A while back there was some discussion on vegetation sampling and my question which perhaps was to far into the thread for anyone to notice was this:

For woody material in the tree and shrub stratums, basal area has been used as a sample method in addition to aerial cover. I have noticed a shift towards using mostly aerial cover in recent years (admittedly, basal area is more work).
What I am wondering is if folks are mostly using percent aerial cover and, are you using the cover of the stems or cover of the canopy? Obviously, the canopy will provide a much higher cover value than the stems and I think this is an area where there is much subjectivity and variation.

Tree sampling vs. shrub sampling will be different whether you are in a dense forest or open forest. In an open forest it is easier for me to just use cover. Shrub stem dbh or density seems out of the question for almost any area so just cover for shrubs would seem to be best to me.

In a dense forest the angle gauge is great at getting basal area (if it isn't too dark), and if you add the species for each "hit" it seems like a reasonable approach to me. How many points it takes to get a good average is the real question. I would recommend coming up with an sample adequacy calculation, and since the values will typically be low numbers you might want to do some kind of tranformation. It can be hard to get sample adequacy when the mean is a small number.

Whether you use a densiometer, a laser, or what I use - the CoverPoint scope that can shoot a point up or down - knowing what species you are hitting in the canopy is hard. It is especially hard (or impossible) to see the canopy above the lower canopy in a dense forest.

Once again, if the forest is more open, then cover works fine for me. In a really dense forest with one or only a few species that are easy to distinguish I would still use cover. In a dense, highly diverse, forest, I might prefer basal area. Density is a difficult if not meaningless value in some cases unless combined with basal area. Do 10 small trees equal one giant tree? Hard to tell unless combined with basal area for a better sense of what the stand looks like.

Bottom line, if all the species are FAC or wetter the significance is minimal. If there is a mix of wetland and upland the issue is more significant.

That's my 2 cents.

Pat

Brian, What is the purpose of your vegetation sampling? Ecological contribution of species? Chemical, biomass, food source, board feet production? Apparently, you are not sampling for delineation purposes.