An interactive Computational geometry package was developed
for the purpose of experimenting with geometry problems in
the Euclidean plane. The package also contains computer graphics
functions to display the result. Application independent functions
were developed that are both flexible and general enough for
creating new geometry experiments as well as...
The purpose of this investigation was to describe tenth grade students' views
of the purposes of geometric proof within the context of their learning. Classroom
observations, the curriculum, assessment tools, journal questions, and a
preconceptions questionnaire were used to provide context for the views expressed by
students from a single...
Prospective teachers enter teacher education programs with previously
formed conceptions of geometry and its teaching. These conceptions help
them make sense of new information about teaching, their roles as teachers,
and their translation of mathematics into learning activities. The purpose of
this study was to investigate the relationships among preservice...
Geometric Problems become increasingly intractable and difficult to visualize as the number of dimensions increases beyond three. Inductions from lower dimensional spaces are possible yet often awkward. This thesis shows how elementary linear algebra, vector calculus, and combinatorics offer improved methods for calculating the dihedral angles of n-simplicies and proving...
Many algorithms in parallel systems can be easily solved if we can generate a Hamiltonian cycle on the underly network. Finding Hamiltonian cycle is a well known NP-complete problem. For specific instances of regular graphs, such as Torus and Gaussian network, one can easily find Hamiltonian cycles. In this thesis,...
The objective of this study was to investigate load paths in an existing light-frame wood structure with complex geometry, using previously established computer modeling methods. The structural model is derived from an existing, multi-level residence located in Corvallis, Oregon. For the purpose of this study, the existing structure was simplified...
Remote sensing forest inventory gained increased attention in the last decade triggered by the decrease in the price of sensors and the explosion of data availability and formats. Evermore, the constant advances in the hardware processing the data emphasized the necessity to develop algorithms to extract forest relevant information from...
Published May 1976. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published May 1976. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
An analysis of forces on two tree intermediate supports is presented. The analysis is in two parts:
The maximum force that the support jack will experience. The movement and forces created in the two tree support by the skyline and carriage. The maximum force on the support jack occurs when...
We studied the feasibility of using end-grain characteristics to match individual boards and cants back to their parent Douglas-fir (Pseudotsuga menziesii) logs. After reviewing marking/reading and biometric automated identification systems, we focused on end-grain biometrics because they appear to have the most promise for sawmills. Biometric identification requires that every...
Measurements of physical tree crown dimensions were of subjective character in the past, even though they can be considered important for the management of many silvicultural operations, such as timing of thinning operations. In our study we investigated if and how measures of physical crown dimensions of trees differed when...
Ideally, dosimetric models for pine trees will accurately reflect the doses to its critical organs. However, existing models (e.g. that in ICRP 108) for the pine tree are over simplified or solely focused on estimating doses to one specific organ, and none of the existing models attempt dosimetry to the...
Understanding canopy radiation regimes is critical to successfully modeling vegetation growth and function.
For instance, the vertical distribution of photosynthetically active radiation (PAR) affects vegetation growth,
informative upon carbon and energy cycling. Availing upon advances in information capture and computing
power, geometrically explicit modeling of forest structure becomes increasingly possible....
The timber shortage in the Pacific Northwest is forcing sawmill owners to
improve the competitiveness of their harvesting and processing
operations. A computer simulation and financial statement analysis were
used to compare the processing efficiency and profitability of three
bucking strategies: log cost minimization (traditional 40-foot preferred-length
logs); hauling length...
Xylem is nonuniform in its structure and function throughout the plant stem. Xylem structure varies from pith to bark, from root to apical meristem, from stem to branch, at nodes vs internodes, and at junctions of branches, stems or roots compared to the internodal regions nearby. At smaller scales, anatomy...
In this work, a fully automated approach to synthesis Metal-Organic Frameworks is presented. We use graph to represent the structure of Metal-organic Frameworks and use graph grammars which are backbone rules and functional group rules to generate metal-organic framework. For a given parameter value of the user defined metal-organic framework,...
This project used a predictive model to map canopy cover of vegetation over seven feet in height (“tall woody vegetation”) at 30-meter resolution over nearly 29 million acres within and adjacent to the range of the greater sage-grouse in Oregon. Although the specific target of the mapping was western juniper...
The portability and reduced price of unmanned aerial systems (UAS) in recent years has led to a broad range of new UAS-enabled scientific inquiries, including for forestry. Small, consumer-grade UAS are advantageous for forest measurements due to their portability, ease and safety of deployment, and notably, they are currently the...
Accurate freeway travel time estimation is of increasing importance for the travelers’ information and route guidance system. A non-parametric statistical methodology known as regression trees is deployed in this research for dynamically and accurately estimating freeway travel times for the I5-I205 loop in the Portland Metro area of Oregon using...
Ecologists have historically used species-area relationships (SARs) as a tool to understand the spatial distribution of species. Recent work has extended SARs to focus on individual-level distributions to generate individual species area relationships (ISARs). The ISAR approach quantifies whether individuals of a species tend have more or less species richness...
Growing trees as a green manure crop together with an annual food crop is a new technology for farmers in Oregon. To promote farmer participation and to acquire a broad knowledge of the processes involved in species interactions, three feasible alley cropping and two sweet corn monocrop planting patterns were...
Species' distributions across the landscape are perhaps the least understood yet most conspicuous features of life on earth. Ecologists have long studied species' distributions; yet, many questions remain about why species occur where they do. Such questions persist largely because species' distributions are complex systems with challenging properties like non-linearity,...
Laser Scanning represents a new opportunity in forestry to effect meaningful change in the methods used for collection and analysis of inventory data. With the ability to collect spatial information in 360 degrees, while fluidly tracking the sensor and building the final point cloud, large tracks of terrestrial LiDAR based...
Estimating volume gains in genetically improved stands at rotation age is challenging because first-generation progeny tests in Douglas-fir were typically established to measure the relative growth performance of individual trees from open-pollinated parent trees. The overall goal of this dissertation research was to improve growth simulation of genetically improved Douglas-fir...
Forest management is rapidly undergoing a transformation from a discipline based on efficient commodity production to one for multiple uses, especially on federally managed land in the United States. This new management paradigm has challenged silviculturists to develop and adapt forest management techniques that can deal with increased demands. Using...
Biodiversity loss is of global concern, and is due in part to deforestation and high consumer demand for wood and wood products. The neotropical tree species Cedrela odorata (“Spanish cedar” or “cedro”) is economically valuable for its wood and faces threats of overexploitation. Due to strong similarities in wood features...
Many aquatic habitats in coastal Oregon have been impacted by historic land use practices that led to losses of in-stream wood and associated degraded fish habitats. Many of these streams are now bordered by stands of dense second growth forests (30–80 years) that are incorporated into riparian buffer zones with...
Successful pruning relies on accurately identifying the 3D structure of tree branches and leaders. However, this task is arduous in an agricultural setting due to the complexity of scenes, the presence of clutter, and variable weather conditions. This project addresses these challenges by leveraging advancements in 2D image segmentation and...
The behavior of coniferous trees subjected to wind loading was investigated through a series of experiments and also through simulation modeling. Previous studies that measured the natural oscillation frequencies and damping ratios were reviewed and equations were developed for predicting the natural frequency of a tree from the ratio of...
The purpose of this study was to examine the geometry of enclosed
circles in order to predict the probable effects of increment
boring methods used in determining basal area growth. Of specific
concern was the comparison of areas derived from sets of borings
taken from opposite sides of the tree...
In the past half century, industrial robots have developed a strong presence in manufacturing. They now commonly perform tasks such as materials handling, assembly, welding, and painting. Unfortunately robotic machining tasks have seen limited deployments. The majority of machining robots are designed for soft materials like wood or plastic and...
As CAD tools become more sophisticated, engineers are able to more easily create complex part geometries with minimal mass given strength and stiffness requirements. However, these complex part geometries can be difficult to subtractively manufacture, which consequently increases manufacturing cost and production time. This thesis presents a method independent of...
DSA (Diffusion Synthetic Acceleration) has been developed to accelerate the SN transport iteration. We have developed solution techniques for the diffusion equations of FLBLD (Fully Lumped Bilinear Discontinuous), SCB (Simple Corner Balance) and UCB (Upstream Corner Balance) modified 4-step DSA in x-y geometry. Our first multi-level method includes a block...
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....
Forest growth and yield models are critical to supporting decision making in forestry, but often lack considerations for wood properties. The feasibility of simulating wood properties in the context of a Douglas-fir individual tree growth and yield model was evaluated. This assessment explored the effect of predicted sapwood width, stem...
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Figure 4.7 Knot geometry for a typical tree in the Roeh and Maguire (1997) dataset (DBH = 26
Assembly planning is a crucial task for every manufacturing product. In general, assembly operations consume more than 30% of the total manufacturing time and cost. Therefore, any effort in optimizing assembly will have a significant impact on the economic success of manufacturing. Finding an optimal assembly plan by hand is...
As manufacturing advancements continue to develop, designers must be able to consider these technologies during the design process. Unfortunately, many of these new technologies, such as additive and advanced joining, have many nuances that require expert knowledge to effectively apply. Additionally, new design techniques, such as topology optimization, allow users...
In this work we propose a curve approximation method that operates in the curvature
domain. The curvature is represented using one of several different types of
basis functions (linear, quadratic, spline, sinusoidal, orthogonal polynomial), and the
curve's geometry is reconstructed from that curvature basis. Our hypothesis is that
different curvature...
We study the four-quark interaction as a first step in understanding the
QCD origin of the nuclear force in nature. We simulate QCD on a 20 x 20 x 20 x 32
space-time lattice with the simplifying quenched and static approximations, and
with the SU(2) gauge group. Recent four-quark simulations...
The forest products industry often uses intermediate-support cable logging systems to transport logs from the harvest site to a staging area. A method is presented to assist in the analysis and design of these cable systems. The method determines tensions in individual cables, forces on and stresses in the support...
Douglas-fir is the most commercially important timber species in the US Pacific Northwest due to its ecological prevalence and its superior wood attributes, especially strength and stiffness properties that make it highly prized for structural applications. Its economic significance has led to extensive establishment and management of plantations over the...
Two-phase flow in a fractal-like branching microchannel heat sink may have
enhanced heat transfer capabilities over single phase flow in the same branching
channel network. In order to exploit this potential, a complete understanding
of flow boiling in this geometry is required. The fractal-like geometry is similar
to that of...
Aims:
While lateral root mass is readily detectable with ground penetrating radar (GPR), the roots beneath a tree (below-stump) and overlapping lateral roots near large trees are problematic for surface-based antennas operated in reflection mode. We sought to determine if tree size (DBH) effects GPR root detection proximal to longleaf...
Landslides are a natural hazard that have major societal, economic, and
environmental impacts. The understanding of landslides begins with the observation that
they are a spatial problem. Spatial relationships have historically been explored with
maps, and landslides are no different. Such maps range in focus from inventory maps,
which identify...
Existing graphics systems are too large for students to study in an introductory computer graphics course. We have implemented a lightweight, object-oriented graphics system called OGS for instruction. OGS is written in Java. It demonstrates how a graphics system is implemented from scratch and is intended to help students understand...
Realistic (ideally photorealistic) real-time rendering has remained an elusive goal in computer graphics. While photorealistic rendering has certainly been achieved at the expense of tremendous computational resources and corresponding rendering times; real-time rendering typically must accept a great number of compromises to achieve adequate performance, such as aliasing artifacts, the...
Computing eigenpairs of a matrix corresponding to a specific geometry in the complex plane is an important topic in real time signal processing, pattern recognition, spectral analysis, systems theory, radar, sonar, and geophysics. We have studied the matrix sign and matrix sector function iterations to extract the eigenpairs belonging to...
This paper introduces a simple yet effective shape analysis mechanism for geometry processing. Unlike traditional shape
analysis techniques which compute descriptors per surface point up to certain neighborhoods, we introduce a shape analysis
framework in which the descriptors are based on pairs of surface points. Such a pairwise analysis approach...
Branched covering spaces are a mathematical concept which originates from complex analysis and topology and has found applications in tensor field topology and geometry re-meshing. Given a manifold surface and an N-way rotational symmetry field, a branched covering space is a manifold surface that has an N-to-1 map to the...
Many applications in computer graphics and geometry processing rely on the ability to
locally orient 2D and 3D entities on a surface, or inside a volume, such as the sinusoidal
kernels in Gabor noise, the color and geometry textures in pattern synthesis, and the
finite elements in remeshing. In these...
Recognizing the importance of native black cottonwood-dominated riparian
forests is especially important to preserve, protect, and manage for biodiversity in
the Willamette River Valley. Species composition, structure, and biomass along a
successional gradient from stand initiation to late succession of black cottonwood
(Populus balsamfera L. subsp. trichocarpa (T. & G.)...
Strobilus production, growth, and morphology of Pacific yew (Taxus brevifolia Nutt.) were examined at three sites in the Cascade Mountains and one site in the Willamette Valley of western Oregon. Strobilus production on branch segments was positively associated with overstory openness for male and female trees at all four sites...
There is still scholarly debate on the impacts of large floods on the geomorphic evolution of mountain rivers. Understating the geomorphic effects of large flows in mountain rivers is challenging given the hydraulic complexity of these systems and the inherent unpredictability of large floods. Prior work has demonstrated that extreme...
This thesis is on the existence and uniqueness of weak solutions to the Navier-Stokes equations in R3 which govern the velocity of incompressible fluid with viscosity ν. The solution is obtained in the space of tempered distributions on R3 given an initial condition and forcing data which are dominated by...
We describe a series of novel computational models, CERENKOV (Computational Elucidation of the REgulatory NonKOding Variome) and its successors CERENKOV2, CERENKOV3, and Convolutional CERENKOV3, for discriminating regulatory single nucleotide polymorphisms (rSNPs) from non-regulatory SNPs within non-coding genetic loci. The CERENKOV models are designed for recognizing rSNPs in the context of...
Moisture loss from fresh fruits results in lost revenue to producers, storage/packing companies, distributors, and increased prices for the consumer. Improved methods of storage and handling are necessary to help prevent moisture loss and retard spoilage. A literature review was conducted to improve knowledge on past and current studies involving...
This thesis presents an efficient computational voxelization approach that utilizes the graphics pipeline. Our approach is hybrid in that it performs a precise gap-free computational voxelization, employs fixed-function components of the GPU, and utilizes the stages of the graphics pipeline to improve parallelism. This approach makes use of the latest...
Resolving the debate surrounding the nature and controls of seasonal variation in the structure and metabolism of Amazonian rainforests is critical to understanding their response to climate change. In situ studies have observed higher photosynthetic and evapotranspiration rates, increased litterfall and leaf flushing during the Sunlight-rich dry season. Satellite data...
Full Text:
. Consequently,
evidence of dry season greening in geometry corrected satellite datawas ignored and the absence
Silvicultural regimes that aim at an increased stand structural diversity typically promote small-scale heterogeneity in horizontal and vertical structures, e.g. through the creation of gaps. We used terrestrial laser scanning (TLS) to investigate impacts of altered growing conditions on trees adjacent to artificial gaps as compared to responses of trees...
Coarse resolution imagery, such as that produced by the MODIS instrument, poses the challenge of estimating sub-pixel proportions of di erent land cover types. This problem is di cult because of the variety and variability of vegetation within individual pixels. This thesis describes and compares two existing algorithms for estimating...
Headwater streams are generally small, first-order streams that can comprise up to 80% (by stream length) of the drainage network in mountainous areas of the Pacific Northwest. These streams are intimately connected with downstream reaches, serving as a source of sediment, woody debris, organic matter and nutrients. The surrounding forests...
Woody riparian vegetation is an essential component of riparian ecosystems, responsible in part for the maintenance of functional ecological processes. The plant community composition and distribution provide an indication of the underlying mosaic of environmental attributes and processes. Restoration and management of riparian communities have been hindered by the lack...
Landslides are an insidious natural hazard, which can result in significant damage to public infrastructure. Limited monitoring tools are available, particularly tools suitable for use in forested environments. These tools often only allow a few locations across the slide to be monitored. Terrestrial Laser Scanning (TLS) shows promise as a...
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natural features such as tree trunks. The presented
methodology searches through the noisy point cloud
The goal of this research project is to determine the fractal nature, if any, which
surface water waves exhibit when viewed on a microscopic scale. Due to the
relatively recent development of this area of mathematics, a brief introduction to the
study of fractal geometry, as well as several examples...
Resolving the debate surrounding the nature and controls of seasonal variation in the structure and metabolism of Amazonian rainforests is critical to understanding their response to climate change. In situ studies have observed higher photosynthetic and evapotranspiration rates, increased litterfall and leaf flushing during the Sunlight-rich dry season. Satellite data...
Full Text:
greening
purely
an
artefact
of
variations
in
sun-‐sensor
geometry
The International Commission on Radiological Protection (ICRP) has modeled twelve reference animals and plants (RAPs) with simple geometric shapes to be used when estimating radiation dose to non-human biota (NHB). In recent years, there has been interest in creating more realistic models in order to better understand the radiation interactions...
Tree-like patterns are ubiquitous in nature. Botanical trees, river networks, and blood systems are the most well-known examples of complex hierarchical systems met in observations. Interestingly, many of such systems exhibit statistical self-similarity. There are two main types of self-similarity: Horton self-similarity and Tokunaga self-similarity. Although there is an increased...
Shallow landslides are destructive natural hazards that result in widespread losses, both of infrastructure and lives, throughout the world. To help mitigate the impact of landslide hazards, they are commonly characterized across a regional scale by (1) their location and likelihood using susceptibility maps, (2) their magnitude and frequency using...
In this study an improved model of biomass and nutrient estimation of coastal Douglas-fir (Psuedotsuga menziesii) in the Pacific Northwest has been developed across a wide range of stand management regimes. This study quantifies and defines the type and intensity of biomass harvest and associated removal for actively managed stands...
Plants respond to defoliation in many different and complex ways, depending on their growth habit and form as well as the extent and duration of the defoliation. Tree crowns have been shown to be quite sensitive to disturbances such as defoliation, however quantitative relationships have rarely been developed, making the...
Intensive management of young-growth Douglas-fir plantations has emphasized volume growth over wood quality. A better understanding of the variables that affect wood quality is needed so that wood quality and stand yield can be systematically combined into a silviculture program. This experiment utilized two separate experiments to establish the relationship...
An interactive computer graphics package was developed for the
purpose of solving certain geometric problems in the Euclidean plane.
The Geometric Graphics Package provides basic application-independent
functions for creating arbitrary views of two-dimensional objects and
for supporting interaction between the application program and its
user. The application program contains a...
In many traditional computer graphics applications, rendered scenes typically utilize 3D meshes to represent objects within an environment. As the demand to further improve the realism of graphics applications increases, such as for movies and games, it is becoming more important to represent the inner volumes of object meshes. In...
Metal organic Frameworks (MOFs) that experience stimuli induced structural transformation could enable a whole new class of materials with remarkable properties. Photoactuating moieties in the structure could effect changes in the pore space or macroscale shape change enabling light driven gas separation and actuators. Here, we present a novel approach...
Although there has been extensive research on the geomorphic and ecologic role of
large woody debris (LWD) in streams, the dynamics of LWD in streams are poorly
known due to various measurement difficulties during floods. In this thesis I present the
results of two flume experiments on the dynamics of...
Coniferous trees are a major North American crop that has been intensively managed for its commercial value, while also serving as critical habitat for abundant wildlife and as carbon sinks. Having diverse functions, North American temperate coniferous forests have become a research hotspot for numerous scientific studies aiming to integrate...
Stream buffer strips are an important tool for protecting the stream environment. This research documents the losses from 40 stream buffer strips, in the Western Cascades of Oregon, established 1 to 15 years before the study. Predictive equations are developed
which identify the major reasons for buffer strip losses. Losses...
The 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model published previously, renewal models are utilized to represent elastic-rebound-implied probabilities. A new methodology has been developed that solves applicability issues in...
Lodgepole pine (Pinus conorta) is a widely distributed forest type across western North America. Central Oregon lodgepole pine forests are ecologically unique when compared to other lodgepole pine ecosystems. Sierra lodgepole pine (Pinus contorta ssp. murrayana) is the dominant variety and often exists as the climax species on pumice soils,...
Forest ecosystem dynamics emerges from nonlinear interactions between adaptive biotic agents (i.e., individual trees) and their relationship with a spatially and temporally heterogeneous abiotic environment. Understanding and predicting the dynamics resulting from these complex interactions is crucial for the sustainable stewardship of ecosystems, particularly in the context of rapidly changing...
Student activities and instructor-made models are described to facilitate and encourage other instructors to develop their own appropriate activities and models for teaching the three-dimensional structure of wood.
The teaching activities include making several annual rings with straws pushed into clay, drawing wood’s structure onto a piece of paper that...
In the Pacific Northwest, regulatory agencies have recently
implemented management strategies for restoration and maintenance of wood
recruitment to streams over time. This allochthonous organic material is a
critical component in the geomorphic and biological structure of forested
streams. Mathematical models are commonly used to evaluate long-term
wood dynamics in...
Significant improvements in production effectiveness have resulted from
implementing cellular manufacturing systems (CMS). Following the cell formation, an
important issue that needs to be addressed is the unequal cell (or department/facility)
layout problem, which is the sub-issue in the CF problem. The work reported in this
thesis illustrates the assignment...
Fluid simulation on interacting deformable surfaces is a challenging problem that has many applications. In this paper, we present a framework in which artistic as well as physically realistic flows can be generated on surfaces during deformation and collision. Our simulation system provides comprehensive control over the motion and deformation...
• Reduced lignin content in perennial crops has been sought as a means to
improve biomass processability for paper and biofuels production, but it is unclear
how this could affect wood properties and tree form.
• Here, we studied a nontransgenic control and 14 transgenic events containing
an antisense 4-coumarate:coenzyme...
In the wake of climate change, the risk of heat related illnesses has continuously increased over the past several decades. While thermal management solutions have continued to improve, there is a need for efficient cooling systems that conform with the human body. This study combines the solutions from fractal-like flow...
Poor material utilization is inherent to conventional manufacturing processes, leading to high material waste and machining times. Additive manufacturing processes attempt to solve this issue by allowing production of near-net shapes, but the processes may be too expensive or infeasible. By leveraging both processes in a single part, the waste...
A two-dimensional model was developed to predict concentration profiles from passive, laminar mixing of concentration layers formed in a fractal-like merging channel network. Both flat and parabolic velocity profiles were used in the model. A physical experiment was used to confirm the results of the model. Concentration profiles were acquired...
Image segmentation continues to be a fundamental problem in computer vision and image understanding. In this thesis, we present a Bayesian network that we use for object boundary detection in which the MPE (most probable explanation) before any evidence can produce multiple non-overlapping, non-self-intersecting closed contours and the MPE with...
The International Commission on Radiological Protection (ICRP) has modeled twelve reference animal and plant (RAP) species using simple geometric shapes in Monte–Carlo (MCNP) based simulations. The focus has now shifted to creating voxel phantoms of each RAP to advance the understanding of radiation interactions in nonhuman biota. The work contained...
The objective of this dissertation was to understand the physical mechanisms affecting inversion events in a complex forested mountain landscape. This work was motivated by the long-term studies of climate at the Andrews Forest, short-term studies of vertical temperature, light, wind, and moisture gradient in old-growth trees, and interest in...
Bio-cementation is a promising method for the liquefiable mitigation of loose saturated sands. In the improvement process a bacterium that can be found naturally in soil deposits is fed urea. The bacterium consumes and breaks down the urea to form ammonium and carbonate. In the presence of calcium, calcium carbonate...
Analytical techniques are utilized in a wide variety of applications. Traditionally, analytical measurements are achieved by trained personnel in a laboratory setting using expensive scientific instruments, which limits their applicability in resource-limited areas and point-of-care applications. Therefore, the concept of enabling these laboratory-based qualitative and quantitative assays in microfluidic device...
It is known that soil biota affects water dynamics through various complex mechanisms. The impact on retention by soil biota are due to a combination of changes to pore geometry, pore clogging by biofilms, biofilms that serve to connect thin water films across many pores as the soil dries, and...
