Browsing by Author "Mugasha, Wilson Ancelm"

Now showing 1 - 7 of 7

Allometric models for estimating tree volume and aboveground biomass in lowland forests of Tanzania
(International Journal of Forestry Research, 2016) Mugasha, Wilson Ancelm; Mwakalukwa, Ezekiel Edward; Luoga, Emannuel; Malimbwi, Rogers Ernest; Zahabu, Eliakimu; Silayo, Dos Santos; Sola, Gael; Crete, Philippe; Henry, Matieu; Kashindye, Almas
Models to assist management of lowland forests in Tanzania are in most cases lacking. Using a sample of 60 trees which were destructively harvested from both dry and wet lowland forests of Dindili in Morogoro Region (30 trees) and Rondo in Lindi Region (30 trees), respectively, this study developed site specific and general models for estimating total tree volume and aboveground biomass. Specifically the study developed (i) height-diameter (ht-dbh) models for trees found in the two sites, (ii) total, merchantable, and branches volume models, and (iii) total and sectional aboveground biomass models of trees found in the two study sites. The findings show that site specific ht-dbh model appears to be suitable in estimating tree height since the tree allometry was found to differ significantly between studied forests. The developed general volume models yielded unbiased mean prediction error and hence can adequately be applied to estimate tree volume in dry and wet lowland forests in Tanzania. General aboveground biomass model appears to yield biased estimates; hence, it is not suitable when accurate results are required. In this case, site specific biomass allometric models are recommended. Biomass allometric models which include basic wood density are highly recommended for improved estimates accuracy when such information is available.
Biomass and volume models based on stump diameter for assessing degradation of Miombo woodlands in Tanzania
(Hindawi, 2019) Manyanda, Bernardol John; Mugasha, Wilson Ancelm; Nzunda, Emannuel F; Malimbwi, Rogers Ernest
Models to estimate forest degradation in terms of removed volume and biomass from the extraction of wood fuel and logging using stump diameter (SD) are lacking. The common method of estimating removals is through estimating diameter at breast height (D) by applying equations relating measured D and SD. The estimated D is then used to estimate biomass and volume by means of allometric equations, which utilize D. Through this sequence of procedures, it is apparent that there is an accumulation of errors. This study developed equations for estimating volume, aboveground biomass (ABG), and belowground biomass (BGB) using SD in miombo woodlands of mainland Tanzania. Volume models were developed from 114 sample trees while AGB and BGB models were developed from 127 and 57 sample trees, respectively. Both site specific and regional models were developed. Over 70% of the variations in BGB, AGB, and volume were explained by SD. It was apparent that SD is inferior compared to measured D in explaining variation in volume and BGB but not AGB. However, the accuracy of BGB and volume estimates emanating directly from SD were far better than those obtained indirectly, i.e., volume or BGB estimates obtained from estimated D from SD, since the latter is affected by accumulation of regression equation errors. For improved accuracy of ABG, BGB, and volume estimates, we recommend the use of site specific models. However, for areas with no site specific models, application of regional models is recommended. The developed models will facilitate the addition of forest degradation as a REDD+ activity into the forthcoming FREL.
Carbon stocks for different land cover types in Mainland Tanzania
(2019-04) Malimbwi, Rogers; Zahabu, Eliakimu; Njana, Marco Andrew; Mugasha, Wilson Ancelm; Mauya, Ernest William
Background: Developing countries participating in the mitigation mechanism of reducing emissions from defor- estation and forest degradation (REDD+), are required to establish a forest reference emission level (FREL), if they wish to seek financial support to reduce carbon emissions from deforestation and forest degradation. However, establish- ment of FREL relies heavily on the accurate estimates of carbon stock as one of the input variable for computation of the emission factors (EFs). The product of an EF and activity data, such as the area of deforestation, results in the total emissions needed for establishment of FREL. This study presents the carbon stock estimates for different land cover classes based on an analysis of Tanzania’s national forest inventory data generated through the National Forest Resources Monitoring and Assessment (NAFORMA). Results: Carbon stocks were estimated in three carbon pools, namely aboveground, belowground, and deadwood for each of the three land cover classes (i.e. Forest, non-forest, and wetland). The weighted average carbon stock was 33.35 t C ha −1 for forest land, 4.28 t ha −1 for wetland and 5.81 t ha −1 for non-forest land. The uncertainty values were 0.9% for forest land, 11.3% for wetland and 1.8% for non-forest land. Average carbon stocks for land cover sub-classes, which make up the above mentioned major land cover classes, are also presented in our study. Conclusions: The values presented in this paper correspond to IPCC tier 3 and can be used for carbon estimation at the national scale for the respective major primary vegetation type for various purposes including REDD+. However, if local based estimates values are needed, the use of auxiliary data to enhance the precision of the area of interest is recommended. Keywords: Carbon stock, REDD+, FREL, Emission factor, Uncertainty
Drivers and their influences on variation of aboveground carbon removals in miombo woodlands of mainland Tanzania
(BMC [Commercial Publisher], 2020-05) Manyanda, Bernardol John; Nzunda, Emmanuel Fred; Mugasha, Wilson Ancelm; Malimbwi, Rogers Ernest
Background Removals caused by both natural and anthropogenic drivers such as logging and fire causes substantial carbon emissions. Better insights into drivers and their variations of aboveground carbon removals is therefore needed. We assessed the drivers of aboveground carbon (AGC) removals and quantified the dynamics of removals-induced carbon emissions due to drivers using the National Forest Resources Assessment and Monitoring (NAFORMA) data sets in R software. Miombo woodlands which is the largest forest formations covering about 93% of forest land in mainland Tanzania was the case study.
Effects of drivers and their variations on the number of stems and aboveground carbon removals in miombo woodlands of mainland Tanzania
(BMC, 2021) Manyanda, Bernardol John; Nzunda, Emmanuel F; Mugasha, Wilson Ancelm; Malimbwi, Rogers Ernest
Background: Removals caused by both natural and anthropogenic drivers such as logging and fire in miombo woodlands causes substantial carbon emissions. Here we present drivers and their effects on the variations on the number of stems and aboveground carbon (AGC) removals based on an analysis of Tanzania’s national forest inven- tory (NFI) data extracted from the National Forest Resources Assessment and Monitoring (NAFORMA) database using allometric models that utilize stump diameter as the sole predictor. Results: Drivers of AGC removals in miombo woodlands of mainland Tanzania in order of importance were timber, fire, shifting cultivation, charcoal, natural death, firewood collection, poles, grazing by wildlife animals, carvings, graz- ing by domestic animals, and mining. The average number of stems and AGC removals by driver ranged from 0.006 to 16.587 stems ha −1 year −1 and 0.0–1.273 tCha −1 year −1 respectively. Furthermore, charcoal, shifting cultivation and fuelwood caused higher tree removals as opposed to timber, natural death and fire that accounted for higher AGC removals. Conclusions: Drivers caused substantial effects on the number of stems and carbon removals. Increased mitigation efforts in addressing removals by timber, fires, shifting cultivation, charcoal and natural death would be effective in mitigating degradation in miombo woodlands of Tanzania. Additionally, site-specific studies need to be conducted to bring information that would be used for managing woodlands at local levels. This kind of study need to be con- ducted in other vegetation types like montane and Mangrove forest at national scale in Tanzania.
Estimates of volume and carbon stock removals in miombo Woodlands of mainland Tanzania
(2020) Manyanda, Bernardol John; Nzunda, Emmanuel F; Mugasha, Wilson Ancelm; Malimbwi, Rogers Ernest
Miombo woodlands are major vegetation type covering about 93% of the forest land of Mainland Tanzania. It forms an integral part of the rural landscape in Tanzania and plays a crucial role in providing a wide range of goods and services including carbon sequestration. However, the sustainability of forest resources is mostly affected by the magnitude of its utilization. There should be a balance between the forest growth and removals. Nevertheless, the magnitude of removed volume and carbon in the country is not known. Quantification of volume, biomass, and carbon stocks removals is vital in developing effective climate change mitigation strategies, decision making, and promoting sustainable forest management. Based on the National Forest Resources Monitoring and Assessment data (NAFORMA) comprising 7,026 stumps collected from 16,803 circular plots of 10 m and 15 m radii established in Miombo woodlands of Mainland Tanzania, volume and carbon stock removals were estimated with the use of models that utilize stump diameter (SD) as the sole predictor. Results indicate that the annual volumes, aboveground biomass removed, and belowground biomass removed were 1.71 ± 0.54 m 3 ha −1 year −1 , 1.23 ± 0.37 t ha −1 year −1 , and 0.43 ± 0.12 t ha −1 year −1 , respectively. In addition, the corresponding aboveground and belowground carbon removed were found to be 0.6 ± 0.18 tC ha −1 year −1 and 0.21 ± 0.05 tC ha −1 year −1 respectively. Since the estimated annual volume removals exceed estimated mean annual increment of 1.6 ± 0.2 m 3 ha −1 year −1 in Miombo woodlands, the removals indicate unsustainability that would end up into forest degradation. The results also show that removals are more prominent in the following categories: shifting cultivation, production forest, grazing land, general land, village land, and Eastern and Southern zones. This paper calls for increased appropriate management strategies to ensure sustainability in these land categories and in the entire Miombo woodlands of Mainland Tanzania.
Stump height: a potential escalator of wood volume and carbon removals in miombo woodlands of mainland Tanzania
(Springer, 2022-04) Manyanda, Bernardol John; Malimbwi, Rogers Ernest; Mugasha, Wilson Ancelm; Nzunda, Emmanuel F.
Mitigation and adaptation to climate change in developing countries require sustainable forest management through either retaining the forest unharvested, i.e., conservation or an increased need for proper tree harvesting. However, significant number of trees harvested in miombo woodland of mainland Tanzania are not cut at the specified stump height, i.e., 15 cm from the ground. Leaving extra stump height (ESH) would escalate wood vol- ume removals and hence carbon emissions. Better insights on the extent of wood volume and carbon emissions of ESH in miombo woodlands are apparently needed. This study intended to estimate volume and carbon of ESH in miombo woodland of mainland Tan- zania. Based on a sample of 5 264 stumps collected in miombo woodlands of Mainland Tanzania, total annual volume and annual carbon per hectare of ESH were estimated by using equation applicable to cylinder in R software. Result revealed that total annual vol- ume, annual volume and carbon per hectare lost through ESH were 3 800 000 m −3 year −1 , 0.098 ± 0.034m 3 ha −1 year −1 and 0.028 ± 0.009 tCha −1 year −1 , respectively. The volume and carbon loss from ESH per hectare per year escalate 6% and 5% of more volume and car- bon removals, respectively, in the entire miombo woodlands and its categories in mainland Tanzania. Since annual volume loss of ESH is almost 1⁄4 of annual volume deficit of 19.5 million m 3 year −1 , the deficit and further removals could be lowered through adhering to appropriate harvesting regulations.