Preliminary assessment of forest structure, management and carbon stocking in Tanzania Miombo woodland

Abstract

Wildfires are critical in miombo forests across the African continent causing loss of biodiversity, human properties and increasing climate change impacts. Within a broader project which seeks to develop a strategy to reduce wildfires in miombo woodlands of Tanzania, we report on the preliminary findings based on initial field data collected in situ to set a baseline for further work. The project covers three miombo biomes in three districts (Handeni, Kilosa and Kilwa) in Eastern Tanzania covering nine forest reserves managed under different authorities namely, central government, local districts and village communities. The aim of the current study were therefore, to describe species composition and structure of the forest communities, profile initial carbon stock in trees, herbaceous layer and soil within permanent survey plots, in effort to examine the potential of using fire reduction strategy as a potential tool of carbon sequestration in miombo woodlands.. The research team used permanent forest plots to collect vegetation and soil data. Simlarly available models were used to estimate carbon stocking. More than 200 species of trees and shrubs totaling 506 individual trees (dbh >4 cm) were recorded and Kilosa site contributed the largest proportion (40.7%) to the tree abundance total. This was followed closely by Kilwa (35.6%) and Handeni (20.7%). Species richness and diversity varied considerably within and between the study sites. Kilwa had the highest species richness and Handeni the lowest. Analysis of community assemblages revealed strongly distinct forest communities both at local and regional level between Kilwa and other sites. Carbon stocks in trees and soil were significantly different among sites and were higher than previously reported for other miombo woodland elsewhere in Tanzania. On the average tree carbon ranged from 21.42-44.12t/ha, the highest stock reported in Kilosa site due to assemblage of large trees. The general picture of carbon stock indicated that early burning is better for carbon storage than late burning or no burning. The lack of fire reduction strategy overrides the dynamics of forest stand structure and the potential for carbon sequestration by these forests as wildfires appear to be critical across the study area. There is dire need for a comprehensive strategy to reducing forest fires across the miombo biomes which together will help mitigate climate change impacts in Tanzania.