Describes the following geographic races of Pinus contorta: Rocky Mountain-Intermountain, Sierra-Cascade, Coastal, Mendocino, White Plains, and Del Norte.

Excerpt from The Genetics of Lodgepole Pine Lodgepole pine is a small tree, and only recently has it been heavily utilized in its native range. In northwestern Europe, however, the ability of some seed sources to grow well on poor sites and in cold climates has interested foresters for many years, and the species is now widely planted in the British Isles and Sweden. The oldest fossils of lodgepole pine are several million years old, but there is no evidence that the species was widespread until the late Pleistocene. It was an important pioneer following glacial melting, and occupied its extensive northern range by migration from the south and possibly from far-northern refugia. Lodgepole pine has been successfully crossed with only two other species: jack pine and Virginia pine. Crossability with jack pine is moderately high, and the two species hybridize naturally in Canada. Many northern Rocky Moun tain stands have jack pine-like characteristics, but the extent of introgression from jack pine is uncertain. Lodgepole x jack hybrids are fertile, but pollen abortion is sometimes high. Hybrids of Sierra Nevada parentage have not grown well in most other environments. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Topics include the resource, physiology and genetics, site classification, factors Influencing productivities, regeneration, management, harvest and utilization of the most widely distributed conifer in western North America.