The goal of this phase of the study was to develop a model of the Tualatin River incorporating Scoggins Creek and Hagg Lake. This tool will be used in conjunction with a hydrologic model, the EPA HSPF model (Johnson, Imhoff, and Kittle, 1984), to analyze management strategies to improve water...
The purpose of this study was to develop a mass-balance model for total suspended solids in the Tualatin River in order to better understand the clarity-turbidity problem in the river. Major sources and sinks of suspended solids in the river were identified, and seasonal effects were explored. The study also...
The report describes the results of model calibration and validation, and evaluates the extent to which runoff response to timber harvesting and increased road densities in East Fork Lobster Creek Basin can be simulated, using Precipitation-Runoff Modeling System (PRMS), a deterministic, destributed-parameter-modeling system.
The Tualatin River Basin is located in the Washington County, Oregon. The river was detected having high chlorophyll a concentration and low dissolved oxygen concentration during summer time, which violated DEQ water quality standards. A mathematical model (HSPF) was used to simulate physical, chemical and biological processes in the basin...
Equations for predicting diameter growth are an essential component of single-tree growth and yield models (Munro 1974). Diameter
growth predictions are used to characterize individual-tree development and to project the growth of stand basal area and volume. Both diameter growth and basal area growth have been used as the dependent...
Equations for predicting height from diameter outside bark at breast height (DBH) were generated for 24 tree species in western Oregon. The equations were based on the asymptotic Chapman-Richards function. Because geographic location and site productivity may influence height-diameter relationships, height-diameter measures from 8727 plots were first grouped by site...
Models of stand growth and yield must include an estimate of mortality. For individual-tree/distance-independent growth-and-yield models. it is necessary (1) to predict the probability of death of individual trees and (2) to keep stand projections within reasonable biological limits (e.g., the maximum basal area that the stand can achieve). In...
Equations for predicting individual-tree height growth per 5-year period are presented for Douglas-fir, white fir, grand fir, ponderosa pine, sugar pine, and incense-cedar growing in the mixed-conifer zone of southwest Oregon. The data used to develop the equations came from 3,648 trees sampled from 391 stands in the study area....
This work describes the modeling framework and initial results for CLAWS (Coupled
Landscape And Water System), a physically-based, spatially-distributed hydrologicgeomorphic model that has been coupled with a vegetation dynamics simulation. Spatial variability of topography, soil, vegetation, and climate drive a hydrology module that calculates the water budget at given time...
The equilibrium response of Canadian vegetation to climate and climatic change was modeled at three organizational levels of the vegetation mosaic. The climatic parameters used as model drivers (i.e., snowpack, degree-days, minimum temperature, soil moisture deficit, and actual evapotranspiration) are components of climate that physiologically constrain the distribution of dominant...
