1. Forest Fires and Erosion: Sediment Analysis of Little Lake, Oregon
Rebecca A. Puta
Background
Records of how the climate and vegetation may have changed in an area over time are
found and can be analyzed from a multitude of sources, such as lake and ocean sediments, wind-
blown deposits, ice cores, tree rings, and coral, in addition to historical documents (US Global
Change Research Program, 2003). Paleolimnology (Cohen, 2003) is the study of ancient lake
sediments and the significant paleoenvironmental records preserved in them. These deposits are
records of past vegetation, climate and forest fire frequency changes that span several thousands
of years. Examining these sediments and the organic remains in them gives us a better
understanding of how these systems respond to changes similar in scale to those predicted to
occur in the near future (i.e. global warming). Although lake studies are common, the linkage
between these systems and landscape evolution are not. This study will analyze sediments from
Little Lake to compare with charcoal analysis conducted by Dr. Colin Long of UW-Oshkosh to
test if there are correlations between them.
Little Lake is a small lake located in western Oregon, nestled in the Coastal Range forests
between the Pacific Ocean coast and the Cascade Mountains at 44°10’03” N, 123°35’01”W.
Cool wet winters and warm dry summers characterize the climate of the Oregon Coast Range
(Hemstrom and Logan, 1986). The lightning storms that occur during the dry summer period are
most likely the main source of the forest fires that are quite common in this area, but the logging
industry has also provided the area with an effective ignition source over the last 200 years
(Agee, 1993). As seen in Figure 1 below, the Little Lake area is now predominantly covered by
a second-growth Douglas fir forest. Several other species of hardwood trees occupy the area, but
rushes, sedges, and grasses comprise the land within 60 meters of Little Lake (Worona and
Whitlock, 1995).
Several studies have been done on the pollen analysis, charcoal and organic matter of the
Little Lake site, which has led to the determination that the climate of this area was colder and
drier approximately 42,000 years ago, and that the land supported an array of vegetation much
different from that of the present day. The previous charcoal analyses of the Little Lake
sediments also correlate to changes in forest fire frequency and intensity over time (Long and
Whitlock, 2002). Little research and analysis have been done on the particle-size analysis of
Little Lake sediment, which could provide valuable insight into what sediments have been
covering the immediate landscape and has been deposited into the lake, whether from erosion or
from a fire event, and possibly the intensity of the fire event. This study has the potential to
unlock a copious amount of information about the environmental changes of the past and present
at Little Lake.

2. The Project
Dr. Colin Long of UW-Oshkosh has been studying Little Lake for over 10 years and is
considered one of the foremost experts of the site. Dr. Long has already collected 152 samples
from Little Lake and is conducting charcoal analysis on them. He sent the samples to UW-
Platteville for organic matter content analysis and particle-size analysis. This project will use the
commonly accepted methods of loss on ignition, charcoal separation, and particle size analysis
on the sediment samples from Little Lake. While each method/test is important to the project,
the most significant is the particle size analysis because it has the potential to unlock the most
about this area and how its environment has changed over time. Researchers studying this area
have concentrated primarily on organic and charcoal matter in the Little Lake sediments, leaving
the door wide open for a vast amount of information that could be derived from particle-size
analysis of the sediment. The data derived from the laboratory tests of this project will be used
to relate any changes in sediment size to possible changes in the frequency or intensity of past
forest fires in the area, whether those fires also affected the changes in the type of sediment that
accumulated at the Little Lake site, and how being up or down wind of the fires may have
affected sediments in the lake. All of this information may then be used and tied together to
determine what the past climate of the area may have looked like and how drastically or minutely
it has changed compared to the climate of the present day.
The Solution
The loss on ignition (LOI) procedure has shown strong correlations with determining the
organic and carbonate content in lake sediments according to Heiri, Lotter, and Lemcke (2001).
The weight percent of organic matter and carbonate content in the 152 sediment samples will be
determined by loss on ignition (LOI) following Heiri, Lotter, and Lemcke (2001). LOI uses
Figure 1: Photograph of Little Lake, Oregon provided by Dr. Colin Long.

3. sequential heating in a Leco TGA 701 Thermogravimetric Analyzer muffle furnace. The
samples are heated to 550°C and 950°C, which are temperatures that organic matter and
carbonate are combusted. The samples are weighed before and after they are heated. The latter
weight is subtracted from the former, which is then divided by the initial weight and multiplied
by 100 to determine the weight percent of organic matter and carbonate content.
Prior to particle-size analysis, the samples must first undergo a charcoal separation
because it could affect the analyses. Ferrous sulfate will be used to cause any charcoal to float
from the sediments. The density of the ferrous sulfate falls between charcoal and sand/silt grains
so the charcoal tends to float on top of the liquid. Samples will be pretreated for charcoal
removal at the Williams Laboratory in the UW-Madison Geography Department. These
pretreatments will take about one week and require travel from Platteville to Madison during the
summer. This quick and simple method has been shown to produce good, useful results.
Lastly, particle-size analysis will be performed following Sperazza (2004), to determine
the size of the sediments in each of the samples and how the size changes among the samples.
Laboratory equipment available for this is a Malvern Mastersizer 2000E laser diffraction
particle-size analyzer. This is a fairly inexpensive and easy to perform procedure that returns
very precise and easy to analyze results on the particle size of the samples run. In the laboratory,
the samples will be dispersed by chemical treatment (NaHMP) and ultrasound, and analyzed on
the Malvern Mastersizer 2000E following Sperazza et al. (2004). Each sample takes
approximately ten minutes to analyze. The data for the samples are then represented on a graph
that shows the particle size of the sediment (in micrometers, µm) and change in volume. The
peak of the curve indicates what the sediment is primarily comprised of, and as the curves from
other samples are also placed on the graph, it is easy to see the minute or significant changes in
the particle size from sample to sample. Figure 2 is an example of the data from the particle-size
analysis of three soil samples taken from the Platteville Gun Range, which indicates that while
all three samples are significantly comprised of clay sediment, there are small changes in the
amount of clay found in each sample. The Malvern Mastersizer is not only a simple and efficient
method of particle-size analysis, but also displays the resulting data in a very understandable and
easy to decipher format.
Dissemination Plan
There are a multitude of ways to disseminate the results of this project, primarily at
scientific poster sessions and professional meetings in the fields of geology and geography. If
the lab work can be completed before October 2008, the first presentation could be at the
National Geological Society of America (GSA) meeting. This meeting will be held in Houston,
Particle Size Distribution
0.1 1 10 100 1000
Particle Size (µm)
0
1
2
3
4
5
6
7
Volume(%)
Figure 2: An example of what the
data from a particle-size analysis
will look like. This was a sample
of sediment taken from the
Platteville Gun Range.

4. Texas, and will allow some of the most recognizable, experienced, and influential professionals
in the fields of geography, geology, and sedimentology to see and hear about the results of the
project firsthand. If the work cannot be completed in this amount of time, though, there is a
regional meeting for the North-Central Section of the GSA that will be held in Ypsilanti,
Michigan in April 2009, and allows for the same type of presentation to professionals in the
same fields of study, but concentrated in this particular section of the United States. The results
of this project will also be presented at the UW-Platteville Research/Poster Day, the ‘Posters in
the Rotunda’ for scientific posters and research held annually in Madison, WI, the UW System
Undergraduate Research Symposium, as well as at any other scientific research/poster sessions
available in the area that this project qualifies for. There is also the possibility of assisting in the
publishing of a professional research paper that ties together the results of this project with the
information that Dr. Colin Long has on the area, and the conclusions that can be made related to
paleoenvironments and paleolimnology.
Benefits
This project not only benefits scientists studying how paleoenvironments changed or
were affected in this area, but it also has many personal benefits for me. By majoring in
Geography, with a particular interest in Physical Geography, this project will illuminate the
possibilities of what types of research are currently being done and what jobs will need to be
filled. It will also give me the skills and knowledge of how to conduct my own research project,
as well as how to use common, modern techniques that influence the way research is done. My
career plans are to work outdoors conducting research on soil, rocks, plate tectonics, and
possibly even volcanoes. Having the laboratory, analytical, and dissemination knowledge and
experience will only further increase my abilities and likeliness of finding a position in field
research. This project could very well be the hand that turns the knob on the opening door of my
future in physical geography.
Bibliography
Agee J.K. 1993. “Fire ecology of Pacific Northwest forests.” Island
Press: Washington, D.C.
Cohen, A.S. 2003. Paleolimnology. Oxford University Press. 3-5.
Heiri, O., Lotter, A., and Lemcke, G. 2001. “Loss on ignition as a method for estimating
organic and carbonate content in sediments: reproducibility and comparability of results.”
Journal of Paleolimnology 25: 101-110.
Hemstrom, M.A., and Logan, S.E. 1986. “Plant association and management
guide Siuslaw National Forest.” USDA For. Serv.
Rep. No. R6-Ecol 220.1986a.
Konert, M., Vandenberghe J., 1997. “Comparison of laser grain size analysis
with pipette and sieve analysis: a solution for the underestimation of the clay
fraction.” Sedimentology 44, 523-535.
Last, M. and Smol, J. 2001. Tracking Environmental Change Using Lake Sediments, Volume 1:
Basin Analysis, Coring, and Chronological Techniques. Kluwer Academic Publishers. 1.

5. Long, C. and Whitlock, C. 2002. “Fire and Vegetation History from the Coastal Rain Forest of
the Western Oregon Coast Range.” Quaternary Research, 58: 215-225.
Sperazza M., Moore, J.E., Hendrix, M.S., 2004. “High-resolution particle size
analysis of naturally occurring very fine-grained sediment through laser diffractometry.”
Journal of Sedimentary Research 74, 736-743.
US Climate Change Science Program: Paleoenvironment and Paleoclimate.
http://www.usgcrp.gov/usgcrp/ProgramElements/paleo.htm October 12, 2003
Whitlock, C. and Larsen, C. 2001. Tracking Environmental Change Using Lake Sediments,
Volume 3: Terrestrial, Algal, and Siliceous Indicators. Kluwer Academic Publishers. 75-76.
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Little Lake, central Coast Range, Oregon.” Geological Society of America Bulletin 107, 867-
876.