Digital Commons Network^™

Measuring And Modeling Northeastern Forest Ecosystem Response To Environmental Stresses, Jennifer Caroline Jenkins

Doctoral Dissertations

Because forest responses to CO$\sb2$ fertilization and associated climate change are likely to be extremely complex, numerical models representing forest response to an integrated set of future conditions can be useful predictive tools. I compared predictions of forest net primary productivity (NPP) made by two ecosystem process models (PnET-II and TEM 4.0) using different climate scenarios, spatial resolutions, and methods of representing land cover and soils. Decreasing spatial resolution did not appreciably change NPP estimates. Input datasets, particularly climate, land cover, and soil water holding capacity, were important sources of variability in NPP estimates. These datasets interacted with model structures …

Dynamics Of Dissolved Organic Carbon During Weathering And Soil Formation, Kimberly Linnea Mccracken

Doctoral Dissertations

Interactions between dissolved organic carbon (DOC) and mineral soils were examined in field and laboratory experiments. Specific emphasis was given to factors influencing DOC mobility and element release during mineral weathering and soil formation. Soil chemical and physical properties controlling equilibrium concentrations of DOC (DOC$\rm\sb{np})$ in coarse-textured forest soils were investigated using laboratory batch reactors and the initial mass isotherm approach. The influence of DOC concentration on release of metals and silica was investigated in four soil parent materials. One of four acid treatments (0.001 N HNO$\sb3$ and three concentrations of forest floor leachate) or distilled water were added to …

Timber Price Trends, Jack Lutz

Doctoral Dissertations

Timber price forecasts are important components of timberland investment analysis. Econometric models used in forecasting timber prices can be complex because demand for timber is derived through demand for other products such as paper and housing. In contrast to econometric methods, time series analysis or autoregressive techniques allow price forecasts to be made from the timber price series themselves.

A necessary condition for using time series techniques is that the timber price series be stationary or mean-reverting. The primary hypothesis in this study was that timber prices would not be stationary and time series techniques could not be applied to …

Bioavailability Of Nutrients And Metals Following Land Application Of Organic Wastes, Jianqiang Zhao

Doctoral Dissertations

Field, greenhouse and laboratory studies were conducted to investigate the effects of soil-incorporated organic wastes on nitrogen release patterns, groundwater nitrate-nitrogen levels, nutrient/metal uptake, and plant yield.

Three field studies with corn (Zea mays L.) were conducted during 1993 to 1997 at three locations in New Hampshire using a randomized complete block design with three or four replications, two or three waste materials as main plots, and various application rates as subplots. Compared to dairy manure, Concord biosolids showed a slower release rate measured as soil NO$\sb3$-N concentrations in early season but higher post-harvest levels of soil NO$\sb3$-N.

Groundwater NO$\sb3$-N …