fringe will help HOLD the water, not wick it away..it was a "style" thing as was said...but, if "real history" ain't your thang, feel free to fringe freely
Mitch - I've gotta agree about the fringe soaking up and holding water (based on 40+ years of wearing it) - the idea of wicking sounds good but it only wicks it up not away.......
Whangs were made from it (documented), but it wasn't purpose added for that reason - carrying a chunk of spare hide is a better way.
Style seems to be a major reason - especially when one considers that long fringe was most popular amongst the Plains/Transmontane horse Indians of the dry west - riding a horse with that fringe flowing just plum looks good! (early clothing of the same tribes shows little evidence for fringe)
Now as for real history I'll disagree - for the western fur trade of at least the 1830's and later fringe, especially in the 6-7 inch length on coats and pants is well documented for "whites" as well as NDNz - as always it depends on who, when, and where..........
For documentation on fringe being worn start with:
A. J. Millers - prints and notes
BOB 7 has an excellent article on the trapper's clothing of the period - it includes info on the use of fringe
With cross referencing as to dates - the Mtn Man Sketchbooks 1 & 2 by the MOFT
Rex Allen Normans book Sketchbook 1837 and Sean Webster's "In the Image of A. J. Miller are other good resources....
that's just the tip of the proverbial berg........