If you change the BAF in the middle of a cruise, then you are changing the survey intensity in the middle of a cruise and plot to plot statistics will no longer be valid. I know Atterbury allows changing the BAF mid cruise and even a per tree basis, but if there is not consistent BAF usage between all plots, then plot to plot stats will not be valid. Volume and other measures can still be calculated, but the sample stats can't.
Now, changing the BAF during a cruise is not the same as doing a Big BAF or Count Plot sample. Big BAF and Count Plots are examples of what is called Double Sampling. Double Sampling is statistically correct, and has been shown to be more efficient for a cruiser's time while in the field. Everyone should consider using it. The important difference from changing BAFs mid cruise is that in Double Sampling you are consistently using your BAFs throughout the cruise so plot to plot stat's are OK.
Another way of putting it is changing BAFs change the likelihood of selecting trees to measure. If the likelihood is changing from plot to plot, then the trees on each plot are really not comparable to each other.
So for Assisi, the real answer is unfortunately no. But, Double Sample IS a huge part of Assisi's features. You can set the measure and count BAFs as you need at the start of each cruise and they can be different for each cruise. Just be sure to not change them during a cruise. Ie, make the plots you want to compile together have the same sample intensities.
Rich
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Loren,
If you change the BAF in the middle of a cruise, then you are changing the survey intensity in the middle of a cruise and plot to plot statistics will no longer be valid. I know Atterbury allows changing the BAF mid cruise and even a per tree basis, but if there is not consistent BAF usage between all plots, then plot to plot stats will not be valid. Volume and other measures can still be calculated, but the sample stats can't.
Now, changing the BAF during a cruise is not the same as doing a Big BAF or Count Plot sample. Big BAF and Count Plots are examples of what is called Double Sampling. Double Sampling is statistically correct, and has been shown to be more efficient for a cruiser's time while in the field. Everyone should consider using it. The important difference from changing BAFs mid cruise is that in Double Sampling you are consistently using your BAFs throughout the cruise so plot to plot stat's are OK.
Another way of putting it is changing BAFs change the likelihood of selecting trees to measure. If the likelihood is changing from plot to plot, then the trees on each plot are really not comparable to each other.
So for Assisi, the real answer is unfortunately no. But, Double Sample IS a huge part of Assisi's features. You can set the measure and count BAFs as you need at the start of each cruise and they can be different for each cruise. Just be sure to not change them during a cruise. Ie, make the plots you want to compile together have the same sample intensities.
Rich