DO INHERENT AND INDUCED MIOMBO TREE TRUNK MACRO-STRUCTURAL CHARACTERISTICS INFLUENCE REGENERATION AFTER CUTTING FOR CHARCOAL PRODUCTION?

Abstract

This study assessed the influence of tree trunk macro-structural characteristics on species’ potential for regeneration after cutting for charcoal production. The main objective of the study was to determine regeneration responses of species harvested for charcoal production. Diametre of the stump, bark thickness, cambium and heart wood thickness, rough and smooth bole textural groups and others were examined. Such information was necessary for regulating harvesting systems and influencing policy adjustments regarding the harvesting strategies for trees used in charcoal production. Ten transects 100 metres long each were placed parallel to each other at a minimum interval of 30 metres apart in areas where trees had been cut for charcoal in the last four years (2013 – 2017). Along each transect, five 20 m x 20 m plots were set and all tree stumps inside the plot identified and examined. The major objectives were to determine the influence of structural characteristics on the species’ potential to regenerate. Bark thickness for instance, was considered to be an important stem charesctristic as it protects the living stem tissue particulalry against wildfire. Results obtained showed that the hypotheis inititally advanced that in addition to soil moisture and nutrients, macro-structural components of each tree species influenced regeneration was false. It was initially thought that larger proportions of tree trunk macro-structural characteristics would yield higher and faster regeneration and vice versa but this was found to be false. All species with varying macrostructural characteristics successfully regenerated. The results were therefore, inconclusive and further research is required to be conducted in different agro-ecological zones to investigate other factors that may be critical in influencing regeneration. Factors such as root structure and root depth, soil structure and moisture retention capacity, level of accumulation of chemical compounds such as resins, phenols, and terpenes between species and age groups or stem size require detailed investigation. With regard to the survival of saplings after regeneration, it was recommended that formulation and implementation of a community-based fire management plan would enhance the survival of saplings. Good fire management practices together with soil moisture and fertility promote the ecological forest restoration of miombo woodlands.