The Value of Archaeology
Why should sites be preserved? Sites are finite (there are only so many of them) because the people who made them during their everyday activities only created a limited number, and man and nature constantly degrade what is left. All human societies change, and in changing, leave behind a record of that change. Thus, sites of the past are not under the same economic, technological and social systems as site made today. The past cannot be recreated. It is the only record left for non-writing groups.
Sites are fragile, in that any disturbance in the position of the artifacts or features or trash destroys the patterns that are their primary scientific value. Their internal patterns and soil features can be disturbed by natural processes such as freeze/thaw cycles, plant growth, erosion, and earthquakes.
As noted above, sites are non-renewable because the cultures and life ways that made them change over time and past patterns become "extinct". Once a social and cultural system is gone, it is gone forever. The only traces left are the limited number of archaeological sites that are in a constant state of slow decay.
Sites are systemic in that they are a record of a specific set of events at a specific place at a specific point in time, distinct from all other events at all other times and places. Sites reflect human behavior and choices representative of the cultural and social milieu, and as such, they are unique. For "prehistoric" societies, archaeological sites are the only record that the culture left behind. They can tell the story of the past people who lived here. They can be used to reconstruct how human groups adapted to changing conditions, past life ways, past economies, past technologies, past trade and political processes. Archaeological sites give the past a "voice". They show how people made choices in their interaction with the physical environment (the earth and its resources), the biotic environment (plants and animals), and the cultural environment (cooperating and non-cooperating other human beings).
Disturbance or destruction of a site is like tearing the pages out of, or burning, the last copy of a book. Once gone, it is gone forever. When our ancestors came to this continent, they brought Old World diseases that devastated the Indian populations. For some groups, the process brought extinction. The destruction of the archaeological record is almost an act of ultimate genocide, the wiping out of the very traces of their past existence.
Archaeological sites provide a long record of human exploitation of the environment. Since the environment consists of three parts: the physical, the biotic and the cultural ... archaeology furnishes humanity with evidence that societies have destroyed their environmental support systems through physical over exploitation, destruction of natural habitat, and collapse of socio-economic and political systems.
Archaeologist study soils and geomorphology. They record erosion and deposition sequences. They look for clues in the remains of the plants and animals to determine where and how they were exploited. Other disciplines used to understand archaeological data include history, hydrology, geology, pedology, meteorology, zoology, forensics, ecology and chemistry. Archaeological sites have scientific significance to many disciplines as they help reconstruct the who, what, when, where, how and why of culture process, evolution and ecology. Sites also have public values for interpretation, education, recreational tourism and a sense of our common human past. Archaeology "debunks" popular mythology and acts as a check and balance on historical interpretation. Sites have ethnic significance to specific groups. In many cases, their lineal descendants still exist. Sites may have traditional social or religious values to a living community, and may be important to those communities in maintaining their identity as a community. Without archaeology, almost 99% of human "history" would be unknown.
Why Preserve So Many?
You must think in the long term to understand the philosophy behind the need to preserve archaeological sites.
Not every archaeological site contains sufficient data to study the basic who, what, when, where, how and why questions. Often only a small part of the full archaeological record is present in any one site. People did many different things in different places and changed over time. Some site are specialized sub-parts of an overall socio-economic system. Luckily, people repeat actions at many locations so there is redundancy.
Many sites must be studied at many locations that were occupied at roughly the same time to build up the data needed to reconstruct average patterns. Keep in mind that Indians occupied Oregon for the last 13,000 years. Even one site a year for the entire state would total 13,000 sites. Since Oregon is located at the junction of the NW Coast, Plateau, Inter-Mountain, Great Basin and California-chaparral continental ecozones, one site per year per ecozone would be 650,000 sites. Since cultures tend to stay relatively static until pushed into change from changing conditions, blocks of time much larger than a "year" can be used as a model for preservation. In Oregon, the Periods (like Late Archaic) are units at multi-thousands of years. But since different activities happened in different places throughout ecozones, numerous sites within the zones need to be studied to gather the data that is necessary and sufficient to understand human prehistory and adaptation.
Slowly, through planned research, models are created and tested to explain the data. In all cases, intact archaeological sites are the key to unlock the puzzle of the past. A way of looking at archaeology is to use the jigsaw puzzle as a model. Visualize a jigsaw puzzle with billions of pieces and covering an area the size of a football field. Within this larger puzzle are nested sub-puzzles and within those sub-puzzles are smaller still sub-puzzles ... and so on. Perhaps one square foot contains a puzzle that can be reconstructed into a picture that has meaning ... but some or many of the pieces are missing. Luckily, this same picture more or less repeats elsewhere (in limited numbers) in the overall design ... but these similar images are not exactly alike (they contain variations). Because of vandalism and effect of things like the wind blowing pieces away, and because parts are scattered around, it is very hard to solve even the smallest of the sub-parts. Your job is to do that, also solve the larger patterns up to and including the football sized puzzle as a whole. That is the archaeologists nightmare and challenge. Actually, it is a lot of hard work wrapped up in fun.
This is why archaeologist take the default assumption that a site should be protected unless it is proven to be worthless for research by professional evaluation (and for Indian sites, with written evaluation from the appropriate Indian tribal government). That is why archaeologist , and tribes, work together to enact laws to protect sites from destruction and damage. Not all sites are important under current values. Not all sites merit protection or preservation. But the values of sites change as methods, techniques, and theories change. In general, archaeologist are looking for ways to find information that is important. Data, and information, are important to the archaeologist if it advances, alters, confirms or refutes current theories, hypothesis, empirical observations or methodologies. Archaeological evaluations of significance are made in these terms. Tribes may have different values, and as sovereign governments, their evaluations are made in terms defined by each government.
Current Oregon state law can be found in Oregon Revised Statute 97.740 (Indian Graves and Protected Objects), 358.905 (Archaeological Objects and Sites), and 390.235 (Archaeological Sites and Historical Materials: permits). Oregon Administrative Rule 736-51-000 covers archaeological permits under ORS 390.235.