DISTRIBUTION, STRUCTURE, COMPOSITION, USES AND THREATS TO BAMBOO NATURAL STANDS IN MARIASHONI AND NJORO AREAS, MAU FOREST COMPLEX, NAKURU COUNTY, KENYA

Abstract

Increasing demand for bamboo products and clearing of bamboos for cultivation pose significant threats to indigenous bamboo forests in Mariashoni and Njoro forests. This study investigated bamboo distribution in Mariashoni and Njoro forests from 2000 to 2011, determined their structure, composition, uses and threats to the resource. Satellite images of the area for 2000 and 2011 and field survey data on forest characteristics for three blocks were compared. The blocks were selected by variation in elevation and perceived levels of disturbance. Structure and composition were characterized by density, frequency, diameter at breast height and height of trees. Questionnaires were also administered to 131 stakeholders to establish uses and threats to bamboo forests. Data were then analyzed by ANOVA and T-test for species diversity and similarity between blocks. Chi-square and pearson‟s correlation tested variation and relationship in responses by stakeholders. Results show that closed canopy bamboo increased by 295ha from 221ha in 2000 to 516ha in 2011, while 165ha were converted into farmlands. The surveys showed that closed canopy bamboo had a higher stocking of trees and seedlings than open canopy bamboo which had a higher stocking of saplings. Basal area was lower in closed canopy bamboo than open canopy bamboo. In blocks, block I (the less disturbed site) had a higher stocking of trees and seedlings than block II and III (the more disturbed sites) which had a higher stocking of saplings. Basal area was also larger in block I than in block II and III. The distribution of bamboo showed a reverse-J curve, while Oleaceae, Fabaceae and Cupressaceae families were dominant. Species diversity and composition were insignificantly different (p>α) between blocks. Bamboo was exploited mostly for domestic uses, and poverty level was major the factor influencing extraction. Major threats to the forests were charcoal burning, logging and bamboo extraction. Sensitizing the local community on forest management and conservation, initiation of livelihood options in adjacent areas, and afforestation were mentioned as the best means of conserving the forests.