i know this is kind of an older post but wanted to add my thoughts.
The wooded areas are good for a few reasons.
1.) Less likely that someone else has detected there already.
2.) Don't need to be as neat when digging just need to fill the hole back in.
3.) When you drop things in the woods they are less likely to be found. (less foot traffic, harder to see items on the ground as opposed to a freshly mowed evenly cut grass field.)
disadvantages of wooded areas
1.) Nature. Ticks, mosquitos, poison ivy/oak/sumac etc. I got shots for lyme disease a few years back so the ticks don't bother me too much but I still spray on the deet around my boots and hat. Depending on where you live somethings are worse than others but for me there is nothing worse in the woods than getting poison ivy/oak on you. I was immune when I was younger but not anymore. You essentially have to throw away everything you were wearing depending on how much got on you. Been close to a three weeks and i'm still getting blisters and rashes from it(Because I forgot to clean the oils off my MD after I got contaminated!!!)
2.) People that don't have binoculars use their rifle scopes to get a better look at you.
I know people already mentioned some or all of these. Just wanted to solidify some tips I've read and lived that I strongly agree with.