[R-sig-Geo] how to test for effect of spatial scale

[Maurizio Mencuccini]

Hi there,

I have a dataset consisting of measurements of tree size taken in more 
than 200 forest plots along a regular grid within a forest. For each 
plot, i can build summary statistics such as frequency distributions of 
such characters (e.g., height, diameters, etc).
I have the expectation that such distribution would conform to a 
theoretical distribution at a very large spatial scale and indeed if I 
aggregate all data for all plots, my empirical curve fits the expected 
curve rather well.
My objective is to detect at what spatial scale would such a theoretical 
prediction begin to break down, i.e., if I begin to disaggregate the 
data to include all the (n-1) plots close to each other, all the (n-2), 
etc., down to statistics collected independently for each plot, when 
does the mean distribution calculated for all possible combinations at 
that scale begin to depart significantly from the expected curve.
I cannot figure out how to approach the problem. It is not point 
pattern, nor does it seem to be geostatistics (building a semi variogram 
would help but only partially). The question is really about data 
aggregation at different spatial scales for plots that are close to each 
other.

Any help appreciated.

thanks
Maurizio Mencuccini
school of Geosciences
University of Edinburgh (UK)

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

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