Treesearch

Multivariate regression equations were developed for predicting board-foot (Int. 1/ 4-inch log rule ) and cubic-foot volumes in each 8.15-foot section of trees of four Hawaii hardwood species. The species are koa (Acacia koa), ohia (Metrosideros polymorpha), robusta eucalyptus (Eucalyptus robusta), and saligna (E. saligna). The four independent variables used are d.b.h., merchantable length, form class, and the diameter at the top of the merchantable length.

Picloram, in spray and pellet forms, was tested for its ability to kill chaparral species at several sites in southern California, in 1963. This herbicide proved to be as effective as brushkiller (2.4-D and 2,4, 5-T) or slightly more so. Both herbicides kilIed chamise readily at low rates, but failed to kill scrub oak. Kill of other species varied between these two extremes. Excellent kill of all species after re-treatment with picloram was obtained at one test site.

Ninety-year-old stands of the Pacific ponderosa pine and Pacific ponderosa pine-Douglas-fir types yielded 53 to 110 tons of slash to the acre after logging on the Challenge Experimental Forest, Yuba County, Calif. Fine slash (under 4 inches d.i.b.) contributed 61 to 64 percent of this weight.

Ohia trees less than 6 inches d .b.h. on the island of Hawaii were killed by injection of undiluted 2,4.S-T ester. This chemical was less effective on larger trees. Injections applied in September and January were more effective than the May applications. Injections of 2,4-D were relatively ineffective, any season of the year, even for small trees. Tardon 22K proved 100 percent effective in a single, unreplicated trial.

From 1959 to early 1966, tree failures caused an average of more than two injuries or deaths per year on forest recreation sites in California. Annual property damage is estimated at $25,100. Conifers accounted for three of every four accidents reported; pines and true firs were involved in 6 of every 10 incidents involving property damage, and in 9 of every 10 failures resulting in death or injury. These findings are from data reported by or through Federal land agencies.

After a wiIdfire, some brushland soils in southern California have been found to include a non-wettable layer. This formation may be the result of hydrophobic material volatilizing and later condensing. In burning experiments, hydrophobic substances from ceanothus litter and non-wettable soil were moved downward into an underlying wettable sand by temperature gradients. The wettable sand acquired a marked resistance to wetting after the burning treatment.

At the Institute of Forest Genetics, Placerville, California), we have recently organized a specialized herbarium of pines (Pinus) and firs {Abies). Incorporated in it are the many specimens that have accumulated since the Institute was established in 1925. Like the Eddy Arboretum, the herbarium is an integral part of our research program, which is concerned with the genetic improvement of conifers native to the western United States. Interspecific hybridization and geographic variability are important parts of the program, and the herbarium is particulary useful in documenting this research.

Two MAP (Macro Assembly Program) language routines are descrived. They permit Fortran IV programs to read binary tapes generated by Fortran II programs, on the IBM 7090 and 7094 computers. One routine is for use with 7040/44-IBSYS, the other for 7090/94-IBSYS.

A water emulsion malathion spray, applied by helicopter at the rate of 1 lb. of insecticide in 25 gallons of water, effectively controlled the pine needle-sheath miner (Zelleria haimbachi Busck). Numbers of insects in the sprayed area were reduced by 98.6 percent 24 hours after treatment.

Two MAP (Macro Assembly Program) computer routines for packing and unpacking fixed point data are described. Use of these routines with Fortran IV Programs provides speedy access to quantities of data which far exceed the normal storage capacity of IBM 7000-series computers. Many problems that could not be attempted because of the slow access-speed of tape memory can be attacked in this manner.