Woodland structure, basic density and above ground carbon stock estimations of wet miombo woodlands in Mbozi district, Tanzania.

Abstract

Species diversity, stocking, carbon stock and wood basic density for wet miombo woodlands of Iwuma forest reserve in Mbozi District were assessed. Biophysical data were collected through common methodology in forest inventory. Systematic sampling design technique was used to co \teet \\\tmmat\o\\ \n 31 Tectangu\aT p\ots measuring 20m x 40m each. Trees with DBH ~ 5 ern were identified and measured for DBH, height, crown diameter and crown height. A total of 820 wood cores were extracted from different tree species identified and recorded in the forest. Data were analysed for species composition, diversity,stocking, carbon stocks and basic density. Carbon was estimated through multiplying tree volume by basic density. The most dominant tree species were Brachystegia boehemii, Brachystegia spiciformis and Parinari excelsa. The Shannon- Wiener Index of Diversity was 1.3 and Simpson's Index was 0.4 which show a low diversity of tree species in the site. Mean stem density, basal area and volume were 553 (SPH), 9.60 m2ha-1 and 60.29 rrr'ha' respectively. About 87% (34.54 t ha') of the total carbon stocks (39.46 t ha') was contributed by the three most dominant species; Brachystegia boehemii, Brachystegia spiciformis and Parinari excelsa. There was a large variation in basic density between tree species whereby, Combretum zeyherii had the highest basic density of 0.59gcm-3, followed by Julbernadia globiflora (0.49gcm-\ Parinari excelsa (0.47gcm-\ Brachystegia spiciformis (0.46gcm-3) and Brachystegia boehemii (0.44gcm-3) and the minimum basic density was 0.41 gem" for Despems abysinica. Based on the above findings, the study recommends; sustainable management practices, especially for the three dominant tree species to enhance their management and conservation for climate change mitigation and provide information for REDD+ projects of Tanzania and the global at large.