Questions from the Field ...
"I have traveled all this distance, shouldnt I measure all the trees now that I am here?"
This is an very practical question. We hear this all the time.
What a silly notion. Would you say "I have traveled all this way, shouldnt I dig a 3 soil pit, even though a 8" one will do? Shouldnt I paint numbers on all sides of the trees since I have come all this way? Shouldnt I measure bark thickness 10 times on each tree after walking all this distance? Shouldnt I put in a HUGE fixed plot with lots of trees? Maybe I need a prism that picks up 30 trees?"
Of course you would not do those things. What you want to do is something useful after that long walk. If more measured trees are needed then by all means take them. If you do not need to measure trees then put your effort into something that does matter. Putting in a cluster of 3 more count plots comes to mind, for instance.
If you are walking a long way to put in a plot, which some of you will often do when working on a large inventory, then give some thought to what will give you a better answer when you get there. In general, the travel time has nothing to do with the ratio between count and measure plots.
Some inventory groups make the very sensible decision to plan for a days work (or half a day) when visiting a site. They might put in 3 counts and 1 measured plot or 6 counts and 2 measured plots, but the ratio of effort would be the same.
This idea that measuring more trees is always helpful is a myth held over from fixed plots, and it was not true with fixed plots either. Think about it there are two problems when processing a fixed plot. How many trees, and how much volume per tree. If the trees were all the same size then why would you waste your time measuring more trees? Certainly you should be counting the trees on the plot and measuring only a few.
Why didn't they do this in the past? Heaven knows like many decisions in life it was made in haste, valued for simplicity, perpetuated in manuals, and petrified as myth. Measuring all the trees was always a bad idea, even with fixed plots, but it hangs on today as something that sounds reasonable until you think about it.
Now whatever you do is always constrained by your ability to process the information, and the computer programs for working with data are a critical constraint on what we do in the woods. If your computer will not handle the variety of options which you would like to have available, then get on the back of the computer geeks to provide it (nicely, if possible).
Would we quietly agree if the computer people said that "variable plots are just too complicated to work with and we will only provide programs for processing 1/5 acre plots?" (those of you who have never put in a string of 1/5 acre plots really should do it for a day to appreciate this example call it training).
No matter how far you go, no matter how expensive it is to get there, no matter how much agony it involves when you get there do something helpful to the final answer. For that you need to look at what you are getting for the measurements you are taking a frequent theme in this newsletter.
As always, the answer is a balance in the information that you get.
Originally published April 1999
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