Treesearch

Dwarfmistletoes (Arceuthobium spp. ) parasitize and damage most native conifers of California. The study of chemical control for dwarfmistletoe on pines and true firs was resumed in 1959. Over the past 5 years, 246 tests on 2, 516 trees of five species have been started, Many phenoxy herbicides and some other materials were applied as sprays in fuel oil and water carriers. An isooctyl ester of 2, 4, 5-trichlorophenoxy butyric acid is the most promising herbicide so far tested for direct spray treatment of dwarfmistletoe on pines.

Presents rating curves applicable to small and large flume installations in which approach velocity permits a hydraulic control to exist. The accuracy to be expected from these curves is tabulated and plotted against field observations. The rating curves should be considered only indicative of the actual flow rates when applied to runoff containing appreciable debris quantities. Criteria are given for modifying field installations, without a hydraulic control at the flume inlet.

Eight hybrid and native pines were planted in 1950 on three locations of the Stanislaus-Tuolumne Experimental Forest. Height, diameter, and survival data were recorded annually. Physical injuries from snow, insects,and animals were surveyed in 1962. After 12 years, the most promising hybrid at 5,200 and 5,400 feet elevation was Jeffrey x (Jeffrey x Coulter). This backcross hybrid showed little damage from insects, snow, or porcupines.

An upholsterer's hog-ringer, with Hill's No. 1 pig rings, increased production of one-foot-square wire seed traps by 25 percent. A design modification allowed two bottom sections to be cut from a 36-inch roll of wire.

Intermingled pines and mountain whitethorn were treated with foliar sprays of 2,4-D and 2,4,5-T to test their effects according to (1) season of year, (2) concentration of spray on individual tree-brush clumps, and (3) spray dosage applied on an area basis. Spraying with 2,4,5-T in September resulted in the best tree growth and most brush kill; 2,4-D caused the most tree damage and was less effective as a brush killer. The best brush kill resulted from application rates of 400 to 600 ppm of 2,4,5-T, but these concentrations reduced tree growth. After two full growing seasons, average...

The fungus Colletotrichum gloeosporioides, previously reported infecting only the true fir form of dwarfmistletoe, Arceuthobium campylopodum f. Abietinum, also infects A. campylopodum f. typicum and A. americanum in California. Isolates of this fungus from each form or species of dwarfmistletoe are culturally distinct from one another. Differences in mycelial growth, colony color, and diameter growth and sporulation were noted. Cross inoculation showed that the fungus is not host specific. All three isolates will infect the dwarfmistletoe forms and species mentioned. Results of the studies...

Two corn plant samples, one cut in the fall while green, the other after weathering over the winter, exhibited strikingly different combustion properties. The increased susceptibility to flaming combustion of the spring-harvested sample is attributable to its decreased ash content, and not directly to its moisture content.

Recognizing that weather is an important factor in the spread of both urban and wildland fires, a study was made of the synoptic weather patterns and types which produce strong winds, low relative humidities, high temperatures, and lack of rainfall--the conditions conducive to rapid fire spread. Such historic fires as the San Francisco fire of 1906, the Berkeley fire of 1923, the Chicago fire of 1871, the Bel Air- Brentwood fire of 1961, and the Hamburg firestorm of 1943 were undoubtedly influenced by the weather pattern occurring at the time. If critical fire weather periods can be...

Registration data at campgrounds where fees are charged can provide information that will be useful in planning and design of facilities and in outdoor recreation research. Several available sources of information are described, and proposals for effective collection and use of registration data are suggested.