Browsing by Author "Manyanda, Bernardol John"

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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.
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.
Estimation of tree removals in Miombo woodlands of mainland Tanzania
(Sokoine University of Agriculture, 2020) Manyanda, Bernardol John
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 miombo woodlands resources depend on the balance between increment/growth rate and the magnitude of utilization. While many studies have been conducted to evaluate growth rate/increment little has been done to evaluate tree removals in miombo woodlands of mainland Tanzania. Quantification of volume, biomass, and carbon stocks removals is vital in developing effective climate change mitigation strategies, decision making, and promoting sustainable forest management.The overall objective of this study was to assess volume and carbon removals in miombo woodlands of mainland Tanzania as a result of tree cutting. Specifically, the present study intended to: 1), develop biomass and volume models based on stump diameter for assessing forest removals; 2) estimate volume and carbon stocks removals as a result of tree cutting; 3) examine drivers of removals and their influences on aboveground carbon removals in miombo woodlands and 4) estimate volume loss due to extra stump height in miombo woodlands of mainland Tanzania. To this end, two main data sets were used. The first is composed of field data collected from miombo woodlands located in three regions i.e. Manyara, Tabora and Lindi. The data were used for developing individual tree biomass and volume models essential for estimating biomass and volume removals directly from stump diameter (SD). Estimating volume and biomass directly from SD has an advantage of reducing the accumulated errors that could results from estimation of diameter at breast height (DBH) of the removed tree and used the estimated DBH to estimate volume and biomass from available equation that utilize the estimated DBH. The second is stumps data (diameter and height) collected during the implementation of the Tanzania National Forest Resources Monitoring and Assessment (NAFORMA). This data set were requested from Tanzania Forest Services agency (TFS), Tanzania Forestry Research Institute (TAFORI), and Sokoine University of Agriculture through the National Carbon Monitoring Centre (NCMC).This data set were used to respond to the objective two, three and four of this study. All the data were analysed in R software. Results revealed that, in all the models developed, SD explained over 70% of the variations in belowground biomass (BGB), aboveground biomass (AGB) and volume. By applying the developed models to the NAFORMA stump data, the estimated mean annual volume, AGB and BGB removals in the entire miombo were 1.71±0.54 m3ha- 1year-1, 1.23±0.37tha-1year-1, and 0.43±0.12 tha-1 year -1 respectively. The drivers of removals were, timber extraction, fire, shifting cultivation, charcoal, natural death, firewood collection, poles, grazing wild, carving, grazing domestic and mining activities. The estimated removed AGC ranged from 0.0 to 1.273tCha-1year-1 with the highest removals accounted by timber and the lowest by mining activities. Since the estimated annual volume removals exceed estimated mean annual increment of 1.6±0.2m3 ha-1yr -1 in miombo woodlands, the removals indicate unsustainability utilization of woodlands resource. This imply that the emission is relatively higher than the sequestration. The results also revealed that removals are more prominent in the following categories; shifting cultivation, production forest, grazing land, general land, village land, Eastern and Southern zones. Furthermore, total annual wood volume, annual volume and carbon per ha lost through extra stump height (ESH) were 3 800 000m-3year-1, 0.098 ± 0.034 m3ha-1year-1 and 0.028±0.009 tCha-1year-1 respectively. Based on these findings, it is recommend that, regional developed models should be applied over a wide range of conditions in miombo woodlands of mainland Tanzania under the threshold of tree diameter sizes used in the modelling. Furthermore, we recommend that the site-specific models should be applied for local inventories in their respective sites. For reducing emissions emanating from removals and by considering national circumstances, all categories of miombo woodlands should be managed although the management (in terms of tree removals) intensity and priorities should consider those categories with unsustainable removals. Similarly, all drivers of removals should be managed and priority should be to those drivers with the highest contribution to removals. Since the estimated annual volume loss through ESH (i.e. 3.8 million m3year-1) is almost ¼ of the annual volume deficit of 19.5 million m3year-1 reported by NAFORMA, the deficit and further removals could be lowered through proper adherence to appropriate harvesting procedures in the miombo woodlands of Tanzania. Moreover, the use of alternative sources of energy particularly clean energy and planting trees for wood energy must continue to be emphasized. Additionally, it is recommend that stumps data should be used to estimate volume and carbon removed and assess drivers of volume and carbon removals in other vegetation types i.e. mangrove forest, lowland forest, humid montane forest and thickets. This would bring tree removal information at national scale and improve future estimates of Forest Reference Emission Level (FREL).
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.