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Bolsinger, Charles L. 1988. The hardwoods of California's timberlands, woodlands, and savannas. Resour. Bull. PNW-RB-148. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 148 p. The results of a statewide inventory of California's hardwood resources are presented. This is the first comprehensive inventory with tree and stand measurements ever conducted in the extensive oak woodlands. In timberland areas where hardwoods had been previously inventoried, improved procedures and volume equations developed specifically for the major California hardwood species were used in the new inventory. Included are details on area and volume of hardwoods by ownership; growth and mortality of hardwoods on timberland; hardwood tree cutting on timberland and woodland; the extent of types and species occurrence; stand characteristics; regeneration; extent of grazing in woodland areas; and changes in hardwood area from 1945 to 1985. Research Summary Hardwood forest types occupy 9.6 million acres in California, about 25 percent of the total forest area and 9.5 percent of the State's total land area. Hardwoods also occur as scattered trees, stringers, or clumps on an estimated 8.2 million acres of conifer types, 1.8 million acres of rangeland (savanna), and 1.7 million acres of chaparral. The total area of hardwood occurrence is estimated to exceed 21 million acres. About 2.2 million acres (23 percent) of the total area in hardwood types are classified as timberland, areas capable of growing industrial wood. Most of the timberland on which hardwoods occur is capable of growing conifer trees. The major species of hardwoods on timberland are tanoak, Pacific madrone, California black oak, and canyon live oak. About 7.4 million acres (77 percent) of hardwood types are classified as woodland. These areas are not capable of growing commercial quantities of industrial wood. They are capable of growing firewood, fenceposts, and small quantities of industrial wood. The majority of the woodland types is grazed by livestock. The major species on woodland are coast live oak, interior live oak, blue oak, valley oak, and Oregon white oak. Canyon live oak, common on timberland, also is found on several hundred thousand acres of woodland. Seventy-two percent of the hardwood area is in private ownership; 16 percent is in National Forests; and 12 percent is managed by other governmental organizations including the State, counties, Bureau of Land Management (U.S. Department of the Interior), and U.S. Department of Defense. About 577,000 acres of hardwood types are in parks and wilderness. Total estimated volume of hardwood growing stock in the State is 12.5 billion cubic feet. This includes the sound volume in straight bole sections of trees above a 1-foot stump and to the point where the bole is 4 inches in diameter in trees 5.0 inches and larger. The total estimated volume in trees 5.0 inches and larger, including all bole sections, stumps, limbs, branches, and tips, is 18.4 billion cubic feet. The estimated volume of hardwoods in saw logs suitable for lumber is 5.3 billion cubic feet, about 25 billion board feet. As with area, private landowners hold the largest portion of the total hardwood timber volume, 67 percent. National Forests contain 26 percent; lands managed by other public agencies, 7 percent. California's hardwoods are extremely variable in tree quality, stand density, and stand composition. Species such as giant chinkapin, eucalyptus, and tanoak tend 'to be straight and single stemmed with small limbs and gradually tapering boles. At the other extreme are live oaks and Pacific madrone, which often are crooked and multistemmed with large limbs and rapidly tapering boles. Tanoak and madrone stands are typically dense, with many trees per acre. Large specimens are common. Blue oak stands are typically sparse; widespread clearing in blue oak for range improvement and recent cutting of fuelwood have lowered the average density even more. Large blue oak trees are not common. Regeneration of hardwoods, indicated by seedlings and saplings on sample plats, varies by type. In general, timberland hardwoods are regenerating well. In woodland areas, oak seedlings and saplings were found in great abundance in canyon live oak stands, and in moderate amounts in interior live oak, California black oak, and Oregon white oak stands. Regeneration was relatively sparse in coast live oak and blue oak stands and almost nonexistent in valley oak stands. Some valley oak seedlings and saplings were found in stands of other species. Since 1945, the total area of hardwood types on timberland is estimated to have increased by about 760,000 acres. Tanoak and madrone are the major types that increased. Over the same period, hardwood woodland area is estimated to have decreased by about 1.2 million acres. Blue oak and valley oak are the major types that have decreased. The primary cause of the increase in hardwoods on timberland was logging. Conifers were removed, and hardwoods were usually left; in some cases, they rapidly resprouted or seeded in after logging. Several factors resulted in the decrease in hardwood woodland areas. Between 1945 and the early 1970's, rangeland improvement was the primary cause of woodland conversion. Since the early 1970's, clearings have decreased; urban and suburban expansion has become the main cause of conversion, followed by road construction. The recent increase in fuelwood cutting has reduced the number of trees, but has had little impact per se on the area of woodland. Most permanent clearings apparently are for other purposes, though the wood removed is often used for fuel. Residential and recreational developments in-process were found on 279,000 acres of woodland. The time frame for these potential conversions was not determined. These developments were in coast live oak, valley oak, blue oak, and eucalyptus stands. In timberland areas, in hardwood stands as well as in conifer stands, hardwood volume has increased substantially since the early 1950's, a direct result of logging practices and land management activities. Hardwood growth rates have been higher than those for conifers, and mortality rates lower. Hardwood timber cutting has been but a fraction of growth and total inventory volume. Growth rates were not determined for hardwoods in woodland, but a system of permanent plots was installed from which future growth rates can be determined, along with cutting rates and other changes. The estimated area of woodland in which cutting had taken place, based on a one-time visit to sample plots, is 300,000 acres in the past 5 years or 60,000 acres per year. Intensity of cutting ranged from one tree per acre to 90 percent of the stand. Excluded were areas that had been converted from woodland to nonforest in range clearing; residential developments; and other conversions. Grazing had occurred within the past year on 55 percent of all woodland plots visited. Grazing intensity varied considerably by type. A larger percentage of the blue oak, coast live oak, interior live oak, and valley oak types had been grazed than of black oak and canyon live oak types,