Treesearch

Four seed sources of Jeffrey pine (Pinus jeffreyi) were selected for testing through controlled inoculation for resistance to dwarf mistletoe (Arceuthobium campylopodum). The pines were 7 years old and part of a progeny test planting established by the USDA Forest Service's Institute of Forest Genetics, Placewille, California. One of the seed sources {Foresthill) was considered from previous studies to be highly resistant. It was also found to be resistant in this study. Test trees were inoculatedin 1980 and 1981 with about 13,500 seeds of dwarf mistletoe. A high proportion of the seeds...

Ponderosa pines with little or no dwarf mistletoe in infested stands on the Deschutes, Ochoco, and Rogue River National Forests in Oregon were tested for resistance to dwarf mistletoe (Arceuthobium campylopodum). Small trees produced by grafting scions from the resistant and susceptible candidates onto seedling rootstock were planted in 1967-69 beneath a heavily infested stand of ponderosa pine in central Oregon. Between 12 and 15 grafted trees from each of 30 resistant parent selections and about the same number from each of eight susceptible parents were included in a replicated,...

An equation is given to estimate 10-year height increment for young-growth red fir trees in California and southern Oregon. The independent variables are the individual tree, stand, and site characteristics significantly related to a tree's height growth. Data used to develop the equation came from stem analysis of 492 trees sampled from 56 stands in the study area. Parameter estimates for the predictive equation were obtained using least-squares linear regression.

Approximately 3.200 trees in young mixed-conifer stands were examined for pest activity and human-caused or mechanical injuries, and approximately 25 percent of these trees were randomly selected for stem analyses. The examination of trees felled for stem analyses showed that 409 (47 percent) were free of pests and 466 (53 percent) had one or more pest categories. Incense-cedar contained the fewest number of pests with 133 out of 193 trees (69 percent) free of pests, and 60 trees or .31 percent with one or more pests. White fir and ponderosa pine trees had the highest percentage of pests...

Visitors to wildland areas of the United States see an untold variety of natural and manmade features that comprise our national landscape. Efforts to assess public perceptions and concerns about the land and its management led to development of sensitivity levels that were presumed to be a measure of viewer concern for what they saw in the landscape. Sensitivity levels, however, measured frequency of visitor presence along travel routes, not visitor concern. A study was done to identify what people saw in slides of managed and unmanaged landscapes and to determine whether they liked what...

Periodic (10-year) diameter increment of individual red fir trees in Califomia and southern Oregon can be predicted from initial diameter and crown ratio of each tree, site index, percent slope, and aspect of the site. The model actually predicts the natural logarithm of the change in squared diameter inside bark between the startand the end of a 10-year growth period. To estimate diameter increment, the predicted value is converted to a change in diameter outside bark. Data used to develop the model came from 1500 tree samples from 56 young-growth stands in the study area. Coefficients...

Abstract - Improvements upon the Birkbeck bedload sampler (Reid et al., 1980) were implemented in the North Fork of Caspar Creek, a gravel-bedded stream draining 383 ha in northern coastal California. Bedload sediment falls through a slotted plate covering a .125-m3 steel box set within a formed concrete pit in the streambed. In the original Birkbeck design, a water-filled pressure pillow beneath the box responded to the weight of accumulating sediment and the overlying water column.

Abstract - The proliferation of commercial non-programmable data loggers in the past five years has done little to increase sediment sampling efficiency in remote locations. Recent advances in microelectronics have encouraged the development of commercial, low-power, programmable data loggers at reasonable cost. Although some facets of hydrologic data collection may lend themselves to fixed-time sampling intervals, sampling efficiency in many applications can be improved using a programmable data logger. For example, controlling the collection of suspended sediment with a probability...