Genetic Conservation of Insular Populations of Monterey Pine (Pinus Radiata D. Don)

Abstract

Monterey pine (Pinus radiata D. Don) has only five extant native populations: three disjunct populations along the coast of California, USA and two on Mexican islands. All populations have been influenced by human activity, but the island populations in particular have been affected by introduced biota. On Guadalupe Island, the pine population has suffered drastically from overgrazing by introduced goats. We visited both island populations and described their status, took measurements, and made seed collections. We counted approximately 200 mature pine trees and virtually no seedlings on Guadalupe Island: a reduction of approximately half the population in the last 50 years. The trees are all large (mean diameter of 144 cm) -considerably larger than trees from the other four populations -and arguably near the end of their natural lifespan. The population on Cedros Island is much more robust, with thousands of trees. None sampled were as large as those on Guadalupe Island (mean diameter of 20 cm) and many groves were young and even-aged -presumably the consequence of natural regeneration after a recent fire. Tissue samples from trees on both islands did not show evidence of infection from the pitch canker pathogen, Fusarium circinatum, that has caused significant mortality in the three mainland populations. Caution is recommended in any restoration activity for the Guadalupe Island pines. Inbreeding levels could indicate the need for some planting or seeding intervention but there are also risks associated with this. Natural regeneration -after goat removal -is preferred.

Genetic Variability and Differentiation Among Populations of the Azorean Endemic Gymnosperm Juniperus brevifolia: Baseline Information for a Conservation and Restoration Perspective

“…In these and other islands, where J. brevifolia is very rare, such as Faial, Corvo, and particularly Santa Maria (where J. brevifolia is almost extinct), inbreeding depression could be a severe problem. Especially in island conifers (e.g., Monterrey pine; Rogers et al 2006), inbreeding can have a variety of manifestations, with broad ranges in severity, and be expressed at various life stages.…”

Survey of damaging pests and preliminary assessment of forest health risks to the long term success of Pinus radiata introduction in Sichuan, southwest China

“…Other insects causing minor damage in California include aphids, borers, caterpillars, moths and a pine cone beetle, Conophthorus radiatae Hopkins (McDonald and Maacke 1990). The most recent scientific expedition to the native P. radiata populations on the two Mexican Islands has found some damages by cone beetles on Guadalupe Island and also spittle bug (Aphrophora canadensis Walley, Homoptera: Cercopidae) on Cedros Island (Rogers et al 2006). The beetles and the spittle bug have been associated with the development of pitch canker disease in California (Storer et al 1995;Storer et al 2002).…”

“…Originating from a very restricted natural distribution along the central coast of California, United States and the Cedros and Guadalupe islands off Baja California in Mexico, Pinus radiata (D. Don) has been introduced over the last 150 years to many parts of the world as an exotic species for afforestation (Scott 1960;Lavery and Mead 1998;Rogers 2002;Rogers et al 2006). It has now become one of the most widely planted exotic pine species in the world, particularly in winter or uniform rainfall environments of the Southern Hemisphere, mostly with a Mediterranean climate (Lewis and Ferguson 1993;Lavery and Mead 1998).…”

Product and Residue Biomass Equations for Individual Trees in Rotation Age Pinus radiata Stands under Three Thinning Regimes in New South Wales, Australia

“…Pinus radiata D. Don, native to a Californian central coastal environment and to two Mexican islands off Baja California, is the most extensively planted exotic coniferous species in the Southern Hemisphere (see [24][25][26][27]). Because of its growth performance, responsiveness to management and cultivation and the usefulness of its wood for lumber, veneer and pulp, it has become the mainstay of the forest economy in Australia, Chile, New Zealand, Spain and South Africa, serving domestic markets and generating income from export [24,[27][28][29][30].…”