Treesearch

Carbaryl is registered for control of the western spruce budworm (Choristoneura occidentalis Freeman), at the dosage rate of 1.12 kg per hectare. That rate and two lower ones were field tested in western Montana in July 1979 to determine if a lower rate would be as effective as the registered dosage. Each dosage was applied to five randomly selected 20-ha plots by helicopter with Beecomist nozzles while larvae were in the fifth and early sixth instars. Reduced dosages of 0.28 and 0.56 kg a.i. per hectare resulted in 83 and 93 percent population reduction, respectively, compared with 93...

Eucalypts have a number of characteristics affecting processing and utilization that distinguish them from other woods. The major current interest in the eucalypts is as a fuel. Possible demand as a chemical feedstock, for pulp-wood, panel products, lumber or round timbers should be considered in initial planning and management as a hedge against changes resulting from economic, political or environmental pressures. In general, returns to the grower will be maximized by concentration on maximum yield (cubic volume x specific gravity) for energy, chemical feedstock and pulpwood uses....

A study of the major Eucalyptus globulus stands throughout California conducted by Woodbridge Metcalf in 1924 provides a complete and accurate data set for generating variable site-density yield models. Two models were developed using linear regression techniques. Model I depicts a linear relationship between age and yield best used for stands between five and fifteen years old. Model II depicts a sigmoidal relationship between age and yield with slightly poorer statistical fit but greater reliability beyond fifteen years of age. Significant independent variables used in Model I are:...

Sugar maple seeds were collected from populations spaced along two altitudinal gradients in the White Mountains of New Hampshire. When grown in a uniform environment, progeny of stands less than 0.8 km apart differed significantly in photosynthesis, respiration, and leaf characteristics, despite a lack of physical barriers to gene migration. Sugar maple is a long-lived (200-300 yr) species with continuous distribution, but adaptive adjustment along the altitudinal gradient has occurred in only 8,000 yr, the time since colonization of the White Mountains in the wake of glacial melting....

A 17.5-acre non-irrigated biomass energy plantation has been established near San Luis Obispo. This joint California Polytechnic State University - California Department of Forestry project is measuring plot growth response of seven eucalyptus species for three spacing trials and for the effect of fertilization. All study plots are replicated. Site preparation strategy, planting, and maintenance and protection problems are discussed. The most important problem is the heavy weed growth. Herbicides and mechanical methods were used to control competing vegetation. A continuous effort is...

A.FO.CEL has developed a technique for mass propagation by cuttings of Eucalyptus in France. This technique is described from the selection of the ortet to the mass propagation of the clone for afforestation: the first stage is the mobilization of the ortet, the second stage is called pre-propagation which includes rejuvenating and rooting conditioning, the third stage is mass propagation. The mass propagation is realized from successive propagations of mother trees; the number of which increases from generation to generation by including the new rooted cuttings. We give practical advices...

Six promising eucalypt species, suitable for fiber or biomass production, have been identified with some confidence: Eucalyptus camaldulensis, E. dalrympleana, E. viminalis, E. nitens, E. globulus, and E. grandis. The Forest Service's Institute of Forest Genetics has established provenance or seed source tests of E. camaldulensis, E. grandis, E. nitens, and the E. dalrympleana-E. viminalis complex. In E. camaldulensis, the Lake Albacutya source is outstandingly superior to any other, and can probably double yields previously achieved with this species in California. Growth among E. grandis...

In the young-mature mixed-conifer and hardwood forests of north-central California, a dense and persistent hardwood understory competes with the conifers for space, nutrients, and water. Clear-cutting with intensive site preparation often is the most appropriate silvicultural regeneration method. This report, the result of 20 years of research on the Challenge Experimental Forest in Yuba County, California, evaluates one approach to clearcutting. Topics discussed are broadcast burning, windrow and burning, seedfall, rodents, woody shrubs, seedling stocking, and early growth of conifers....

Clines, including hybrid zones, have long been studied empirically and theoretically, especially for the opportunity they present to study evolutionary forces (Sumner, 1929; Haldane, 1948; Barber and Jackson, 195 7). Recent theoretical studies have emphasized that clines may be important in speciation (summarized in Endler, 1977). This emphasis has motivated mathematical modelling of gene flow and selection (Endler, 1973; Slatkin, 1973; Nagylaki, 1975, 1976), and has renewed interest in the origin and evolution of steep clines (Endler, 197 7; Moore, 197 7).

Abstract - A depth proportional intake boom for portable pumping samplers was used to collect suspended sediment samples in two coastal streams for three winters. The boom pivots on the stream bed while a float on the downstream end allows debris to depress the boom and pass without becoming trapped. This equipment modifies point sampling by maintaining the intake nozzle at the same proportion of water depth regardless of stage. Data taken by pumping samplers with intakes mounted on the boom were compared with depth integrated hand samples. Pumped samples showed higher concentrations then...