Having been inspired by Davetb's tree-supported bog, I've started construction on our own. Our noble firs are planted at 2m spacings fairly accurately, and are brashed up to a height of 8 feet, so four of them made a natural support.
I started with two lengths of 4x4 larch, coach-screwed into the trunks of the trees, then laid 3x2 joists on these, finishing with a floor of 6x1 larch. The walls will be clad in feather edge boards up to around a metre above floor level, with reed screening above that. The roof is corrugated transparent sheeting which will catch rainwater for collection into a water butt for hand washing.
Here's the progress so far:
The ground slopes gently downwards from the camera position towards the bog, so the steps will be at the front (where the ground is highest) and the "hole" at the back to give a good 1 metre drop. The bottom area will also be screened with reed screening.
The larch is not ours. It comes from a local sawmill. Great material to work with, and resistant to rot. Half the price of the equivalent size treated softwood in B&Q.
I'm really using this as an experiment in construction techniques, as I'd quite like to build and set up an art studio deep in our woodland. Ideally for this I'd get hold of a chainsaw mill and produce our own planks and beams. That's a project for the next year or so.
Making slow progress as I'm having to combine it with all the other stuff that needs doing in the woodland at the moment.
Here's the - ahem - hole..
And here's the view looking up through the roof..