 33 trees revealed that the major component was a-pinene, with P-pinene, 3-carene, and limonene present in lesser amounts. The monoterpene profiles of different populations varied somewhat from each other, but the overall profile of big cone Douglas fir was clearly different from that of Douglas fir. There was no evidence for gene flow between the southernmost population of Douglas fir at Lompoc and the closest population of big cone Douglas fir at Figueroa, sites separated by only 34 km. 

Ching, K.K. 1959. Hybridization between Douglas-fir and big-cone Douglas-fir. Forest Science 5 246-254. 

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