Tree Bog

One thing our woodland lacks is any sort of..ahem.."facilities".  As we put the Management Plan into action, we are hoping to attract some volunteers to help, and also to offer a limited amount of paid-for camping for those interested in what we are doing.  So, toilet facilities of some kind are pretty much essential.

Problems: No running water, no mains drainage, difficult to access for emptying of, say, a septic tank.

Solution: Some kind of waterless composting toilet arrangement.


Composting toilets work on the principle of aerobic digestion.  A conventional toilet seat sits on top of a box into which the - er.. "business" is deposited, followed by a handful of sawdust.  Provided there is airflow, and you keep the urine out, nature does its work and composts the stuff down in an odour-free fashion.  All that's needed is to shovel out what is now compost after a few months and make productive use of it.

The challenge is dealing with the urine.  If it gets into the pile odours will form apparently, as the process goes "anaerobic".  Many composting toilets deal with this with a urine-separator, that diverts the urine away down a pipe and into a soak-away.  Or, users are simply instructed to wee elsewhere.  OK for the gents, not great for the ladies.

A tree bog works like a composting toilet, but is situated in an area with growing trees, and is elevated above the ground.  The "business" simply falls to the ground where it breaks down and the nutrients are absorbed by the trees.  Similar principles apply as with regular composting toilets.  It's important to add some extra carbon, in the form of sawdust or similar, and urine contamination should be kept to a minimum.

As we are surrounded by trees, I decided to build a tree bog a little way away from the area we have earmarked for camping.  The aim is that, with only occasional use, the system will be able to break down the input at a suitable rate that it won't build up to excess and become a smelly problem.


Our woodland is an artificial plantation with the trees planted at 2 metre spacings, so four of them made a natural support for the toilet.

The picture above shows the "foundations" going in.  Two bearers of 4" x 4" larch, secured by 2 x substantial coach screws into each tree.  There will be 3" x 2" joists on top, supporting 6" x 1" floor boards.  The loo hole will be in the front left.

General view is that tree bogs should be at least a metre above the ground.  The ground in the picture slopes gently from back right to front left, giving us the metre we need above the loo hole.  Steps will be placed on the right, from where the ground is highest.

Next steps will be to construct the roof and walls above the floor.  The roof will be sloping, covered with corrugated plastic to catch rainwater.  This will be held in a water butt to provide hand washing facilities in the toilet.  We've also salvaged a wash hand basin from the bathroom refit we're having done at home.

The area below the floor will be screened with bamboo screening for aesthetic reasons and to keep out some of the larger wildlife.

We're just waiting on the materials for the next stage, and I'll post updates on here as the project progresses.  I'm hosting a photo shoot and barbecue with our local camera club in August, so it will need to be finished by then!