Eucalyptus in Kenya; Impacts on Environment and Society

Eucalyptus trees were introduced to Kenya a little over a century ago. European colonization along with the development of a railway system increased the demand for a fast growing wood source. The expansion of the tree across the fertile lands in Kenya raises concerns about the environmental impact on ecosystems where it has been introduced. These concerns include degraded soils, loss of water resources, co-introduction of ectomycorrhizal species, and allelopathy. Economic benefits to local landowners were also explored as well as the potential for large Eucalyptus woodlots to maximize the sequestration of CO2 from the atmosphere. This was examined through farmer interviews and the collection of data from both Eucalyptus and indigenous forests. The results indicate that the density of Eucalyptus varied by age and species and managed harvest rates could be utilized to maximize carbon content in Eucalyptus to increase carbon sequestration potential of woodlots. In the greenhouse study of allelopathy, Eucalyptus did inhibit the growth and germination of the test plants. The indigenous plants were the most strongly affected. The soil analyses indicate that overall, Eucalyptus may not have a strong effect on the soils but do have a significant effect on soil moisture and diversity found within the woodlots. Ectomycorrhizal fungi were molecularly identified as some of the same species associating with Eucalyptus in Australia, indicating co-introduction. Farmers indicated that they were aware of the environmental concerns associated with cultivating Eucalyptus but the economic benefits were greater than the environmental issues. @2016 by Brandy Garrett Kluthe All Rights Reserved Acknowledgement I would like to thank my advisor, Dr. Steve L. Stephenson, for his knowledge, support and guidance during my research. It was a pleasure to work with you. I would also like to thank my committee members, Dr. Stephen K. Boss, Dr. Malcolm K. Cleaveland, Dr. John C. Dixon, and Dr. Jason A. Tullis. Collectively, you taught me, advised me, and dedicated so much time to this research. I have learned so much from you all, even the importance of a comma. Thank you to the Environmental Dynamics and the Biological Sciences departments for supplies, office space and use of equipment. I would especially like to acknowledge JoAnn Kvamme, the program coordinator of the ENDY program, who keep me on track and up to date on everything related to my dissertation and, most importantly, provided me friendship and support. Appreciation is also extended to Phanuel O. Oballa, Jared Amwatta Mullah, Joram M. E. Mbinga and Willis A. Atie and several other individuals associated with the Kenya Forest Research Institute (KEFRI); George G. Ndiritu and the staff of the National Museums of Kenya; and Francis Onduso, research colleague and guide in Kenya. Special thanks are extended to the Finlay and Sotik tea plantations for allowing sampling to be carried out in their woodlots. My network of family and friends deserve a special acknowledgement for their support. I would like to thank Amie O. West, my cohort and constant confidant, whom I depended on for advice and a laugh. Thank you to my parents, who instilled in me the confidence to try new things and never give up. Lastly, I would like to thank John Kluthe for being my rock and holding down the home front during my many absences down the rabbit hole of research.