I found one in the middle of Arusha, and several more in sparsely-treed habitat near Arusha National Park. I have no comparison with actual forest, but they do occur in moderately- to heavily-disturbed areas.

Annual CITES export quotas for K. tavetana were set to 3,000 wild collected individuals between 2000 and 2013 and 83-170 (272 average) captive born individuals per year from Tanzania (CITES 2013). Between 1977 and 2011 (2012 and 2013 trade data is incomplete or unavailable) a total of 35,248 live individuals were exported from Tanzania for the pet trade (total of all undeclared, captive breeding, personal and commercial exports), of which 582 were reported as either captive bred or ranched (UNEP-WCMC 2013). All these exports occurred from 1994 on, and all export of individuals reported as either captive bred or ranched occurred between 1999 and 2011 (UNEP-WCMC 2013). Annual exports of this species peaked in 2003 with 3,533 individuals exported and from 2002 through 2011 annual exports averaged 2,500 individuals (UNEP-WCMC 2013). A further 100 live farmed individual Kinyongia tavetana were exported from Kenya for commercial purposes in 2011 (UNEP-WCMC 2013), however this may actually represents exports of K. boehmei.

References:

Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 2013. CITES Export Quotas. Available at: http://www.cites.org/eng/resources/quotas/index.php. (Accessed: 11 Aug 2013).
UNEP-WCMC. 2013. CITES Trade Database. Available at: http://www.unep-wcmc-apps.org/citestrade/expert_accord.cfm?CFID=50172297&CFTOKEN=72268891. (Accessed: 11 Aug 2013).