There is considerable evidence that the growth and elongation of
plant roots increases linearly or almost linearly with increasing water
contents or decreasing moisture-tension of soil. If this is true it is
difficult to distinguish the effects of different water contents on absorption
phenomena such as water or ion uptake...
A standard tool in general relativity is the 3+1 or ADM point of view, namely
slicing spacetime into spacelike hypersurfaces of constant time and then describing
physics in terms of time-dependent quantities on a typical such hypersurface. Much
less well-known is the 1+3 point of view, in which one foliates...
A parametric manifold is a manifold on which all tensor fields depend on an additional parameter, such as time, together with a parametric structure, namely a given (parametric) one‐form field. Such a manifold admits natural generalizations of Lie differentiation, exterior differentiation, and covariant differentiation, all based on a nonstandard action...
A parametric manifold can be viewed as the manifold of orbits of a (regular) foliation of a manifold by means of a family of curves. If the foliation is hypersurface orthogonal, the parametric manifold is equivalent to the one‐parameter family of hypersurfaces orthogonal to the curves, each of which inherits...
The hydrophobicity of soils of the Deschutes National Forest was
studied. The soils are Cindery Typic Cryorthents, formed in cinders
and ash from Mt. Mazama. Ponderosa pine is the dominant overstory
vegetation. Of particular interest was the effect of prescribed
burning on hydrophobicity. Fire has been shown to cause a...
Douglas-fir seedlings were inoculated with different species of
ectomycorrhizae-forming fungi in order to test the concept that
ectomycorrhizae enhance the drought tolerance of seedlings and to
investigate the mechanisms responsible for this effect.
Seedlings were transplanted at age 6 to 8 weeks into pots
containing pasteurized loam soil and inoculated...
The principles of continuum mechanics provide a consistent
framework for the derivation of mathematical statements describing
transport of water and solute, and growth in plant tissue. These
derivations are based upon the explicit consideration of the tissue as
a mathematical continuum composed of a cell wall matrix, water, and
solute...
A microclimatology study was conducted on a high elevation clearcut
near the summit of Mt. Ashland in southwest Oregon to evaluate the effects
of frost on Douglas-fir seedling growth and survival. Frost and low
temperatures cause seedling stress through frost damage, frost desiccation,
increased root resistance, and decreased rates of...
In order to develop three models for use in quantifying the
environmental conditions of reforestation, extensive measurements
required for energy balance calculations were taken for a
reforestation site in southwest Oregon. The models are used to
decrease the number of measurements required to properly evaluate
the potential for heat or...
Sulfur-coated urea (SCU), a slow release nitrogen fertilizer,
may be economically competitive with conventional fertilizers, but
little is known of the mechanism of urea release from SCU and the
environmental factors which affect the urea release rate. Objectives
of this thesis were: (1) to determine factors which affect the rate...
