The Pines of Cedros and Guadalupe Islands

Abstract The pines of Cedros and Guadalupe Islands are related to Monterey pine (Pinus radiata) and bishop pine (P. muricata). They are of interest and possible value its their own right, and as sources of additional genetic variation for breeding programs with Monterey and bishop pine. Preliminary tests indicate a significantly greater resistance of the pines of both islands to Dothistroma pini, compared with mainland Monterey pine. This paper describes the islands, the pine populations on the islands, and the history and location of known plantations of pines from the islands. The Guadalupe Island population includes essentially no young trees, and is in danger of extinction. One tree is of larger diameter than any known native Monterey pine or bishop pine. In general, the diameters of mature trees observed on Cedros Island were much smaller than those of mature trees on Guadalupe, although the heights of the tallest trees on the two islands are nearly identical.