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Am working on a little primer for communities about measuring the growth of tropical trees, and I spent most of yesterday playing with spreadsheets. The book is largely based on the growth data collected by forestry ejidos in the Selva Maya (see Selva Maya III and Reading the Bands). Data is a bit noisy, and the relationships between size and diameter growth are not as clear as I would like (see jumble of points in the diameter/growth scattergram shown at the lower right of the computer screen). That said, the data do provide a strong estimate of the average annual growth rate of each species (inset shows that the standard errors around the mean are less than 2.0%, i.e. Mean=0.38043006 and Std. Error = 0.00620184). Mean growth estimates with standard errors as large as 10.0% are routinely used for management planning, so I am actually quite pleased with this result.

Am hoping that I can finish the primer before the end of the year. Will be in Spanish (thx, Silvia).

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