Prior to using multivariate techniques I needed to organize the data into a flat file for use in Excel and SAS. (Fig. 2)
Climate variables of initial interest were monthly temperature and precipitation. I downloaded these from NASA in column format, and filled in the gaps in the record using Climate PP software (see Data References). Each climate variable occupies a column organized by calendar year. The tree ring files had to be converted from International Tree Ring DataBase format to column format. There are a number or premade programs that perform this function, however, importing the ITRDB file into excel manually with a fixed width format was simple. I removed the columns identifying the number of trees included in the tree ring series and transposed the decadal rows of ring widths into a single column.