
On Jan 24, 2012, at 2:16 AM, C Hess wrote:

> Dear Listusers,
> 
> i had some difficulties in finding a proper model in R for my work in a tree-ring analysis. Still working on statistical basics I'am asking here for some hints or tipps which will help me on my way to find a model I could use in R.
> 
> My data sample is a time-series of annual tree-ring widths as the response. Explanatory variables are three 2-Level factors (species,age,soil) and as continuous variables temperature, precipitation and an element input into the ecosystem.
> 
> At the end I want to find out, if there is an effect on the tree-ring width based on the interaction of the climate-data and the element input.
> 
> Best regards
> Carsten

Are you looking to apply standard tree-ring analyses, but in R?  Or are you are starting from scratch with dendrochronology?  If the latter, a review of the literature would be important, where the topics of detrending, chronology-building, and "pre-whitening" abound.  If the former, you can start with the arima() function in the stats package, part of the standard distribution.  You can build time-series models with covariates (after you build chronologies), and estimate time-varying coefficients for them.

?arima

HTH
> 
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Don McKenzie
Research Ecologist
Pacific Wildland Fire Sciences Lab
US Forest Service

Affiliate Professor
School of Environmental and Forest Sciences
University of Washington

phone: 206-732-7824
dmck@uw.edu





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