A few ideas via Pinterest for ways to tie a camping / forest theme together with your stationery designs.
All you need to pull of the forest theme is plenty of textured fabrics and papers in neutral colours. Add in wild flowers and berries, a few feathers and an abundance of green with natural lighting and you've just become you're photographers dream.
With this theme, rough is better so it's a great chance to have a relaxed style with high impact.
Images links via pinterest:
Three - my own work
Five - my own photography