The work upon which this publication is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1964 and by the United States Department of Agriculture, Forest Service, Pacific Northwest Forest...
Fire is a major disturbance process in many forests. Long-term studies of the biogeochemical effects of fires, especially on soils, are very rare.
Consequently, long-term effects of fire on soils are often hypothesized from
short-term effects. In a chronosequence study, I studied 24 western Cascades
(Oregon) forest stands thought to...
Growing societal demand for forest products is pressuring managers to increase productivity from a finite land area, and it is expected that increased supply will come mostly from expansion of intensively managed stands. The USDA Forest Service and numerous collaborators created the Long-Term Soil Productivity (LTSP) network of research sites...
Recent catastrophic wildfires have forced the forest management community to develop new strategies for reducing forest fuels. Tightly spaced understory trees often create a fire ladder allowing surface fires to encroach into the crowns of overstory trees. This situation can lead to intensive, catastrophic, stand-replacement forest fires. Mechanical removal or...
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3.0 SOIL COMPACTION AND VISUAL SOIL DISTURBANCE
FOLLOWING TWO MECHANICAL FOREST FUEL
Tree species directly and indirectly affect soil nutrient cycles. I sought to characterize soils and foliage associated with four common canopy tree species (Douglas-fir, western hemlock, western redcedar, and bigleaf maple) in mixed-species old-growth forests of the Oregon Coast Range and to determine whether and how soils differ among the...
This research addressed the opportunity to obtain baseline data for both stream chemistry and soil resources for an intensively managed forest watershed, encompassed by the North and South Forks of Hinkle Creek Watershed Research and Demonstration Area Project near Sutherlin, Oregon. A solid representative database for both stream and soil...
The objectives of this thesis were to examine the links between soil microbial community composition and function using the nitrogen (N) cycle as a model for these interactions and to assess the impact of environmental factors such as microclimate, vegetation type, and nutrient availability on microbial diversity and N transformations...
Mixed-conifer stands of grand fir (Abies grandis (Dougl. ex D. Don) Lindl., Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), and ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were fertilized with nitrogen and combination treatments of nitrogen, phosphorus, potassium, and sulfur to test their effects on trees and associated insects during...
The authors varied the number of red alder retained with 300 Douglas-fir per acre on a high-quality site in coastal Oregon. Alder densities of 0, 20, 40, and 80 per acre were tested. The authors' fifth treatment eliminated nitrogen-fixing alder, but substantial nitrogen fertilizer. Treatment 6 had neither thinning nor...
Belowground carbon (C) storage and quality of soil organic matter (SOM) in
forest soils have implications for sustainable forest management and C sequestration,
but how these pools change in response to management is poorly understood. I
investigated whether fertilization and competing vegetation control, applied alone or
in combination early in...
Understanding how N availability influences base cation stores is critical for long-term ecosystem sustainability. Indices of nitrogen (N) availability and the distribution of nutrients in plant biomass, soil, and soil water were examined across ten young, unpolluted Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Range spanning a three-fold soil...
Forest roads produce fine sediment with traffic during wet weather. If the forest road is connected to a stream it can be a source of turbidity and fine sediment that may be detrimental to aquatic organisms especially salmonids.
The goal of this work was to investigate turbid runoff during wet-weather...
The objective of this study was to examine the variation among ammonia-oxidizing and denitrifying communities in soils of a natural Fennoscandian boreal forest and of a forest with a long history of fertilization with different levels of nitrogen (N), and to examine whether there are any changes in the microbial...
Disturbance, whether natural or of human origin, modifies to varying degrees
many ecosystem attributes. Fire is a natural process in the montane forests of southern
Oregon but for much of the 20th century fire was viewed as an apocalypse and thus
fervently suppressed. Effective natural resource management requires an
understanding...
Chemical and microbial analyses were made at four seasonal intervals on soil horizons under red alder, conifers, and mixed
alder-conifers at the Cascade Head Experimental Forest, established in 1937 by the U. S. Forest Service near Otis, Oregon.
Microbial analyses showed that although plate counts of molds and bacteria fluctuated...
Soil organic carbon (SOC, kg C m-2) is an important component in evaluating global C stores. The nitrogen (TN, kg N m"2) cycle is closely linked to C and understanding its role is also important. Contents and distributions of SOC and TN in soil profiles, to 1-meter depth, were estimated...
Early in the planning of the Coniferous Biome research program, it was recognized that Experimental Watersheds 6, 7, and 8 in the
H. J. Andrews Experimental Forest might provide ideal study sites for certain phases of the Biome program. A study was funded during year 1 (1970) to provide necessary...
Findley Lake watershed is located in the Snoqualmie National Forest and has a surface area of 259 ha (1 Mi²). The lake is at an elevation of 1128 m (3701 ft) but the ridges attain elevations of 1450 m (4750 ft).
The Cougar Mountain Formation, consisting of lava flows, conglomerate,...
Early in the planning of the Coniferous Biome program It was recognized that experimental watersheds 2 and 3 in the H. J. Andrews Experimental Forest might provide ideal study sites for certain phases of the Biome
program. A study was funded during year 1 (1970) to provide necessary background ecological...
During Biome 1, our primary objective was identification of the dominant fungi involved in litter decomposition. Two survey methods
were used: (1) a survey of macrofungi occurring on Watershed 2 based on fruiting bodies collected and cultures; and (2) a survey of microfungi on decomposing foliage based on cultures isolated...
The conceptual framework of an erosion model has been designed to link processes of mass wasting, surface erosion, and channel storage and transport. A program to stimulate mass wasting will be based on a variation of the factor of safety approach which balances forces tending to drive mass movement against...
Data on soil temperature at two locations and five depths, tensiometer readings, and soil moisture release curves for the soils of Findley Lake are presented in this report.
Goals in 1972 included characterization of the soils of the
Oregon IBP reference stands, development of information on the soils
throughout the H. J. Andrews Experimental Forest, and evaluation
of nutrient provision to the major kinds of soils. Field reconnaissance,
soil morphology studies, and sampling were carried out.
Lab analyses...
This is the annual report from the investigators responsible for soil
characterization at the Findley Lake watershed. Soil characterization
is complete for two soils and is in progress on six others. Site
preparation for years 3 and 4 is complete except for lysimeter
installation.
Field and laboratory studies are being conducted to describe the hydrologic properties of soil and to determine the timing pathway of precipitation and snowmelt water as it moved through forested soil on a steep slope. Hydrologic properties include hydraulic conductivity, porosity, pore-size distribution, moisture characteristics, stone content, and soil depth....
Air temperatures at i m and soil temperatures at 2C cm are reported for
twenty-one forest stands in the central Western Cascader of Oregon. Records
began in 1970 for some stands, in 1971 or 1972 for most. Temperature Growth
Index for a stand, based on temperature effects on Douglas-fir seedling...
Field reconnaissance, soil sampling, and laboratory analyses were
conducted to characterize the soils of the 50 by 50 meter forest community
reference stand plots in and near the H. J. Andrews Experimental
Forest. Soil descriptions, chemical and physical properties, soil classification,
and nutrient capital information for mineral soils are summarized....
The following report Introduces a documentation scheme for flow
oriented ecosystem models and shows its application to a carbon-water
model developed within the coniferous biome. This documentation scheme
has remained operative through revision of this model and expansion of
It to include nutrient flows. This model and subsequent versions are...
Measurement of plant moisture stress of 1-2 m understory conifers
was made in "reference stands" on the H. J. Andrews Experimental
Forest in 1970-1972. Maximum stress each year (measured between midnight
and dawn) is closely correlated with the position of each community
along one axis of an ordination of the...
Monitoring soil density on three sites during repeated trips with a high-speed skidder showed that: During the first 20 trips, soil density primarily increased between depths of 2 to 4 inches; Density increased most during the first few trips; Density continued to increase slowly in amount and depth with the...
The objectives of this thesis were to evaluate the responses of soil microbial communities to physical and chemical disturbances, and associate these responses with soil functional stability and changes in soil quality. The first study consisted of application of heat shocks (HS) to soils with contrasting land use history to...
Silvicultural canopy gaps are emerging as an alternative management tool to accelerate development of complex forest structure in young, even-aged forests of the Pacific Northwest. I investigated patterns of nitrogen (N) availability along transects through 0.1 and 0.4 ha silvicultural gaps in three 50-70 year old Douglas-fir forests of western...
Soils are a globally significant carbon (C) pool and have the potential to respond to elevated CO2 and environmental changes through positive feedback cycles that enhance the turnover of soil organic matter (SOM). Understanding the mechanisms governing the turnover of SOM is particularly important for modeling the fate of C...
Carbon sequestration in tropical secondary forests growing in all climates must be quantified to understand their potential role in adaptation and mitigation strategies of global climate change. Total aboveground biomass (TAGB), soil carbon, and total ecosystem carbon (TEC) were measured in 54 secondary forests growing along a broad bioclimatic gradient...
Predictive Soil Mapping (PSM) has recently become an attractive method for soil scientists wishing to develop a more objective and efficient approach to mapping soils. Due to the potential PSM has for reducing the effort to produce soil maps, as well as its ability to improve the classification accuracy of...
Sustainable management of planted forests requires maintenance of soil function
to promote 1) root growth; 2) storage and cycling of water and nutrients; 3) optimal gas
exchange; and 4) biological activity. Soil quality measurements can be used to monitor
short- and long-term changes in these soil functions, allowing managers to...
Unpaved roads are sources of chronic sediment in forested watersheds. Bare soil on roads is exposed to erosion from rainfall and runoff Published research on sediment production from forest roads focuses primarily on road characteristics. Since water drives the mechanics of sediment transport, hydrologic variables should correlate with sediment production....
Management practices following forest harvest can affect long-term soil productivity through alteration of soil carbon (C) and nitrogen (N) pools, but processes contributing to change are poorly understood. I assessed effects of three levels of logging-debris retention in combination with initial or annual applications of competing vegetation control (CVC) following...
This study evaluated the effects of a crawler tractor, a rubber-tired skidder, and a torsion suspension vehicle on several soil and hydrologic properties in the western Sierra Nevada Mountains of California. Four sites, with soil textural classes ranging from a loam to a loamy sand and elevations between 680 and...
Soil infiltration and wettability measurements during the first year following a broadcast burn in the Siskiyou Mountains of
southwest Oregon, have illustrated the magnitude of the effects of light-to-moderate intensity burning on hydrological soil
properties. A prescribed fire near White Creek in late spring significantly reduced soil infiltration for 4...
Debris flows in the Pacific Northwest play a major role in routing wood and sediment stored on hillslopes and in first- through third-order channels to higher order channels and valley floors. Forest practices on steep, unstable slopes and removal of riparian trees along low-order streams can affect the frequency, magnitude,...
Rainfall, discharge, traffic, and suspended sediment
were monitored for a period of 4.5 months at three
locations on a secondary haul road at Polk Inlet, Alaska to
determine the important processes and variables involved in
surface road erosion for this area. Three sites all less
than 500m² and within 5...
The purpose of this study was to examine certain hydrologic
properties of the soil and subsoil on a steep forested slope and relate
these -rceTties to the movement of water via subsurface routes.
The hydrologic properties examined were bulk density, soil texture,
total porosity, pore size distribution, saturated hydraulic conductivity,...
A study was conducted to investigate the influence of root reinforcements on soil strength and the initiation of static liquefaction in forest soils. The design and operation was developed of an apparatus capable of modeling rainfall-induced shallow hill-slope failures that also permitted observation of the soil volume change tendencies at...