Although the Eastern Arc Mountains provide timber to many people, most timber harvesting takes place on an illegal basis. We used our database of ~2000 forest plots and ~550 disturbance transects (which quantify both standing stocks of timber and rates of cutting) to construct a production model of timber across the Arc. In 2013, we will relate these results to our stock data and a model of tree growth to see how observed offtake rates compare with estimates of sustainable harvesting rates.
We conducted interviews with ~75 dealers and carpenters - and used national household census data to build a model of the use of timber from the Eastern Arc. We have subsequently coupled this with the information from the interviews on how timber is distributed along road networks to build a flow model.
Results to date suggest that the value of timber harvested from the Eastern Arc runs at least over $10 M annually. Harvesting rates are higher in unprotected areas, but harvesting also occurs in those protected areas as enforcement is weak. Once at the roadside, timber is transported by truck as cut planks, hidden under crops and other goods. The main buyers are richer households in the larger cities, but also in smaller towns with rapid population growth.
Ahrends, A., Burgess, N.D., Milledge, S.A.H., Bulling, M.T., Fisher, B., Smart, J.C.R., Clarke, G.P., Mhoro B.E. and S.L. Lewis (2010) Predictable waves of sequential forest degradation and biodiversity loss spreading from an African city. Proceedings of the National Academy of Sciences USA, 107, 14556-14561.
Ahrends, Antje (2010) Do we know enough? The impacts of data biases, insufficient sampling and degradation on biodiversity estimates in Tanzanian forests – implications for conservation planning. Partly supported PhD thesis. University of York, UK.
Makero, Joseph (2009) Timber in the Eastern Arc Mountains. Masters thesis, Sokoine University of Agriculture, Morogoro, Tanzania.