Abstract

A comparative study was conducted at four locations namely Ngare Ndare, Daaba, Kulamawe and Ntumburi to assess gum arabic yield per tree per picking for different varieties of natural stands Acacia senegal (var. kerensis; var. senegal and var. leiorhachis) in Kenyan drylands for a period of five months. Sample plots measuring 1 hectare were established, one at each study site. Trees in each sample plot were measured for basal diameter and classified into three diameter classes (3.0-6.0, 6.1-9.0 and 9.0 cm). 10 trees from each diameter class were tapped while another 10 trees left untapped. Data collected was analyzed using Genstat version 10.0. Results showed that there was a significant difference in gum arabic yield (p<0.001) between tapped and non-tapped A. senegal trees as well as between tree stems and branches. Tapping increased gum arabic yield by 77.42%. Yield was highly affected by soil moisture and soil temperature, correlating negatively and positively respectively. Trees with basal diameter of 3.0-6.0 cm produced high quantities of gum arabic than big trees of basal diameter >6.0 cm for A. senegal varieties senegal and leiorhachis (p<0.001). These findings in the present study can be used for predicting yield in relation to the variety and site.

Key words: Natural stands, gum arabic, yield, Acacia senegal varieties, tree tapping, basal diameter.