I usually carry a baggy full of the white puffy seed things you get out of milk weed pods. It is amazing, even on days the wind seems "steady" or calm, to see where that thing ends up. When you think of the complication of the fluid dynamics of that air flowing through the trees, hills, etc it is beyond calculation, let alone me (a jackass) sitting in my stand and determining where my scent is actually being carried/dispursed. You can have a general idea, but specifics.... forget about it.

Where we hunt elk the thermals can really get the wind swirling in the morning. That swirling has cost me more chances at elk than I can even remember. They play a HUGE role in hunting mountainous terrain, and usually they play the role of the spoiler