-1 Tree diversity in western Kenya: using profiles to characterise richness and evenness R. KINDT 1,* , P. VAN DAMME 2 and A.J. SIMONS 1 1 ICRAF, PO Box 30677-00100, Nairobi, Kenya; 2 Ghent University, Laboratory of Tropical and Subtropical Agriculture and Ethnobotany, Coupure Links 653, B-9000 Gent, Belgium; *Author for correspondence (e-mail: R.Kindt@CGIAR.org; phone: 254-2-524000 or 1-650-8336645; fax: 254-2- 524001 or 1-650-8336646) Received 18 May 2004; accepted in revised form 7 January 2005 Key words: Accumulation, Agroforestry, Diversification, Domestication, Evenness, Rarefaction, Re´nyi diversity profile, Richness Abstract. Species diversity is a function of the number of species and the evenness in the abundance of the component species. We calculated diversity and evenness profiles, which allowed comparing the diversity and evenness of communities. We applied the methodology to investigate differences in diversity among the main functions of trees on western Kenyan farms. Many use-groups (all trees and species that provide a specific use) could not be ranked in diversity or evenness. No use- group had perfectly even distributions. Evenness could especially be enhanced for construction materials, fruit, ornamental, firewood, timber and medicine, which included some of the most species-rich groups of the investigated landscape. When considering only the evenness in the dis- tribution of the dominant species, timber, medicine, fruit and beverage ranked lowest (>60% of trees belonged to the dominant species of these groups). These are also use-groups that are mainly grown by farmers to provide cash through sales. Since not all communities can be ranked in diversity, studies that attempt to order communities in diversity should not base the ordering on a single index, or even a combination of several indices, but use techniques developed for diversity ordering such as the Re´nyi diversity profile. The rarefaction of diversity profiles described in this article could be used in studies that compare results from surveys with different sample sizes. Introduction One of the objectives of tree domestication research, in general and more specific, in western Kenya is the diversification of tree species composition in agroecosystems (Kindt and Lengkeek 1999; Kindt et al. 2004). In the realm of agroforestry, underpinning the need for diversification is the desire to enhance the stability and productivity of agroecosystems (ICRAF 1997; Atta-Krah et al. 2004). Diversity means different things to different people. Most often in natural or agricultural systems, species counts (species richness) are provided as the measure of diversity. Continuing this logic, diversification means adding more species. Species diversity, however, is a function of the number of species, and the evenness in distribution of species’ abundances (Magurran 1988; Purvis and Hector 2000). Options for diversification can therefore be dissociated into interventions that target richness and those that target evenness. Biodiversity and Conservation (2006) 15:1253–1270 Ó Springer 2006 DOI 10.1007/s10531-005-0772-x