This investigation involved post-colonial (∼85 years old), ponderosa pine (Pinus ponderosa var. scopulorum Engelm.) growing at ∼2,255 m in northern Arizona an area that historically experienced a wildfire event every 5-20 years. Such fires were typically limited to surface fuels and thus seldom effected stand replacement. However, since the settlement of European peoples in approximately the 1880's fire cycles have been dramatically altered by the systematic suppression of all wildland fire. This change greatly increased seedling survivorship, and has resulted in a forest with historically unprecedented stem densities. Under current conditions, with individual trees receiving insufficient nourishment, many ponderosa pine forests have demonstrated stagnated growth and increased risk of pathogenic attack or catastrophic wildfire. In response to deteriorating forest conditions and the building threat of wildfire many forest managers are exploring methods of reestablishing natural cycles to restore historical stand dynamics. Typically this effort has included timber harvesting and/or the use of prescribed fire. In this application timber harvesting typically involves removing the younger cohort of post-settlement trees. While the objectives of prescribed fire are similar to timber harvesting, fire is by its nature less precise; treatment can not be limited to a target demographic. As a result, the application of prescribed fire can lead to different stand conditions than tree removal. It is also common (especially under extreme stem densities) to have a timbering operation precede a fire treatment. The impact of these three scenarios on residual ponderosa pine tree reserves is not well understood. This project has taken part in cooperation with the USDA Forest Service and the national Fire and Fire Surrogate task group. The experiment was arranged with a 2 x 2 factorial design which resulted in four treatments. Plots were either timber harvested, burned with prescribed fire, cut than burned, or left untreated with treatment application occurring in 2002-03, three years prior to initial sampling. Trees were sampled with one of two methods. Initially a randomly selected coarse lateral root was mechanically exposed for three meters; roughly the average canopy drip line radius whereupon root tissue was extracted at intervals starting at the root collar. This disruptive method was eventually replaced by limiting sampling to the root collar. To slow metabolic activity root tissue samples were field chilled before being oven dried. Dried samples were ground through a 40# mesh and then triple-extracted with ethanol for carbohydrate quantification with high performance liquid chromatography (HPLC). Carbohydrate samples were processed at the University of Massachusetts Cranberry Experiment Station in Wareham MA. with an ion exchange column and a refractive index detector using water as a mobile phase. Starch quantifications were conducted on sub-samples by Cumberland Valley Analytical Services INC. (Maugansville, MD.) using an alpha-amylase digestion and color metric evaluation on an Astoria auto analyzer. As a result of this project it was determined that the ponderosa pine root non-structural carbohydrate components are sucrose, glucose, fructose, xylose and starch. Reserve concentrations of soluble (EtOH) carbohydrates declined significantly between May and August on plots that were not treated with prescribed fire, burning eliminated this seasonal difference. Starch and total non-structural carbohydrates were also found to be lower in August (compared to May) suggesting that during the summer (May–August), ponderosa pine must draw upon reserves. It was also found that carbohydrate concentrations increased significantly with distance from the root collar. When sampled on a monthly basis it was determined that carbohydrates, both individually and collectively, were significantly affected by the month of sampling and that overall timber harvesting reduced total soluble (EtOH) sugar concentrations. It is believed that collectively carbohydrate concentrations were a reflection of the bi-modal precipitation pattern of northern Arizona; spring snow-melt in particular, appears to have significant increased stored reserves. Key Words: Pinus ponderosa, prescribed fire, restoration, Southwest, thinning

The goal of this research has been to enhance vapor generation techniques for atomic spectrometry--particularly for atomic absorption spectrometry--through more fundamental examinations of gas-liquid separation processes, expansion of flow injection vapor generation's usefulness through the development and improvement of specific applications, and examination of how flow injection vapor generation's capabilities can be extended through gas-phase preconcentration in hydride generation and examination of generating alternative metal vapors from volatile metal chelates. Gas-liquid separation efficiency for a commercially available flow injection vapor generation apparatus was determined via mercury cold vapor generation with amalgam concentration of the mercury vapor. The efficiency obtained, combined with efficiency information obtained by other investigators of flow injection-hydride generation, demonstrated that the apparatus achieves virtually complete separation for mercury vapor and the hydride-forming elements. This highly efficient vapor generation apparatus was then used for the development of specific applications. Determinations of arsenic in highly interfering transition metal matrices, on-line decomposition of organomercury species prior to mercury cold vapor generation, and on-line pre-reduction of arsenic following species-selective pretreatment of urine samples have all been developed. The capabilities of flow injection vapor generation were also extended in this work. Peltier coolers were used to preconcentrate stibine vapor (SbH$\sb3)$ prior to detection, leading to enhanced sensitivity for antimony. Volatile metal chelates were also synthesized on-line--particularly Cu(trifluoroacetylacetone)$\sb2$--in an attempt to extend the range of elements determinable by flow injection vapor generation.

A comparison of features between pans developed in the glaciated terrain of Massachusetts and those considered diagnostic to fragipans reveals numerous similarities. The overall morphology of both pan types includes high and low chroma mottles, bleached prism faces (polygons), numerous clay skins, vesicles, evidence of an eluviated horizon, and a massive to platy structure. Most pans observed have a sufficient clay accumulation to qualify as argillic horizons indicating that illuviation is occurring. The pans also have high bulk densities and low permeabilities. The Massachusetts pans exhibit micromorphology including the presence of: argillans, ferrans, skeletans, grain argillans (clay bridges), and a sepic fabric; all are common pedogenic features and typical to fragipans. Examination of the chemistry and mineral assemblages (both clay and heavy minerals) of the soils studied also suggests that pedogenic processes have altered the glacial till parent material. The pan is slightly more weathered, typically having lower pH and base saturation, more developed clay minerals, and stained and etched heavy minerals than the underlying till. Two of the soils investigated have aeolian components that are easily identified based on the heavy mineral assemblages. New England fragipans exhibit the typical brittle character and slaking in water commonly associated with all fragipans. Shear strength analysis indicates that removal of clay is primarily responsible for a decrease in strength, yet silica is also indicated as contributing to the strength of the pan. Pebble fabric analysis indicates that the fabric of the pan is consistent with that of the late Wisconsinan Upper Till whereas fabric of the till beneath the pan suggests that it is Illinoian (early Wisconsinan) Lower Till with the exception of the sandy Ridgebury soil. This determination sets the age for the material comprising the pan to approximately 18 ka. Evidence of pedogenic development is observed in the micromorphology, chemistry, mineralogy, and strength of the fragipans investigated. The similarities between the pans investigated and the taxonomic diagnostic indicators suggest that the pans have formed via similar processes as those developed elsewhere.

Two immunoassay formats were developed for the detection of low levels of the insect growth regulator, methoprene. The generation of methoprene-specific antibodies needed for such assays relied on the preparation of a methoprene-carrier immunogen. 11-Methoxy-3,7,11-trimethyl-2E,4E-dodecadienoic acid was covalently bound to a protein carrier via a spacer group. Two activated ester methods were used to prepare the immunogen, one of which forms a water soluble, activated ester of methoprene. Polyclonal antibodies raised against the methoprene immunogen were highly specific for methoprene. An indirect enzyme-linked immunosorbent assay (iELISA) and a competitive inhibition enzyme immunoassay (CIEIA) were developed using the polyclonal antisera. The range of the methoprene indirect ELISA was from 5 to 300 ng/mL (ppb), with an I$\sb{50}$ of 50 ng/mL, while the CIEIA has a range from 1.0 to 10 ppb, with an I$\sb{50}$ of 3.5 ppb. An indirect ELISA was also developed for insect juvenile hormone III from rabbit polyclonal antisera. The synthesis of several juvenile hormone derivatives used to prepare a juvenile hormone immunogen is described. The immunogen consisted of juvenile hormone III bound to a spacer arm via an ester, which was bound, in turn to a carrier protein via an amide bond. The resulting immunochemical assay showed high specificity for juvenile hormone III, with an I$\sb{50}$ of 225 ng/well. The juvenile hormone homologs, I and II, had I$\sb{50}$'s of 5000 and 800 ng/well, respectively. Other juvenile hormone analogs cross reacted with the juvenile hormone III antibody to a much lesser degree. The juvenile hormone III indirect ELISA has great potential for becoming the first readily available, easy-to-use analytical technique for the quantification of the hormone from biological materials.

To determine whether a strong association between leukemia incidence between 1978 and 1986 and potential for exposure to radiation emitted from the Pilgrim 1 nuclear power plant in Plymouth, Massachusetts was a spurious finding resulting from either (1) failure to account for temporal variation in the level of radioactivity released from the plant or (2) inattention to certain potentially confounding factors, additional age/sex-matched case-control analyses controlled for the effects of socioeconomic status (SES), work history, and cigarette smoking were performed with data collected in the Southeastern Massachusetts Health Investigation--a study of leukemia among residents aged 13 and older of 22 southeastern Massachusetts towns. None of the additional analyses, including incorporation of emissions data into the exposure-assessment scheme and crude attempts to control for (1) medical-radiation exposure, (2) potential for exposure to pesticides sprayed on cranberry bogs, or (3) workplace exposure to radiation, chemical solvents, dust, or fumes, altered the finding of a statistically significant dose-response relationship between leukemia incidence and potential for exposure to radioactive emissions. The trend in the association over time was not entirely consistent, however, with the hypothesis that unusually large amounts of radioactivity reportedly released from the plant during the mid-1970s were responsible for the observed effects. Recommendations were made for further study of the Plymouth-area population and for studies of this problem elsewhere.

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