Timber is an important commodity in African towns. This paper reports the findings from research into the supply of timber to Dar es Salaam and Mwanza (Tanzania). Tanzania has reserves of hardwood timber in the natural forest and softwood timber in plantations. Information gathered from consumers, producers and traders was used to estimate consumption, analyse changing patterns of supply and assess sustainability. Analysis of the hardwood supply system (presented as a sub-sector diagram) found it to be ‘slippery’, evolving in response to diminishing resources and a cumbersome and ineffective regulatory regime. With the advent of pit-sawing and other changes, control over the cutting of timber in the natural forest has been lost. Regaining control is unlikely unless effective local community participation can be established. Sustainable management in the plantations is achievable and offers the best chance of ensuring a supply of timber to meet future demands.