Edinburgh is beautiful. But it's a city.
I guess you're talking about Loch lomond, which is closer to Glasgow than Edinburgh. Loch lomond is nice but it's proximity to Glasgow mean its very busy during the summer, so busy that they've actually banned wild camping on the west Bank of the loch (normie from Glasgow were leaving too much rubbish and causing too much damage). Now you can only stay in campsites. You can still camp on the east side of the loch but you need a permit, and there are no roads on the east side of the loch so it's relatively inaccessible.
Closer to Edinburgh is the pentland hills. No forests but there is lots of good hillwalking routes up there and spots to wild camp.
Edinburgh is amazing, especially during August. But it's not where I would go if I was seeking outdoor activities. Edinburgh is in the scottish lowlands. If you just want to get out into nature you should be going to the highlands (Inverness, Fort William, Ullapool, Aviemore).
And a little warning; the midges are an absolute nightmare during August.