The use of species-stem curves in sampling the development of the Zambian miombo woodland species in charcoal production and slash-and-burn regrowth stands
The use of fixed-area plot methods was considered unsuitable to compare the responses and recovery over time of different miombo woodland species to different land-use practices (i.e. charcoal production and slash-and-burn agriculture). Young regrowth stages have many stems and the older more advanced stages have fewer stems. Different land-use practices in miombo woodland impact on the recovery potential of the woodlands. Timber harvesting does not result in significant change in stocking of the woodland compared to changes in regrowth after vegetation clearing for either charcoal production or slash-and-burn agriculture. After such clearing the woodland regrowth changes from an initial high stocking to a much lower stocking over time. This study in Zambian Copperbelt miombo woodland assessed the feasibility to use species-stem curves to determine the optimum number of stems or plants to record at a sampling point in order to compare species recovery over time in regrowth stands 2-15 years after ending the slash-and-burn and charcoal production activities. The results show that 34 and 31 stems or plants for slash-and-burn and charcoal production regrowth stands, respectively, would adequately capture the representative number of species to describe the plant community of these regrowth stands. The research has also revealed that the use of fixed-area methods would result in the measuring of too many plants in one category (younger stands) with too few in the other category (advanced stands). Therefore, the study explains why, and concludes that, variable plot size is an appropriate method for sampling species recovery in regrowth stands. © NISC (Pty) Ltd.