Soap Creek Valley
How one thesis put spoken memories beside survey notes, maps and air photos.
Soap Creek Valley, Benton County, Oregon (mostly Township 10 South, Range 5 West, Willamette Meridian)
“What did the forests of Soap Creek Valley look like before anyone alive could remember, and how can anyone know?”
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Soap Creek Valley is a valley in the hills a few miles north of Oregon State University. In 1999 Bob Zybach finished a long study of how its forests changed. He recorded people who had lived or worked in the valley for a long time, then checked what they said against old surveys, maps and photos taken from airplanes. This page shows how he put those pieces together. Memory is a fine tool, as long as you check it against a map.
What the record shows
Soap Creek Valley is about 15,000 acres on the east side of Oregon’s Coast Range. It sits in the northwest part of Benton County, right along the line with Polk County.
“Soap Creek Valley drains an eastern slope of the Oregon Coast Range in northwest Oregon.”
Source: Zybach 1999, p. 6
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The most important source was living memory: what people remembered from their own lives. Their memories also helped find and check the other records.
“Living memory is the principal, and foundational, data source used for this study and was a critical element for interpreting, corroborating, and/or locating other sources of data.”
Source: Zybach 1999, p. 21
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The study lists 17 people whose memories were recorded: 5 women and 12 men, born between the 1890s and the 1930s. They had been farmers, ranchers, loggers, foresters, sawmill workers, a botanist, a firefighter and a wildlife expert.
Source: Zybach 1999, p. 39 (Table 4; this page names none of them)
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The oldest people were interviewed first, because their memories reached back the furthest and could be lost the soonest.
“Older participants were given priority and interviewed first whenever possible. This precedence, or bias, was considered worthwhile because the oldest members of potential interviewees held the earliest and most fragile memories of Soap Creek Valley.”
Source: Zybach 1999, p. 36
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Interviews often happened right where things had happened, out on the land. People were shown maps, aerial photographs, sketches, prehistoric tools, even broken glass, old bricks and nails, to help them remember.
“In order to facilitate recall, interviews were often conducted at locations in which specific events had transpired”
Source: Zybach 1999, pp. 46-47
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Every interview was tape-recorded and typed up as a transcript. If an old paper later proved a date wrong, the transcript was fixed and a note added, but the tape kept what was really said. In the typed copy, a written record wins over memory about a date.
“The recording can always be used to determine exactly what was said, and the oral historian can safely quote transcribed text with assurance that historical documentation is given priority over human recollection.”
Source: Zybach 1999, pp. 43-44
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Memories can be wrong, so every story was checked against other evidence, like documents and science. Checking from several directions is called triangulation. Most of the time the stories matched each other closely, whatever a person’s age, schooling or job.
“In most instances, corroboration demonstrated striking degrees of consistency in detail regarding descriptions and interpretations of forest cover change, no matter the ages, academic achievements, or occupations of the various observers”
Source: Zybach 1999, p. 59
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The old land surveys reach back further than anyone’s memory. Memories here begin in the 1890s, timber counts in the 1910s and air photos in the 1930s, and the surveys come before all of them. They also help check later photos and what people remember.
“Land Surveys provided valuable information regarding forest cover patterns that preceded living memory (1890s), timber cruises (1910s), and aerial photographs (1930s).”
Source: Zybach 1999, p. 21
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Photos taken from airplanes cover the valley from 1936 on: ten or more sets of them over the years. Comparing the same spots year after year was the surest way to see change, and the photos also helped people remember.
“Continuous series of aerial photographs provided the surest, most reliable, and most detailed form of repeat photography (Progrotskie 1974; Gruell 1980; Skovlin & Thomas 1995) used for this study.”
Source: Zybach 1999, p. 19
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Putting it all together, the thesis says that in 1826 most trees in the valley were less than 50 years old, and most of the land was bunchgrass and white oak savannah: grassland with scattered oaks.
“Most trees were less than 50 years of age, and most land was bunchgrass and white oak savannah.”
Source: Zybach 1999, p. 208
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The biggest change since then: Douglas-fir trees spread into the grassy prairies and oak savannah. Much of the open country filled in with fir.
“The expansion of Douglas-fir into the grassy prairies and oak savannah of Soap Creek Valley has been the most widespread change in horizontal and vertical forest tree cover patterns to occur during historical time”
Source: Zybach 1999, p. 111
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One big conclusion: people have shaped the valley’s forests for the past 500 years, and probably for 10,000 years or more.
“Humans have been primary shapers of Soap Creek Valley forest cover patterns for the past 500 years”
Source: Zybach 1999, p. 209
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What the record can’t say
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- Gap in the record This page only sums up the study. The interviews themselves are kept at Oregon State University and the Oregon Historical Society.
- Gap in the record The study is about the whole valley. It can’t tell you what grew on one particular piece of land. That takes the land’s own survey notes, photos and people.
- Gap in the record The thesis copies very few of the surveyors’ own words. Typed copies of their notes are kept at the Benton County Surveyor’s office.
- Gap in the record A few dates in the thesis are written two different ways in different places. This page leaves those out instead of guessing which is right.
- Gap in the record The thesis also talks about the people who lived in the valley long before 1826. That story is not retold here. The tribes’ own history offices are the place to start.
What to look up next
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Now try your own place Bring boots; the corner posts won’t come to you.