North American Conifers

The use of volatile chemicals as systematic markers has the obvious advantage of lending itself to quantification through GLC. In many, if not most, of the cases discussed below, qualitative differences in monoterpene profiles would not have been sufficient to allow distinctions to be made between taxa, or even between individuals within a population. This is true because most conifers synthesize many of the same monoterpenes, although often in vastly different relative concentrations. It is these quantitative differences that have been constructively used in the following examples. Structures of the terpenes commonly studied are presented in Fig. 3.7. 

Abies—the true firs—comprise a moderately large genus, 49 species (Mabberley, 1997, p. 1) that include some of the most important commercial species among the conifers, particularly in North America. Some of the more important North American 

Zavarin and his associates have described detailed analyses of the terpenoid constituents of several species of fir. We can start with their study of A. amabilis collected throughout the range of the species (Zavarin et al., 1973). The Pacific silver fir occurs from southeastern Alaska to northern California at mid to higher elevations with a major contribution to the forest flora in coastal British Columbia, the Olympic Mountains (Washington), and in the Cascade Mountains in Washington and Oregon. It is represented in California in only a few sites in the north. Analysis of cortical terpenoids from over 100 trees from 15 sites revealed a comparatively 

The comparatively low level of interpopulational variation in the monoterpenes of A. grandis resembles that for A. amabilis commented upon above. As noted by Zavarin etal. (1977), it is likely that A. occupied much the same areas during 

---

Volatade leaf oil analysis in chemosystematic studies of North American conifers. 

Cates, Rex G. Alexander, H. J. In "Bark Beetles In North American Conifers Ecology and Evolution" J. Mltton and K. Sturgeon, (Eds.) University of Texas Press Austin, Texas, In press. 

Borden J. H. (1982) Aggregation pheromones. In Bark Beetles in North American Conifers, eds J. B. Mitton and K. B. Sturgeon, pp. 74—139. University of Texas Press, Austin. 

The use of essential oils for chemosystematic study of North American conifers has been reviewed and many of the problems of sample collection, analysis, and interpretation of data discussed (von Rudloff, 1975). In addition, specific treatments of Abies, Chamaecyparis, Juniperus, Picea, Pinus, Pseudotsuga, Thuja, and Tsuga are summarized. Sampling of these coniferous trees was found to be most reproducible during the dormant period from fall through winter. 

Chang Y-P 1954 Bark structure of North American conifers. USDA For Serv Tech Bull 1095,... 

Godkin S E, Grozdits G A, Keith C T 1983 The periderms of three North American conifers. Part 2 Fine structure. Wood Sci Technol 17 13-30... 

Dormant western white pine is, along with lodgepole pine, one of the more cold-hardy western North American conifers. Needle desiccation can result from winds or sun causing excessive moisture loss during times when soil is frozen or cold. Western white pine is quite tolerant of heat compared to... 

Critchfield, W.B. 1984. Impact of the Pleistocene on the genetic structure of North American conifers. Pp. 70-118 in Proceedings of the 8th North American Forest Biology Workshop. Dept, of Forest Resources, Utah State University. Logan, UT. 

Godbout, J., J.P. Jaramillo-Correa, J. Beaulieu, and J. Bousquet. 2005. A mitochondrial DNA minisatellite reveals the postglacial history of jack pine Pinus banksiana Lamb.), a broad range North American conifer. Mol. Ecol. In press). 

Hedlin, A.F., H.O. Yates III, D.C. Tovar, B.H. Ebel, T.W. Koerber and E.P. Merkel. 1980. Cone and Seed Insects of North American Conifers. Environment Canada, Canadian Forestry Service, Ottawa. 122 pp. 

Jaramillo-Correa, J.P., J. Beaulieu and J. Bousquet. 2004. Variation in mitochondrial DNA reveals multiple distant glacial refugia in black spruce Picea mariana), a transcontinental North American conifer. Molec. Ecol. 13 212,5-21 AT. 

---