Thesis (M.S.)--Oregon State University, 1978. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

A study was carried out to investigate the effects of slashburning on the nutrient status of two Sub-Boreal Spruce zone ecosystems in the west central interior of British Columbia. The slash, forest floor and mineral soil (0-15 cm depth) in these ecosystems were sampled for mass and nutrient content before and after burning on a recently clearcut site. The forest floor and mineral soil were also sampled for nutrient concentrations nine months following burning. Average losses of organic matter, N, P, S, K, Ca, and Mg to the atmosphere due to slashburning were 11.1 kg/m² and 563, 55, 87, 60, 252, and 16 kg/ha, respectively, from the mesic ecosystems and 11.5 kg/m² and 345, 52, 74, 16, 289, and 177 kg/ha, respectively, from the subhygric/hygric ecosystems. These amounts corresponded to 51, 47, 41, 56, 40, 40 and 20%, respectively, of the total quantities of these nutrients in the slash and forest floor in the mesic ecosystems before burning, and 25, 9, 13, 14, 5, 6 and 17%, respectively, of the cjuantities in the subhygric/hygric ecosystems. There were substantial losses of organic matter from coarse (>8 cm diam.) and fine ≤ 1 cm diam.) slash and the forest floor components. However, nutrient losses were largely attributed to fine slash and forest floor consumption. Nutrient losses from the fine slash appeared to be independent of fire severity, although losses of most nutrients from the forest floor increased with fire severity; in plots in the mesic ecosystems which received moderate impact burns, and plots in the subhygric/hygric ecosystems which received low and moderate impact burns, net gains in forest floor Mg, K, and K and Ca content, respectively, were found. Nine months following burning there were significant increases in pH and total Mg concentrations and decreases in exchangeable K concentrations in the forest floor in the mesic ecosystems and S concentration in the forest floor in plots which had received low impact burns in both ecosystems. Effects of burning on some nutrient concentrations were confounded by the inherent seasonal variability in labile nutrient forms. There were no significant changes in mineral soil nutrient concentrations that could be attributed to burning. However, any such changes of small magnitude would have been difficult to detect due to the high spatial variation in soil nutrient concentrations. The survival and growth of interior spruce seedlings in the first season following outplanting was better in burned than in unburned areas in both ecosystems. However, seedling foliar N and P concentrations were lower in the burned areas. It is concluded that if slashburning is carried out in the mesic ecosystems, low to moderate severity fires should be prescribed to preserve the nutrient capital present in the forest floor. Slashburning would not substantially reduce the nutrient capital of subhygric/hygric ecosystems even with much higher fire severities than were observed in this study. / Forestry, Faculty of / Graduate

Thesis (M.S.)--Oregon State University, 1973. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (MS)--University of Montana, 2009. / Title from author supplied metadata. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 1991. / Typescript (photocopy). Includes bibliographical references (leaves 84-89). Also available online.

Laboratory and greenhouse experiments were carried out with controlled burning and with seedling growth correlated to soil chemical changes. The surface of soil blocks from three sites of the Coastal Western Hemlock Zone were burned at two intensities and planted separately with seeds of Douglas-fir, western hemlock, and western redcedar. Growth data were recorded periodically and dry weights of the seedling crops were obtained to determine treatment differences. The burning procedure showed the insulating and cooling effects of the vaporizing soil moisture. The burning slightly increased germination of Douglas-fir and western hemlock, generally promoted fungal population, and initiated different chemical changes in the soil on each site. Dry matter production, for all species combined, varied with treatment for each site in the following decreasing order: Swordfern site - severely burned, moderately burned, unburned control; Moss site - unburned control, moderately burned, severely burned; Salal site - moderately burned, unburned control, severely burned. Comparisons of dry matter production on control blocks with that in nature indicated that the removal of blocks from the natural environment had significantly changed the original conditions. In consequence, new artificial sites were created. Consistent evidence of the rhizosphere effect was produced on soil pH by seedlings, especially by Douglas-fir. Dormancy was successfully broken in all plants and there was evidence of different responses in photo-periodism with each species. The highest dry matter production was directly related to increased soil pH, to increased partial cation saturation, and to increased concentration of available phosphorus but to a decreased cation exchange capacity. Cation exchange capacity was inversely related to the availability of nutrients. Decrease of cation exchange capacity proved to be a beneficial effect of fire. In this experiment, where the ash was not supplied as usual in a slash burn, the increased base saturation resulted from the decreased cation exchange capacity. As compared with field samples in August 1959, total nitrogen was lower in all blocks in June 1960. Nitrogen increased in the following year in all variants of the Swordfern site and somewhat in unburned control blocks of the Moss and Salal sites. The Swordfern site benefited from burning by accelerated mineralization, which substituted for the deprived seepage. Fire caused the least damage to this habitat. The Moss site suffered heavily by burning, which reduced humus, the main source of nutrition. The unburned blocks were benefited by fast decomposition of humus in the greenhouse. The Salal site's thick raw humus benefited from moderate burn, which removed part of the humus and acted as a fertilizer on the remainder. Severe burning was most harmful on this site by the destruction of the large part of humus. Rich soils, usually with seepage water, are less damaged by fire than poor soils with strong drainage. It is mainly because in rich soils organic matter is at least partly incorporated into the mineral horizon and acts readily after fire especially for nitrogen supply. / Science, Faculty of / Botany, Department of / Graduate

The persistence and severity of water repellency in soils as affected by slashburning was examined in the municipal watersheds of Vancouver by the water drop penetration time (WDPT) and contact angle method, respectively. Also, hydrophobic materials were extracted from soil, separated by column adsorption chromatography, and analysed for functional groups by infrared absorption. Slashburning increased soil water repellency, as indicated by the WDPT method. Precise responses of soil repellency to slashburning were not consistent, as many site specific factors are involved, but increased repellency was evident in soil up to six years following burning. The severity of increased soil repellency caused by slashburning could not be assessed because contact angle determinations using the capillary rise equation and Darcy's Law were not reliable. The WDPT method was more consistent, reliable and simpler than the contact angle method, hence the WDPT method was considered best to indicate the presence of soil water repellency. A combination of polar and non-polar organic solvents, methanol and benzene respectively, extracted hydrophobic compounds from soil. The extractant separated into three fractions, using benzene and increasing proportions of acetone as eluting agents. Virtually all of the extract (90%) was recovered in Fraction I, indicating that the extraction was predominantly non-polar. Fraction II and III accounted for 4 and 6 per cent, respectively, of the applied extractables. Material in all Fractions induced repellency in wettable sand when 1 mg or more was applied to 5 gm of sand. Repellency was increased by heating the extracted materials in sand to 250°C for 10 minutes and was eliminated after heating to 300°C in inverse proportion to the mass applied. At 350°C, hydrophobic materials volatilized and the sand regained wettability. Analysis of an extraction by infrared absorption revealed that hydrophobic substances have hydrophilic and hydrophobic components. Adsorption of hydrophobic materials to soil particles is therefore likely initially by the hydrophilic end leaving the hydrophobic end of the organic molecule to form the outer surface thus preventing water from infiltrating. During slashburns, adsorption of hydrophobic materials is probably enhanced by optimization of close range van der Waals and London forces. / Forestry, Faculty of / Graduate

This analysis provides a relative ranking of six Southern harvesting systems in terms of the costs, capitalization, and operational feasibility of incorporating a Trelan Model C-14 portable chipper or a residue baler to recover logging residues for fuel and fiber on three Southern stand types. The six systems were also considered under six cutting regimes to allow for the varying management objectives employed by woods managers in the South. The Harvesting Systems Simulator was used to perform the analyses. Data was collected from members of the American Pulpwood Association and equipment manufacturers in the South to use as input for the simulations. Each combination of system, stand, and regime was considered in terms of eight factors designed to express system performance. Results of the analysis indicated that logging residue recovery was economically feasible in many Southern harvesting systems. As long as conventional products are merchandized and the flow of those products through the harvesting system is not interrupted, residue recovery will be profitable on most southern stand types. Clearcutting fqr energy and thinning for energy were not economical on any stand due to the loss of revenues from conventional products. As woody fuel prices go up, this situation will change. Results· showed that the machine energy required to produce the residue energy was minimal for all systems on all stands and in all regimes. This indicates that residue recovery is not only economically feasible but energy efficient as well. / Master of Science

Thesis (M.S.)--Oregon State University, 1989. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1975. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.