Tree bog

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A Treebog is a form of waterless, earth closet dry toilet which can have a wide range of species - both trees and wetland marginal plants planted around it.

The main requirement is that the planted species should be nutrient "hungry" and ideally be harvestable too - thus willow cultivars which can be used as a coppice crop for wands ideal to use.

If left unmanaged a Treebog will soon be surrounded by weed species such as nettles but a little management and conscious planting can create a fertile and productive 'bog garden'.

Apart from willow coppice, soft fruit such as black currants and sweet smelling herbs like mint will thrive around a Treebog.

Both the solids and liquids are deposited within the Treebog base where the solids compost and the liquids soak through the soil and its associated dense rootzone where the nitrogen is rapidly absorbed and metabolised by the mycorhyzal species.

The faeces are contained within the Treebog base which is well ventilated to allow aerobic decomposition to occur, the mineralised material feeding the trees around it. Effectively, it is a system for converting urine and fæces to biomass without the need to handle this material.


The term Treebog was first coined Jay Abrahams of Biologic Design and the Treebog can be considered an example of permaculture design.

The treebog is a simple method of composting wastes, and since its introduction in 1995 over 1500 Treebogs have been built in Britain.[citation needed] They have been on sites ranging from fruit farms and pick-your-own enterprises, campsites and an angling lake to annual festival sites, remote/low impact dwellings holiday cottages, allotments and church yards where there is no mains water supply.

The Treebog has attracted the attention of NGOs and aid workers who hope to develop its potential for shanty towns or refugee camps - anywhere that water is scarce and the population pressure on resources is high.[citation needed]


A Treebog is simply a controlled compost heap whose function has been enhanced by use of moisture/nutrient-hungry trees.

They use no water, purify waste as they create willow as a biomass resource, and also contain the organic waste material, thus preventing the spread of disease.

A seating platform/cubicle is mounted at least one meter high. The area beneath the seating platform is enclosed by a double-layer of chicken wire - this acts as an effective child proof barrier. It allows air to circulate through the compost heap.

Sawdust, straw, woodchip, ash or other high carbon matter is used to balance the high nitrogen fæces. One design used Effective Micro-organism bran, which helped keep the Treebog be virtually odour free.[1]

The space between the wire is stuffed with straw which acts as a wick to help sop up excess urine preventing the likelihood of odour problems due to incomplete biological absorption of the nitrogen from the urine. The straw filled wire also enables the pile to be well-aerated whilst acting as a visual screen for the first year’s use.

The structure is surrounded by two closely planted rows of osier or biomass willow cuttings; this living wall of willow can then be woven into a hurdle-like structure and its annual growth can be harvested.


In this case, Bog is a British English slang word for toilet, not to be confused with its other meaning of swampland.

External links[edit]


  1. ^ Tim Green (18 May 2011). "A Loo with a View - Build your own Treebog". Permaculture Magazine. Retrieved 23 February 2012.