This title is part of UC Press's Voices Revived program, which commemorates University of California Press’s mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1981.

This publication is a cooperative effort that includes descriptions of 57 forest pathogens in the Northern Hemisphere considered to be potentially most damaging to forest production in other continents, with recommendations for special precautions to restrict their intercontinental spread. These diseases occur on 87 genera of forest trees, of which 50 genera are important in the United States.

FULL COLOR and Enlarged Edition - California has more than twenty-five native species, natural hybrids, and varieties of oaks (Quercus species). The form of these oaks ranges from large trees, up to about 25 m tall, to shrubs no taller than about 1.5 m. California's native oaks include representatives of three oak subgroups or subgenera (Table 1). Hybridization only occurs between oaks in the same subgroup. In addition, some insects, pathogens, and other agents may selectively colonize or damage oaks in certain subgroups.