Yes, it is, (in UK anyway). An official record of your death is a legal must but that just remains an actual recording of your passing, and not where you are laid to rest. Personally I think that, if you feel this way, it's a bit self indulgent to want to be 'buried in woods.'. There are 'green' companies who do this, but the quickest and simplest thing is to be burned to ash in cremation and just toss your ashes to the 4 winds. Any good funeral director will arrange this for you.