Table of Contents
Abstracts for the H. J. Andrews Experimental Forest Fourth Annual Symposium
Steven H. Ackers, Lawrence S. Andrews, Robert G. Anthony, et al.
Spotted Owl Demography at the H. J. Andrews Study Area
Kari Bisbee, Howard Bruner, Steve Acker, Charles B. Halpern, et al.
Early Succession Synthesis Area: Carbon Dynamics
Kari Bisbee, Richard T. Busing, and Steven L. Garman.
Promoting Old-growth Characteristics and Long-term Wood Production in Douglas-fir
Forests
Hua Chen, Mark E. Harmon, and Hanqin Tian.
Effects of Global Change on Litter Decomposition in Terrestrial Ecosystems
Wynn Cudmore and Susie Kelly.
NCSR—Education for a Sustainable Future
Anthony W. D’Amato, Klaus J. Puettmann, and David E. Hibbs.
Spatial Interaction Dynamics in Mixed Red Alder (Alnus rubra Bong.) and Douglas-fir
(Pseudotsuga menziesii [Mirb.] Franco) Stands
Alex Farrand.
2
2
3
3
4
4
5
5
6
6
7
7
8
Predation, Adult Behavior as Possible Factors Affecting Rates of Return for Stream Insects 8
Steven L. Garman.
Historical and Managed Landscape Patterns in Western Oregon: A Simulation Study
Stanley V. Gregory, Linda R. Ashkenas, Randall C. Wildman.
Dynamics of Large Wood in a Third-Order Cascade Mountain Stream
Stanley V. Gregory, Linda Ashkenas, and Randall C. Wildman.
9
9
10
10
11
Responses of Fish and Salamander Populations to Floods in Streams of the Pacific Northwest
11
Charles B. Halpern.
12
Montane and Subalpine Meadows of the Three Sisters Wilderness Area/Biosphere Reserve,
Oregon: A Community Classification and Gradient Analysis
12
Mark E. Harmon, Jay Sexton, Becky Fasth, Randy Wildman, et al.
Contrasting Patterns of Wood Decomposition and Transport in Upland Versus Stream
Environments
Shannon K. Hayes and Gordon E. Grant.
Geomorphic Response to Peak Flow Increases Due to Forest Harvest Activities, Western
Cascades, Oregon
William T. Hicks and Mark E. Harmon.
Developing a Method to Predict Regional Patterns of Biological Nitrogen Fixation
Scott M. Holub and Kate Lajtha.
13
13
14
14
15
15
16
The Fate and Retention of Organic and Inorganic Nitrogen in a Western Oregon Coniferous
Forest
16
Scott M. Holub, Julie D. Spears, and Kate Lajtha.
17
A Reanalysis of Nutrient Dynamics in Coniferous Coarse Woody Debris. Can. J. For. Res. (In
Press as of 5/01)
17
Julia Jones, David Post, and Barbara Bond.
18
Coupling of Streamflow and Vegetation Water Use at Diurnal, Storm, Seasonal, and
Interannual Time Scales: the Andrews Long-Term Ecological Research Site and Comparisons
with Coweeta, Hubbard Brook and Luquillo LTERs
18
Julia Jones and Reed Perkins.
Rain-on-snow Floods, Forest Canopy Effects, and Flood Routing from the Scale of the
Hillslope to Large (600 sq km) Basins in the Western Cascades, Oregon
Briana Lindh.
Effects of Root Trenching on Understory Plants
Georgianne W. Moore, Barbara J. Bond, Nathan Phillips, and Julia A. Jones.
19
19
20
20
21
Species-specific Differences in Vegetation Water-use Responses to Changes in Soil Moisture
and Vapor Pressure Deficit
21
Deana D. Pennington.
Landscape Dynamics in the Western Cascades of Oregon
David Post, Julia Jones, and Jeff McDonnell.
22
22
23
Intersite Hydrology Comparisons Among Small Basins at Long-term Sites in the LTER, USFS,
USGS WEB, USDA ARS, and Other Networks in the US and Abroad
23
Michele Pruyn.
24
1
A Comparison of Stem Tissue Respiratory Potential Among Various Tree Species
Jeremy J. Rich, Ann T. Mintie, Rachel S. Heichen, Kirk E. Waterstripe, et al.
24
24
H. J. Andrews Microbial Observatory: Soil Nitrogen Cycling and Microbial Biomass Across
Meadow-Forest Gradients
24
Jonathan Smith and Christopher Daly.
H. J. Andrews Temperature Mapping Project
Julie D. H. Spears and Kate Lajtha.
Coarse Woody Debris May Influence Soil Chemistry and Direct Pedogenesis Towards
Podzolization in the Oregon Cascades
Theresa Valentine and Don Henshaw
Study Site Locations on the H. J. Andrews Experimental Forest
Richard H. Waring and Barbara J. Bond.
The Oregon (OTTER) Transect: History and Potential
Kirk E. Waterstripe.
25
25
25
25
26
26
27
27
28
Patterns of Nitrogen Allocation in Ectomycorrhizal Fungal Mats in a Coniferous Forest Soil
28
Randall Wildman and Stanley Gregory.
Aquatic Ecosystem Restoration Project at Quartz Creek
Justin Anderson and Steve Wondzell.
28
28
29
Estimating the Potential for Hyporheic Exchange in Reaches of a Mountain Stream Network
29
David Hulse
Trajectories of Change: Alternative Futures as a Context for Multidisciplinary Research
30
30
Steven H. Ackers, Lawrence S. Andrews, Robert G. Anthony, Rita M. Claremont, Eric D.
Forsman, Gila A. Fox, Timothy S. Fox, David H. Giessler, Elizabeth Glenn, Pete Loschl, Gail S.
Olson, William J. Ripple, James Thailkill, and Sheila I. Turner-Hane.
Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University,
Corvallis, Oregon 97331.
Spotted Owl Demography at the H. J. Andrews Study Area
Spotted owl research in the H. J. Andrews study area has played a central role in the
understanding of spotted owl biology since the early 1970s. An intensive mark-recapture study
was initiated in 1987 with the objective of providing estimates of survival, fecundity, and rate of
2
population change of spotted owls in the central Oregon Cascades. In accordance with the
Northern Spotted Owl Effectiveness Monitoring Plan for the Northwest Forest Plan, these data
were incorporated into range-wide meta-analyses of spotted owl demography conducted in
1993 and 1998. Most recently, efforts are underway to model demographic performance of
spotted owls based on habitat characteristics measured from satellite imagery. The ultimate
goal of the modeling project is to provide a means of predicting spotted owl population
performance by monitoring habitat conditions throughout their range. The H. J. Andrews study
area has served as an important source of data in the development of these models and will
continue to provide data to validate and refine them as needed.
Results from ongoing spotted owl demography research are reported for the H. J Andrews
study area. The progress of the predictive modeling analyses of the H. J. Andrews data is
discussed as are emerging questions and directions for future research.
Kari Bisbee1, Howard Bruner1, Steve Acker2, Charles B. Halpern3, and Mark E. Harmon1.
Department of Forest Science, Oregon State University, Corvallis, OR 97331; 2National Park Service, Pacific West
Region, Seattle, WA 98104; 3College of Forest Resources, University of Washington, Seattle, WA 98195.
1
Early Succession Synthesis Area: Carbon Dynamics
Remote sensing studies indicate that the rate of development of conifer dominance after clearcut harvest varies considerably on the Andrews. The objective of the LTER Early Succession
Synthesis Area is to investigate how variation in the rate of development of conifer dominance
influences ecosystem function. In 1999, three plots were established in each of 12 sites in and
near the H. J. Andrews: six with “slow” development of conifer dominance and six with “fast”
development of conifer dominance. Also, half of the sites were from low (< 900 m) and half
were from high (> 900 m) elevations. To understand the effect of rate of development of conifer
dominance on carbon (C) dynamics, coarse and fine woody debris mass and forest floor mass
were measured in each stand. Initial results show that coarse woody debris mass, fine woody
debris mass, and forest floor mass were similar for stands with slow and fast development of
conifer dominance and high and low elevations.
3
Kari Bisbee1, Richard T. Busing2, and Steven L. Garman1.
Department of Forest Science, Oregon State University, Corvallis, OR 97331; 2Forestry Sciences Laboratory, Corvallis,
OR 97331.
1
Promoting Old-growth Characteristics and Long-term Wood Production in Douglasfir Forests
Trade-offs among wood production, wood quality and ecological characteristics in the
management of harvested forest stands are explored through model simulation of various
silvicultural regimes. Long-term production of merchantable wood, production of various types
of high-quality wood, and the level of certain quantitative ecological indicators are projected for
coniferous forests of Pacific Northwestern USA. The set of ecological indicators used is based on
the species composition and physical structure of old, unlogged forest stands. Simulations are
performed with an ecological model of forest stand dynamics that tracks the fate of live and
dead trees. Short rotations (<50 yr) produce the least amount of high-quality wood over the
multi-century simulation period. They also fail to generate ecological attributes resembling
those of old forest stands. Production of high quality wood is moderate to high under all
rotations of 80 years or more; however, most ecological indicators require longer rotations
unless alternatives to clearcutting are applied. Alternatives examined include retention of 15%
cover of live tree canopy at each harvest in combination with artificial thinning between
harvests. Thinning from below can expedite the development of large live and dead trees, and
canopy height diversity without greatly diminishing wood quantity or quality. Proportional
thinning retains understory stems, thereby expediting the recruitment of shade-tolerant trees. A
possible drawback to thinning, particularly proportional thinning, is the diminished production
of clean-bole wood at rotations of 150- and 260-years. It is concluded that most wood quantity,
wood quality and ecological objectives can be met with long rotations (ca 260 yr). Certain
objectives can be met with shorter rotations (80 to 150 years) when treatments of thinning and
canopy tree retention are applied.
4
Hua Chen1, Mark E. Harmon1, and Hanqin Tian2.
Department of Forest Science, Oregon State University, OR 97331; 2The Ecosystem Center, Marine Biological
Laboratory, Woods Hole, MA 02543.
1
Effects of Global Change on Litter Decomposition in Terrestrial Ecosystems
Understanding the response of litter decomposition to elevated CO2 atmospheric concentration,
global warming, and change in precipitation is of crucial importance in understanding soil
organic matter formation and carbon sequestration in terrestrial ecosystems. In this review, we
use published results, laboratory incubation results of decomposing roots, and leaf litter
decomposition data in the coniferous forests of the Pacific Northwest of USA to assess the
potential effects of global change (e.g., elevated CO2 atmospheric concentration, global
warming, and precipitation change) on litter decomposition in terrestrial ecosystems. Elevated
CO2 concentration influences litter decomposition indirectly by decreasing litter substrate
quality and increasing soil moisture content in dry grassland ecosystems. According to 17
published studies, doubled ambient CO2 concentration decreased the average N concentration of
tree litters and herbaceous litters by 19.6% and 9.4%, respectively. The average lignin: N ratio of
tree litters and herbaceous litters increased 36.3% and 5.5%, respectively, due to CO2 enrichment.
Such substrate quality changes should generally lead to a reduction in the decomposition rate of
litters. Global warming directly increases litter decomposition, however, the Q10 value used to
express this stimulatory effect decreases with increasing temperature. The degree that global
precipitation change influences litter decomposition will depend on the potential magnitude of
this change as well as the current moisture conditions. Even within a single region like the
Pacific Northwest of USA, the responses of litter decomposition to altered rainfall can be
divergent, with some sites increasing, others decreasing, and others remaining relatively
unchanged. Several research areas are identified for reducing the uncertainties in the effects of
global change on litter decomposition in terrestrial ecosystems.
5
Wynn Cudmore and Susie Kelly.
Northwest Center for Sustainable Resources (NCSR), Chemeketa Community College, Salem, Oregon 97309.
NCSR—Education for a Sustainable Future
Funded by National Science Foundation's Advanced Technological Education program, the
Northwest Center for Sustainable Resources is a collaborative effort of partners from Oregon,
Washington, northern California, Maryland, and Minnesota, including high schools,
community colleges, four-year colleges and universities, private industries, government
agencies, and American-Indian tribes. The Center's main activities focus on curriculum
development, teaching enhancement institutes, and national dissemination of products.
The Center is developing curriculum products that incorporate higher levels of mathematics
and science into natural resources technology programs. Ecosystem management is central to
the project, which emphasizes goals designed to maintain existing biodiversity, evolutionary
and ecological processes within ecosystems, and accommodate human uses within these
constraints.
KEY ACTIVITIES
Curriculum development: Among 10 community colleges in five states, curricula has been
developed and tested in natural resource-based associate degree programs.
Teaching enhancement institutes: Field-and laboratory-based experiences are being offered for
teachers from all levels of education around the country, along with tours of world-class
research sites, and other professional development activities.
Promotion and dissemination: NCSR materials are being showcased at key national and
regional conferences and symposia, and are being posted in an electronic clearinghouse.
Promotional products include reports entitled: Visions for Natural Resource Education and
Ecosystem Science for the 21st Century, American Indian Perspectives: Nature, Natural Resources, and
Natural Resources Education, and Educator's Guide to Natural Resources Program Development.
RESOURCES AND PRODUCTS AVAILABLE
Course materials for two-year and undergraduate four-year college programs are available in
these areas: environmental and biological sciences, fisheries, forestry, geographic information
systems, and wildlife. Field-based faculty institutes, including the Ecosystem Institute, Natural
Resources Institute, and GIS Institute, are offered in partnership with Oregon State University
and others.
VISIT OUR WEBSITE
http://www.ncsr.org
6
Anthony W. D’Amato, Klaus J. Puettmann, and David E. Hibbs.
Department of Forest Science, Oregon State University, Corvallis, OR 97331.
Spatial Interaction Dynamics in Mixed Red Alder (Alnus rubra Bong.) and Douglasfir (Pseudotsuga menziesii [Mirb.] Franco) Stands
Fifty-three years of stand development in mixed red alder and Douglas-fir stands will be
evaluated to determine the long-term interaction (i.e. competition and facilitation) dynamics in
mixed red alder and Douglas-fir stands in western Oregon and Washington. Spatial
measurements will be analyzed to evaluate the influence of tree spatial arrangement on
interaction over time in sample stands. Thirty-eight years of stand measurements from a stemmapped mixed red alder and Douglas-fir stand at Delezene Creek, WA will be utilized. In
addition, 15 years of stand measurements from mixed red alder and Douglas-fir test plantations
at the Cascade Head and H. J. Andrews Research Forests will also be utilized. Spatial
measurements and additional stand measurements will be made at these study areas this fall to
further facilitate spatial interaction analyses. The influence of various factors on interaction
during the course of stand development will be evaluated to create a model to predict
individual tree growth of red alder and Douglas-fir at different spatial arrangements,
proportions of mixture, and ages.
7
Alex Farrand.
Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331.
Predation, Adult Behavior as Possible Factors Affecting Rates of Return for
Stream Insects
In order to successfully reproduce and oviposit adult aquatic insects have adapted a variety of
behavioral traits to minimize their exposure to predators, to adverse environmental conditions,
and to increase their chances of finding a mate. Examples of such behaviors include swarming,
crepuscular/nocturnal emergence, and short and long emergence periods, to name a few. The
purpose of this proposed study is to determine if differences in overall adult survivorship exist
between aquatic insect taxa exhibiting different behavioral characteristics and exposed to
different levels of predation pressure.
To test the hypothesis that certain behaviors and relative densities of riparian predators affect
the rates by which adult aquatic insects return to the stream, species will be sampled in
emergence traps as well as with specialized “return traps” in Lookout Creek, a fourth-order
stream in the Western Cascades of Oregon and within the H. J. Andrews Experimental Forest.
Return rates will be determined for selected taxa based on numbers of individuals trapped at
the time of their emergence and return to the stream. The targeting of selected taxa for analysis
is based on prior emergence data obtained from Mack Creek, a third-order tributary, for
mayflies (Order: Ephemeroptera; Harper, et. al., 1995) and caddisflies (Order: Trichoptera;
Anderson, et. al., 1984). Concurrently with emergence and return trapping, predator densities in
the riparian zone will be censused. Insectivorous birds and bats will be counted along the
riparian corridor during emergence events, as well as invertebrate predators such as spiders
and ground beetles. Predator densities and return rates will be analyzed for any statistical
correlation. It is hoped that this study will be able to evaluate certain behavioral traits exhibited
by insects in terms of how many are successful in completing their short adult life stage and
returning to the stream based on their relative exposure to riparian predators. It should also
provide greater insight into the trophic linkage between aquatic insect prey and terrestrial
predators and how this biotic interaction affects both communities.
8
Steven L. Garman.
Department of Forest Science, Oregon State University, Corvallis, OR 97331.
Historical and Managed Landscape Patterns in Western Oregon: A Simulation
Study
There is increasing interest in using historical, natural landscape patterns as a template for landuse planning in the Pacific Northwest. In this study, trends in historical patterns of the Blue
River Watershed, located in the Willamette National Forest in west-central Oregon, were
simulated using fire frequency and size information from fire-history reconstruction studies,
and compared to current federal management guidelines for this watershed.
Historical and managed patterns differed in three important ways. 1) Simulated historical
disturbance resulted in greater amounts of structurally diverse forests over time than the
proposed management strategy for matrix lands. 2) Patches of structurally complex forests were
up to five times larger and more contiguous over time in the historical landscape compared to
the managed landscape. 3) The simulated historical regime had a more even mixture of
different structural-complexity classes compared to the management strategy, which promoted
the dominance of forests of low-intermediate complexity. Understanding the functional
significance of these differences in landscape structure is an ongoing effort in the H. J. Andrews
LTER program.
9
Stanley V. Gregory, Linda R. Ashkenas, Randall C. Wildman.
Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331.
Dynamics of Large Wood in a Third-Order Cascade Mountain Stream
All pieces of large wood (>10 cm diameter, > 1 m length) in a 1-km reach of Mack Creek were
tagged and inventoried from 1985-1998. Standing stock, geomorphic position, input rates, and
movement rates were determined from inventories and annual change. The old-growth reach
was 760 m long. Densities of large wood in the old-growth reach are 239 pieces per 100 m or
0.24/m2. Total wood volume in the active channel was 81.2 m3/100 m or 0.08 m3/m2. Most of the
number of pieces of wood were found in the active channel (48%), and 22% were on the
floodplain, and 28% were partly in the channel and partly on the hillslope or floodplain. Twothirds of the pieces were not oriented either parallel or perpendicular to the axis of the channel.
Only 6% of the pieces had a rootwad connected. Half of the logs were in their original position.
Almost 80% of the pieces were in an accumulation of three pieces or more. Most of the pieces
(51%) were in decay class 3, and intermediate stage of decay. The major agent of stability was
other logs (31%), followed by boulders (9%) and trees (3%). Most of the length of wood was in
the zone between low water surface and bankfull (54%), but the highest proportion of volume
was found adjacent to the active channel 40%). In general, less than 1% of the logs moved in any
year, though 11% of the pieces moved during the 1996 flood. In the clearcut reach, more than
25% of the pieces moved. Input rates were highly variable and more closely related to climatic
events than discharge events. Probability of movement during high flows was significantly
correlated to length of log, stability, and geomorphic location. All pieces of wood that moved
during the 14-yr record were less than the width of the active channel, and most pieces that
moved more than 300 m were less than 2 m in length. Wood dimensions, channel morphology,
and hydrologic regimes play important roles in understanding dynamics of large wood in river
networks.
10
Stanley V. Gregory, Linda Ashkenas, and Randall C. Wildman.
Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331.
Responses of Fish and Salamander Populations to Floods in Streams of the Pacific
Northwest
A major flood in February 1996 dramatically altered riparian and stream ecosystems
throughout much of the Pacific Northwest to an extent not experienced in over 30 years.
Alteration of stream channels and riparian vegetation by the flood was extremely patchy. Some
reaches exhibited major channel shifts, with channels moving laterally 50-100 m. Other reaches
experienced extensive movement of sediments through existing pools and riffles. Though flows
were 1-3 m above bankfull flow, bedforms and riparian plant communities in some reaches
showed only minor changes. Responses of aquatic vertebrates varied greatly. Cutthroat trout
populations (Oncorhynchus clarki) experienced zero to minor reductions, but benthic fishes, such
as sculpins (Cottus sp.) and Pacific giant salamanders (Dicamptodon tenebrosus), exhibited
population reductions of up to 90%. More than 35% of the marked trout in an old-growth forest
reach survived the flood and persisted in the same reach that they were found in the summer
before the flood. Trout population increased sharply in years after the flood due to high rates of
fry recruitment, which may be related to spawning habitats created by gravel deposition.
Salamander populations have recovered more slowly than trout populations. Positive effects of
disturbance in streams may include depositing spawning gravel, flushing silt from interstitial
spaces, forming and deepening pools, and creating complex wood habitats.
11
Charles B. Halpern.
College of Forest Resources, University of Washington, Seattle, Washington 98195.
Montane and Subalpine Meadows of the Three Sisters Wilderness Area/Biosphere
Reserve, Oregon: A Community Classification and Gradient Analysis
Meadows occupy a small portion of the largely forested central Cascade region, but support a
large proportion of the regional flora. Despite the ecological importance and aesthetic value of
these non-forested ecosystems, there have been few studies of their composition, distribution,
and environmental correlates. I present a plant community classification and gradient analysis
of the montane and subalpine meadow vegetation of the Three Sisters Wilderness Area,
Oregon, a UNESCO Biosphere Reserve representing the northern half of the Sierra-Cascade
Province. Species composition and environmental data were collected in 152 plots representing
a broad array of elevations, landforms, and hydrologic conditions. Classification (TWINSPAN)
and indirect gradient analysis (detrended correspondence analysis or DCA) were used to define
21 plant communities and to describe and interpret relationships with measured environmental
variables. Among the full array of plots, ordination axes were strongly correlated with
elevation, slope, and various landform attributes. Ordinations of subsets of the data revealed
strong associations with topographic position (lower slopes to ridgetops in the montane zone),
and microtopographic variables that influence the duration of snowpack and seasonal
availability of soil moisture (in the subalpine zone). Global warming and associated changes in
the amount or form of precipitation (snow vs. rain) may alter the composition and spatial
distribution of communities through effects on soil moisture availability, snow accumulation, or
length of the growing season. The current classification and gradient analysis document
existing patterns and relationships and provide a baseline for assessing future changes.
Detrended
correspondence
analysis (DCA)
ordination of meadow
sample plots from the
Three Sisters
Wilderness Area /
Biosphere Reserve,
Oregon. The strength
and direction of
correlations between
environmental variables
and DCA axes are
represented by the
length and direction of
arrows.
800
DCA Axis 2
600
Elevation
Dry soils
% Slope
Upper
slopes
400Flats, basins
Organic
soils Standing water
200
0
0
200
400
DCA Axis 1
600
800
12
Mark E. Harmon1, Jay Sexton1, Becky Fasth1, Randy Wildman2, Linda Ashkenas2, and Stanley
Gregory2.
Department of Forest Science, and 2Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR
97331.
1
Contrasting Patterns of Wood Decomposition and Transport in Upland Versus
Stream Environments
The rate that wood decomposes in stream systems has rarely been studied in a quantitative
manner. A 14 year long study from the H. J. Andrews in which the decomposition of three
species (Alnus rubra, Pseudotsuga menziesii, and Tsuga heterophylla ) of logs was examined in a
third-order stream (Lookout Creek) allows us to contrast this process to that and in an adjacent
upland forest. Logs 20-30 cm in diameter and 2.5 m long were either placed on the soil surface
or added to the Lookout Creek channel. The movements of logs in the channel have been
tracked since 1985 when the experiment started. Destructive sampling of these logs occurred
2,4, 6, 10, and 14 years after placement. When logs were sampled, 6 cross-sections were
removed at systematic intervals and examined for changes in density, moisture content,
nutrient content, and decomposer colonization patterns. Preliminary analysis indicates that
while decomposition for the upland logs averaged twice that of the stream logs, that biological
decomposition was quite rapid for some stream logs. Physical fragmentation of stream logs was
quite rapid, with bark being lost from some logs within a few years, accounting for about half
the stream mass loss. However, after 14 years, many of the upland logs had also undergone
fragmentation, particularly of the bark layer. Decomposition rate varied with species with Alnus
rubra >> Tsuga heterophylla > Pseudotsuga menziesii. Transport within the stream system was
limited to about 2 km of movement despite the occurrence of several extreme flood events.
Table 1. Mean decomposition rate-constants (per year) after 14 years of decomposition of logs of three
species.
Species
Environment
Terrestrial
Aquatic
Alnus rubra
0.089
0.030
Pseudotsuga
menziesii
0.019
0.021
Tsuga
heterophylla
0.034
0.015
13
Shannon K. Hayes1 and Gordon E. Grant2.
Department of Geosciences, Oregon State University; 2USDA Forest Service, Pacific Northwest Research Station.
1
Geomorphic Response to Peak Flow Increases Due to Forest Harvest Activities,
Western Cascades, Oregon
A persistent and often contentious debate surrounds evaluating effects of forest harvest
activities on streamflow. Despite decades of paired-watershed studies world-wide, the jury is
still out on the magnitude, persistence, and mechanisms responsible for peak flow changes
following timber harvest. Recent studies examining long-term streamflow data from paired
watershed studies in the H .J. Andrews Experimental Forest and other basins in western
Oregon, reached conflicting conclusions on the magnitude and causes of peak flow changes
(Jones, 2000; Jones and Grant, 1996, 2000; Thomas and Megahan, 1998, 2000; Beschta et al., 2000). But
no studies have evaluated the geomorphic response to observed peak flow changes– a question
of great interest in interpreting potential downstream consequences of forest management on
channels and ecosystems.
Since the relation between sediment transport and discharge typically follows a power law,
small increases in discharge can translate into large increases in sediment transport. But
interpreting the geomorphic effects of peak flow increases is confounded by the fact that timber
harvest typically influences both the hydrologic regime and sediment supply of a watershed,
making it difficult to isolate the peak flow effect alone. We address this problem by using
paired-watershed data from Watersheds 1 and 2 to predict streamflow response in the absence
of cutting. We combine the predicted hydrology with observed relations between discharge and
sediment transport to disentangle the relative effects of changes in hydrology and sediment
supply. Results indicate that while peak flow increases alone can account for modest increases
in both suspended and bedload transport in Watershed 1, the peak flow effect is dwarfed by the
increased supply of sediment following treatment (Fig. 1). The most significant geomorphic
effects of harvest-induced hydrologic changes may be due to increased water availability on
hillslopes and roads, leading to increased frequency of mass movements.
Figure 1. Watershed 1 Post-treatment Sediment Yields
14
William T. Hicks and Mark E. Harmon.
Department of Forest Science, Oregon State University, Corvallis, OR 97331.
Developing a Method to Predict Regional Patterns of Biological Nitrogen Fixation
Nitrogen is an important nutrient regulating plant growth and decomposition, yet we have not
developed accurate regional estimates of biological nitrogen inputs. As in many regions,
nitrogen is a limiting nutrient to tree growth in the Pacific NW. Globally, humans have
approximately doubled terrestrial nitrogen inputs producing beneficial as well as severe and
long-term consequences. Understanding changes at the global level requires accurate
assessment of regional nitrogen cycling. The objective of my research is to create a spatially
explicit biological nitrogen input budget for the Pacific Northwest. This will be based on
previous research on the activity and distribution of the nitrogen fixing organisms. Extensive
research has been conducted on the physiology and rates of nitrogen fixation in lichens, plants
such as Alnus, and Ceanothus, and asymbiotic microorganisms in woody debris, soil, and litter.
With some minor modification, existing work with spatial models, regional inventory
databases, and remote sensing can be used to determine relatively accurate distributions and
biomass of lichens, Alnus, Ceanothus, and woody debris. By coupling the data on abundance and
activity of nitrogen fixers, models can be developed to estimate nitrogen fixation rates and how
this process will respond to change in key “driving” variables such as climate and land use
allowing me to answer the following questions:
1. How do the different nitrogen fixers compare in terms of total and subregional input?
2. How might future changes in climate affect biological nitrogen inputs?
3. How have humans, through land use and management, altered biological nitrogen
inputs?
15
Scott M. Holub and Kate Lajtha.
Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331.
The Fate and Retention of Organic and Inorganic Nitrogen in a Western Oregon
Coniferous Forest
Organic nitrogen from the N2-fixing epiphytic lichen, Lobaria oregana, contributes up to 80% of
new N inputs in Pacific Northwest old-growth forests. Our objective was to determine the
ecosystem pools involved in the retention of complex organic N inputs and to compare those
results with inorganic N over the course of one year in a mid-elevation old-growth forest at the
H. J. Andrews LTER. We added 15N-labeled Lobaria, bread yeast, tannin-complexed yeast, and
NH4Cl separately to large in situ soil cores. Upon collection, each core was separated into
understory plant, moss, litter/O horizon, 0-5 cm soil, and 5-15 cm soil pools. All pools were
analyzed for total 15N. Litter and 0-5 cm soil pools were also analyzed for inorganic N, DON,
and microbial biomass N. Selected 0-5 cm soils were separated using density fractionation. Total
15N recovery over all dates was not significantly lower than 100%. For all treatments, the
litter/O horizon was the largest sink for the added N, although the mineral soil horizons tended
to increase as a sink through time. Little of the total 15N was found as inorganic N. The light and
heavy density fractions showed similar 15N labeling, which indicated that the sink
strength per N molecule was similar in both fractions. Our results indicate that the soil pools at
our site at H. J. Andrews have substantial ability to retain organic and inorganic N forms.
16
Scott M. Holub, Julie D. Spears, and Kate Lajtha.
Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331.
A Reanalysis of Nutrient Dynamics in Coniferous Coarse Woody Debris.
Can. J. For. Res. (In Press as of 5/01)
We analyzed net N, P, K, Ca, and Mg fluxes from coarse woody debris (CWD) by developing a
'volume adjusted method' and applying it to existing chronosequence studies of CWD in
coniferous forests. Unadjusted nutrient concentrations may overestimate the actual amount of a
given nutrient remaining or accumulating in CWD, because mass loss, primarily as microbially
respired CO2, occurs during decomposition. This overall mass loss tends to increase nutrient
concentrations (e.g., g-N / g-CWD) by decreasing the denominator and can therefore be
misleading as an indicator of nutrient gain or loss. Our 'volume adjusted method' corrects for
mass loss, by assuming a constant volume as CWD decays. We determined that most nutrients
show a net loss from CWD as decay progresses. CWD showed net losses of Ca through
moderately late stages of decay, when some studies began to show increases. CWD also
exhibited an initial net loss of P followed by a net gain during moderate stages of decay. CWD
had high net losses of K that were maintained in later stages of decay. CWD showed a
diverging trend for Mg, where several studies showed net gains and several showed net losses.
Usually there was no net change in N in early to moderate stages of decay, but N increased in
CWD by later decay. We discuss the significance of the results, possible nutrient flux pathways
into and out of CWD, and the use of a conservative tracer to correct for mass loss.
17
Julia Jones1, David Post2, and Barbara Bond3.
Department of Geosciences, Oregon State University, Corvallis, OR 97331; 2CSIRO Land and Water, PMB PO
Aitkenvale, Queensland 4814, Australia; 3Department of Forest Science, Oregon State University, Corvallis, OR 97331.
1
Coupling of Streamflow and Vegetation Water Use at Diurnal, Storm, Seasonal, and
Interannual Time Scales: the Andrews Long-Term Ecological Research Site and
Comparisons with Coweeta, Hubbard Brook and Luquillo LTERs
This study examines the multiple temporal scales at which streamflow is coupled to vegetation
water use at four forested long-term ecological research sites, and the implications of this
coupling for streamflow responses to climate change, natural or human disturbance. At the
Andrews, water use by 450-yr-old Douglas-fir dominated forest ecosystems produces detectable
signals in streamflow at the diurnal, storm, seasonal, and interannual time scales. Diurnal
influences are most apparent during summer baseflow recession in this xeric climate. Water use
and/or interception by the forest canopy apparently affects the magnitude peak discharges
during fall and spring storm rain events and winter rain-on-snow events. At the seasonal time
scale, water use by vegetation during the summer and fall is coupled to winter and spring
precipitation. At the interannnual time scale, vegetation water use varies systematically with
precipitation. At other forested sites, coupling may occur predominantly at certain time scales.
For example, at Hubbard Brook the seasonal coupling between snowmelt and water use by
deciduous vegetation is a dominant feature of the ecosystem, and at Coweeta seasonal water
use by deciduous vegetation also has a major influence upon streamflow. In contrast, at
Luquillo, the coupling between near daily precipitation and streamflow dominates. Disturbance
histories and forest types also influence the magnitude and duration of streamflow responses to
forest canopy removal; the largest, longest-lasting response occurred at the Andrews, the site
with the highest leaf area and longest time since disturbance. Thus, climate change, natural
disturbance, and land use (e.g., forest canopy removal) have predictable effects upon
streamflow at the time scales at which coupling between vegetation and streamflow occurs.
18
Julia Jones1 and Reed Perkins2.
Department of Geosciences, Oregon State University, Corvallis, OR 97331; 2Environmental Sciences, Queens College,
Charlotte, NC 28274.
1
Rain-on-snow Floods, Forest Canopy Effects, and Flood Routing from the Scale of
the Hillslope to Large (600 sq km) Basins in the Western Cascades, Oregon
The influence of climate change and forest canopy removal upon the magnitude of large (10- to
100-yr return period) floods is a controversial subject the Pacific Northwest. This paper
examined the differences in peak discharge magnitudes and timing between rain and rain-onsnow events in a lysimeter, small basins (<1 sq km), and large basins (60 to 600 sq km) in the
western Cascades of Oregon, using long-term streamflow records from 1964 to 1991. Events
were retrospectively classified as rain or rain-on-snow using a distributed parameter hydrologic
model (MHMS). Small rain-on-snow events (300 to 500 mm of precipitation) had consistently
higher peak discharges than rain events with equivalent precipitation inputs, at the scale of the
lysimeter, the small (forested) basin, and the large (partially harvested) basin. In contrast, large
rain-on-snow events (600 to 700 mm of precipitation) had higher peak discharges than rain
events at the scale of the large basin, but not at the scale of the small (forested) basin. During
large, rain-on-snow events, peak discharges from small, forested basins occurred within one or
two hours of the peak in the large basin, but large, rain events were much less synchronized. In
small basins, removal of the forest canopy increased the magnitude of peak discharges during
both small and large rain-on-snow events, but had less effect upon peak discharges during rain
events. Removal of the forest canopy in small, low-elevation basins (in the “transient snow
zone”) had no effect upon peak timing, but removal of the forest canopy in small, highelevation basins decreased the synchroneity of flood peaks. This paper evaluates how the
presence of a snowpack influences the routing of flood peaks during large precipitation events,
and how future climate change or forest canopy removal may influence the magnitude of 10- to
100-yr flood events in 60 to 600 sq km basins.
19
Briana Lindh.
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331.
Effects of Root Trenching on Understory Plants
Trees influence the understory environment via both above and belowground effects. Installing
trench plots from which tree roots are excluded provides a gauge of the belowground effect of
trees on understory herbs. Although herbs and shrubs generally respond very vigorously to the
exclusion of tree roots, relatively little data exists on the effects of trench plots on understory
herbs.
Root exclusion plots (belowground gaps) were installed as part of the experimental canopy gap
study at the H. J. Andrews and Wind River. These plots were installed in 1990 and monitored
for soil moisture response (Andy Gray, manuscript submitted), nitrogen mineralization, and
belowground nutrient loss. I sampled the plant communities in these plots in the summer of
2000, 10 years after they were installed. The plots are 3m square and have stainless steel mesh
and/or black plastic lining the trenches to a depth of 1m. The design was a fully randomized
factorial design including both trenching and clipping of aboveground plant parts. The four
treatment combinations were replicated four times, in a closed-canopy and a gap location at
Wind River and at the H. J. Andrews.
Trenching had a positive effect on total additive plant cover. Total number of flowering plants
also tended to be higher in trenched plots, but this effect was less consistent. Different species
responded most vigorously at the Andrews and at Wind River. Clipping eliminated most
existing plants; this release from competition led to establishment of more diverse assemblages
in all plots in the sun and in trenched shade plots. In an ordination of plots in species space,
trenching and canopy openness correlated with the same axis, suggesting that increasing
aboveground and belowground resources may yield similar effects on community composition.
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20
Georgianne W. Moore1, Barbara J. Bond1, Nathan Phillips2, and Julia A. Jones3.
Departments of Forest Science1 and Geosciences3, Oregon State University, Corvallis, OR 97331, 2Department of
Geography, Boston University, Boston, MA 02215.
Species-specific Differences in Vegetation Water-use Responses to Changes in
Soil Moisture and Vapor Pressure Deficit
Generally, assumptions about species-specific differences are made in scaling sap flow
measurements to estimate stand transpiration. Current management practices often alter
species composition, which can influence spatial and temporal distributions of water use.
However, little is known about how species-level differences are manifested at stand scales in
complex forest landscapes. This study seeks to better understand how transpiration of
individual species respond to two major environmental controls, vapor pressure deficit (e) and
soil moisture (). The species of interest were co-occurring old-growth Tsuga heterophylla
(western hemlock) and Pseudotsuga menziesii (Douglas-fir) trees in the western Cascades of
Oregon. Diel measurements of sap flow (Granier 1987),  (water content reflectometry), and e
were collected throughout the end of the summer 2000, from the time when soil moisture was at
its driest (end of August) until the time when sap flow rates had declined substantially due to
low temperatures, low light, and high humidity (end of November). We asked whether sap
flow rates in the early afternoon in these two conifer species respond differently to changes in 
(daily max) after accounting for differences due to changes in e (daily max), which otherwise
dominates the sap flow response and obscures what is happening with changes in  alone.
Similarly, we were also interested in whether Douglas-fir and hemlock respond differently to
changes in e, after accounting for differences due to changes in . Our evidence suggests that
there are significant differences between the two species in response to  (p = 0.0451). A 5%
increase in  was associated with an estimated 15% decrease in sap flow in Douglas-fir. Whereas,
a 5% increase in  was associated with an estimated 19% increase in sap flow in hemlock.
Douglas-fir and hemlock also responded differently to changes in e (p = 0.0206). A doubling of
e is associated with an estimated 39% increase in Douglas-fir sap flow and 57% increase in
hemlock sap flow. This result suggests that hemlock is 1.4 times more sensitive to changes in e
than Douglas-fir during this “wetting up” period after the summer drought.
21
Deana D. Pennington.
Department of Geosciences, Oregon State University, Corvallis, OR 97331.
Landscape Dynamics in the Western Cascades of Oregon
Human modification of natural landscapes may have numerous, largely unknown effects. Since
natural processes themselves modify the landscape through time, it is relevant to determine
how human disturbed landscapes differ from those produced by natural disturbance processes,
and the effect of that divergence of conditions on ecosystem processes. The purpose of this
study is to compare natural and human forest disturbance patterns through space and time, and
the effect of differing patterns on vegetation cover and associated ecosystem processes.
Landscapes representative of a range of wildfire and timber harvest patterns are created using
computational methods, resulting age class distributions are compared, stratified in several
ways, and additive models of carbon sequestration, evapotranspiration, water yield, and habitat
are calculated. Results indicate that the landscape as a whole probably is representative of the
range of conditions produced by Holocene wildfire disturbance, especially during early
Holocene warm periods, however, stratifications suggest that extreme conditions on private
industrial and wilderness lands probably do not have historic analogs. The high disturbance
rates on private industrial lands result in decreased carbon sequestration, decreased
evapotranspiration, and higher water yield. While higher water yield is beneficial to public well
being, the longer term effects of decreased carbon sequestration are uncertain, and may result in
climatic/precipitation feedbacks. Conversely, the complete lack of disturbance in wilderness
areas probably has negative implications for biota, removing open and edge environments
important for predators. Therefore, there are tradeoffs involved in any harvest management
plan.
22
David Post1, Julia Jones2, and Jeff McDonnell3.
CSIRO Land and Water, PMB PO Aitkenvale, Queensland 4814, Australia, 2Departments of Geosciences and 3Forest
Engineering, Oregon State University, Corvallis, OR 97331.
1
Intersite Hydrology Comparisons Among Small Basins at Long-term Sites in the
LTER, USFS, USGS WEB, USDA ARS, and Other Networks in the US and Abroad
Long-term records from small, continuously-monitored basins provide an unparalleled source
of information about precipitation and streamflow in a wide range of ecosystem types. This
study explores how these records can be used to infer the roles of water storage in snowpacks
and soils, and water use by vegetation, and how these ecosystem properties have changed over
time in response to land use, natural disturbance, and climate change. This study uses simple
statistical measures of precipitation, streamflow, and their relationships at various time scales
(daily, monthly, annual, decadal) to conduct comparisons among sites that vary in their climate,
vegetation type, or disturbance history. Initial comparisons among “control” basins at four
forested LTER sites (Andrews, Coweeta, Hubbard Brook, Luquillo) illustrate that soil and snow
reservoirs function differently among the various sites, and that disturbance histories at these
sites influence the long-term relationship between precipitation and streamflow. Disturbance
histories and vegetation types also influence the magnitude and duration of streamflow
response to vegetation removal by natural disturbance or land use. In addition, streamflow
responses to long-term changes in climate can be traced. Collectively, these characteristics and
comparisons suggest that an ecologically-relevant classification scheme for small basins could
be developed. This poster provides examples of ongoing work and invites collaboration by
groups who have long-term records from small basins.
23
Michele Pruyn.
Departments of Forest Products and Forest Science, Oregon State University, Corvallis, OR 97331.
A Comparison of Stem Tissue Respiratory Potential Among Various Tree Species
Tree species vary in amount and composition of sapwood (SW). We suggest that stem capacity
to maintain SW is determined by adjustments in the balance of various physiological
mechanisms employed in species acclimation and survival. To elucidate species differences in
stem SW capacity, we compared innerbark (IB) and SW metabolism among 4-8 tree species from
three sites in Oregon. Cores were removed from stems at breast height and divided into IB,
outer, middle, inner SW, and heartwood (HW). CO2 fluctuation from each sample, referred to as
respiratory potential and quantified via a gas chromatograph, was the gauge for tissue
metabolism. CO2 release increased with respect to radial position away from pith. On average
IB activity was 2-5 times that of SW, and HW was the least active, releasing little to no CO2.
Although we found significant differences in SW and IB activity among species, we found no
relationship between SW activity and species percent volume SW parenchyma (%PVOL)
reported in the literature. However, IB activity was inversely proportional to %PVOL. These
potential differences in IB and SW carbon flux among species suggest that accurate prediction of
whole-tree level respiration rates is contingent on knowing species-specific physiological
details.
Jeremy J. Rich1, Ann T. Mintie2, Rachel S. Heichen3, Kirk E. Waterstripe3, Nancy J. Ritchie1,
Kimberly H. Lamothe1, Peter J. Bottomley1,2, Kermit Cromack3, Jr., David D. Myrold1,3
Departments of 1Crop and Soil Science, 2Microbiology, and 3Forest Science, Oregon State University, Corvallis, OR
97331.
H. J. Andrews Microbial Observatory: Soil Nitrogen Cycling and Microbial Biomass
Across Meadow-Forest Gradients
We compared nitrogen cycling processes and microbial biomass in meadow and forest soils
located in the Cascades Mountains of Oregon. Samples were taken along transects that crossed
a meadow-forest ecotone at two sites in the H. J. Andrews Experimental Forest. Mean rates for
potential denitrification and nitrification were 11- to 16-fold higher in the meadow soil
compared to the forest. Net nitrogen mineralization (NO3- + NH4+) was three-fold higher in the
meadow. Eighty-four percent of the mineralized N in the forest was in the form of NH4+ and
100% of the mineralized N in the meadow existed as NO3-. Fungal biomass increased by
approximately three-fold in the forest soil. No difference in bacterial biomass or chloroform
fumigation biomass was detected. The results indicate that differences exist between the
meadow and forest soil with respect to the nitrogen cycle and fungal biomass.
24
Jonathan Smith and Christopher Daly.
Department of Geosciences, Oregon State University, Corvallis, OR 97331.
H. J. Andrews Temperature Mapping Project
This project is a master’s thesis in the Department of Geosciences at Oregon State University.
Under the technical direction of Dr. Christopher Daly at the Spatial Climate Analysis Service,
Jonathan Smith is working toward mapping the temperature distribution of the H. J. Andrews
Experimental Forest. The goal of the project is to create the most accurate possible map of the
monthly temperature regimes in the H. J. Andrews area. Specifically, this will involve
maximum and minimum monthly temperatures. To date, no such detailed map of this area
exists, although reliable climate records in the area date far enough back to provide the
necessary data. At this point the project has involved the application of appropriate data quality
control measures and the construction of the most complete possible dataset from the many
climate stations throughout the Andrews over the years. Work on the ongoing project will be
presented at the symposium; interested parties can access a website which chronicles the work
at http://www.ocs.orst.edu/pub/smithjw/hja/index.html .
Julie D. H. Spears and Kate Lajtha.
Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331.
Coarse Woody Debris May Influence Soil Chemistry and Direct Pedogenesis
Towards Podzolization in the Oregon Cascades
Coarse woody debris (CWD) may affect pedogenesis through the release of dissolved organic
matter (DOM) rich in acidic substances. Acidic DOM has been implicated in many soil
processes such as podzolization, the displacement of anions from the soil matrix, the release of
P from iron and aluminum hydroxides and the dissolution of soil minerals. We investigated the
potential contribution of CWD to podzolization and the influence of CWD on soil nutrients in
the Oregon Cascades. We measured soil solution from lysimeters at different depths under
coarse woody debris for total DOC, organic acids, and polyphenols. DOC was further separated
by chemical fractionation. We also sampled soil for total C, N and P, water soluble organic C,
pH, exchangeable acidity and cations, exchangeable Al and Fe in BaCl2, aluminum and iron
bound PI and Po, and sodium pyrophosphate, ammonium oxalate, and citrate-dithionate
extractable Al and Fe. We found lower pH (p<0.004), higher exchangeable acidity (p<0.008) and
more exchangeable aluminum (p<0.04) and iron (p<0.06) 0-5 cm under CWD than in adjacent
soils. At 30-60 cm there were fewer differences between control soils and soils with CWD. These
results suggest that CWD acidifies the surface soil as it decomposes by decreasing exchangeable
bases and increasing exchangeable acidity and aluminum. CWD may have a long-term
influence on soil pedogenesis and thus, removal may alter ecosystem processes such as nutrient
cycling, pedogenesis and C storage.
25
Theresa Valentine and Don Henshaw
USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331.
Study Site Locations on the H. J. Andrews Experimental Forest
Many studies have been conducted on the H. J. Andrews Experimental Forest beginning in the
early 1950’s. Maintaining a historical record of the geographic locations for these studies is
critical for the determination of future study sites and to ensure the preservation of long-term
control areas. Knowing the history of each study site will also ensure that future studies are not
compromised by past activities on a site. For example, nutrient, fertilizer, or herbicide
applications, or other site contamination must be documented to maintain the integrity of
future research. Mapping these locations will be important for developing plans for protection
from fire, vandalism, or other disturbance.
Documenting long-term study data including tracking study site locations is a major endeavor.
Researchers, students, and information managers are attempting to locate the geographic
locations of these studies. Studies are located on a map, digitized, and saved in a spatial
database. Information on status of study, years of study, principle investigator, the Forest
Science Data Bank (FSDB) database identifier, as well as other metadata for compliance with the
Federal Geographic Data Committee (FGDC) standard is maintained. The FSDB identifier will
allow the integration of spatial databases with the existing FSDB tabular databases, as well as
the integration of study metadata.
A dynamic website for searching and displaying study site locations has been developed.
Researchers can display subsets of study locations, along with information on control areas,
disturbed areas, and other basic information such as roads and streams. Future website
development will integrate the FSDB with spatial databases and allow users to search the FSDB
for a specific study and have the study site locations appear dynamically on a map.
Currently, the study locations are being digitized and checked for errors. Researchers are being
asked to review core LTER data stored within the FSDB, and to provide additional study
location data for these data sets. Lists of all Andrews Forest LTER databases and GIS layers are
available at this poster session.
26
Richard H. Waring and Barbara J. Bond.
Department of Forest Science, Oregon State University, Corvallis, OR 97331.
The Oregon (OTTER) Transect: History and Potential
To ecologists, an analysis of vegetation patterns and processes across steep environmental
gradients provides the opportunity to test methods and models in search for general principles.
The Oregon Transect (Oregon Transect for Terrestrial Ecosystem Research, OTTER) includes
the steepest gradient in precipitation and forest productivity available in North America. Since
its establishment by H.L. Gholz in 1979, the Transect has served as a benchmark for ecological
studies. It was here that leaf area estimates were first attained and related to annual water
balances and productivity. A full range of meteorological data were acquired during a NASA
campaign in the 90’s that provided, and continues to provide, a basis for testing a number of
process models, some driven completely with satellite-derived information, others linked to
analysis of stable isotopes. Recently, with the installation of towers, component processes
affecting water, energy, and carbon exchange have been continuously monitored and modeled.
The original sites have been expanded to calibrate new aircraft-borne sensors carrying radar,
lasers, and high-resolution spectrometers. On the ground, new techniques are being developed
for using stable isotopes to study ecosystem-scale processes. We invite LTER scientists to
expand activities across the Oregon Transect and to take advantage of data previously acquired
and stored at the Oak Ridge National Laboratory Distribution Active Archive Center
[http://www-eosdis.ornl.gov].
27
Kirk E. Waterstripe.
Department of Forest Science, Oregon State University, Corvallis, OR 97331.
Patterns of Nitrogen Allocation in Ectomycorrhizal Fungal Mats in a Coniferous
Forest Soil
This proposed research project will describe spatial and temporal patterns of nitrogen uptake
and accumulation by ectomycorrhizal fungal mats, and transfer of nitrogen from mats to trees.
Fungal mats appear to make up a significant portion of microbial biomass in some forest soils.
Mat soils are characterized by higher levels of organic N, greater microbial biomass, and higher
rates of respiration than non-mat soils. This study will examine partitioning of 15N from organic
and inorganic sources into mycelium, fruiting bodies, and associated trees. The effect of season
on allocation pattern will also be determined. Rates of uptake for 15N from both sources will be
measured. An additional experiment will determine which areas of fungal mats are actively
metabolizing substrate and acquiring nitrogen. From this project, we hope to clarify role of
ectomycorrhizal fungal mats in uptake and transport of N to trees, and determine how
association with a fungal mat affects nitrogen nutrition of a seedling. By describing the
distribution of fungal activity and N assimilation, we plan to obtain a better understanding of
the spatial scale of nitrogen cycling mediated by fungi. This research will take place at the H. J.
Andrews Experimental Forest, and is being funded by a Microbial Observatory grant from the
National Science Foundation.
Randall Wildman and Stanley Gregory.
Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, 97331.
Aquatic Ecosystem Restoration Project at Quartz Creek
A stream restoration project was initiated at Quartz Creek in 1988 to study the changes in the
geomorphic and biological attributes associated with the installation of log accumulations. The
stream reach was intensively studied for 1 year before log installation and each year thereafter
for 5 years. The stream reach was again monitored in 1996 and 1997, corresponding to before
and after two major flood events in 1996. Changes in channel structure include the increase in
pool habitat by 6% and an increase in side-channel habitat by 20%. Recruitment of wood by the
installed accumulations was faster than expected. The restoration reach has developed the
amounts and sizes of wood that would be expected in a stream flowing through old-growth
forests in this basin. Retention of potential food resources, as measured by leaves, has
approximately tripled. Channel bedform, measured at monumented cross-sections, changed at
28 of the 48 structures with 11 exhibiting downcutting and 17 exhibiting deposition. Twentyone of the 48 installed structures have shifted or moved downstream over the twelve-year
period. Differences in the degree of cabling (full, partial, and none) applied to the structures had
no apparent effect on persistence of structures. Trout populations within the restoration site
have been variable with an average increase of 21% above the populations in 1988.
28
Justin Anderson1 and Steve Wondzell2.
Department of Forest Science, Oregon State University, Corvallis, OR 97331; 2PNW Research Station, Olympia, WA
98512.
1
Estimating the Potential for Hyporheic Exchange in Reaches of a Mountain Stream
Network
Hyporheic zones have been shown to be important components of stream ecosystems
functioning in nutrient exchange, material processing, regulation of stream temperatures, and
as habitat for biota that are part of complex food webs.
This study is part of an ongoing research effort to use a computer-based groundwater modeling
system to upscale estimates of hyporheic exchange flow from small study sites to the entire
stream network draining the H. J. Andrews Experimental Forest. Recent accomplishments of
this research effort include documentation of geomorphic control on hyporheic exchange, and
the calibration of models that have been used to estimate the amount of exchange flow
generated by certain geomorphic features in short stream reaches. These models are useful
tools, but the extent to which they represent the actual geomorphic variability in the stream
network is unknown.
The objectives of this study are directed at characterizing the geomorphic variability of stream
reach types in Lookout Creek and its tributaries, and at developing a way to evaluate the
potential for hyporheic exchange within stream reaches by analyzing stream longitudinal
profiles. The study will take place in the H. J.Andrews Experimental Forest. Specific objectives
are to: 1) describe the stream network as a set of distinct representative stream reach types
based on valley characteristics and stream order, 2) quantify differences in the character,
distribution and abundance of important geomorphic features among stream reach types, 3)
quantify the relative contribution of individual geomorphic features to the total variation in
longitudinal and cross-valley hydraulic gradients within stream reach types, 4) rank reaches
according to the amount of potential for hyporheic exchange in stream reaches based on an
analysis of the variation in longitudinal and cross-valley hydraulic gradients, and 5) use
MODFLOW to model representative stream reach types and investigate the expected
differences in hyporheic exchange flow.
(Note: Abstract not listed in Table of Contents)
29
David Hulse
Landscape Architecture, University of Oregon
Trajectories of Change: Alternative Futures as a Context for Multidisciplinary
Research
Several projects now underway in the Pacific Northwest are attempting to apply a
multidisciplinary approach for 1) balancing ecological needs for restoration with social
constraints on where and how to invest in restoration and 2) efficiently using scarce economic
resources, incentives, and regulatory authority to accomplish ecological and economic goals.
These projects occur at federal, state and local levels. The need for geographic prioritization of
where and when to make these investments is common to all these efforts, as is their concern for
the interactions of people, terrestrial and aquatic systems. This presentation will use work
underway in Western Oregon’s Willamette River Basin to illustrate how multidisciplinary
teams of natural and social scientists are using change over time in natural and cultural
phenomena as criteria in geographic prioritization for ecosystem restoration at several spatial
extents.
Relevant background information is available at:
http://www.orst.edu/dept/pnw-erc/ (Pacific Northwest Ecosystem Research Consortium)
http://www.oregonwri.org (Willamette Restoration Initiative and their Basin Restoration
Strategy recently submitted to the Governor and Oregon legislature)
and
http://ise.uoregon.edu (Institute for a Sustainable Environment, University of Oregon)
(Note: Abstract not listed in Table of Contents)
30