Aboveground biomass and carbon stock of Usambara tropical rainforests in Tanzania

Abstract

Forest Above ground biomass (AGB) and carbon stock (AGC) estimation is important for carbon budget accounting, sustainable forest management as well as for understanding the role of forest ecosystem in the climate change mitigation. In the recent decade, there has been a growing global interest on quantifying AGB and AGC in the tropical countries. However, the information on AGB and AGC at local and subnational scales in most of the tropical forests is scattered and not consolidated. In this study, we reviewed the existing information on AGB and AGC for tropical rainforests of northern Tanzania. We used both data published in the peer-reviewed literature and data from unpublished sources provided by various sources.

Our results showed that, there are three types of data sources and methods used for estimation of AGB and AGC. These included, field, geographical information system and remote sensing. Of all the methods, field based method was applied to a large extent. The average reported minimum values of AGB and AGC are 177.00 Mg ha^-1 and 88.5 Mg ha^-1, and the maximum average values are 872 Mg ha^-1 and 436 Mg ha^-1 respectively. Overall, the average values of AGB and AGC in the Usambara tropical mountain forests (UTMFs) are 351.08 Mg ha^-1 and 175.54 Mg ha^-1 respectively. Forest structure parameters, particularly tree sizes and number of tree stems, were the major structure parameters reported to affect the amount of AGB and AGC. To conclude, the study revealed that there is a progressive trend in the estimation of AGB and AGC in the UTMFs. However, more update and effective forest survey data and methods are needed particularly in west Usambara mountain forests block.