Treesearch

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...

Trunk diameters of Eucalyptus robusta trees shrink and swell as bark moisture content changes. Diameter variations from this cause as measured on six trees with a dial-gage dendrometer were less than 1 percent of trunk diameter. To compare this variation with the variation in d.b.h. measurements that can result from personal techiques of using a standard diameter tape, seven foresters each independently measured the same 40 robusta trees on the same day. Variations in diameters at breast height from personal measurement techiques exceeded d.b.h. variation due to changing bark moisture content.

A computerized method for gathering market area information from campground permits has been developed. Point-of-origin and length-of-stay of campground users can be estimated and summarized quickly and inexpensively. The method should be equally useful for public as well as private campgrounds-provided basic registration data are available and can be processed according to theprescribed format.

Stabilized pyrethrins were test in a laboratory spray chamber to provide information for planning field trials of this insecticide against the western spruce budworm (Choristoneura occidentalis Freeman). No significant differences were found in toxicity to instars 3 to 6. Stabilizers appear to have had no effect on basic contact toxicity. The commercial formulation of pyrethrins was as toxic as the laboratory formulated standard. Probably only slight residual activity can be expected. No effect on basic contact toxicity could be produced by increasing concentration through a range of about...