Species diversity in Eucalyptus camaldulensis woodlots and miombo woodland in Northeastern Zimbabwe

The tree species diversity, ground vegetation species richness, and soil characteristics were studied for Eucalyptus camaldulensis woodlots and the natural miombo woodlands in the Mukarakate Area of Northeastern Zimbabwe. The woodland characteristics were measured and soil samples were taken at a total of thirty-four miombo woodland plots and twenty-seven eucalyptus plantations. The number of tree species was significantly higher for the miombo woodland sites than for the eucalyptus woodlots. The Berger-Parker and Shannon-Wiener Index values for species diversity were higher for the tree species found on the miombo woodland sites. There were no significant differences between the eucalyptus woodlots and the miombo woodlands in the percentage of grass cover and the number of grass and herb species. The same grass and herb species were common in both the woodlots and the woodlands. The older woodlots had significantly more tree and herb species than the younger woodlots. Soil nutrient analyses showed no significant differences between the woodlots and the woodlands regarding their available phosphorus and total nitrogen, but the total phosphorus and total carbon were higher for the miombo woodlands. The results suggest that E. camaldulensis woodlots established in areas that were formerly fields and grazing areas in the savannah-like conditions pertaining in Southern Africa do not cause the loss of species richness or soil nutrients. In heavily deforested areas eucalyptus woodlots may even contribute positively to the protection and preservation of indigenous trees species and other flora.