Treesearch

Wildflower growth, meadow conditions, and grazing methods were compared in the Bogard area, Lassen National Forest, northeastern California. The two grazing methods were rest-rotation, in which range units are periodically rested from grazing, and free-choice, in which range units are not provided any rest periods from use. The results suggest that grazing per se need not be detrimental to the growth of wildflowers, and that both adequate beef production and esthetic values can be achieved by finding the right balance between rest and grazing for mountain meadows.

The density and flowering of California-poppy (Eschscholzia californica var. peninsularis Green), amount of bare ground, and occurrence of other plants were studied in an old field and a stubble field near Madera, California. The stubble field had more poppy plants per unit of area, more plants flowering, and more bare ground than the old field. The two fields differed in how often other plants were found. The results suggest that a site disturbance that produces a harsh microclimate or reduces competition or both will favor California-poppy and that this variety tends to associate more...

The suitability of wood for various uses can be determined by synthesizing single growth-ring density curves from accumulated means of wood density classes. Wood density gradients across growth rings were measured in large increment cores from 46-year-old ponderosa pines (Pinus ponderosa Laws.) by using X-rays. Of the 48 trees analyzed, 36 had been thinned 10 years earlier, then fertilized; six had been thinned only; and six were unthinned. Wood density distribution curves for growth rings in all trees were combined to produce a single representative curve for each group of trees. Relative...

The black twig borer (Xylosandrus compactus Eichhoff), first discovered in Hawaii in 1961, has become widespread on many host plants throughout the islands. Beetle infestations have caused heavy damage to trees but only recently have attacks been associated with death of apparently vigourous trees in forest stands. The beetle and its associated micro-organisms have been identified as associated with the death of five tree species in planted forests on Oahu.

The maximum distance of spread of dwarf mistletoes from isolated overstory pines into surrounding reproduction averages 120 feet. The rate of infection in young trees declined as distance from the seed source increased and was generally greatest in the direction of prevailing winds. This pattern of infection was similar to the previously reported pattern of seed dispersal. Each isolated, mature pine infected with dwarf mistletoe provided inoculum to infest about 1 acre of pine reproduction. Such residual trees left after fire or logging should be removed.

Site index is difficult to estimate with any reliability in ponderosa pine (Pinus ponderosa Laws.) stands below 20 yeas old. A method of estimating site index based on 4-year height intercepts (total length of the first four internodes above breast height) is described. Equations based on two sets of published site-index curves were developed. They worked equally well for plantations and natural stands in northern California.

Several tree species are now being planted in Hawaii to reforest areas on which firetree (Myrica faya Ait.)-a plant pest of little commercial value-has been killed. The potential of converting cull trees of five ofthe replacement species into growing stock trees by coppicing was evaluated. Australian toon and tropical ash showed the greatest potential for conversion; hoop-pine and Moreton-Bay-chestnut, intermediate potential; and Queensland-maple, least potential. Stump decay was not a factor with any species. And pruning paint did not affect decay or sprout behavior in any species.

Four paint combinations applied to simulated vertical siding of four wood species have been exposed outdoors in Hawaii since 1964. A three-coat, self-primed latex application is holding up best, with oil base primed latex, three-coat oil base, and two-coat oil base combinations next best in that order. Australian toon is holding paint best, followed by redwood, robusta eucalyptus, and Douglas-fir. For good service, durability, and appearance, three coats of self-primed latex on Australian toon or redwood are recommended.

Recovery from flood-accelerated sedimentation affects both estimates of long-term average deposition and short-term monitoring of changes. "Years to return to normal" for 10 watersheds in northern California after a major flood accelerated sediment concentrations were analyzed. Returns to normalcy took from 0 to 9 years; rate of decline was related to both amount of initial acceleration by the flood and differences in watersheds. years to recovery increased with these four factors: coefficient of path lengths in the watershed, area of poor logging, area of steep grassland, and percent of...

The specific gravity (air-dry volume, ovendry weight) of Eucalyptus robusta wood was tested within and between trees from 10 stands. Mean specific gravity was 0.603, but the range in individual samples for 50 trees was 0.331 to 0.869, and was 0.357 to 0.755 within one cross section. A consistent increase was recorded in all trees from pith to cambium and from butt to top. Mean for brittleheart (brash wood near the pith) was 0.503, considerably lower than that for normal wood at 0.651. Manufacturing problems caused by density variation could be reduced by sorting before sawing and during...