Treesearch

Five meshes (1/8 to 1 inch) of 16-gauge steel wire fences, 3 feet high, were tested as possible ground fire barriers in 4 fuel types. The 1/8-inch mesh stopped only 1 test fire but retarded others; 1/4-inch mesh retarded some. The results suggest that further trials may be worthwhile.

A prototype ignition package containing an incendiary powder and designed for slash and brush burning jobs showed some promise, but the unit tested was not superior to such conventional devices as fusees, diesel backpack type flamethrowers, Very pistols, and drip torches.

Greenhouse and nursery studies suggest that graphs of "effective" day and night temperatures provide a convenient method to compare nursery sites and to evaluate the effects of temperature on seedling root growth. Comparisons of root response under different natural temperature regimes should provide inforrnation use ful 'for the production of higher quality nursery stock and for interpretation of the more detailed studies in controlled-temperature chambers.

Under the short growing season of the Sierra Nevada, both flowering and seed dispersal of Arceuthobium campylopodum occurred earlier in the fall and dispersal extended for a shorter duration than at lower elevations and along the coast of California. Also in years of above normal surrmer temperatures, flowering and seed dispersal occurred earlier in the season than in years of below normal temperature.

Measurements were taken of 25 exotic tree species planted in 1959 in the Waiakea Arboretum near Hilo, Hawaii. After 5 years, some species show good survival and growth, but seven pines failed to survive. All plantings have suffered from shallow soil, and competition from wild vegetation.

A heavy stand of conifer saplings and poles on the Stanislaus National Forest was thinned, piled, and chipped. The study sought to determine the amount of material removed and the cost of chipping. Slash disposal costs were $9.66 per ton for dry material, and $11.81 per ton for green slash.

Data accumulated for more than 25 years from old-growth sugar pine stands in central California showed that the mountain pine beetle preferred to attack mature and overmature trees with the most decadent crowns. Analyses included four age groups and eight crown types. Beetle outbreaks in second-growth sugar pine were nondiscriminating between trees. These outbreaks developed during drought when heavy populations were reared in snow-breakage debris.

Describes how to make an economical "can-cone"-type storage precipitation gage, based on one originally designed by the California Department of Water Resources. The cone was modified by including an inner skirt to prevent loss of water between the cone and can. Periodic records of precipitation are obtained by stick measurement. Five complete cones cost $120.

A new electronic instrument, called the Heterodyne Vegetation Meter to measure herbage yield and utilization was built and tested. The instrument proved to be reliable and rapid. Further testing will be conducted.

A hybrid pine developed in the course of forest-tree improvement research. by the U. S. Forest Service has caught the interest of Christmas tree growers. It is a hybrid between two races of lodgepole pine (Pinus contorta) produced at the Institute of Forest Genetics at Placerville, California, and has some desirable attributes for use as a Christmas tree: good form and color, relatively rapid growth, and early production of persistent cones.