PINE FORESTS OF CALIFORNIA

B. O. HUGHES, DUNCAN DUNNING.

The national forests of California have 7.7 million acres of land suitable for growing timber as the primary crop. Of this total, 5.6 million acres bear virgin or old-growth forests unaffected by lumbering and 1.2 million acres have younger stands left in the first logging operation. The rest is not stocked with trees, mostly because of fires before the late 1890's.

In converting these three kinds of areas to well-ordered croplands, forest managers must reckon with a complex mixture of assets and liabilities. Generally speaking, the national forests are not the most favorably situated timberlands in the State. The more accessible, more productive lands passed to private ownership before the forests were established.

Five conifers make up more than 95 percent of the volume of the standing timber. Of these, ponderosa pine is the most generally useful and of widest occurrence. The fine-textured sugar pine commands the highest price, but constitutes only one-tenth of the volume. Both pines reach their best development along the western slope of the Sierra Nevada.

Douglas-fir and white fir each make up about one-third of the timber volume and are important components of the mixed forests of both the Sierra Nevada and Coast Range, sometimes forming almost pure stands.

California incense-cedar occurs intermingled with the other species, forming only one twenty-fifth of the volume. It is presently the world's most important pencil wood and is prized for fence posts, rails, and other uses requiring resistance to decay.

Native hardwood trees are of relatively minor importance in California. The introduction of valuable timber hardwoods from the Eastern States or elsewhere has not been successful. Nor are any introduced conifers known that are more generally useful and that could survive and grow better than the natives. Several promising hybrid pines are now being tested; some of these may prove useful in certain localities.

Ponderosa pine is the mainstay of the national forest management, with sugar pine the favored species in restricted, highly productive localities. By good management the proportion of these trees in the stands can be considerably increased and serious insect damage, diseases, and soil deterioration common in single-species forests can be avoided. But constant care is needed to keep these two valuable pines from being crowded out by the associated firs and cedar, which are more easily established by natural seeding.

All the five native conifers can grow rapidly and attain merchantable saw-timber dimensions of 18 to 50 inches in diameter in 75 to 150 years, according to quality of soil.

The problem of transforming the wild natural forests for more efficient timber growth has one highly favorable aspect: The high values stored in the large smooth stems of the old trees that occasionally exceed 600 years in age. Some of this reserve capital can be reinvested in the forest to correct the many deficiencies. Provision for this has been made through the Knutson-Vandenberg Act, which authorized the planting of fail-places, removal of undesirable trees and brush, pruning crop trees, and other stand improvement.

A notable deficiency of the virgin forest is that the land is now stocked with trees only to a little more than 60 percent of its capacity. Good management aims to increase stocking by about one-third. Accomplishing this is made difficult by an excess of old trees. The large, old trees contain from 60 to 95 percent of the stand's saw-timber volume. This is slow-growing or deteriorating timber ready for harvesting; it should be replaced. Thus, growing stocks must first be reduced before they can be built up by natural regeneration or planting into thriving forests that contain young trees for future harvests.

Reconstructing the stands by planting or seeding is made difficult by hosts of aggressive shrubs manzanitas, ceanothus, and others growing between the trees or waiting as seed to take possession of the soil when trees are cut. Squirrels, chipmunks, and mice add to the difficulties by destroying tree seed; rabbits damage the natural or planted seedlings. Cone- and seed-destroying insects are serious pests, as are the cutworms and weevils that kill seedlings.

Insect enemies of larger trees are a serious menace to the timber kept in reserve as growing stocks. Sometimes the pests force premature or undesirably heavy cutting. The worst are bark, or engraver, beetles. Their depredations exceed the losses caused by fire.

Of tree-killing diseases, the blister rust of sugar pine is the most feared, although it has not yet become widespread. The ring scale fungus, the Indian paint fungus, the incense-cedar dry-rot, and many other fungi, which are not primarily tree killers, nevertheless cause heavy losses by destroying the heartwood of standing trees.

The climate of California often gets bad marks perhaps unjustly from forest managers. The long, warm, dry summers contribute to an excessive fire danger. As to tree growth, however, better understanding gained in recent years tends to discount the opinion that high summer temperatures and low growing-season rainfall are extremely adverse features. The trees are well adjusted to survive these normal rigors of their environment. Close observation has shown that most failures of planting and natural seeding resulted from crowding by weeds and shrubs, damage by rodents and insects, or faulty timing and methods. More knowledge and improved skill can overcome these obstacles.

With respect to topography and transportation, the national forests in California have disadvantages as compared with other forest regions. The bulk of the timber covers the manifold ridges and canyons of the western Sierra Nevada and northern inner Coast Range between altitudes of 3,000 and 7,000 feet. The Coast Range timber is least accessible by roads. Terrain of the northeastern volcanic plateau, with its extensive forests of ponderosa pine, is more favorable.

Offsetting the difficulties of transport is the large and expanding local market for lumber. From one-third to one-half of the lumber manufactured by the mills in the State goes into production and marketing of farm crops. The growing population is bringing to the State new industries and new home building likely to maintain a good local market for wood.

The varied pattern of land ownership in California also complicates timber management. There are about 18,300 private holdings of forest land in the State as a whole, many of which are inside the national forest boundaries. Fire control has long been accomplished by cooperation among the private owners, the State Board of Forestry, and the Forest Service under provisions of the Clarke-McNary Law. Recent congressional and State laws also provide for cooperative defense against insect enemies and tree diseases. Another recent congressional law the Sustained-Yield Unit Act authorizes cooperative management of the interdependent private and federal timber, but no agreements have yet been consummated. Problems arising from divided responsibility have been simplified in many instances by land exchanges.

The wood-growing capacity of the national forests of California under good management is estimated to be slightly more than a billion board feet a year. The allowable cut during the period of converting the old growth to thrifty and well-ordered stands is restricted to 972 million board feet. The volume actually logged has averaged much below the allowable cut and in 1947 was 555 million feet. The rate of cutting obviously can be increased by opening up inaccessible areas.

After cutting started in 1898, the proportion of the sawmill production in the State that came from the national forests rose gradually to about 10 percent in 1939. Thereafter the proportion has risen more rapidly, reaching 20 percent in 1947. Depletion of the more accessible private timber doubtless will continue this trend in cutting on the public forests. An era of accelerated use is at hand, presenting the opportunity to improve and intensify all management procedures.