Treesearch

The knobcone X Monterey pine hybrid (Pinus attenuata Lemm. X P. radiata D. Don) has been outplanted in many places in California, among them the Redwood Experimental Forest and vicinity in north coastal California. Survival and growth in the early years were satisfactory. In 1966, red band needle blight was found to be infecting the plantations. Many of the trees have died. It appears that most of the trees on the best site will die from the needle blight. But one hybrid plantation so far shows no evidence of infection. It lies on a site four times higher in elevation and farther inland,...

The effects of boron and salts in spoil material on survival and growth of 44 grass, shrub, and tree species were tested under greenhouse conditions. The spoil used was from the Angeles Tunnel of the California Aqueduct's West Branch now being built. Several species within each plant group apparently can tolerate boron, but field tests will be needed before most of them can be recommended for widespread planting.

Test plots in a brushfield near Mount Shasta, California, were cleared by bulldozing in 1961, and planted with ponderosa pine seedlings in 1962. Brush regrowth was subjected to varying levels of control by spraying with herbicides. In the first 5 years, brush control definitely promoted the growth of pine seedlings. And this early control also promises to reduce the amount of hazardous brush fuels in the plantations for an indefinite period.

Primary forest products harvested in Hawaii in 1969 were valued at $331,000-a $3,000 drop from the value of the harvest surveyed in 1967. Sawlogs and veneer logs were the most important products. Koa and robusta eucalyptus were the primary sawlog species. Albizia and robusta eucalyptus provided most of the veneer logs.

For best results, direct-seeding of Douglas-fir in northern California should be done in November or December. In trials on two National Forests, sowing in those months resulted in significantly more seedlings than sowing in February or March. Also, more seedlings became established on fine-textured red soils than on coarser gray-brown soils. On red soils, more seedlings developed on south aspects; on gray-brown soils, more developed on north aspects. Some seeds particularly on spring sown plots-did not germinate until the second growing season.

Tree species capable of thriving on soils in high rainfall areas are needed in Hawaii for reforestation. The soils are highly leached and infertile.Two native and 12 introduced tree species were planted at two sites to determine adaptability. Survival, growth, vigor, and form were appraised 1 to 7 years after planting. Performance varied-both within and between species. No one species was outstanding, but several showed qualities that could be used to develop productive forests of mixed species.

Ten insecticides were tested in aerosol form against adult needle miners of the genus Coleotechnites collected from the Winema National Forest in Oregon and from the lnyo National Forest in California. In these laboratory tests, the pyrethrins were the most toxic. They were about six to seven times more toxic than malathion-the insecticide considered the most effective in suppressing needle miner epidemics. None of the chemicals other than pyrethrins was clearly more toxic than malathion. All candidates except trichlorfon caused 90 percent mortalities at 0.35 µg. .per sq. cm. (equivalent...

Forty insecticides and an antifeeding compound were tested on pandora moth larvae (Coloradia pandora Blake) in the second and third instars. A total of 21 insecticides were more toxic at LD90 than DDT, providing a good choice of candidates for field testing. Ten exceeded DDT in toxicity tenfold or more. These were, in descending order of toxicity at LD90: pyrethrins, tetramethrin, Zectran MA (a degradation product of Zectran), Dursban, N-4543, allethrin, aminocarb, B-10119, Zectran, and dichlorvos. Pyrethrins, more toxic by an order of magnitude than the second place candidate, appear to...

To aid in appraising timber on lands acquired for the Redwood National Park, in northern California, local gross volume tables were developed for Spaulding and Humboldt log rules. This note includes the Spaulding table. The Humboldt tables is 70 percent of the Spaulding table for each category listed. Readers are cautioned that they tables produced in this study do not represent the range of conditions throughout the redwood type.

Foliage injury and over-all tree damage to ponderosa pine plantations from aerial sprays of 2,4,5-T in 1965 were evaluated. Damage in 1966 was compared to tree growth from 1966 to 1968. The herbicide treatment caused above-normal damage to young trees when applied in September in a year with above-average summer precipitation and freezing weather soon after treatment. In the second year after spraying, the damaged pines improved greatly in vigorand appearance. And by the third year, their height growth was about the same as the undamaged trees. Recovery was more complete and control of...