bronze age environment and economy in the troad - Universität ...

chapter 2: methods
2 Methods
2.1 From sampling to species list
2.1.1 Sampling and recovery
The methodology of sampling was a popular subject at the end
of the 1970s and beginning of the 1980s, and enough has been
written about the ‛right’ way to sample to give the beginners
options to develop their own sampling strategy (e.g. Nesbitt
and Samuel 1989, van der Veen and Fieller 1982, Mueller
1975).
Archaeobotanists were looking for sampling strategies
adaptable to all sites to fulfil the aim of comparability between
sites, but from the literature it becomes quite clear that each
sampling strategy has to be adapted to the conditions on each
excavation. In consequence different sampling strategies are
usually combined within one excavation.
M. Jones (1991) discusses four different sampling strategies.
‛Haphazard or grab sampling’ is described as unstrategic and
passive: differences of structures are not taken into account and
these unrecognised factors are interpreted as part of the data
itself. ‛Haphazard sampling’ might happen in large excavations
with excavators with different levels of experience. However,
today one might assume that such excavations are rare, where
nobody has any idea where or what they are excavating.
Usually there is some kind of documentation about the sample
context. ‛Purposive or judgement sampling’ is described as the
most effective sampling method in terms of information
content, but has the danger of being too presumptuous. It seems
to be the most commonly practised sampling strategy. Who
would ignore their knowledge about the site in the search for
further discoveries ‛Interval sampling’, conducted with a grid
over the excavation surface, is described as dangerous, because
there will be a loss of information and problems in separating
the differences within one population from those of the surface.
It seems quite unlikely that anybody would only sample with
this method, and would neglect all the other finds from the
excavation. With the ‛probabilistic or random sampling’ the
probability that each unit will be sampled is the same. Under
the condition that excavators know in advance the structuring
of the whole site and can clearly define all the contexts, they
can sample those contexts with random numbers and finally,
calculate the representativeness of the samples. Patterns might
be accidental, however, and if additionally the sampling rate is
low, this method can also lead to misinterpretation. When
‛random sampling’ is applied and previous knowledge
neglected, one might not sample the most important contexts in
terms of the actual broadness of the species spectrum (van der
Veen 1983). A pattern like the one Jones used for his
interpretation of ‛consumer’ and ‛producer sites’ might emerge
accidentally. ‛Random sampling’, therefore, is more
appropriate as an additional method rather than a basic one (M.
Jones 1984).
The only way to exclude accidental patterns is to enlarge the
coverage of the sampling. This latter method seems to be most
commonly used on excavations with large-scale
archaeobiological investigation. Though in most cases it is not
possible to sample the whole sediment from a site and to
ameliorate representativeness by high coverage,
archaeobotanists disagree about which sampling method
provide samples that are more or less representative for the
whole site. Some archaeologists assume ‛random sampling’
obtains the most representative samples for a site (M. Jones
1991), others argue that randomly chosen samples are not
representative of the whole site, because plant remains are not
randomly distributed over the site (Schaaf 1981), which is an
assumption not many archaeobotanists agree with.
However, it is obvious that large amounts of samples, of large
volume, from the widest possible range of contexts, to get a
broad spectrum of species make an investigation representative
(Jones 1983b, Jacomet, Brombacher and Dick 1989).
Between 1991 and 1996 a total of 456 botanical samples were
taken at Troy and Kumtepe. The material analysed includes
only the 363 samples taken from 1991 to 1995. These are 38
samples from Kumtepe and the remainder from the different
periods of Troy (only those samples with more than 20 items
are listed in the appendix; for sample location see Map 2).
The sampling took place under different criteria. The number
of samples from each site (Troy and Kumtepe) was partially
related to the size of the settlements. Including the Lower City
of the Late Bronze Age, Troy measures more than 200000 m²,
while Kumtepe is only about 14000 m². To date, only about
640 m² were excavated and sampled at Troy, which makes it
clear that although a lot of sediment was floated for botanical
remains, the representativeness of these samples of the whole
site might be questionable. ‛Random sampling’ always proved
to be incompatible with the excavation methods at Troy. It
seemed more sensible to rely on the excavators’ experience to
define contexts. To describe the sampling method in Troy and
Kumtepe in the terms used here, an extended kind of
‛judgement sampling’ would be the most appropriate.
Samples were taken by the archaeobotanist, but also by the
excavators. When samples were taken by the excavators, an
instruction sheet for sampling and documentation was distributed.
10140 litres of sediment were floated. The sample sizes
were between one and 260 litres with a mean of 30 litres,
which is often recommended as a standard size for botanical
samples. Samples of more than 100 litres were ‛stored’ on big
plastic sheets and floated in periods of lower ‛sample income’.
Big contexts were also checked for their homo-or heterogeneity
by sectioning the surface and processing the sediment separately.
The documentation sheet that came along with the
samples provided information including the date, trench, coordinates,
a context definition or at least description of features,
dating (stratigraphic or typological), a sediment description,
the sediment volume and a rough sketch of the location of
the sample within the excavated area.
In the case of large contexts, such as floors, samples were taken
at several different locations, in order to determine whether
there was any spatial patterning within these contexts. The
result was either that different activity zones could be recognised
(as in D8), or that no significant differences over the surface
could be detected (as in A7), in other words that subsamples
would have been representative of the whole context.
These contexts are described in chapter 3.
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